73 results on '"Mark A. DeCoster"'
Search Results
2. Intranasal Delivery of Cell-Penetrating Therapeutic Peptide Enhances Brain Delivery, Reduces Inflammation, and Improves Neurologic Function in Moderate Traumatic Brain Injury
- Author
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Yaswanthi Yanamadala, Ritika Roy, Afrika Alake Williams, Navya Uppu, Audrey Yoonsun Kim, Mark A. DeCoster, Paul Kim, and Teresa Ann Murray
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traumatic brain injury ,TBI ,secondary injury ,peptide therapeutics ,cell penetrating peptide ,proinflammatory cytokines ,Pharmacy and materia medica ,RS1-441 - Abstract
Following traumatic brain injury (TBI), secondary brain damage due to chronic inflammation is the most predominant cause of the delayed onset of mood and memory disorders. Currently no therapeutic approach is available to effectively mitigate secondary brain injury after TBI. One reason is the blood–brain barrier (BBB), which prevents the passage of most therapeutic agents into the brain. Peptides have been among the leading candidates for CNS therapy due to their low immunogenicity and toxicity, bioavailability, and ease of modification. In this study, we demonstrated that non-invasive intranasal (IN) administration of KAFAK, a cell penetrating anti-inflammatory peptide, traversed the BBB in a murine model of diffuse, moderate TBI. Notably, KAFAK treatment reduced the production of proinflammatory cytokines that contribute to secondary injury. Furthermore, behavioral tests showed improved or restored neurological, memory, and locomotor performance after TBI in KAFAK-treated mice. This study demonstrates KAFAK’s ability to cross the blood–brain barrier, to lower proinflammatory cytokines in vivo, and to restore function after a moderate TBI.
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- 2024
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3. Ion-Selective Membrane-Coated Graphene–Hexagonal Boron Nitride Heterostructures for Field-Effect Ion Sensing
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Nowzesh Hasan, Urna Kansakar, Eric Sherer, Mark A. DeCoster, and Adarsh D. Radadia
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Chemistry ,QD1-999 - Published
- 2021
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4. Negative Feedback Role of Astrocytes in Shaping Excitation in Brain Cell Co-cultures
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Elnaz Khezerlou, Neela Prajapati, and Mark A. DeCoster
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astrocyte ,calcium imaging ,glutamate ,excitotoxicity ,neurons ,blood brain barrier ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Glial cells play an important role in maintaining neuronal homeostasis and may thus influence excitability in epileptogenesis. These cells in the brain have glutamate (Glu) transporters, which remove this neurotransmitter from the extracellular space. Lack of negative (−) feedback makes local neuronal circuits more excitable and potentially contributing to epileptogenic phenomena. In this study, the role of glial cells in providing (−) feedback is shown through different models of brain cells in culture imaged for intracellular calcium concentration [(Ca2+)i]. Moreover, here we study the individual cells by putting them in categories. Neuronal networks with high and low (−) feedback were established by using anti-mitotics to deplete glial cells. Separate stimuli with very low subthreshold concentrations of Glu (250–750 nM) were added to cultures to test if the order of stimulations matter in regard to calcium dynamics outcomes. Additionally, KCl and ATP were used to stimulate glial cells. We found that for cultures high in (−) feedback, order of the stimulus was not important in predicting cellular responses and because of the complexity of networks in low (−) feedback cultures the order of stimulus matters. As an additional method for analysis, comparison of high (−) feedback cultures, and pure astrocytes was also considered. Glial cells in pure astrocyte cultures tend to be larger in size than glial cells in high (−) feedback cultures. The potential effect of (−) feedback at the blood brain barrier (BBB) was also considered for the inflammatory responses of nitric oxide (NO) production and [Ca2+]i regulation using brain microvascular endothelial cells (BMVECs). The inflammatory and calcium signaling pathways both indicate the negative feedback role of astrocytes, poised between the BBB and structures deeper within the brain, where neuronal synapses are homeostatically maintained by glial uptake of neurotransmitters.
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- 2021
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5. The Immunomodulatory Potential of Copper and Silver Based Self-Assembled Metal Organic Biohybrids Nanomaterials in Cancer Theranostics
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Neela Prajapati, Anik Karan, Elnaz Khezerlou, and Mark A. DeCoster
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Copper/silver nano particles ,nitric oxide ,glioma ,brain microvascular endothelial cells ,tumor microenvironment ,inflammatory stimulus ,Chemistry ,QD1-999 - Abstract
Copper high aspect ratio structures (CuHARS) and silver cystine nanoparticles (AgCysNPs) are two unique micro/nano particles under study here that show extensive anti-cancer effects on a glioma tumor cell line. These micro/nano particles have shown potent toxicity in the presence of inflammatory stimulus (combination of tumor necrosis factor, [TNF] and lipo-polysaccharide, LPS). CuHARS with a concentration of 20 μg/ml uniquely increased the catalytic generation of nitric oxide (NO), an important contributor in the immune system. This NO was generated in a cell culture tumor microenvironment (TME) in the presence of 25 µM S-nitrosothiol (cysteine-NO) and the inflammatory stimulus. CuHARS increased the NO production by 68.75% when compared to untreated glioma cells with CysNO and inflammatory stimulus. The production of NO was significantly higher under similar circumstances in the case of normal primary structural cells like brain microvascular endothelial cells (BMVECs). The production of NO by BMVECs went up by 181.25% compared to glioma cells. This significant increase in the NO concentration could have added up to tumorigenesis but the anti-cancer effect of CuHARS was prominent enough to lower down the viability of glioma cells by approximately 20% and increased the metabolism of structural cells, BMVECs by approximately 200%. The immunomodulatory effect of NO in the TME under these circumstances in the presence of the novel micro/nano material, CuHARS has risen up compared to the effect of inflammatory stimulus alone. The potency and specific nature of these materials toward tumor cells may make them suitable candidates for cancer treatment. Successive treatment of CuHARS to glioma cells also proved to be an effective approach considering the decrease in the total count of cells by 11.84 fold in case of three successive treatments compared to a single dose which only decreased the cell count by 2.45 fold showing the dose-dependent increasing toxicity toward glioma cells. AgCysNPs are another potent nanomaterial which also proved its significant toxic nature toward tumor cell lines as demonstrated here, but their immunomodulatory response is still unclear and needs to be explored further.
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- 2021
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6. Tagged Halloysite Nanotubes as a Carrier for Intercellular Delivery in Brain Microvascular Endothelium
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Mahdi Yar Saleh, Neela Prajapati, Mark A. DeCoster, and Yuri Lvov
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halloysite (HNT) ,brain delivery ,endothelia cell ,nanomaterial application ,drug–drug interactions ,Biotechnology ,TP248.13-248.65 - Abstract
Neurological disorders that are characterized by unpredictable seizures affect people of all ages. We proposed the use of nanocarriers such as halloysite nanotubes to penetrate the blood–brain barrier and effectively deliver the payload over an extended time period. These 50-nm diameter tubes are a natural biocompatible nanomaterial available in large quantities. We proved a prolonged gradual drug delivery mechanism by the nanotube encapsulating rhodamine isothiocyanate and then ionomycin into brain microvascular endothelial cells (BMVECs). Through delayed diffusion, the nanotubes effectively delivered the drug to the primary BMVECs without killing them, by binding and penetration in time periods of 1 to 24 h.
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- 2020
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7. Morphological Changes in Astrocytes by Self-Oxidation of Dopamine to Polydopamine and Quantification of Dopamine through Multivariate Regression Analysis of Polydopamine Images
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Anik Karan, Elnaz Khezerlou, Farnaz Rezaei, Leon Iasemidis, and Mark A. DeCoster
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astrocyte ,polydopamine ,dopamine ,neurotransmitter ,image analysis ,Organic chemistry ,QD241-441 - Abstract
Astrocytes, also known as astroglia, are important cells for the structural support of neurons as well as for biochemical balance in the central nervous system (CNS). In this study, the polymerization of dopamine (DA) to polydopamine (PDA) and its effect on astrocytes was investigated. The polymerization of DA, being directly proportional to the DA concentration, raises the prospect of detecting DA concentration from PDA optically using image-processing techniques. It was found here that DA, a naturally occurring neurotransmitter, significantly altered astrocyte cell number, morphology, and metabolism, compared to astrocytes in the absence of DA. Along with these effects on astrocytes, the polymerization of DA to PDA was tracked optically in the same cell culture wells. This polymerization process led to a unique methodology based on multivariate regression analysis that quantified the concentration of DA from optical images of astrocyte cell culture media. Therefore, this developed methodology, combined with conventional imaging equipment, could be used in place of high-end and expensive analytical chemistry instruments, such as spectrophotometry, mass spectrometry, and fluorescence techniques, for quantification of the concentration of DA after polymerization to PDA under in vitro and potentially in vivo conditions.
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- 2020
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8. Self-Assembled Metal–Organic Biohybrids (MOBs) Using Copper and Silver for Cell Studies
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Neha Karekar, Anik Karan, Elnaz Khezerlou, Neela Prajapati, Chelsea D. Pernici, Teresa A. Murray, and Mark A. DeCoster
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self-assembly ,amino acid ,copper-containing high-aspect ratio structures (CuHARS) ,silver nanoparticles ,anti-cancer ,cystine-capped nanoparticles ,functionalization ,Chemistry ,QD1-999 - Abstract
The novel synthesis of metal-containing biohybrids using self-assembly methods at physiological temperatures (37 °C) was compared for copper and silver using the amino acid dimer cystine. Once assembled, the copper containing biohybrid is a stable, high-aspect ratio structure, which we call CuHARS. Using the same synthesis conditions, but replacing copper with silver, we have synthesized cystine-capped silver nanoparticles (AgCysNPs), which are shown here to form stable colloid solutions in contrast to the CuHARS, which settle out from a 1 mg/mL solution in 90 min. Both the copper and silver biohybrids, as synthesized, demonstrate very low agglomeration which we have applied for the purpose of applications with cell culture methods, namely, for testing as anti-cancer compounds. AgCysNPs (1000 ng/mL) demonstrated significant toxicity (only 6.8% viability) to glioma and neuroblastoma cells in vitro, with concentrations as low as 20 ng/mL causing some toxicity. In contrast, CuHARS required at least 5 μg/mL. For comparative purposes, silver sulfate at 100 ng/mL decreased viability by 52% and copper sulfate at 100 ng/mL only by 19.5% on glioma cells. Using these methods, the novel materials were tested here as metal−organic biohybrids (MOBs), and it is anticipated that the functionalization and dynamics of MOBs may result in building a foundation of new materials for cellular applications, including cell engineering of both normal and diseased cells and tissue constructs.
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- 2019
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9. Early glioma is associated with abnormal electrical events in cortical cultures.
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Jude P. Savarraj, Kinsey Cotton Kelly, and Mark A. DeCoster
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- 2019
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10. Ion-Selective Membrane-Coated Graphene–Hexagonal Boron Nitride Heterostructures for Field-Effect Ion Sensing
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Eric A. Sherer, Urna Kansakar, Adarsh D. Radadia, Mark A. DeCoster, and Nowzesh Hasan
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Materials science ,business.industry ,Graphene ,General Chemical Engineering ,Transconductance ,Transistor ,Oxide ,Field effect ,Heterojunction ,General Chemistry ,Article ,Ion ,law.invention ,Chemistry ,chemistry.chemical_compound ,Membrane ,chemistry ,law ,Optoelectronics ,business ,QD1-999 - Abstract
An intrinsic ion sensitivity exceeding the Nernst-Boltzmann limit and an sp 2 -hybridized carbon structure make graphene a promising channel material for realizing ion-sensitive field-effect transistors with a stable solid-liquid interface under biased conditions in buffered salt solutions. Here, we examine the performance of graphene field-effect transistors coated with ion-selective membranes as a tool to selectively detect changes in concentrations of Ca2+, K+, and Na+ in individual salt solutions as well as in buffered Locke's solution. Both the shift in the Dirac point and transconductance could be measured as a function of ion concentration with repeatability exceeding 99.5% and reproducibility exceeding 98% over 60 days. However, an enhancement of selectivity, by about an order magnitude or more, was observed using transconductance as the indicator when compared to Dirac voltage, which is the only factor reported to date. Fabricating a hexagonal boron nitride multilayer between graphene and oxide further increased the ion sensitivity and selectivity of transconductance. These findings incite investigating ion sensitivity of transconductance in alternative architectures as well as urge the exploration of graphene transistor arrays for biomedical applications.
