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Hyaluronic acid (HA) eye drop solution is widely used to treat and manage various corneal diseases like keratoconus (after corneal cross-linking) and dry eye syndrome. However, ocular dosage forms like eye drop solution affect the routine life style of patients due to frequent dosing schedule. In this study, HA and reduced graphene oxide (rGO) was directly loaded in the silicon contact lenses (HA-GO-DL) and compared with the conventional soaking method (HA-GO-SM). The contact lenses at lower level of rGO showed permissible swelling and transmittance properties. The water retention property of HA-GO-DL contact lenses was confirmed by water evaporation studies. The flux data of HA-GO-SM contact lenses showed high burst release with 24 h release duration. While, HA-GO-DL lenses confirmed low burst with sustained release up to 96 h. In ocular irritation study, the HA-GO-DL-2 lenses was found to be safe. The HA-GO-DL-2 batch showed high HA-tear fluid concentration (rabbit model) and improvement in the rabbit tear fluid volume (Schirmer strip studies) in comparison to the soaking method (HA-GO-SM-2) and eye drop solution. The study successfully demonstrate the potential of HA-GO loaded contact lenses to improve tear fluid volume to manage various ocular diseases like dry eye syndrome.

Currently, conjunctivitis is treated using ofloxacin eye drop solution, which shows low bioavailability and patient non-compliance. Ofloxacin loaded contact lens can be used to overcome the issues related to eye drop solutions (i.e. low bioavailability and frequent instillation). However, the conventional soaking method shows poor ofloxacin uptake and significantly affect the swelling and optical properties of the contact lenses. The current research investigates the effect of microemulsion on the ofloxacin uptake and its effect on the physical properties of the contact lens along with ofloxacin-release kinetics. In comparison to the conventional soaking method (Of-SM, ofloxacin-packaging solution), the ofloxacin loaded microemulsion-soaked contact lenses (Of-ME) showed improved drug uptake and physical properties of the contact lenses. The

Glioblastoma multiforme (GBM) is the most common malignant primary neoplasm of the adult central nervous system originating from glial cells. The prognosis of those affected by GBM has remained poor despite advances in surgery, chemotherapy, and radiotherapy. Photochemical internalization (PCI) is a release mechanism of endocytosed therapeutics into the cytoplasm, which relies on the membrane disruptive effect of light-activated photosensitizers. In this study, phototherapy by PCI was performed on a human GBM cell-line using the topoisomerase II inhibitor etoposide (Etop) and the photosensitizer protoporphyrin IX (PpIX) loaded in nanospheres (Ns) made from generation-5 polyamidoamine dendrimers (PAMAM(G5)). The resultant formulation, Etop/PpIX-PAMAM(G5) Ns, measured 217.4 ± 2.9 nm in diameter and 40.5 ± 1.3 mV in charge. Confocal microscopy demonstrated PpIX fluorescence within the endo-lysosomal compartment, and an almost twofold increase in cellular uptake compared to free PpIX by flow cytometry. Phototherapy with 3 min and 5 min light illumination resulted in a greater extent of synergism than with co-administered Etop and PpIX, notably, antagonism was observed without light illumination. Mechanistically, significant increases in oxidative stress and apoptosis were observed with Etop/PpIX-PAMAM(G5) Ns upon 5 min of light illumination in comparison to treatment with either of the agents alone. In conclusion, simultaneous delivery and endo-lysosomal co-localization of Etop and PpIX by PAMAM(G5) Ns leads to a synergistic effect by phototherapy, in addition, the finding of antagonism without light illumination can be advantageous in lowering the dark toxicity and improving photo-selectivity.

Surface-enhanced Raman spectroscopy (SERS), as a label-free, highly sensitive analytical method, has become an important tool for providing substance fingerprints. In this study, silver nanoparticles containing thiosulfate ions and calcium ions (Ag@SCNPs) have been used as an enhanced substrate to eliminate the interference of impurities on DNA signals. Intrinsic structural information on single-strand DNA (ssDNA) was directly obtained through SERS. The improved enhancement system was used to explore the base-stacking rules of ssDNA in a solution environment. For the first time, single-base insertion mutations and deletion mutations, as well as their exact mutation sites, were identified, and Raman spectra with high stability, repeatability, and high signal-to-noise ratio were obtained. The method is simple, fast, and accurate, and the detection process is nondestructive. It has potential to be applied in the fields of medical diagnosis and genetics research.

The present study aims to reveal the operational characteristics of the needle-free injector. Effects of operating parameters on the injection performance were experimentally investigated. A visualization experiment was performed to describe the dispersion pattern of water in gel. The results show that the peak stagnation pressure increases continuously with the driving pressure. The injection process comprises two distinct stages, which are characterized by the penetration and the dispersion of the drug, respectively. The nozzle diameter imposes a significant effect on the penetration ability of the needle-free injector. As the nozzle diameter increases, the stagnation pressure decreases nearly linearly and the injection duration is considerably shortened, but the jet power is increased. Among the three nozzle diameters investigated, the nozzle diameter of 0.25 mm satisfies the proposed criterion of the injection power. It is evidenced through the visualization experiment that the maximum penetration depth increases with the nozzle diameter. The width of the projection area of the water bulk is insensitive to the nozzle diameter. For a certain nozzle diameter, the projection area of the diffused water bulk increases linearly with increasing liquid volume.