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- 2021
11. Efficient LRP1-Mediated Uptake and Low Cytotoxicity of Peptide L57 In Vitro Shows Its Promise as CNS Drug Delivery Vector
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Teresa A. Murray, Neela Prajapati, Mark A. DeCoster, Scott Poh, and Jolin P. Rodrigues
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Peptidomimetic ,Pharmaceutical Science ,02 engineering and technology ,Pharmacology ,Blood–brain barrier ,030226 pharmacology & pharmacy ,Article ,03 medical and health sciences ,Drug Delivery Systems ,0302 clinical medicine ,medicine ,Animals ,Viability assay ,Cytotoxicity ,Receptor ,Receptors, Lipoprotein ,Chemistry ,Brain ,Endothelial Cells ,021001 nanoscience & nanotechnology ,LRP1 ,Rats ,medicine.anatomical_structure ,Pharmaceutical Preparations ,Transcytosis ,Blood-Brain Barrier ,Drug delivery ,Peptides ,0210 nano-technology - Abstract
Although an abundance of drug candidates exists which are aimed at the remediation of central nervous system (CNS) disorders, the utility of some are severely limited by their inability to cross the blood brain barrier. Potential drug delivery systems such as the Angiopep family of peptides have shown modest potential; however, there is a need for novel drug delivery candidates that incorporate peptidomimetics to enhance the efficiency of transcytosis, specificity, and biocompatibility. Here, we report on the first in vitro cellular uptake and cytotoxicity study of a peptidomimetic, cationic peptide, L57. It binds to cluster 4 of the low-density lipoprotein receptor-related protein 1 (LRP1) receptor which is expressed in numerous cell types, such as brain endothelial cells. We used early-passage-number brain microvascular endothelial cells and astrocytes harvested from rat pup brains that highly express LRP1, to study the uptake of L57 versus Angiopep-7 (A7). Uptake of L57 and A7 showed a concentration-dependent increase, with L57 being taken up to a greater degree than A7 at the same concentration. Additionally, peptide uptake in LRP1-deficient PEA 10 cells had greatly reduced uptake. Furthermore, L57 demonstrated excellent cell viability versus A7, showing promise as a potential drug delivery vector for CNS therapeutics.
- Published
- 2021
12. An enzyme-based electrochemical biosensor probe with sensitivity to detect astrocytic versus glioma uptake of glutamate in real time in vitro
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Chao Tan, Shabnam Siddiqui, Teresa A. Murray, Mahboubeh Madadi, Urna Kansakar, Nam Nguyen, Prabhu U. Arumugam, Mark A. DeCoster, and Jessica L. Scoggin
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Central nervous system ,Biomedical Engineering ,Biophysics ,Glutamic Acid ,Biosensing Techniques ,02 engineering and technology ,01 natural sciences ,Neurochemical ,Glioma ,Electrochemistry ,medicine ,Humans ,Electrochemical biosensor ,chemistry.chemical_classification ,010401 analytical chemistry ,Glutamate receptor ,Electrochemical Techniques ,General Medicine ,021001 nanoscience & nanotechnology ,medicine.disease ,In vitro ,0104 chemical sciences ,Enzyme ,medicine.anatomical_structure ,chemistry ,Astrocytes ,0210 nano-technology ,Neuroscience ,Biotechnology ,Astrocyte - Abstract
Glutamate, a major excitatory neurotransmitter in the central nervous system, is essential for regulation of thought, movement, memory, and other higher functions controlled by the brain. Dysregulation of glutamate signaling is associated with severe neuropathological conditions, such as epilepsy, and glioma, a form of brain cancer. Glutamate signals are currently detected by several types of neurochemical probes ranging from microdialysis-based to enzyme-based carbon fiber microsensors. However, an important technology gap exists in the ability to measure glutamate dynamics continuously, and in real time, and from multiple locations in the brain, which limits our ability to further understand the involved spatiotemporal mechanisms of underlying neuropathologies. To overcome this limitation, we developed an enzymatic glutamate microbiosensor, in the form of a ceramic-substrate enabled platinum microelectrode array, that continuously, in real time, measures changes in glutamate concentration from multiple recording sites. In addition, the developed microbiosensor is almost four-fold more sensitive to glutamate than enzymatic sensors previously reported in the literature. Further analysis of glutamate dynamics recorded by our microbiosensor in cultured astrocytes (control condition) and glioma cells (pathological condition) clearly distinguished normal versus impaired glutamate uptake, respectively. These results confirm that the developed glutamate microbiosensor array can become a useful tool in monitoring and understanding glutamate signaling and its regulation in normal and pathological conditions. Furthermore, the developed microbiosensor can be used to measure the effects of potential therapeutic drugs to treat a range of neurological diseases.
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- 2019
13. Morphological Changes in Astrocytes by Self-Oxidation of Dopamine to Polydopamine and Quantification of Dopamine through Multivariate Regression Analysis of Polydopamine Images
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Farnaz Rezaei, Mark A. DeCoster, Leon D. Iasemidis, Elnaz Khezerlou, and Anik Karan
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Polymers and Plastics ,Central nervous system ,Article ,lcsh:QD241-441 ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,astrocyte ,lcsh:Organic chemistry ,In vivo ,Dopamine ,image analysis ,medicine ,Neurotransmitter ,polydopamine ,030304 developmental biology ,0303 health sciences ,Chemistry ,General Chemistry ,In vitro ,medicine.anatomical_structure ,Polymerization ,Cell culture ,Biophysics ,dopamine ,030217 neurology & neurosurgery ,Astrocyte ,medicine.drug ,neurotransmitter - Abstract
Astrocytes, also known as astroglia, are important cells for the structural support of neurons as well as for biochemical balance in the central nervous system (CNS). In this study, the polymerization of dopamine (DA) to polydopamine (PDA) and its effect on astrocytes was investigated. The polymerization of DA, being directly proportional to the DA concentration, raises the prospect of detecting DA concentration from PDA optically using image-processing techniques. It was found here that DA, a naturally occurring neurotransmitter, significantly altered astrocyte cell number, morphology, and metabolism, compared to astrocytes in the absence of DA. Along with these effects on astrocytes, the polymerization of DA to PDA was tracked optically in the same cell culture wells. This polymerization process led to a unique methodology based on multivariate regression analysis that quantified the concentration of DA from optical images of astrocyte cell culture media. Therefore, this developed methodology, combined with conventional imaging equipment, could be used in place of high-end and expensive analytical chemistry instruments, such as spectrophotometry, mass spectrometry, and fluorescence techniques, for quantification of the concentration of DA after polymerization to PDA under in vitro and potentially in vivo conditions.
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- 2020
- Full Text
- View/download PDF
14. Cellulose-based biomaterials integrated with copper-cystine hybrid structures as catalysts for nitric oxide generation
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Gustavo del Real, Anik Karan, Margarita Darder, and Mark A. DeCoster
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Materials science ,Cell Survival ,Colony Count, Microbial ,chemistry.chemical_element ,Biocompatible Materials ,Bioengineering ,02 engineering and technology ,engineering.material ,Nitric Oxide ,010402 general chemistry ,01 natural sciences ,Catalysis ,Nanocellulose ,Biomaterials ,chemistry.chemical_compound ,Coating ,Elastic Modulus ,Spectroscopy, Fourier Transform Infrared ,Escherichia coli ,Polyamines ,Staphylococcus epidermidis ,Animals ,Cysteine ,Cellulose ,S-Nitrosothiols ,Brain ,Endothelial Cells ,021001 nanoscience & nanotechnology ,Ascorbic acid ,Copper ,Rats ,0104 chemical sciences ,Solvent ,Kinetics ,Cellulose fiber ,chemistry ,Chemical engineering ,Mechanics of Materials ,Microvessels ,engineering ,Cystine ,0210 nano-technology ,Porosity ,Polyallylamine hydrochloride - Abstract
Bionanocomposite materials were developed from the assembly of polymer-coated copper-cystine high-aspect ratio structures (CuHARS) and cellulose fibers. The coating of the metal-organic materials with polyallylamine hydrochloride (PAH) allows their covalent linkage to TEMPO-oxidized cellulose by means of EDC/NHS. The resulting materials can be processed as films or macroporous foams by solvent casting and lyophilization, respectively. The films show good mechanical behavior with Young's moduli around 1.5 GPa as well as resistance in water, while the obtained foams show an open network of interconnected macropores with average diameters around 130 μm, depending on the concentration of the initial suspension, and compression modulus values around 450 kPa, similar to other reported freeze-dried nanocellulose-based aerogels. Based on these characteristics, the cellulose/PAH-CuHARS composites are promising for potential biomedical applications as implants or wound dressing materials. They have proved to be effective in the decomposition of low molecular weight S-nitrosothiols (RSNOs), similar to those existing in blood, releasing nitric oxide (NO). This effect is attributed to the presence of copper in the crystalline structure of the CuHARS building unit, which can be gradually released in the presence of redox species like ascorbic acid, typically found in blood. The resulting biomaterials can offer the interesting properties associated with NO, like antimicrobial activity as preliminary tests showed here with Escherichia coli and Staphylococcus epidermidis. In the presence of physiological concentration of RSNOs the amount of generated NO (around 360 nM) is not enough to show bactericidal effect on the studied bacteria, but it could provide other properties inherent to NO even at low concentration in the nM range like anti-inflammatory and anti-thrombotic effects. The cytotoxic effect recorded of the films on rat brain endothelial cells (BMVECs) is least significant and proves them to be friendly enough for further biological studies.
- Published
- 2020
15. Early glioma is associated with abnormal electrical events in cortical cultures
- Author
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Kinsey Cotton Kelly, Jude P.J. Savarraj, and Mark A. DeCoster
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0206 medical engineering ,Biomedical Engineering ,Brain tumor ,Cell Culture Techniques ,02 engineering and technology ,Disease ,Biology ,030218 nuclear medicine & medical imaging ,Rats, Sprague-Dawley ,03 medical and health sciences ,0302 clinical medicine ,Glioma ,medicine ,Extracellular ,Animals ,Cerebral Cortex ,Neurons ,Electrodiagnosis ,Cytarabine ,Signal Processing, Computer-Assisted ,Neurophysiology ,Spinal cord ,medicine.disease ,020601 biomedical engineering ,In vitro ,Computer Science Applications ,medicine.anatomical_structure ,nervous system ,Gliosis ,medicine.symptom ,Neuroscience ,Microelectrodes - Abstract
The prodromal stages of some neurological diseases have a distinct electrical profile which can potentially be leveraged for early diagnosis, predicting disease recurrence, monitoring of disease progression, and better understanding of the disease pathology. Gliomas are tumors that originate from glial cells present in the brain and spinal cord. Healthy glial cells support normal neuronal function and play an important role in modulating the regular electrical activity of neurons. However, gliomas can disrupt the normal electrical dynamics of the brain. Though experimental and clinical studies suggest that glioma and injury to glial cells disrupt electrical dynamics of the brain, whether these disruptions are present during the earliest stages of glioma and glial injury are unclear. The primary aim of this study is to investigate the effect of early in vitro glial pathology (glioma and glial injury in specific) on neuronal electrical activity. In particular, we investigated the effect of glial pathology on neural synchronization: an important phenomenon that underlies several central neurophysiological processes (ScienceDirect, 2018 ). We used two in vitro disease samples: (a) a sample in which cortical cultures were treated with anti-mitotic agents that deplete glial cells and (b) a glioma sample in which healthy cortical cells were cultured with CRL-2303 (an aggressive glioma cell line). Healthy cortical culture samples were used as controls. Cultures were established over a glass dish embedded with microelectrodes that permits simultaneous measurement of extracellular electrical activity from multiple sites of the culture. We observed that healthy cortical cultures produce spontaneous and synchronized oscillations which were attenuated in the absence of glial cells. The presence of glioma was associated with the emergence of two types of "abnormal electrical activity" each with distinct amplitude and frequency profile. Our results indicate that even early stages of glioma and glial injury are associated with distinct changes in neuronal electrical activity. Graphical abstract.
- Published
- 2018
16. Integration of a Copper-Containing Biohybrid (CuHARS) with Cellulose for Subsequent Degradation and Biomedical Control
- Author
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Zach Norcross, Margarita Darder, Urna Kansakar, Anik Karan, Mark A. DeCoster, National Science Foundation (US), Ministerio de Economía y Competitividad (España), and Ministerio de Educación y Ciencia (España)
- Subjects
Health, Toxicology and Mutagenesis ,Composite number ,Cystine ,lcsh:Medicine ,chemistry.chemical_element ,Biocompatible Materials ,02 engineering and technology ,010402 general chemistry ,composites ,01 natural sciences ,Article ,Nanomaterials ,biohybrids ,chemistry.chemical_compound ,Centrifugation ,cellulose ,degradation ,nanomaterials ,cell culture ,green materials ,copper ,Cellulose ,Aqueous solution ,lcsh:R ,Public Health, Environmental and Occupational Health ,Water ,Cell culture media ,021001 nanoscience & nanotechnology ,Copper ,0104 chemical sciences ,chemistry ,Chemical engineering ,0210 nano-technology - Abstract
We previously described the novel synthesis of a copper high-aspect ratio structure (CuHARS) biohybrid material using cystine. While extremely stable in water, CuHARS is completely (but slowly) degradable in cellular media. Here, integration of the CuHARS into cellulose matrices was carried out to provide added control for CuHARS degradation. Synthesized CuHARS was concentrated by centrifugation and then dried. The weighed mass was re-suspended in water. CuHARS was stable in water for months without degradation. In contrast, 25 μg/mL of the CuHARS in complete cell culture media was completely degraded (slowly) in 18 days under physiological conditions. Stable integration of CuHARS into cellulose matrices was achieved through assembly by mixing cellulose micro- and nano-fibers and CuHARS in an aqueous (pulp mixture) phase, followed by drying. Additional materials were integrated to make the hybrids magnetically susceptible. The cellulose-CuHARS composite films could be transferred, weighed, and cut into usable pieces; they maintained their form after rehydration in water for at least 7 days and were compatible with cell culture studies using brain tumor (glioma) cells. These studies demonstrate utility of a CuHARS-cellulose biohybrid for applied applications including: (1) a platform for biomedical tracking and (2) integration into a 2D/3D matrix using natural products (cellulose)., This work was funded with the support of grant awards from the National Science Foundation (NSF #1547693 and NSF#1632891), and the MINECO (Spain) project MAT2015-71117-R. M. Darder acknowledges the joint sponsorship by the Fulbright Scholar Program and the Spanish Ministry of Education.
- Published
- 2018
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17. Lab-on-a-chip mRNA purification and reverse transcription via a solid-phase gene extraction technique
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Karl H. Hasenstein, Mark A. DeCoster, Gergana G. Nestorova, Nam Nguyen, and Niel D. Crews
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0301 basic medicine ,Microfluidics ,Biomedical Engineering ,Bioengineering ,01 natural sciences ,Biochemistry ,law.invention ,03 medical and health sciences ,law ,Cell Line, Tumor ,Lab-On-A-Chip Devices ,Spheroids, Cellular ,Tumor Cells, Cultured ,Animals ,Sample preparation ,Dimethylpolysiloxanes ,RNA, Messenger ,Messenger RNA ,Chromatography ,Chemistry ,Oligonucleotide ,010401 analytical chemistry ,Extraction (chemistry) ,Solid Phase Extraction ,RNA ,General Chemistry ,Reverse Transcription ,Lab-on-a-chip ,Microfluidic Analytical Techniques ,Reverse transcriptase ,0104 chemical sciences ,Rats ,Nylons ,030104 developmental biology ,Biomedical engineering - Abstract
Extraction and purification of high quality RNA is a crucial initial step required for a variety of genomic assays. We report a solid phase gene extraction (SPGE) method for automated extraction, purification and reverse transcription of mRNA in a microfluidic device. This is performed using a 130 μm diameter stainless steel needle that is amino-linked to dT(15) oligonucleotides for selective hybridization of mRNA. By inserting this probe into the biological sample for only 30 seconds, mRNA is captured with high selectivity and a yield greater than 10 pg per mm of probe length. The probe is then inserted into a lab-on-a-chip device, where the bound poly-adenylated RNA is thermally released and immediately reverse transcribed for subsequent PCR amplification. The insertion of the probe into the microfluidic device is straightforward: the microchannel is formed with an elastomer (PDMS) that, when punctured, will seal around the probe. The specificity and RNA loading capacity of the probes were evaluated using conventional qPCR. This procedure was successfully used to extract, purify, and transcribe mRNA from rat glioblastoma cell spheroids in less than seven minutes. Analysis of the product confirmed that the SPGE technique selectively captures and inherently purifies high-quality mRNA directly from biological material with no need for additional pre-processing steps. Integrating this elegant sample preparation method into a complete lab-on-a-chip system will substantially enhance the speed and automation of mRNA assays for research and clinical diagnostics.
- Published
- 2017
18. Layer-by-layer nanoencapsulation of camptothecin with improved activity
- Author
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Chaitanya R Joshi, Tatyana S. Levchenko, Pravin Pattekari, Vladimir P. Torchilin, Mark A. DeCoster, Tatsiana Shutava, Yuri Lvov, and Gaurav Parekh
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Cell Survival ,Polymers ,Chemistry, Pharmaceutical ,Drug Compounding ,Pharmaceutical Science ,Polyethylene glycol ,Article ,Nanocapsules ,Polyethylene Glycols ,chemistry.chemical_compound ,Drug Stability ,Cell Line, Tumor ,medicine ,Animals ,Nanotechnology ,Technology, Pharmaceutical ,Organic chemistry ,Polylysine ,Particle Size ,Solubility ,chemistry.chemical_classification ,Brain Neoplasms ,Heparin ,Hydrolysis ,Polymer ,Hydrogen-Ion Concentration ,Antineoplastic Agents, Phytogenic ,Polyelectrolyte ,Rats ,Molecular Weight ,Kinetics ,chemistry ,Camptothecin ,Chemical stability ,Glioblastoma ,Nuclear chemistry ,medicine.drug - Abstract
160 nm nanocapsules containing up to 60% of camptothecin in the core and 7–8 polyelectrolyte bilayers in the shell were produced by washless layer-by-layer assembly of heparin and block-copolymer of poly- l -lysine and polyethylene glycol. The outer surface of the nanocapsules was additionally modified with polyethylene glycol of 5 kDa or 20 kDa molecular weight to attain protein resistant properties, colloidal stability in serum and prolonged release of the drug from the capsules. An advantage of the LbL coated capsules is the preservation of camptothecin lactone form with the shell assembly starting at acidic pH and improved chemical stability of encapsulated drug at neutral and basic pH, especially in the presence of albumin that makes such formulation more active than free camptothecin. LbL nanocapsules preserve the camptothecin lactone form at pH 7.4 resulting in triple activity of the drug toward CRL2303 glioblastoma cell.
- Published
- 2014
19. Synthesis and Post-Synthesis Optimization of Novel Copper Biocomposites and Exploration of Potential Applications
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David Milam, Mark A. DeCoster, and Sneha Deodhar
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Materials science ,Biocompatibility ,chemistry ,Nano ,HARS ,chemistry.chemical_element ,Degradation (geology) ,Surface modification ,Thermal stability ,Nanotechnology ,Post synthesis ,Copper - Abstract
Previous experiments have documented the discovery of novel high-aspect ratio structures (HARS) composed of cystine and copper synthesized in a physiological environment. These HARS scale in size from nano to micro dimensions and have favorable properties such as biocompatibility, long-term stability, and non-agglomerating properties. Here we tested for: optimal synthesis conditions, stability limits, and their application to uniformly coat films. Because the HARS have an amino acid component, functionalization using layer-by-layer techniques may provide strategies for improved imaging, masking, and ordering the structures for controlled interaction with cells in 2d and 3d spaces.
- Published
- 2016
20. Novel Scalable Nano-and Micro-High-Aspect Ratio Structure (HARS) Biocomposites Generated under Physiological Conditions
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Mark A. DeCoster
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Nanocomposite ,Materials science ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Copper ,0104 chemical sciences ,chemistry ,Drug delivery ,Nano ,HARS ,Nanometre ,0210 nano-technology - Abstract
We report novel synthesis for composites under physiological conditions, resulting in high-aspect ratio structures (HARS). These HARS contain copper and cystine. They are extremely stable in dry or liquid form, and have very low agglomeration. Diameters of the HARS range up from 20 nm, and length scales from nanometers to micrometers. Copper in the HARS imparts potential biological applications as copper has antimicrobial and anti-cancer effects. These HARS are degradable once interacting with cells, indicating potential new avenues for drug delivery.
- Published
- 2016
21. Interaction of Degradable and Non-degradable Biomaterial with Brain Cells for Tissue Engineering and Cancer Treatment
- Author
-
Urna Kansakar, Miles Delahoussaye, Yuri Lvov, Mark A. DeCoster, Nam Nguyen, and Renata T. Minullina
- Subjects
Materials science ,Biomaterial ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Halloysite ,0104 chemical sciences ,Cancer treatment ,Tissue engineering ,Cell culture ,Microscopy ,Drug delivery ,Fluorescence microscope ,engineering ,0210 nano-technology ,Biomedical engineering - Abstract
This research compares interaction of two non-degradable materials: 2 µm fluorescent beads and halloysite nanotubes (HNTs) and one degradable biomaterial -- High Aspect Ratio Structure (HARS) biocomposites, with microglial brain cells. White light and fluorescence microscopy were used to capture images and were analyzed using Image Pro Plus 7.0 software. Results show interactions between microglial cells and biomaterials which can be carried out for applications in tissue engineering as well as for testing anti-cancer effects.
- Published
- 2016
22. Use of Randomized Submaximal Glutamate Stimulus to Interpret Glial Effects on Neuronal Calcium Dynamics
- Author
-
Kinsey Cotton Kelly, Katie Evans, Mihaela Paun, and Mark A. DeCoster
- Subjects
medicine.medical_specialty ,Neurodegeneration ,Neurotoxicity ,Glutamate receptor ,Area under the curve ,chemistry.chemical_element ,Biology ,Calcium ,Stimulus (physiology) ,medicine.disease ,Calcium in biology ,Endocrinology ,medicine.anatomical_structure ,chemistry ,Internal medicine ,medicine ,Neuron ,Neuroscience - Abstract
Glutamate (GLU) binding to neurons can cause dynamic changes in intracellular calcium. We tested effects of a 3-group submaximal glutamate stimulus (250, 500 and 750 nanomolar GLU in randomized orders) on neurons in culture, and measured intracellular calcium dynamics in cultures high and low in glia at 8 and 9 days in vitro. Gliadepleted cultures responded to increasing GLU with synchronized dynamics, leading to a greater “area under the curve” (AUC) for intracellular calcium over time. The AUC determined if the neuron would respond dynamically to the next addition of glutamate. This observation was not displayed within cultures high in glia, where AUC returned to baseline with every GLU addition, regardless of order of addition. Furthermore, the 3-group stimulus resulted in decreasing average AUC, regardless of order. In contrast, for cultures depleted of glia, the deciding factor of a responding cell to dynamically respond to GLU additions depended on the ability of the cell to distribute the calcium load (AUC) of the prior addition. Determining how neurons respond and behave such as in the presence of functional or dysfunctional glia, may help our understanding of signal processing in the brain.