Gene transfection is a valuable tool for analyzing gene regulation and function, and providing an avenue for the genetic engineering of cells for therapeutic purposes. Though efficient, the potential concerns over viral vectors for gene transfection has led to research in non-viral alternatives. Cationic polyplexes such as those synthesized from chitosan offer distinct advantages such as enhanced polyplex stability, cellular uptake, endo-lysosomal escape, and release, but are limited by the poor solubility and viscosity of chitosan. In this study, the easily synthesized biocompatible and biodegradable polymeric polysorbate 80 polybutylcyanoacrylate nanoparticles (PS80 PBCA NP) are utilized as the backbone for surface modification with chitosan, in order to address the synthetic issues faced when using chitosan alone as a carrier. Plasmid DNA (pDNA) containing the brain-derived neurotrophic factor (BDNF) gene coupled to a hypoxia-responsive element and the cytomegalovirus promotor gene was selected as the genetic cargo for the in vitro transfection-guided neural-lineage specification of mouse induced pluripotent stem cells (iPSCs), which were assessed by immunofluorescence staining. The chitosan-coated PS80 PBCA NP/BDNF pDNA polyplex measured 163.8 ± 1.8 nm and zeta potential measured −34.8 ± 1.8 mV with 0.01% (w/v) high molecular weight chitosan (HMWC), the pDNA loading efficiency reached 90% at a nanoparticle to pDNA weight ratio of 15, which also corresponded to enhanced polyplex stability on the DNA stability assay. The HMWC-PS80 PBCA NP/BDNF pDNA polyplex was non-toxic to mouse iPSCs for up to 80 μg/mL (weight ratio = 40) and enhanced the expression of BDNF when compared with PS80 PBCA NP/BDNF pDNA polyplex. Evidence for neural-lineage specification of mouse iPSCs was observed by an increased expression of nestin, neurofilament heavy polypeptide, and beta III tubulin, and the effects appeared superior when transfection was performed with the chitosan-coated formulation. This study illustrates the versatility of the PS80 PBCA NP and that surface decoration with chitosan enabled this delivery platform to be used for the transfection-guided differentiation of mouse iPSCs.

Here, a primer-template conversion-based cascade signal amplification strategy is described for the sensitive detection of polynucleotide kinase (PNK) activity. This strategy integrated rolling circle amplification (RCA) and multiple-repeated-strand displacement amplification (MRSDA) with G-quadruplex based fluorescence lighting-up assay. A delicate dumbbell-shaped DNA probe with 5′-hydroxyl terminus was designed, in which G-quadruplex and half recognition site of nicking enzyme Nb.BbvCI were encoded in two loops respectively. Under the action of PNK, the 5′ terminus on dumbbell probe was firstly phosphorylated, and then the dumbbell was cyclized with the catalyzation of T4 ligase to become the RCA template. The RCA process produced multiple copies of the prolonged primer. After that, under the assistance of nicking enzyme Nb.BbvCI, a primer-template conversion occurred, which converted the primer and template of RCA into the template and primer of the subsequent MRSDA, respectively. The MRSDA generated multiple repeated ssDNA sequences which possessed G-quadruplexes for outputting signal by lighting-up fluorescence of thioflavin T (ThT). The cascade signal amplification of RCA and MRSDA provided high detection sensitivity, and the target-dependence of template in cascade signal amplification led to a low background. The method showed excellent detection limit of 0.2 × 10−6 U μL−1 in buffer and 5 cells in cell lysate sample. Moreover, this method displayed favorable selectivity when interfering proteins were present. The developed strategy has good practical potential for PNK activity detection in clinical diagnosis and medical research.

The over-use of antibiotics has caused a number of problems such as contamination of antibiotic residues and virus resistance, and therefore has attracted global attention. In this study, spectroscopic techniques and molecular docking were employed to predict conformational changes and binding interaction between two cephalosporins (cefaclor and cefixime) and calf thymus DNA (ctDNA). Fluorescence and UV-vis spectra suggested that static quenching was predominant and cephalosporin bound to the groove region of ctDNA. Binding parameters calculated by the Stern-Volmer and Scatchard equations showed that cephalosporin bound to ctDNA with a binding affinity in the order of 103 L mol-1 . Thermodynamic parameters further indicated that the reaction was a spontaneous process driven by enthalpy and entropy, and that the main binding force was an electrostatic force. The effects of iodide, denaturant, thermal denaturation and pH on a cephalosporin-Hoechst-DNA complex were also studied, and the results confirmed that cephalosporin bound to the groove area of DNA. Finally, these results were further confirmed by molecular docking and electrochemical studies.

Muscle invasive bladder cancer (MIBC) is characterized by a poor overall survival rate in patients. Therefore, innovation and evaluation of idea anti-cancer compounds is of importance for reducing the mortality of MIBCs. The chemotherapeutic activity of ChlA-F, a novel C8 fluoride derivative of cheliensisin A with potent anti-neoplastic properties, was barely investigated. We reported here that ChlA-F treatment significantly induced miR-494 expression and suppressed cell invasion in human MIBC cells. Our results indicated that miR-494 was downregulated in M1 metastatic BC patients in comparison to non-metastatic (M0) BC patients, and such downregulation was also well correlated with over survival rate for MIBC patients. Mechanistically, ChlA-F-induced upregulation of miR-494 was due to a HuR-mediated increase in JunB mRNA stabilization and protein expression, which led to an increase in miR-494 transcription via directly binding to the miR-494 promoter region, while the upregulated miR-494 was able to bind the 3'-UTR region of c-Myc mRNA, resulting in decreased c-Myc mRNA stability and protein expression and further reducing the transcription of c-Myc-regulated MMP-2 and ultimately inhibiting BC invasion. Our results provide the first evidence showing that miR-494 downregulation was closely associated with BC metastatic status and overall BC survival, and ChlA-F was able to reverse the level of miR-494 with a profound inhibition of human BC invasion in human invasive BC cells. Our studies also reveal that ChlA-F is a promising therapeutic compound for BCs and miR-494 could also serve as a promising therapeutic target for the treatment of MIBC patients.