- Published
- 2016
23. A simple polymer based electrochemical transistor for micromolar glucose sensing
- Author
-
Mangilal Agarwal, Mark A. DeCoster, Haidar T. Alshakhouri, and Senaka Kanakamedala
- Subjects
Materials science ,Analytical chemistry ,Electrochemistry ,law.invention ,Styrene ,chemistry.chemical_compound ,PEDOT:PSS ,law ,Materials Chemistry ,Glucose oxidase ,Electrical and Electronic Engineering ,Instrumentation ,chemistry.chemical_classification ,biology ,business.industry ,Transistor ,Metals and Alloys ,Polymer ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry ,Electrode ,biology.protein ,Optoelectronics ,business ,Organic electrochemical transistor - Abstract
A simple and inexpensive glucose sensor with micromolar sensitivity is demonstrated. The sensor utilizes a poly(3,4-ethyelenedioxythiphene) poly(styrene sulfonate) (PEDOT:PSS) based electrochemical transistor in which all the electrodes and the channel were made with the same polymer. The sensor was fabricated in a one step fabrication process using inexpensive and rapid xurography technique and is able to detect glucose concentrations from approximately 1 μM to 10 mM and showed adequate change for glucose levels in the range of human saliva (8–210 μM) without utilizing any external electron mediators.
- Published
- 2011
24. A new 3D mass diffusion–reaction model in the neuromuscular junction
- Author
-
Weizhong Dai, Frank Jenkins, Mark A. DeCoster, and Abdul Khaliq
- Subjects
Diffusion equation ,Materials science ,Synaptic cleft ,Anisotropic diffusion ,Cognitive Neuroscience ,Models, Neurological ,Population ,Neuromuscular Junction ,Presynaptic Terminals ,Synaptic Membranes ,Synaptic Transmission ,Molecular physics ,Neuromuscular junction ,Quantitative Biology::Cell Behavior ,Diffusion ,Quantitative Biology::Subcellular Processes ,Cellular and Molecular Neuroscience ,medicine ,Animals ,Humans ,Computer Simulation ,Receptors, Cholinergic ,Diffusion (business) ,education ,Acetylcholine receptor ,Motor Neurons ,education.field_of_study ,Quantitative Biology::Neurons and Cognition ,Acetylcholine ,Sensory Systems ,medicine.anatomical_structure ,Synapses ,Neuroscience ,medicine.drug - Abstract
A three-dimensional model of the reaction-diffusion processes of a neurotransmitter and its ligand receptor in a disk shaped volume is proposed which represents the transmission process of acetylcholine in the synaptic cleft in the neuromuscular junction. The behavior of the reaction-diffusion system is described by a three-dimensional diffusion equation with nonlinear reaction terms due to the rate processes of acetylcholine with the receptor. A new stable and accurate numerical method is used to solve the equations with Neumann boundaries in cylindrical coordinates. The simulation analysis agrees with experimental measurements of end-plate current, and agrees well with the results of the conformational state of the acetylcholine receptor as a function of time and acetylcholine concentration of earlier investigations with a smaller error compared to experiments. Asymmetric emission of acetylcholine in the synaptic cleft and the subsequent effects on open receptor population is simulated. Sensitivity of the open receptor dynamics to the changes in the diffusion parameters and neuromuscular junction volume is investigated. The effects of anisotropic diffusion and non-symmetric emission of transmitter at the presynaptic membrane is simulated.
- Published
- 2010
25. Glutamate-mediated CA++ influx and nuclear damage in retinal ganglion cells purified by panning: role of glia
- Author
-
Nicolas G. Bazan and Mark A. DeCoster
- Subjects
Retina ,genetic structures ,Excitotoxicity ,Glutamate receptor ,Retinal ,Biology ,medicine.disease_cause ,Biochemistry ,Retinal ganglion ,Neuroprotection ,eye diseases ,Cell biology ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,medicine.anatomical_structure ,Retinal ganglion cell ,Unoprostone ,chemistry ,medicine ,sense organs ,Neuroscience ,medicine.drug - Abstract
The visual acuity decline in glaucoma is due to degeneration of retinal ganglion cells. We used cell panning with the antibody Thy 1.1 to isolate retinal ganglion cells (RGCs) from rat retina. Individual RGCs were extremely sensitive to glutamate, demonstrating sustained calcium influx responses to 100 nm glutamate. We tested unoprostone for its ability to elicit neuroprotection. This docosanoid decreases intraocular pressure in glaucoma patients and protects mixed retinal ganglion cell cultures from glutamate excitotoxicity and calcium influx. In the presence of retinal glia, RGCs responded to 100 and 500 nm glutamate with transient calcium influx, demonstrating glial buffering effects. Pure retinal glial cultures required on average at least 1 mm glutamate to trigger calcium influx, which was transient and oscillating. Unoprostone (10 μm) inhibited calcium influx stimulated by 5 mm glutamate in retinal glial cultures, while DMSO did not. Unoprostone at 1 μm also blocked neuronal calcium responses to 100 nm glutamate in mixed cultures, while DMSO did not. In RGCs isolated by panning, unoprostone blocked calcium responses to 100 nm glutamate in some cells, while DMSO blocked none. Unoprostone also protected RGCs from 20 μm glutamate-induced toxicity and nuclear damage. We hypothesize that while unoprostone may affect individual RGCs depending on a putative receptor, the presence of retinal glia also plays a key role in neuroprotection and unoprostone action. The use of the cellular model described here and whole retina preparations will be useful to understand the mechanisms of RGC survival. Acknowledgements: Support: Novartis Ophthalmics, Basel, Switzerland.
- Published
- 2008
26. Generation of Scalable, Metallic High-Aspect Ratio Nanocomposites in a Biological Liquid Medium
- Author
-
Justin Huckaby, Kinsey Cotton Kelly, Sneha Deodhar, Jessica R. Wasserman, and Mark A. DeCoster
- Subjects
Copper Sulfate ,Materials science ,Sonication ,General Chemical Engineering ,Metal Nanoparticles ,Nanoparticle ,chemistry.chemical_element ,Bioengineering ,General Biochemistry, Genetics and Molecular Biology ,Nanocomposites ,Metal ,Nano ,Microscopy ,Nanocomposite ,General Immunology and Microbiology ,General Neuroscience ,Copper ,Chemical engineering ,chemistry ,Agglomerate ,visual_art ,Microscopy, Electron, Scanning ,visual_art.visual_art_medium ,Cystine - Abstract
The goal of this protocol is to describe the synthesis of two novel biocomposites with high-aspect ratio structures. The biocomposites consist of copper and cystine, with either copper nanoparticles (CNPs) or copper sulfate contributing the metallic component. Synthesis is carried out in liquid under biological conditions (37 °C) and the self-assembled composites form after 24 hr. Once formed, these composites are highly stable in both liquid media and in a dried form. The composites scale from the nano- to micro- range in length, and from a few microns to 25 nm in diameter. Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (EDX) demonstrated that sulfur was present in the NP-derived linear structures, while it was absent from the starting CNP material, thus confirming cystine as the source of sulfur in the final nanocomposites. During synthesis of these linear nano- and micro-composites, a diverse range of lengths of structures is formed in the synthesis vessel. Sonication of the liquid mixture after synthesis was demonstrated to assist in controlling average size of the structures by diminishing the average length with increased time of sonication. Since the formed structures are highly stable, do not agglomerate, and are formed in liquid phase, centrifugation may also be used to assist in concentrating and segregating formed composites.
- Published
- 2015
27. Fabrication of Interdigitated Micropatterns of Self-Assembled Polymer Nanofilms Containing Cell-Adhesive Materials
- Author
-
Javeed Shaikh Mohammed, Mark A. DeCoster, and Michael J. McShane
- Subjects
Fabrication ,Nanocomposite ,Materials science ,Polymers ,Biomaterial ,Nanotechnology ,Surfaces and Interfaces ,Substrate (printing) ,Condensed Matter Physics ,Article ,Rats ,Surface micromachining ,Cell Adhesion ,Electrochemistry ,Animals ,General Materials Science ,Self-assembly ,Nanoscopic scale ,Lithography ,Cells, Cultured ,Spectroscopy - Abstract
Micropatterns of different biomaterials with micro- and nanoscale features and defined spatial arrangement on a single substrate are useful tools for studying cellular-level interactions, and recent reports have highlighted the strong influence of scaffold compliance in determining cell behavior. In this paper, a simple yet versatile and precise patterning technique for the fabrication of interdigitated micropatterns of nanocomposite multilayer coatings on a single substrate is demonstrated through a combination of lithography and layer-by-layer (LbL) assembly processes, termed polymer surface micromachining (PSM). The first nanofilm pattern is constructed using lithography, followed by LbL multilayer assembly and lift-off, and the process is repeated with optical alignment to obtain interdigitated patterns on the same substrate. Thus, the method is analogous to surface micromachining, except that the deposition materials are polymers and biological materials that are used to produce multilayer nanocomposite structures. A key feature of the multilayers is the capability to tune properties such as stiffness by appropriate selection of materials, deposition conditions, and postdeposition treatments. Two- and four-component systems on glass coverslips are presented to demonstrate the versatility of the approach to construct precisely defined, homogeneous nanofilm patterns. In addition, an example of a complex system used as a testbed for in vitro cell adhesion and growth is provided: micropatterns of poly(sodium 4-styrenesulfonate)/poly-L-lysine hydrobromide (PSS/PLL) and secreted phospholipase A(2)/poly(ethyleneimine) (sPLA(2)/PEI) multilayers. The interdigitated square nanofilm array patterns were obtained on a single coverslip with poly(diallyldimethylammonium chloride) (PDDA) as a cell-repellent background. Cell culture experiments show that cortical neurons respond and bind specifically to the sPLA(2) micropatterns in competition with PLL micropatterns. The fabrication and the initial biological results on the nanofilm micropatterns support the usefulness of this technique for use in studies aimed at elucidating important biological structure-function relationships, but the applicability of the fabrication method is much broader and may impact electronics, photonics, and chemical microsystems.
- Published
- 2006
28. Role of nitric oxide in regulating secreted phospholipase A2 release from astrocytes
- Author
-
Guansong Wang, Bron M Daniel, and Mark A. DeCoster
- Subjects
Lipopolysaccharides ,Time Factors ,Lipopolysaccharide ,Blotting, Western ,Nitric Oxide ,Phospholipases A ,Nitric oxide ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Caffeic Acids ,Phospholipase A2 ,medicine ,Animals ,Drug Interactions ,Enzyme Inhibitors ,Cells, Cultured ,Edetic Acid ,Nitrites ,Chelating Agents ,Cerebral Cortex ,Analysis of Variance ,biology ,Microglia ,General Neuroscience ,Phenylethyl Alcohol ,Embryo, Mammalian ,Rats ,Nitric oxide synthase ,Phospholipases A2 ,NG-Nitroarginine Methyl Ester ,medicine.anatomical_structure ,chemistry ,Biochemistry ,Cell culture ,Astrocytes ,biology.protein ,Neuroglia ,Astrocyte - Abstract
Inflammatory stimuli such as lipopolysaccharide increase nitric oxide and secreted phospholipase A2 release from glial cells. However, the signaling mechanism(s) regulating secreted phospholipase A2 in glial cells is not known. Here, rat brain astrocytes treated with lipopolysaccharide generated nitrite and released secreted phospholipase A2, while microglia generated nitrite without releasing secreted phospholipase A2. Unexpectedly, attenuation of nitrite production by pretreatment with the nitric oxide synthase inhibitor N-Omega-nitro-L-arginine methyl ester greatly enhanced lipopolysaccharide-stimulated secreted phospholipase A2 release from astrocytes; postreatment with N-Omega-nitro-L-arginine methyl ester did not potentiate secreted phospholipase A2 release, and addition of an nitric oxide donor attenuated the secreted phospholipase A2 release. The regulation of secreted phospholipase A2 may act via the transcription factor nuclear factor-kappaB, as a nuclear factor-kappaB inhibitor attenuated lipopolysaccharide-stimulated secreted phospholipase A2 release. These results demonstrate the role of basal nitric oxide levels as a regulator of inflammatory secreted phospholipase A2 release from glial cells of the brain.
- Published
- 2005
29. Micropatterning of Nanoengineered Surfaces to Study Neuronal Cell Attachment in Vitro
- Author
-
J Shaikh Mohammed, Mark A. DeCoster, and Michael J. McShane
- Subjects
Neurons ,Cell signaling ,Materials science ,Nanocomposite ,food.ingredient ,Nanostructure ,Polymers and Plastics ,Biomedical Engineering ,Bioengineering ,Nanotechnology ,Substrate (printing) ,Gelatin ,Rats ,law.invention ,Biomaterials ,food ,law ,Materials Chemistry ,Animals ,Photolithography ,Nanoscopic scale ,Cells, Cultured ,Micropatterning - Abstract
Methods for producing protein patterns with defined spatial arrangement and micro- and nanoscale features are important for studying cellular-level interactions, including basic cell-cell communications, cell signaling, and mechanisms of drug action. Toward this end, a straightforward, versatile procedure for fabricating micropatterns of bioactive nanofilm coatings as multifunctional biological testbeds is demonstrated. The method, based on a combination of photolithography and layer-by-layer self-assembly (LbL), allows for precise construction of nanocomposite films of potentially complex architecture, and patterning of these films on substrates using a modified lift-off (LO) procedure. As a first step in evaluating nanostructures made with this process, "comparison chips," comprising two coexisting regions of square patterns with relevant proteins/polypeptides on a single substrate, were fabricated with poly(diallyldimethylammonium chloride) (PDDA) as a cell-repellent background. Using neuronal cells as a model biological system, comparison chips were produced with secreted phospholipase A2 (sPLA2), a known membrane-active enzyme for neurons, for direct comparison with gelatin, poly-l-lysine (PLL), or bovine serum albumin (BSA). Fluorescence microscopy, surface profilometry, and atomic force microscopy techniques were used to evaluate the structural properties of the patterns on these chips and show that the patterning technique was successful. Preliminary cell culture studies show that neurons respond and bind specifically to the sPLA2 enzyme embedded in the polyelectrolyte thin films and present as the outermost layer. These findings point to the potential for this method to be applied in developing test substrates for a broad array of studies aimed at identifying important biological structure-function relationships.
- Published
- 2004
30. Interplay among platelet-activating factor, oxidative stress, and group I metabotropic glutamate receptors modulates neuronal survival
- Author
-
Peimin Zhu, Nicolas G. Bazan, and Mark A. DeCoster
- Subjects
Azoles ,Free Radicals ,Cell Survival ,Platelet Membrane Glycoproteins ,Isoindoles ,Pharmacology ,Receptors, Metabotropic Glutamate ,medicine.disease_cause ,Neuroprotection ,Antioxidants ,Receptors, G-Protein-Coupled ,Nitric oxide ,Rats, Sprague-Dawley ,Lactones ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Organoselenium Compounds ,Excitatory Amino Acid Agonists ,medicine ,Animals ,Nitric Oxide Donors ,Platelet Activating Factor ,Cells, Cultured ,Neurons ,Cell Death ,L-Lactate Dehydrogenase ,Platelet-activating factor ,Superoxide ,Neurodegeneration ,Vitamin K 3 ,Long-term potentiation ,Hydrogen Peroxide ,medicine.disease ,Rats ,Oxidative Stress ,Ginkgolides ,Neuroprotective Agents ,chemistry ,Biochemistry ,Metabotropic glutamate receptor ,Nerve Degeneration ,lipids (amino acids, peptides, and proteins) ,Diterpenes ,Oxidative stress - Abstract
Platelet-activating factor (PAF) is a potent phospholipid messenger in the nervous system that participates in synaptic plasticity and in pathologic processes, including neurodegeneration. Oxidative stress plays important roles in neuronal cell death. To define the interaction between PAF and oxidative radicals in neuronal death, we studied the effects of PAF in the presence of oxidative radicals in primary neurons in culture. Exogenous PAF (50 μM) caused PAF receptor-independent injury to neurons. A nonneurotoxic PAF concentration (500 nM) potentiated neuronal death caused by hydrogen peroxide as determined by lactate dehydrogenase (LDH) assay, Hoechst staining, and TUNEL analysis, but it did not potentiate neuronal death caused by menadione, a superoxide donor, or by the nitric oxide donors 3-morpholino-sydnonimine (SIN-1) and sodium nitroprusside (SNP). This potentiation of the hydrogen peroxide effect was selectively blocked by a PAF membrane-receptor antagonist, BN52021 (5 μM). The neurotoxic effect of PAF and hydrogen peroxide was also completely blocked by ebselen and partially decreased by pretreatment with (S)-3,5-dihydroxyphenylglycine (DHPG), a group I metabotropic glutamate receptor (mGluR) agonist. This study suggests that PAF-receptor antagonists may be useful for neuroprotection. A similar effect might also be obtained with group I mGluR agonists, probably by way of a different underlying mechanism. © 2004 Wiley-Liss, Inc.
- Published
- 2004
31. The Chaperone Protein 14-3-3η Interacts with the Nicotinic Acetylcholine Receptor α4 Subunit
- Author
-
Magdalen W. Treuil, Jayaraman Rao, Elisabeth M. Jeanclos, Rene Anand, Mark A. DeCoster, and Lin Lin
- Subjects
animal structures ,Forskolin ,biology ,Protein subunit ,Signal transducing adaptor protein ,Cell Biology ,Plasma protein binding ,musculoskeletal system ,Biochemistry ,Cell biology ,chemistry.chemical_compound ,Nicotinic acetylcholine receptor ,chemistry ,Chaperone (protein) ,biology.protein ,Protein kinase A ,Molecular Biology ,Acetylcholine receptor - Abstract
By using the large cytoplasmic domain of the nicotinic acetylcholine receptor (AChR) α4 subunit as a bait in the yeast two-hybrid system, we isolated the first cytosolic protein, 14-3-3η, known to interact directly with neuronal AChRs. 14-3-3η is a member of a family of proteins that function as regulatory or chaperone/ scaffolding/adaptor proteins. 14-3-3η interacted with the recombinant α4 subunit alone in tsA 201 cells following activation of cAMP-dependent protein kinase by forskolin. The interaction of 14-3-3η with recombinant α4 subunits was abolished when serine 441 of the α4 subunit was mutated to alanine (α4S441A). The surface levels of recombinant wild-type α4β2 AChRs were ∼2-fold higher than those of mutant α4S441Aβ2 AChRs. The interaction significantly increased the steady state levels of the α4 subunit and α4β2 AChRs but not that of the mutant α4S441A subunit or mutant α4S441Aβ2 AChRs. The EC50 values for activation by acetylcholine were not significantly different for α4β2 AChRs and α4S441Aβ2 AChRs coexpressed with 14-3-3η in oocytes following treatment with forskolin. 14-3-3 coimmunopurified with native α4 AChRs from brain. These results support a role for 14-3-3 in dynamically regulating the expression levels of α4β2 AChRs through its interaction with the α4 subunit.
- Published
- 2001
32. Interleukin-1 beta activates expression of cyclooxygenase-2 and inducible nitric oxide synthase in primary hippocampal neuronal culture: Platelet-activating factor as a preferential mediator of cyclooxygenase-2 expression
- Author
-
Nicolas G. Bazan, Michael Serou, and Mark A. DeCoster
- Subjects
medicine.medical_specialty ,Platelet-activating factor ,medicine.medical_treatment ,Inflammation ,Biology ,Hippocampal formation ,Nitric oxide synthase ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Endocrinology ,Cytokine ,chemistry ,Internal medicine ,Synaptic plasticity ,Immunology ,medicine ,biology.protein ,Cyclooxygenase ,medicine.symptom ,Receptor - Abstract
Interleukin-1 beta (IL-1β) is an inflammatory cytokine whose expression is elevated in brain during seizures, ischemia, and injury. Expression of IL-1β and its receptor can also be observed in normal brain. Platelet-activating factor (PAF) is also a dual mediator that promotes neuronal plasticity responses as well as inflammation. We have determined the role of PAF in the regulation of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) genes by IL-1β in rat primary hippocampal cultures. As assessed by reverse transcriptase/polymerase chain reaction (RT/PCR), recombinant mouse IL-1β (1 nM) led to an induction of COX-2 mRNA which peaked at 2 hours, declined to baseline levels by 4 hours, began to rise again by 6 hours, and remained elevated at 24 hours post-treatment. iNOS mRNA was also induced, but unlike COX-2, its abundance peaked at 4 hours and decreased by 6 hours to a plateau lasting through 24 hours. Pretreatment with PAF antagonist BN50730 blocked induction of COX-2 mRNA by 2-hour IL-1β treatment, and 2-hour treatment with the PAF analog mcPAF mimicked the effects of IL-1β on COX-2 mRNA levels. Following injury, synaptic plasticity changes may be affected by IL-1β-PAF-COX-2 neuronal signaling. J. Neurosci. Res. 58:593–598, 1999. © 1999 Wiley-Liss, Inc.
- Published
- 1999
33. Neuroprotection by pigment epithelial-derived factor against glutamate toxicity in developing primary hippocampal neurons
- Author
-
Esteban Schabelman, Mark A. DeCoster, Joyce Tombran-Tink, and Nicolas G. Bazan
- Subjects
medicine.medical_specialty ,Basic fibroblast growth factor ,Glutamate receptor ,Excitotoxicity ,Hippocampal formation ,Biology ,medicine.disease_cause ,Neuroprotection ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,PEDF ,Endocrinology ,nervous system ,chemistry ,Internal medicine ,Lactate dehydrogenase ,Toxicity ,medicine ,Neuroscience - Abstract
Pigment epithelial-derived factor (PEDF) has been shown to be a survival factor for cerebellar granule neurons. Here we investigated the ability of PEDF to enhance the survival of hippocampal neurons in culture, and to protect these neurons against acute glutamate toxicity. Hippocampal neurons prepared from 1- to 3-day postnatal rat brain were cultured for either 7 or 14 days in vitro (DIV). At 14 DIV, neurons were only slightly protected (13% +/- 4%) against 50 microM glutamate toxicity when treated with 1 microg/ml of PEDF for 3 successive days before glutamate exposure as measured by lactate dehydrogenase (LDH) release. In comparison, basic fibroblast growth factor (bFGF) at 10 ng/ml for the same treatment period protected 58% +/- 8% of the neurons against glutamate. Using quantitative image analysis of digitized micrographs, we found that the average size of neurons in young, developing hippocampal cultures (7 DIV), was greatly decreased by treatment with 50 microM glutamate. Treatment for up to 5 successive days with 1 microg/ml of PEDF before glutamate addition dramatically increased the average hippocampal neuron soma size, compared to cells treated with glutamate alone. Thus, PEDF may promote the growth of hippocampal neurons, and, if added to developing hippocampal neurons, can also protect these cells from subsequent injury, such as the excitotoxicity of glutamate.