The exciplex-forming mixed host with doped phosphorescent dye shows potential to realize high performance phosphorescent organic light emitting didoes (PhOLEDs). Herein, we report a novel exciplex-forming co-host architecture by combining N,N,10-triphenyl-10H-spiro[acridine-9,9'-fluoren]-3'-amine (SAFDPA) with 4,7-diphenyl-1,10-phenanthroline (Bphen) and its further application in a highly simplified blue phosphorescent OLED structure doped with Iridium(III)bis[(4,6-difluorophenyl)-pyridinato-N, C2′] picolinate (FIrpic). The designed blue emitting OLEDs using SAFDPA: Bphen (1:1, w- w) mixed host architecture show simpler device structure, lower working voltage, better efficiency and better stability than those of the reference device. Particularly, Power efficiency of devices with exciplex-forming co-host is significantly enhanced compared with reference device. An effective and synergistic strategy to design highly simplified PhOLEDs helps to simplify fabrication process and popularize OLEDs technology.

Brachial plexus root avulsion causes severe sequelae Treatments and prognosis face many problems, including inflammatory reaction, oxidative damage, and myelin related inhibitory effect. l -Theanine has anti-inflammatory, anti-oxidative, and neuroprotective effects. NEP1-40 competitively inhibits Nogo-66 receptor (NgR1) promotes axonal regeneration. Forty-eight Sprague-Dawley rats were randomly assigned into four groups to establish an animal model of brachial plexus root avulsion. Inflammation and oxidative damage were evaluated by spectrophotometry and motor function of the upper limbs was assessed via Terzis grooming test after modeling. Immunofluorescence and hematoxylin and eosin staining were utilized to determine the content of reactive oxygen species, activation of microglial cells, neuroprotection, and nerve regeneration. Compared with the control group, the L-Theanine + NEP1-40 group had significantly decreased myeloperoxidase, malondialdehyde, interleukin-6, reactive oxygen species, and microglial cells, significantly increased score on the Terzis grooming test, increased motor neuron content, and thickened muscle fibers, increased area, and appearance of large and clear motor endplate structures. The results of this study suggest that l -Theanine combined with NEP1-40significantly promoted nerve regeneration after brachial plexus root avulsion, and may be a potential treatment for promoting nerve regeneration. Possible mechanisms underlying these results are alleviation of oxidative damage and inflammatory responses in the injured area and antagonism of myelin inhibition.

Depth filtration is a commonly-used bioprocessing unit operation for harvest clarification that reduces the levels of process- and product-related impurities such as cell debris, host-cell proteins, nucleic acids and protein aggregates. Since depth filters comprise multiple components, different functionalities may contribute to such retention, making the mechanisms by which different impurities are removed difficult to decouple. Here we probe the mechanisms by which double-stranded DNA (dsDNA) is retained on depth filter media by visualizing the distribution of fluorescently-labeled retained DNA on spent depth filter discs using confocal fluorescence microscopy. The extent of DNA displacement into the depth filter was found to increase with decreasing DNA length with increasing operational parameters such as wash volume and buffer ionic strength. Finally, using 5ethynyl-2'-deoxyuridine (EdU) to label DNA in dividing CHO cells, we showed that Chinese hamster ovary (CHO) cellular DNA in the lysate supernatant migrates deeper into the depth filter than the lysate re-suspended pellet, elucidating the role of the size of the DNA in its form as an impurity. Apart from aiding DNA purification and removal, our experimental approaches and findings can be leveraged in studying the transport and retention of nucleic acids and other impurities on depth filters at a small scale.

Owing to the insufficient guidance of new bone formation in orthopedic and craniomaxillofacial surgery, construction of a guided bone regeneration membrane to support vascularized bone regeneration remains a challenge. Herein, an electrospun asymmetric double-layer polycaprolactone/collagen (PCL/Col) membrane modified by metal-organic framework (MOF) crystals is developed. The optimization of the PCL/Col weight ratio (1:1 and 1:1.5) enables the composite membrane with a balanced tensile strength (only fell by 49.9% in wet conditions) and a controlled degradation rate (completely degraded at 12 weeks). The MOF crystals can provide a pH-responsive release of Zn2+ ions. In vitro experiments indicate that the barrier layer functions to prevent the infiltration of fibrous connective tissue. The MOF crystal layer functions to enhance osteogenesis and angiogenesis in vitro. Using a rat calvarial defect model, the MOF crystals exhibit a sign of osteoinductivity along with blood vessel formation after 8 weeks post-surgery. Strikingly, when assessed in a chick chorioallantoic membrane model, the MOF modified membrane demonstrates a significant angiogenic response, which can be envisaged as its outstanding merits over the commercially Col membrane. Therefore, the MOF crystals represent an exciting biomaterial option, with neovascularization capacity for bone tissue engineering and regenerative medicine.