- Published
- 1999
34. Glutamate Receptor Signaling Interplay Modulates Stress-sensitive Mitogen-activated Protein Kinases and Neuronal Cell Death
- Author
-
Foster Z. Campbell, Nicolas G. Bazan, Pranab K. Mukherjee, Roger J. Davis, and Mark A. DeCoster
- Subjects
Thienopyridines ,MAPK7 ,Biology ,Hippocampus ,Receptors, N-Methyl-D-Aspartate ,Second Messenger Systems ,Biochemistry ,Phospholipases A ,Animals ,Platelet Activating Factor ,Molecular Biology ,Neurons ,G protein-coupled receptor kinase ,Cell Death ,Metabotropic glutamate receptor 5 ,Metabotropic glutamate receptor 4 ,Metabotropic glutamate receptor 7 ,Metabotropic glutamate receptor 6 ,Azepines ,Cell Biology ,Triazoles ,Recombinant Proteins ,Rats ,Cell biology ,nervous system ,Metabotropic glutamate receptor ,1-Alkyl-2-acetylglycerophosphocholine Esterase ,Calcium-Calmodulin-Dependent Protein Kinases ,Metabotropic glutamate receptor 1 ,Platelet Aggregation Inhibitors ,Signal Transduction - Abstract
Glutamate receptors modulate multiple signaling pathways, several of which involve mitogen-activated protein (MAP) kinases, with subsequent physiological or pathological consequences. Here we report that stimulation of theN-methyl-d-aspartate (NMDA) receptor, using platelet-activating factor (PAF) as a messenger, activates MAP kinases, including c-Jun NH2-terminal kinase, p38, and extracellular signal-regulated kinase, in primary cultures of hippocampal neurons. Activation of the metabotropic glutamate receptor (mGluR) blocks this NMDA-signaling through PAF and MAP kinases, and the resultant cell death. Recombinant PAF-acetylhydrolase degrades PAF generated by NMDA-receptor activation; the hetrazepine BN50730 (an intracellular PAF receptor antagonist) also inhibits both NMDA-stimulated MAP kinases and neuronal cell death. The finding that the NMDA receptor-PAF-MAP kinase signaling pathway is attenuated by mGluR activation highlights the exquisite interplay between glutamate receptors in the decision making process between neuronal survival and death.
- Published
- 1999
35. Recombinant plasma-type platelet-activating factor acetylhydrolase attenuates NMDA-induced hippocampal neuronal apoptosis
- Author
-
Nicolas G. Bazan, Mark A. DeCoster, and Field Ogden
- Subjects
PAF acetylhydrolase ,DNA laddering ,Pharmacology ,Biology ,Hippocampal formation ,Neuroprotection ,law.invention ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,nervous system ,chemistry ,Apoptosis ,law ,Immunology ,Recombinant DNA ,NMDA receptor ,Propidium iodide - Abstract
The bioactive lipid platelet-activating factor (PAF) accumulates in brain during injury, seizures and ischemia and may, in addition, be significant in AIDS dementia and in other neurodegenerative diseases. We have used plasma-type recombinant PAF acetylhydrolase (rPAF-AH) to test the hypothesis that PAF accumulation is involved in early events leading to neuronal apoptosis during excitotoxic neuronal injury. Neuronal cultures were labeled with FITC-12-dUTP (TUNEL technique) and propidium iodide, digitized using fluorescence microscopy and a chilled 3CCD color camera, and analyzed with 2D graphics analysis software. N-methyl-D-aspartate (NMDA) (50 microM, 2 hr) induced a 2.5-fold increase in apoptosis of hippocampal neurons compared with controls when analyzed 24 hr after NMDA treatment. Hippocampal neurons receiving rPAF-AH (20 microg/ml) before, during, and after NMDA treatment demonstrated a concentration-dependent neuroprotective effect which resulted in 47% and 30% neuroprotection against 50 and 100 microM NMDA, respectively. The noncompetitive NMDA receptor antagonist MK-801(300 nM) completely inhibited apoptosis caused by NMDA. The neuroprotective effect of rPAF-AH against NMDA-induced apoptosis was confirmed using as additional criteria, histone release, electron microscopy, and DNA laddering. Neuroprotection elicited by rPAF-AH demonstrates that PAF is an injury mediator in NMDA-induced neuronal apoptosis and that the recombinant protein is potentially useful as a therapeutic approach.
- Published
- 1998
36. Platelet-activating factor is a downstream messenger of kainate-induced activation of mitogen-activated protein kinases in primary hippocampal neurons
- Author
-
Nicolas G. Bazan, Pranab K. Mukherjee, Mark A. DeCoster, and Roger J. Davis
- Subjects
Platelet-activating factor ,Kinase ,medicine.drug_class ,p38 mitogen-activated protein kinases ,Glutamate receptor ,Long-term potentiation ,Kainate receptor ,respiratory system ,Biology ,Receptor antagonist ,Cell biology ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,chemistry ,Biochemistry ,CNQX ,medicine ,lipids (amino acids, peptides, and proteins) - Abstract
Excitatory amino acids transduce physiological and pathological signals to neurons. Similarly, the neuroactive lipid platelet-activating factor (PAF) has been implicated in modulating long-term potentiation and neuronal survival. Excitatory amino acids and PAF have been shown to increase mitogen-activated protein (MAP) kinases in different cell types. Here, we have investigated the similarities and differences between PAF and kainate in activating MAP kinases in primary hippocampal neurons in vitro. Extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 kinases were activated by kainate or PAF in hippocampal neurons. This activation was blocked by the receptor antagonists CNQX and BN 50730 for kainate and PAF, respectively. The PAF receptor antagonist BN 50730 also blocked kainate activation. CNQX had no effect on PAF activation of the kinases, indicating that PAF is downstream of kainate activation. Coapplication of submaximal concentrations of PAF and kainate resulted in a less than additive activation, suggesting similar routes of activation by the two agonists. Both CNQX and BN 50730 blocked kainate-induced neurotoxicity. These results indicate that PAF and kainate activate similar kinase pathways. Therefore, PAF acts downstream of the kainate subtype of glutamate receptors, and when excessive receptor activation takes place, this bioactive lipid may contribute to neuronal cell death.
- Published
- 1998
37. Neuroprotective sigma ligands attenuate NMDA and trans-ACPD-induced calcium signaling in rat primary neurons
- Author
-
Kevin L. Klette, J. E. Moreton, Yu Lin, Frank C. Tortella, Larry E Clapp, and Mark A. DeCoster
- Subjects
N-Methylaspartate ,Sigma receptor ,chemistry.chemical_element ,Calcium ,Ligands ,Neuroprotection ,Calcium in biology ,Rats, Sprague-Dawley ,Calcium flux ,medicine ,Animals ,Receptors, sigma ,Cycloleucine ,Molecular Biology ,Phencyclidine ,Cells, Cultured ,Neurons ,General Neuroscience ,Rats ,Neuroprotective Agents ,Metabotropic receptor ,chemistry ,Biochemistry ,Biophysics ,NMDA receptor ,Neurology (clinical) ,Signal Transduction ,Developmental Biology ,medicine.drug - Abstract
The effect of neuroprotective sigma ligands possessing a range of relative selectivity for sigma and phencyclidine (PCP) binding sites on N-methyl-D-aspartate (NMDA) and (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (trans-ACPD)-stimulated calcium flux was studied in 12-15-day-old primary cultures of rat cortical neurons. In approximately 80% of the neurons tested, NMDA (80 microM) caused a sustained increase in intracellular calcium ([Ca2+]i). With the exception of R-(+)-3-(3-hydroxyphenyl)-N-propylpiperidine hydrochloride ((+)-3-PPP) (previously shown not to be neuroprotective) all of the sigma ligands studied significantly altered NMDA-induced calcium dynamics. The primary effect of dextromethorphan, (+)-pentazocine, (+)-cyclazocine, (+)-SKF10047, carbetapentane, 1,3-di(2-tolyl) guanidine (DTG), and haloperidol was to shift the NMDA response from a sustained, to either a biphasic or a transient, calcium event. In contrast to NMDA, the primary response observed in 62% of the neurons treated with trans-ACPD (100 microM) was a transient elevation in [Ca2+]i. Here, however, only the highly selective neuroprotective sigma ligands (i.e., those lacking substantial PCP binding affinity) significantly decreased the number of transient responses elicited by trans-ACPD whereas the PCP-related sigma ligands such as dextromethorphan, (+)-SKF10047 and (+)-cyclazocine were ineffective. Unexpectedly, (+)-3-PPP potentiated trans-ACPD activity. These results demonstrating attenuating effects of sigma ligands on NMDA-stimulated neuronal calcium responses agree with earlier studies using glutamate and KCl and identify a sigma receptor modulation of functional NMDA responsiveness. Furthermore, the ability of sigma ligands to attenuate NMDA-, trans-ACPD- and KCl-evoked neuronal calcium dynamics indicates that the receptor mechanisms mediating sigma neuroprotection comprise complex interactions involving ionotropic, metabotropic, and even voltage-gated calcium signaling processes.
- Published
- 1997
38. Spectral Element Simulation of Reaction-Diffusion System in the Neuromuscular Junction
- Author
-
Yifan Wang, Don Liu, and Mark A DeCoster
- Subjects
Chemistry ,Mathematical analysis ,medicine.disease ,Neuromuscular junction ,Myasthenia gravis ,medicine.anatomical_structure ,Reaction–diffusion system ,medicine ,Biophysics ,High order ,Diffusion (business) ,Receptor ,Acetylcholine ,medicine.drug ,Acetylcholine receptor - Abstract
Studying the synaptic signal transmission in the neuromuscular junction (NMJ) is central to the understanding of neuromuscular disorders such as myasthenia gravis disease. Investigating the dynamics of acetylcholine and acetylcholine receptors in an NMJ under the conditions of activated enzyme is an important step towards this mission. In this article, we developed a numerical model of high order accuracy for complex geometry to simulate the complex processes in an NMJ cleft. This model has a full description of three-dimensional reaction and diffusion processes with nonlinear reaction source terms and is capable of predicting the concentration rates of acetylcholine with receptors and enzymes. Simulation results agree with experimental measurement of the reported maximum number of open receptors during the course of a normal action potential. The time variation of populations of open receptor as well as concentration rates are investigated and discussed. This model has the potential to further the in depth investigation of dynamics within an NMJ.
- Published
- 2013
39. Synergy by Secretory Phospholipase A2 and Glutamate on Inducing Cell Death and Sustained Arachidonic Acid Metabolic Changes in Primary Cortical Neuronal Cultures
- Author
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Miriam Kolko, Nicolas G. Bazan, Elena B. Rodriguez de Turco, and Mark A. DeCoster
- Subjects
Neurotoxins ,Excitotoxicity ,Phospholipase ,Pharmacology ,Biology ,medicine.disease_cause ,Biochemistry ,Phospholipases A ,chemistry.chemical_compound ,Glutamatergic ,Glutamates ,medicine ,Animals ,Molecular Biology ,Cells, Cultured ,Phospholipids ,Cerebral Cortex ,Neurons ,chemistry.chemical_classification ,Arachidonic Acid ,Cell Death ,Glutamate receptor ,Neurotoxicity ,Fatty acid ,Drug Synergism ,Cell Biology ,medicine.disease ,Rats ,Bee Venoms ,Phospholipases A2 ,chemistry ,NMDA receptor ,Arachidonic acid ,Dizocilpine Maleate - Abstract
Secretory and cytosolic phospholipases A2 (sPLA2 and cPLA2) may contribute to the release of arachidonic acid and other bioactive lipids, which are modulators of synaptic function. In primary cortical neuron cultures, neurotoxic cell death and [3H]arachidonate metabolism was studied after adding glutamate and sPLA2 from bee venom. sPLA2, at concentrations eliciting low neurotoxicity (/=100 ng/ml), induced a decrease of [3H]arachidonate-phospholipids and preferential reesterification of the fatty acid into triacylglycerols. Free [3H]arachidonic acid accumulated at higher enzyme concentrations, below those exerting highest toxicity. Synergy in neurotoxicity and [3H]arachidonate release was observed when low, nontoxic (10 ng/ml, 0.71 nM), or mildly toxic (25 ng/ml, 1. 78 nM) concentrations of sPLA2 were added together with glutamate (80 microM). A similar synergy was observed with the sPLA2 OS2, from Taipan snake venom. The NMDA receptor antagonist MK-801 blocked glutamate effects and partially inhibited sPLA2 OS2 but not sPLA2 from bee venom-induced arachidonic acid release. Thus, the synergy with glutamate and very low concentrations of exogenously added sPLA2 suggests a potential role for this enzyme in the modulation of glutamatergic synaptic function and of excitotoxicity.
- Published
- 1996
40. Brief, high-frequency stimulation of the corticomedial amygdala induces a delayed and prolonged increase of aggressiveness in male Syrian golden hamsters
- Author
-
M. Hebert, James L. Meyerhoff, Mark A. DeCoster, and Michael Potegal
- Subjects
Aggression ,Central nervous system ,Stimulation ,Stimulus (physiology) ,Amygdala ,Behavioral Neuroscience ,medicine.anatomical_structure ,Basal ganglia ,Biological neural network ,medicine ,medicine.symptom ,Psychology ,Neuroscience ,Electrical brain stimulation - Abstract
Brief 200-Hz stimulation of the corticomedial amygdala (CMA) increases the aggressiveness of male Syrian golden hamsters for about 30 min; the effect peaks 10-15 min after stimulation. This effect is sensitive to stimulation amplitude and frequency. Stimulation at the parameters that reduce attack latency increases flank marking but does not affect copulation latency or general activity. Immunocytochemical analysis suggests that stimulation effects may be coupled to c-fos expression and that unilateral stimulation has bilateral effects. CMA stimulation effects appear to mimic part of the time course of behaviorally induced attack priming. The temporal persistence of aggression may result from long-term potentiation-like changes within CMA-related neural circuitry. Once sufficiently aroused, aggressive behavior in various species of fish (e.g., Heiligenberg, 1974), birds (e.g., Curio, 1975), and mammals (e.g., Potegal, 1992) tends to persist in time. Under experimental circumstances in which the aggression-provoking stimulus remains constant, temporal fluctuations in aggressive behavior imply the existence of fluctuations in central control processes. When aggression persists even after the provoking stimulus is withdrawn (e.g., Curio, 1975; Heiligenberg, 1974), such central processes must certainly play a role. We believe that these important but poorly understood internal processes contribute to a variety of phenomena within the domain of aggressive behavior and that any theory of aggression that fails to take them into account must remain incomplete (Potegal, 1994). Accordingly, we have developed an experimental model for the analysis of these processes
- Published
- 1996
41. Dextromethorphan analogs are neuroprotective in vitro and block glutamate-induced excitotoxic calcium signals in neurons
- Author
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Mark A. DeCoster, Frank C. Tortella, Amy Hauck Newman, Kevin L. Klette, and Barbara J. Davis
- Subjects
Central nervous system ,Glutamic Acid ,chemistry.chemical_element ,Calcium ,Pharmacology ,Dextromethorphan ,Neuroprotection ,chemistry.chemical_compound ,Dextrorphan ,medicine ,Animals ,Neurotransmitter ,Phencyclidine ,Cells, Cultured ,Cerebral Cortex ,Neurons ,General Neuroscience ,Glutamate receptor ,Rats ,Neuroprotective Agents ,medicine.anatomical_structure ,chemistry ,Signal Transduction ,medicine.drug - Abstract
Consistent with the neuroprotective effects of the non-opioid antitussive dextromethorphan (DM) described in several models of CNS injury, micromolar concentrations of three novel analogs of DM markedly attenuated the injury produced by glutamate in cultured rat cortical neurons. Furthermore, the neuroprotective actions of the DM analogs correlated with their effects to block glutamate-induced excitotoxic calcium signals and were unrelated to metabolism to the phencyclidine (PCP)-like drug dextrorphan (DX). These observations establish a new class of compounds related to DM which, by virtue of their efficacy to protect neurons against a severe glutamate insult, may possess therapeutic potential as treatment modalities for a number of neurodegenerative diseases.
- Published
- 1995
42. Bionanocomposites for Multidimensional Brain Cell Signaling
- Author
-
Dustin P. Green, R. Idowu, Mark A. DeCoster, C. Jeyasankar, K. Cotton, and James O. McNamara
- Subjects
Chemistry ,Brain Cell ,Neuroscience - Published
- 2012
43. Regulatory effects of the JAK3/STAT1 pathway on the release of secreted phospholipase A2-IIA in microvascular endothelial cells of the injured brain
- Author
-
Jiqiang Zhang, Guisheng Qian, Saiyu Cheng, Wenqin Cai, Mark A. DeCoster, Yaoli Wang, Zhi Xu, Changzheng Wang, Guansong Wang, and Pin Qian
- Subjects
Secreted phospholipase A2-IIA ,Lipopolysaccharide ,Immunology ,Phospholipase ,Permeability ,lcsh:RC346-429 ,Nitric oxide ,Brain microvascular endothelial cells ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,STAT1 ,Phospholipase A2 ,Western blot ,medicine ,lcsh:Neurology. Diseases of the nervous system ,medicine.diagnostic_test ,biology ,General Neuroscience ,Inducible NO synthase ,Molecular biology ,Cell biology ,Nitric oxide synthase ,Neurology ,chemistry ,Cell culture ,biology.protein ,Sodium nitroprusside ,JAK3 ,medicine.drug - Abstract
Background Secreted phospholipase A2-IIA (sPLA2-IIA) is an inducible enzyme released under several inflammatory conditions. It has been shown that sPLA2-IIA is released from rat brain astrocytes after inflammatory stimulus, and lipopolysaccharide (LPS) and nitric oxide (NO) have been implicated in regulation of this release. Here, brain microvascular endothelial cells (BMVECs) were treated with LPS to uncover whether sPLA2-IIA was released, whether nitric oxide regulated this release, and any related signal mechanisms. Methods Supernatants were collected from primary cultures of BMVECs. The release of sPLA2-IIA, and the expression of inducible nitric oxide synthase (iNOS), phospho-JAK3, phospho-STAT1, total JAK3 and STAT1, β-actin, and bovine serum albumin (BSA) were analyzed by Western blot or ELISA. NO production was calculated by the Griess reaction. sPLA2 enzyme activity was measured with a fluorometric assay. Specific inhibitors of NO (L-NAME and aminoguanidine, AG), JAK3 (WHI-P154,WHI), STAT1 (fludarabine, Flu), and STAT1 siRNA were used to determine the involvement of these molecules in the LPS-induced release of sPLA2-IIA from BMVECs. Nuclear STAT1 activation was tested with the EMSA method. The monolayer permeability of BMVECs was measured with a diffusion assay using biotinylated BSA. Results Treatment of BMVECs with LPS increased the release of sPLA2-IIA and nitrite into the cell culture medium up to 24 h. Pretreatment with an NO donor, sodium nitroprusside, decreased LPS-induced sPLA2-IIA release and sPLA2 enzyme activity, and enhanced the expression of iNOS and nitrite generation after LPS treatment. Pretreatment with L-NAME, AG, WHI-P154, or Flu notably reduced the expression of iNOS and nitrite, but increased sPLA2-IIA protein levels and sPLA2 enzyme activity. In addition, pretreatment of the cells with STAT1 siRNA inhibited the phosphorylation of STAT1, iNOS expression, and nitrite production, and enhanced the release of sPLA2-IIA. Pretreatment with the specific inhibitors of NOS, JAK2, and STAT3 decreased the permeability of BMVECs. In contrast, inhibition of sPLA2-IIA release increased cell permeability. These results suggest that sPLA2-IIA expression is regulated by the NO-JAK3-STAT1 pathway. Importantly, sPLA2-IIA augmentation could protect the LPS-induced permeability of BMVECs. Conclusion Our results demonstrate the important action of sPLA2-IIA in the permeability of microvascular endothelial cells during brain inflammatory events. The sPLA2 and NO pathways can be potential targets for the management of brain MVEC injuries and related inflammation.
- Published
- 2012
44. Kappa Opioids
- Author
-
Frank C. Tortella and Mark A. DeCoster
- Subjects
Pharmacology ,business.industry ,medicine.disease ,κ-opioid receptor ,Neuroprotection ,Epilepsy ,Pharmacotherapy ,Drug development ,Opioid ,medicine ,Pharmacology (medical) ,Neurology (clinical) ,business ,Neuroscience ,Spinal cord injury ,Stroke ,medicine.drug - Abstract
Epilepsy and CNS injury identify a heterogenous group of diseases, many of which exhibit refractoriness (e.g., the partial epilepsies) to established drug therapy or, as in the case of brain and spinal cord injuries of variable etiologies, remain a formidable target for successful drug development. As such, the search for safe, effective antiepileptic and neuroprotective drugs continues. Although several CNS targets have been identified for drug development, especially the excitatory amino acid receptors, free-radical systems, gangliosides, and nitric oxide, etc., the opioid system and its diversity of receptors have, until recently, received little attention. This review attempts to focus on one opioid system, namely the kappa receptor class of opioid ligands, specifically addressing the potential anticonvulsant and neuroprotective properties of the arylacetamide series of kappa opioid analgesics as novel pharmacotherapeutic approaches to the treatment of epilepsy, stroke, or trauma related brain or spinal cord injury.
- Published
- 1994
45. A simple enzyme based biosensor on flexible plastic substrate
- Author
-
Ji Fang, Senaka Kanakamedala, Haidar T. Alshakhouri, Mark A. DeCoster, and Mangilal Agarwal
- Subjects
chemistry.chemical_classification ,Conductive polymer ,Analyte ,Materials science ,business.industry ,Polymer ,Glucose oxidase activity ,chemistry ,PEDOT:PSS ,Electrode ,Optoelectronics ,business ,Biosensor ,Polyimide - Abstract
An enzyme based biosensor was fabricated by employing a simple, inexpensive and rapid xurography fabrication process. The electrodes and channel were made from the conducting polymer poly(3,4-ethyelenedioxythiphene) poly(styrene sulfonate) (PEDOT:PSS). PEDOT:PSS was selectively deposited using a polyimide tape mask. The tape mask was peeled off from the substrate after annealing the polymer in vacuum. Polymer wells of defined dimensions were made and were attached to the device to accommodate the solutions. This sensor utilizes the change in current as a parameter to measure different analyte concentrations. Initial experiments were done by using the sensor for glucose detection. The sensor is able to detect the glucose concentrations approximately from 1 μM to 10 mM range covering glucose in human saliva (8-210 μM). The glucose oxidase activity was independently measured using colorimetric method and the results indicate that the sensor retains the enzyme activity and can be used as a biosensor to detect various analytes. The analyte of interest can be measured by preloading the corresponding enzyme into the wells.