Objectives: The present study aimed to develop a random forest (RF) based prediction model for hyperuricemia (HUA) and compare its performance with the conventional logistic regression (LR) model. Methods: This cross-sectional study recruited 91,690 participants (14,032 with HUA, 77,658 without HUA). We constructed a RF-based prediction model in the training sets and evaluated it in the validation sets. Performance of the RF model was compared with the LR model by receiver operating characteristic (ROC) curve analysis. Results: The sensitivity and specificity of the RF models were 0.702 and 0.650 in males, 0.767 and 0.721 in females. The positive predictive value (PPV) and negative predictive value (NPV) were 0.372 and 0.881 in males, 0.159 and 0.978 in females. AUC of the RF models was 0.739 (0.728–0.750) in males and 0.818 (0.799–0.837) in females. AUC of the LR models were 0.730 (0.718–0.741) for males and 0.815 (0.795–0.835) for females. The predictive power of RF was slightly higher than that of LR, but was not statistically significant in females (Delong tests, P=0.0015 for males, P=0.5415 for females). Conclusion: Compared with LR, the good performance in HUA status prediction and the tolerance of features associations or interactions showed great potential of RF in further application. A prospective cohort is necessary for HUA developing prediction. People with high risk factors should be encouraged to actively control to reduce the probability of developing HUA.

We studied a rabbit model of rheumatoid arthritis (RA) to examine the time course of changes in synovial neovascularization based on quantitative power Doppler ultrasound and contrast-enhanced ultrasound (CEUS). Twenty-five male New Zealand rabbits were in the ovalbumin-induced arthritis (OIA) group, and 5 were in the control group. Both rear knee joints of all rabbits were examined using conventional US and CEUS over 16 weeks. The knee synoviums of OIA rabbits were sampled by US-guided biopsy, and expression of CD31 and vascular endothelial growth factor (VEGF) was determined by immunohistochemistry. The correlation of joint damage based on multimodal US with microvessel density (CD31 positivity) and VEGF expression at different times was analyzed. OIA rabbits had increased synovial expression of CD31 and VEGF from weeks 6 to 12 (p < 0.01). During the early stage of CEUS enhancement, "dot enhancement" was more common at weeks 6 and 8, and "stripe enhancement" was more common at weeks 12 and 16 (p < 0.05). There were significant positive correlations of synovial CD31 and VEGF expression with power Doppler image grade, CEUS grade and peak intensity (p < 0.05 for all). Thus, OIA rabbits mimicked early-stage RA at 6 to 8 weeks, middle-stage RA at 8 to 12 weeks and late-stage RA at 12 to 16 weeks. Power Doppler image grade, CEUS grade and peak intensity, especially when combined with CD31 expression data, accurately characterized the extent of synovial vascularization in a rabbit model of RA. Increased vascularity based on CEUS may have value for the early diagnosis of RA.

Nisoldipine represents a compound with diverse pharmacological activities. The interaction between nisoldipine and human serum albumin (HSA) was investigated using various methods, including UV–vis, three-dimensional fluorescence, synchronous fluorescence, electrochemical methods and molecular docking. The decreased quenching constant upon increasing temperatures and UV–vis absorption difference spectrum revealed that there was a static quenching mechanism rather than a dynamic quenching mechanism in the interaction of nisoldipine with human serum albumin. The thermodynamic parameters demonstrated that the binding of nisoldipine to human serum albumin was spontaneous and hydrogen bonding, hydrophobic interactions as well as electrostatic interactions played major roles in the binding process. The binding distance was 2.31 nm, indicating the presence of fluorescence energy transfer. Site marker competitive experiments and molecular docking demonstrated that the binding site of nisoldipine in human serum albumin was site I (subdomain IIA). In addition, three-dimensional fluorescence as well as synchronous fluorescence spectra suggested conformational changes of HSA due to the interaction with nisoldipine.

A rapid and sensitive two-step time-resolved fluorescence immunoassay (TRFIA) was developed for the detection of Shiga toxin 2 (Stx2) and its variants in Shiga toxin-producing Escherichia coli (STEC) strains. In sandwich mode, a monoclonal antibody against Stx2 was coated on a microtiter plate as a capture antibody. A tracer antibody against Stx2 labeled with europium(III) (Eu3+ ) chelate was then used as a detector, followed by fluorescence measurements using time-resolved fluorescence. The sensitivity of Stx2 detection was 0.038 ng/ml (dynamic range, 0.1-1000 ng/ml). The intra- and inter-assay coefficients of variation of the assay were 3.2% and 3.6%, respectively. The performance of the established assay was evaluated using culture supernatants of STEC strains, and the results were compared to those of a common HRP (horseradish peroxidase) labeling immunosorbent assay. A polymerase chain reaction (PCR) for the detection of genes encoding Stx1 and Stx2 was used as the reference for comparison. Correlation between the Stx2-specific TRFIA and PCR was calculated by the use of kappa statics, exhibiting a perfect level of agreement. The availability of the sensitive and reliable Stx2-specific TRFIA method for quantifying Stx2 and its variants in STEC strains will complement bacteria isolation-based platform and aid in the accurate and prompt diagnosis of STEC infections.