- Published
- 2010
46. Hypoxic preconditioning suppresses group III secreted phospholipase A2-induced apoptosis via JAK2-STAT3 activation in cortical neurons
- Author
-
Mark A. DeCoster, Guisheng Qian, Yu-qi Gao, Deshan Zhou, Guansong Wang, Changzheng Wang, and Qi-quan Zhou
- Subjects
Programmed cell death ,biology ,Caspase 3 ,Biochemistry ,Neuroprotection ,Cell biology ,Small hairpin RNA ,Cellular and Molecular Neuroscience ,medicine.anatomical_structure ,Apoptosis ,biology.protein ,medicine ,Neuron ,STAT3 ,Caspase - Abstract
J. Neurochem. (2010) 114, 1039–1048. Abstract Our previous studies show that group III secreted phospholipases A2 (sPLA2s III) induces extensive neuronal apoptosis in brain cortical cultures. However, the molecular mechanisms underlying sPLA2 III-induced neuronal injury/death are still unknown. Also it is not clear whether hypoxic pre-conditioning (HPC) is able to protect neurons from the sPLA2 III insult. In this report, we demonstrate that sPLA2 III significantly decreased production of Bcl-xl and the ratio of Bcl-xl/Bax, and increased expression of Bax, cleaved caspase 3, and cleaved α-Fodrin in primary neuronal culture. HPC prevented the sPLA2 III-induced decreases in production of Bcl-xl and the ratio of Bcl-xl/Bax, and increases in expression of Bax, cleaved caspase 3, and α-Fodrin. However, the HPC-produced neuronal protection was eliminated or attenuated by AG490, rapamycin, and STAT3 shRNA. Our results suggest that sPLA2 III-induced neuronal apoptosis is likely because of its alterations in expression and activity of Bcl-xl, Bax, caspase 3, and its target gene fodrin; and that HPC-produced neuroprotection against the sPLA2 III toxicity is mediated via JAK-STAT signal pathways that regulate the expression of Bcl-xl, Bax, and cleaved caspase 3 in cultured cortical neurons.
- Published
- 2010
47. Hypoxic preconditioning suppresses group III secreted phospholipase A2-induced apoptosis via JAK2-STAT3 activation in cortical neurons
- Author
-
Guansong, Wang, Deshan, Zhou, Changzheng, Wang, Yuqi, Gao, Qiquan, Zhou, Guisheng, Qian, and Mark A, DeCoster
- Subjects
Cerebral Cortex ,Neurons ,STAT3 Transcription Factor ,Group III Phospholipases A2 ,Apoptosis ,Janus Kinase 2 ,Rats ,Rats, Sprague-Dawley ,Hypoxia-Ischemia, Brain ,Nerve Degeneration ,Animals ,Apoptosis Regulatory Proteins ,Ischemic Preconditioning ,Cells, Cultured ,Signal Transduction - Abstract
Our previous studies show that group III secreted phospholipases A(2) (sPLA(2)s III) induces extensive neuronal apoptosis in brain cortical cultures. However, the molecular mechanisms underlying sPLA(2) III-induced neuronal injury/death are still unknown. Also it is not clear whether hypoxic pre-conditioning (HPC) is able to protect neurons from the sPLA(2) III insult. In this report, we demonstrate that sPLA(2) III significantly decreased production of Bcl-xl and the ratio of Bcl-xl/Bax, and increased expression of Bax, cleaved caspase 3, and cleaved alpha-Fodrin in primary neuronal culture. HPC prevented the sPLA(2) III-induced decreases in production of Bcl-xl and the ratio of Bcl-xl/Bax, and increases in expression of Bax, cleaved caspase 3, and alpha-Fodrin. However, the HPC-produced neuronal protection was eliminated or attenuated by AG490, rapamycin, and STAT3 shRNA. Our results suggest that sPLA(2) III-induced neuronal apoptosis is likely because of its alterations in expression and activity of Bcl-xl, Bax, caspase 3, and its target gene fodrin; and that HPC-produced neuroprotection against the sPLA(2) III toxicity is mediated via JAK-STAT signal pathways that regulate the expression of Bcl-xl, Bax, and cleaved caspase 3 in cultured cortical neurons.
- Published
- 2010
48. Biomedical Engineering Bionanosystems Research at Louisiana Tech University
- Author
-
Eric Guilbeau, Lynn Walker, Hisham Hegab, Jon Pratt, Mark A. DeCoster, Chad O'Neal, Long Que, June Feng, Stan A. Napper, Despina Davis, Mangilal Agarwal, John F. McDonald, Chester G. Wilson, Daniela S. Mainardi, Sandra Zivanovic, Scott Alan Gold, James Palmer, Tabbetha Dobbins, Yuri Lvov, Shathabish Gowda, and Dale Snow
- Subjects
Corn ethanol ,Engineering ,Waste management ,business.industry ,Biofuel ,Emerging technologies ,Bioenergy ,Cellulosic ethanol ,Fossil fuel ,Energy Independence and Security Act of 2007 ,Biomass ,business - Abstract
The nature of this project is to equip and support research in nanoengineered systems for biomedical, bioenvironmental, and bioenergy applications. Funds provided by the Department of Energy (DoE) under this Congressional Directive were used to support two ongoing research projects at Louisiana Tech University in biomedical, bioenvironmental, and bioenergy applications. Two major projects (Enzyme Immobilization for Large Scale Reactors to Reduce Cellulosic Ethanol Costs, and Nanocatalysts for Coal and Biomass Conversion to Diesel Fuel) and to fund three to five additional seed projects were funded using the project budget. The project funds also allowed the purchase and repair of sophisticated research equipment that will support continued research in these areas for many years to come. Project funds also supported faculty, graduate students, and undergraduate students, contributing to the development of a technically sophisticated work force in the region and the State. Descriptions of the technical accomplishments for each funded project are provided. Biofuels are an important part of the solution for sustainable transportation fuel and energy production for the future. Unfortunately, the country's appetite for fuel cannot be satisfied with traditional sugar crops such as sugar cane or corn. Emerging technologies are allowing cellulosic biomass (wood, grass, stalks, etc.) tomore » also be converted into ethanol. Cellulosic ethanol does not compete with food production and it has the potential to decrease greenhouse gas (GHG) emissions by 86% versus current fossil fuels (current techniques for corn ethanol only reduce greenhouse gases by 19%). Because of these advantages, the federal government has made cellulosic ethanol a high priority. The Energy Independence and Security Act of 2007 (EISA) requires a minimum production of at least 16 billion gallons of cellulosic ethanol by 2022. Indeed, the Obama administration has signaled an ambitious commitment of achieving 2 billion gallons of cellulosic ethanol by 2013. Louisiana is well positioned to become a national contributor in cellulosic ethanol, with an excellent growing season, a strong pulp/paper industry, and one of the nation's first cellulosic ethanol demonstration plants. Dr. Palmer in Chemical Engineering at Louisiana Tech University is collaborating with Drs. Lvov and Snow in Chemistry and Dr. Hegab in Mechanical Engineering to capitalize on these advantages by applying nanotechnology to improve the cellulosic ethanol processes. In many of these processes, expensive enzymes are used to convert the cellulose to sugars. The nanotechnology processes developed at Louisiana Tech University can immobilize these enzymes and therefore significantly reduce the overall costs of the process. Estimates of savings range from approximately $32 million at each cellulosic ethanol plant, to $7.5 billion total if the 16 billion gallons of cellulosic ethanol is achieved. This process has the advantage of being easy to apply in a large-scale commercial environment and can immobilize a wide variety or mixture of enzymes for production. Two primary objectives with any immobilization technique are to demonstrate reusability and catalytic activity (both reuse of the immobilized enzyme and reuse of the polymer substrate). The scale-up of the layering-by-layering process has been a focus this past year as some interesting challenges in the surface chemistry have become evident. Catalytic activity of cellulase is highly dependent upon how the feed material is pretreated to enhance digestion. Therefore, efforts this year have been performed this year to characterize our process on a few of the more prevalent pretreatment methods.« less
- Published
- 2010
49. No Direct Neuronotoxicity by HIV-1 Virions or Culture Fluids from HIV-1-Infected T Cells or Monocytes
- Author
-
Monte S. Meltzer, Jorge L. Ribas, Mark A. DeCoster, Henry U. Bryant, Jan M. Orenstein, Howard E. Gendelman, and Edward W. Bernton
- Subjects
endocrine system ,Cell Survival ,T-Lymphocytes ,Neurotoxins ,Immunology ,Human immunodeficiency virus (HIV) ,Neuropathology ,Biology ,Virus Replication ,medicine.disease_cause ,Animal origin ,Monocytes ,Virus ,Mycoplasma ,Virology ,medicine ,Animals ,Humans ,Cells, Cultured ,Neurons ,Microglia ,Monocyte ,Virion ,virus diseases ,Cell Differentiation ,Rats, Inbred Strains ,T lymphocyte ,In vitro ,Culture Media ,Rats ,Microscopy, Electron ,Infectious Diseases ,medicine.anatomical_structure ,HIV-1 - Abstract
Macrophages and microglia are the principal target cells for human immunodeficiency virus (HIV) in brain, and as such, are likely participants in the neuropathology of HIV infection. In a model system for this process, we found that fluids from human monocyte cultures enhanced survival and differentiation of the neurons in fetal rat brain explants. In contrast, fluids from HIV-infected monocyte cultures were strongly toxic to neurons and paradoxically enhanced the proliferation of glial cells. Further, neuronotoxic activity in these fluids was mediated through activation of NMDA binding receptors on the neurons and was inhibited by any of several different NMDA antagonists. Neuronotoxic activity was directly related to contamination of the HIV virus stock with Mycoplasma arginini and M. hominis. Pure cultures of mycoplasma, bacterial lipopolysaccharide (LPS), or murine recombinant tumor necrosis factor alpha (rTNF alpha) each induced neuronotoxicity which exactly mirrored that induced by the contaminated HIV stock. It is likely that mycoplasma or components of the mycoplasma plasma membrane stimulate TNF alpha production by the glial cells in the brain explants. Indeed, careful depletion of glial cells in these explants prevented mycoplasma or LPS-mediated neuronotoxicity. No neuronotoxicity was evident with HIV-1 virus stock, HIV-1 gp120, or culture fluids from HIV-infected T cells or monocytes when these preparations were free of contamination by mycoplasma and LPS. These findings suggest caution in interpretation of those experiments in which similar contamination has not been rigorously excluded.
- Published
- 1992
50. Porous biocompatible three-dimensional scaffolds of cellulose microfiber/gelatin composites for cell culture
- Author
-
Qi Xing, Si Chen, Mark A. DeCoster, Feng Zhao, Yuri Lvov, and James O. McNamara
- Subjects
business.product_category ,food.ingredient ,Materials science ,Surface Properties ,Biomedical Engineering ,Biocompatible Materials ,Biochemistry ,Gelatin ,Biomaterials ,Extracellular matrix ,chemistry.chemical_compound ,food ,Microfiber ,Ultimate tensile strength ,Materials Testing ,Humans ,Cellulose ,Composite material ,Molecular Biology ,Cells, Cultured ,Cell Proliferation ,Tissue Engineering ,Tissue Scaffolds ,Mesenchymal Stem Cells ,General Medicine ,Adhesion ,Cellulose fiber ,chemistry ,business ,Porosity ,Biotechnology ,Micropatterning - Abstract
Physiological tissues, including brain and other organs, have three-dimensional (3-D) aspects that need to be supported to model them in vitro. Here we report the use of cellulose microfibers combined with cross-linked gelatin to make biocompatible porous microscaffolds for the sustained growth of brain cell and human mesenchymal stem cells (hMSCs) in 3-D structure. Live imaging using confocal microscopy indicated that 3-D microscaffolds composed of gelatin or cellulose fiber/gelatin both supported brain cell adhesion and growth for 16days in vitro. Cellulose microfiber/gelatin composites containing up to 75% cellulose fibers can withstand a higher mechanical load than gelatin alone, and composites also provided linear pathways along which brain cells could grow compared to more clumped cell growth in gelatin alone. Therefore, the bulk cellulose microfiber provides a novel skeleton in this new scaffold material. Cellulose fiber/gelatin scaffold supported hMSCs growth and extracellular matrix formation. hMSCs osteogenic and adipogenic assays indicated that hMSCs cultured in cellulose fiber/gelatin composite preserved the multilineage differentiation potential. As natural, biocompatible components, the combination of gelatin and cellulose microfibers, fabricated into 3-D matrices, may therefore provide optimal porosity and tensile strength for long-term maintenance and observation of cells.
- Published
- 2009
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