A novel MNAzyme signal amplification strategy was developed for enzyme-free and label-free detection of DNA-binding proteins. This strategy relied on the binding-mediated MNAzyme cleavage and G-quadruplex-based light-up fluorescence switch. Three DNA sequences were designed to construct the MNAzyme in which DNA1 (including half binding site of the target protein and a toehold sequence) and DNA2 (including another half binding site of the target protein and one MNAzyme partzyme) firstly hybridized. The target protein recognized the binding sites on DNA1-DNA2 hybrid to form a stable protein-DNA1-DNA2 conjugates. Then, the MNAzyme was assembled with the presence of DNA3 which contained another MNAzyme partzyme and the complementary sequence of DNA1. The active MNAzyme cleaved DNA4 to release the G-quadruplex that was locked in the stem of DNA4. Finally, N-methyl mesoporphyrin IX (NMM) was inserted into the released G-quadruplex structure and the fluorescence signal was turned on. Taking nuclear factor-κB p50 (NF-κB p50) as the model, the limit of detection was low to 0.14 nM. Furthermore, the sequence-specific recognition of NF-κB p50 with DNA displayed excellent selectivity and specificity. The results in present work showed that this strategy will be a promising tool for DNA-binding proteins analysis in biomedical exploration and clinical diagnosis.

Significant amounts of soluble product aggregates were observed during low-pH viral inactivation (VI) scale-up for an IgG4 monoclonal antibody (mAb IgG4-N1), while small-scale experiments in the same condition showed negligible aggregation. Poor mixing and product exposure to low pH were identified as the root cause. To gain a mechanistic understanding of the problem, protein aggregation properties were studied by varying critical parameters including pH, hold time and protein concentration. Comprehensive biophysical characterization of product monomers and aggregates was performed using fluorescence-size-exclusion chromatography, differential scanning fluorimetry, fluorescence spectroscopy, and dynamic light scattering. Results showed IgG4-N1 partially unfolds at about pH 3.3 where the product molecules still exist largely as monomers owing to strong inter-molecular repulsions and favorable colloidal stability. In the subsequent neutralization step, however, the conformationally changed monomers are prone to aggregation due to weaker inter-molecular repulsions following the pH transition from 3.3 to 5.5. Surface charge calculations using homology modeling suggested that intra-molecular repulsions, especially between CH2 domains, may contribute to the IgG4-N1 unfolding at ≤ pH 3.3. Computational fluid dynamics (CFD) modeling was employed to simulate the conditions of pH titration to reduce the risk of aggregate formation. The low-pH zones during acid addition were characterized using CFD modeling and correlated to the condition causing severe product aggregation. The CFD tool integrated with the mAb solution properties was used to optimize the VI operating parameters for successful scale-up demonstration. Our research revealed the governing aggregation mechanism for IgG4-N1 under acidic conditions by linking its molecular properties and various process-related parameters to macroscopic aggregation phenomena. This study also provides useful insights into the cause and mitigation of low-pH-induced IgG4 aggregation in downstream VI operation.

Two anthracyclines, doxorubicin and epirubicin have been widely used alone or in combination with other antitumor reagents in the chemotherapeutic treatment of various malignancies. Although therapeutic efficacy of anthracyclines has been studied extensively, precise cytotoxic mechanism of these drugs is not been completely elucidated. Here we show that epirubicin-induced degradation of transmembrane protein gp130 contributes to antitumor effect of epirubicin. gp130 is degraded by epirubicin in a proteasome- and autophagy-dependent manner. Epirubicin induces activation of p38-MK2 signaling pathway to phosphorylate gp130 at Ser 782, which results in gp130 internalization and degradation by lysosome. Although mutation of Ser 782 to Ala or Cys in gp130 upregulates global epirubicin-induced autophagy, reduced degradation of gp130 accompanied with enhanced Stat3 phosphorylation at tyrosine 705 is observed. We also show that epirubicin-resistant tumor cells express higher level of gp130. Altogether, our results indicate that degradation of gp130 and subsequent reduction of gp130-Stat3 signaling contributes to epirubicin-induced tumor cell death.

Cerebrovascular disease is the main cause of death in the world. Here, we explored whether circulating serum miR-148b-3p, miR-151b and miR-27b-3p could be as potential diagnostic biomarkers for diagnosing acute ischemic stroke. Seventy-seven IS patients and forty-two healthy controls matched for age and sex were enrolled in the present study. Blood samples were drawn from IS patients within the 24 h. The correlation analysis was performed by Spearman. The ability to distinguish patients from healthy controls was determined by receiver operating characteristic (ROC) curve. The expression of circulating serum miR-148b-3p was significantly decreased, whereas miR-151b and miR-27b-3p were elevated significantly compared with controls. ROC analysis showed area under the ROC curve (AUC) of miR-148b-3p, miR-151b and miR-27b-3p to be 0.6647, 0.6852 and 0.6657, respectively. While the AUC increased to 0.8103 for the combination of miR-148b-3p and miR-27b-3p. Blood miR-151b level was negatively correlated with insulin-like growth factor-1 (IGF-1), and miR-27b-3p level was negatively correlated with IGF-1 and insulin-like growth factor binding protein-3, respectively. Our findings suggest that miR-148b-3p, miR-151b and miR-27b-3p may serve as blood-based biomarkers for diagnosing ischemic stroke patients, and the combination of miR-148b-3p and miR-27b-3p may be more powerful.

Camptothecin (CPT) and 10-hydroxycamptothecin (HCPT) are two anti-tumor agents that cause the tumor cell death by inhibiting the degradation of the cleaved DNA strand. In the current study, we researched the interactions of CPT/HCPT and bovine serum albumin (BSA) with the multi-spectroscopy method, electrochemical method and molecular docking method. The inverse ratio of Ksv and Ka to temperature and the difference in UV–vis absorption indicated that there was a formed complex in both CPT-BSA system and HCPT-BSA system when they titrated into BSA solution, cyclic voltammetry and AC impedance experiments confirmed this phenomenon. The thermodynamic data demonstrated that hydrogen bonding as well as electrostatic interactions might be the leading force when they bound to BSA. The experiments of site competition and molecular docking showed that both CPT and HCPT bind to BSA on site I. Furthermore, the three-dimensional fluorescence, synchronous fluorescence and circular dichroism spectroscopy demonstrated that presence of CPT/HCPT changed the conformation of BSA.

Heavy metal contamination in environment and food has attracted intensive attention from the public since it poses serious threats to ecological system and human health. Traditional detection methods for heavy metals such as atomic absorption spectrometry have a fairly low detection limit, but the methods have many limitations and disadvantages. Therefore, it is of significance to develop a rapid technology for real-time and online detection of heavy metals. The electrochemical aptasensor-based technology is promising in the detection of heavy metals with advantages of high sensitivity, specificity, and accuracy. Although its development is rapid, more researches should be carried out before this technology can be used for on-site detection. In this review, the origin, basic principles and development of electrochemical aptasensors are introduced. The applications of nanomaterials and electrochemical aptasensors for the detection of heavy metals (mainly mercury, lead, cadmium, and arsenic) are summarized. The research and application tendency of electrochemical aptasensors for detection of heavy metals are prospected.

In this study, an up-converting phosphor technology-based lateral-flow (UPT-LF) assay was developed to detect severe fever with thrombocytopenia syndrome virus (SFTSV) total antibodies rapidly and specifically. SFTSV recombinant N protein (SFTSV-rNP) was coated on analytical membrane for sample capture, up-converting phosphor (UCP) particles were used as the reporter, the luminescence emitted by UCP particles was converted to a measurable signal by a biosensor. The performance of UPT-LF assay was evaluated by testing 302 field serum samples by ELISA (enzyme-linked immunosorbent assay), Western blotting and UPT-LF assay. UPT-LF assay exhibited a lower detection limit than ELISA, and a satisfied level of agreement was exhibited by Kappa statistics (Kappa coefficient = 0.938). Considering Western blotting as the reference for comparison, the sensitivity and specificity of UPT-LF assay could reach 98.31% and 100%. UPT-LF assay showed no specific reaction with hantavirus total serum antibodies, which avoids the misdiagnosis of SFTSV from hantavirus that could cause similar clinical symptoms. UPT-LF assay was able to achieve acceptable results within 15 min and needed only 10 μL sample for each test. As a whole, UPT-LF assay is a candidate method for on-site surveillance of SFTSV total antibodies owing to its excellent sensitivity, specificity, stability, easy operation and for being less time consuming.

This study was performed to examine whether the AF4/FMR2 family, member 1 (AFF1) rs340630 polymorphism is involved in the genetic background of rheumatoid arthritis (RA) in a Chinese population. Two different study groups of RA patients and controls (328 RA patients and 449 healthy controls in the first study group; 232 RA patients and 313 controls in the second study group) were included in our study. Overall, there was no significant difference in either genotype (P=0.71 and 0.64 in the first and second study group, respectively) nor allele (in the first study group: A vs G, P=0.65, OR=1.05, 95%CI=0.85-1.29; in the second study group: G vs A, P=0.47, OR=1.10, 95%CI=0.86-1.40) frequencies of AFF1 rs340630 polymorphism between RA patients and controls. Our study represents the first report assessing the association of AFF1 rs340630 polymorphism with RA risk. No significant evidence was found for the dominant or recessive models. Further case-control studies with larger sample sizes and fine-mapping studies are needed to clarify the role of AFF1 in the genetic basis of RA.

Physical cues of cellular environment affect cell fate and differentiation. For example, an environment with high stiffness drives mesenchymal stem cells (MSCs) to undergo osteogenic differentiation, while low stiffness leads to lipogenic differentiation. Such effects could be independent of chemical/biochemical inducers.Stiffness and/or topography of cellular environment can control MSC differentiation and fate determination. In addition, physical factors such as tension, which resulted from profound cytoskeleton reorganization during MSC differentiation, affect the gene expression essential for the differentiation. Although physical cues control MSC lineage specification probably by reorganizing and tuning cytoskeleton, the full mechanism is largely unclear. It also remains elusive how physical signals are sensed by cells and transformed into biochemical and biological signals. More importantly, it becomes pivotal to define explicitly the physical cue(s) essential for cell differentiation and fate decision. With a focus on MSC, we present herein current understanding of the interplay between i) physical cue and factors and ii) MSC differentiation and fate determination.Biophysical cues can initiate or strengthen the biochemical signaling for MSC fate determination and differentiation. Physical properties of cellular environment direct the structural adaptation and functional coupling of the cells to their environment.These observations not only open a simple avenue to engineer cell fate in vitro, but also start to reveal the physical elements that regulate and determine cell fate.

Predicting membrane protein type is a meaningful task because this kind of information is very useful to explain the function of membrane proteins. Due to the explosion of new protein sequences discovered, it is highly desired to develop efficient computation tools for quickly and accurately predicting the membrane type for a given protein sequence. Even though several membrane predictors have been developed, they can only deal with the membrane proteins which belong to the single membrane type. The fact is that there are membrane proteins belonging to two or more than two types. To solve this problem, a system for predicting membrane protein sequences with single or multiple types is proposed. Pseudo-amino acid composition, which has proven to be a very efficient tool in representing protein sequences, and a multilabel KNN algorithm are used to compose this prediction engine. The results of this initial study are encouraging.

Farnesoid X receptor (FXR) has been confirmed to sense bile acids in various tissues. However, its expression in brain neurons remains obscure. In this study, we identified FXR mRNA and protein expression in mouse brain neurons and in mouse/human brain tissues. FXR was predominantly localized in the nucleus in cultured neurons, but in neurons in vivo, it mainly appeared in the cytoplasm. In nuclear compartments, the neuronal FXR exhibited a punctate distribution. Activation of FXR increased the small heterodimer partner (SHP) mRNA and protein expression levels in cultured neurons and in brain tissues. These findings will help explore new functions of FXR in the brain.

Communication between endothelial and smooth muscle cells (SMCs) contributes to atherosclerosis induced by atherogenic factors, such as oxide LDL. Asymmetric dimethylarginine (ADMA), a newly found cardiovascular risk factor, accumulates in the culture medium of oxide LDL (oxLDL)-treated endothelial cells and positively correlates with atherosclerosis. This study demonstrates that ADMA mediates the communication between endothelial cells and SMCs induced by oxLDL leading to SMC migration. In addition, the present study suggests exogenous ADMA directly induces SMC migration via p38 and ERK1/2 MAPK signaling transduction way. Investigations to identify the factors regulating VSMC migration may provide novel insights into atherosclerosis and its complications.

Palmar fibromatosis is a benign fibroproliferative tumor of unknown etiology, with a high rate of recurrence after excision. The offending cells of palmar fibromatosis are myofibroblasts and the cellular origin of other myofibroblasts has previously been reported to be the bone marrow. However, further clarification of the relationship between bone marrow precursors and palmar fibromatosis is required. Stem cells (SCs) are known to exist in various tissues, but whether SCs can be isolated from fibromatosis tissue is still unclear. The purpose of this study was to isolate and identify stem cells from human palmar fibromatosis, and to evaluate the differences in the differentiation and fibrogenic capacities of bone marrow stem cells (BMSCs) and fibromatosis-derived stem cells (FSCs). We found that FSCs had better fibrogenic differentiation potential than BMSCs, whereas BMSCs had better adipogenic and chondrogenic differentiation capacities. Treatment with transforming growth factor-β1 increased the expression of α-smooth muscle actin, and types III and I collagen significantly more in FSCs than in BMSCs. An in vivo study further confirmed the results of fibrogenesis and suggested that FSCs can recapitulate the fibromatosis nodule. In summary, their myofibroblastic differentiation both in vivo and in vitro makes FSCs a potential cell source for future applications in murine models of fibromatosis or fibrogenesis.

Here we present a simple, highly efficient, universal automatic kinetics switch (AKS) gene synthesis method that enables synthesis of DNA up to 1.6 kbp from 1 nM oligonucleotide with just one polymerase chain reaction (PCR) process. This method eliminates the interference between the PCR assembly and amplification in one-step gene synthesis and simultaneously maximizes the amplification of emerged desired DNA by using a pair of flanked primers. In addition, we describe an analytical model of PCR gene synthesis based on the thermodynamics and kinetics of DNA hybridization. The kinetics difference between standard PCR amplification and one-step PCR gene synthesis is analyzed using this model and is validated using real-time gene synthesis with eight gene segments (318–1656 bp). The effects of oligonucleotide concentration, stringency of annealing temperature, annealing time, extension time, and PCR buffer conditions are examined systematically. Analysis of the experimental results leads to new insights into the gene synthesis process and aids in optimizing gene synthesis conditions. We further extend this method for multiplexing gene assembly with a total DNA length up to 5.74 kbp from 1 nM oligonucleotide.

Calcineurin (CN) is the receptor for two immunophilin–immunosuppressant complexes, Cyp–CsA and FKBP-FK506. It is a heterodimer composed of a catalytic subunit (CNA) and a regulatory subunit (CNB). It is also inhibited by its own auto-inhibitory domain (AID). Loop 7 is a β-hairpin within CNA that makes close contact with bound immunophilin–immunosuppressant complexes and with the AID. To investigate the role of Loop 7 in inhibition, we generated a series of deletion and substitution mutants and examined their inhibition by Cyp–CsA, FKBP-FK506 and an AID peptide. Our results demonstrate that the contacts made by Loop 7 are critical for its role in CN inhibition. Intriguingly, single residue deletions of Val314 and neighboring residues increased inhibition by FKBP-FK506 >6-fold, whereas they reduced Cyp–CsA inhibition >3-fold and abolished inhibition by the AID peptide. Most of the single substitution mutations also decreased Cyp–CsA inhibition. Loop 7 thus plays different roles in the inhibition of CN by the different inhibitors.

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Both the intestine and liver develop from the endoderm, yet little is known how these two digestive organs share and differ in their developmental programs, at the molecular level. A classical forward genetic screen, with no gene bias, is an effective way to address this question by examining the defects of the intestine and liver in obtained mutants to assess mutated genes responsible for the development of either organ or both. We report here such a screen in zebrafish. ENU was used as the mutagen because of its high mutagenic efficiency and no site preference. Embryos were collected at 3.5 dpf for RNA whole mount in situ hybridization with a cocktail probe of the intestine marker ifabp and the liver marker lfabp to check phenotypes and determine their parental heterozygosis. A total of 52 F2 putative mutants were identified, and those with general developmental defects were aborted. To rule out non-inheritable phenotypes caused by high mutation background, F2 putative mutants were outcrossed with wild type fish and a re-screen in F3 generations was performed. After complementation tests between F3 mutants with similar phenotypes originating from the same F2 families, a total of 37 F3 mutant lines originated from 22 F2 families were identified after screening 78 mutagenized genomes. Classification of mutant phenotypes indicated that 31 out of the 37 mutants showed defects in both the intestine and liver. In addition, four "intestine specific mutants" and two "liver specific mutants" showed selectively more severe phenotype in the intestine and liver respectively. These results suggested that the intestine and liver share a substantial number of essential genes during both organs development in zebrafish. Further studies of the mutants are likely to shed more insights into the molecular basis of the digestive system development in the zebrafish and vertebrate.

In spinal cord injury, the injury could trigger some inhibitory signal cascades to promote chondroitin sulfate proteoglycans (CSPGs), the structures of scar tissues, formation. CSPGs could limit axonal regeneration mainly through the glycosaminoglycan (GAG) chain in the lesion site were suggested. We hypothesized that the digestion of CSPGs by chondroitinase ABC (ChABC) might decrease the inhibitory effects of limiting axonal re-growth after spinal cord injury. We compared the digesting products of CSPGs such as 2B6 by ChABC with the untreated control group and found no immunostaining of 2B6 in control group. The smaller size scars of ChABC-treatment were observed via CS-56, a type of CSPGs, 8 weeks after transection by immunohistochemistry. The inhibitory effects of CSPGs withdraw GAGs following ChABC-treatment would reduce, and immunopositive GAP-43 newly outgrown fibers were identified. In the animal trials, ChABC-treatment could improve motor function through BBB locomotor's test and reduce limiting ability of scar tissues to promote axonal regeneration via changing the structure of CSPGs by immunohistochemistry with GAP-43.

Calcineurin (CN) is a heterodimer composed of a catalytic subunit (CNA) and a regulatory subunit (CNB). Loop 7 lies within the CNA catalytic domain. To investigate the role of Loop 7 in enzyme activity, we systematically examined all its residues by site-directed deletion mutation. Our results show that the Loop 7 residues are important for enzyme activity. Besides deleting residues V314, Y315 or N316, enzyme activity also increased dramatically when residues D313 or K318 were deleted. In contrast, almost all activity was lost when L312 or N317 were deleted. Ni2+ and Mn2+ were effective activators for all active mutants. However, whereas the wild-type enzyme was more efficiently activated by Ni2+ than by Mn2+ with 32P-labeled RII peptide as substrate, the reverse was true in all the mutants. We also found that the effect of Loop 7 on enzyme activity was substrate dependent, and involved interactions between Loop 7 residues and the unresolved part of the CN crystal structure near the auto-inhibitory domain and catalytic site.

The flat-facet model has been implicitly assumed for the structure of the image surface by most conventional speckle-reduction algorithms. However, this model is rarely found in a real ultrasound (US) image. To preserve the higher order structures and to capture the spatially variant property of the speckle, a new adaptive speckle-reduction algorithm, called the symmetrical speckle-reduction filter (SSRF), was developed based on the slope-facet model. The basic idea of the SSRF was to estimate the uncorrupted signal on the largest symmetrical slope facet centered at each target pixel. The symmetry constraint ensured the correctness of the mean value. An empirical speckle model was incorporated to account for the nature of the speckle in US image. A two-stage despeckling strategy was employed to enhance the statistical reliability of each estimate by forming a union of a set of symmetrical despeckling windows. The proposed SSRF algorithm was compared with two filtered-based and one wavelet-based approaches and the experimental results showed that the proposed SSRF outperformed these three previous approaches in both the synthetic images and the clinical US images tested in this study. (ming@lotus.mc.ntu.edu.tw)

The capture of circulating tumor cells (CTCs) from cancer patient blood enables early clinical assessment as well as genetic and pharmacological evaluation of cancer and metastasis. Although there have been many microfluidic immunocapture and electrokinetic techniques developed for isolating rare cancer cells, these techniques are often limited by a capture performance tradeoff between high efficiency and high purity. We present the characterization of shear-dependent cancer cell capture in a novel hybrid DEP-immunocapture system consisting of interdigitated electrodes fabricated in a Hele-Shaw flow cell that was functionalized with a monoclonal antibody, J591, which is highly specific to prostate-specific membrane antigen expressing prostate cancer cells. We measured the positive and negative DEP response of a prostate cancer cell line, LNCaP, as a function of applied electric field frequency, and showed that DEP can control capture performance by promoting or preventing cell interactions with immunocapture surfaces, depending on the sign and magnitude of the applied DEP force, as well as on the local shear stress experienced by cells flowing in the device. This work demonstrates that DEP and immunocapture techniques can work synergistically to improve cell capture performance, and it will aid in the design of future hybrid DEP-immunocapture systems for high-efficiency CTC capture with enhanced purity.

Polymeric composite materials hold promise for versatile advanced applications. Of utmost importance for these applications is incorporating inorganic particles within polymer matrices which lead to multifunctional polymeric composites with desired functions. Specifically, thermosensitive polymeric hydrogels incorporating particle fillers have elicited widespread interest because of promising applications in drug delivery, tissue engineering, and medical devices. Although these materials are frequently discussed in many research fields, there are no decisive conclusions reported in literature, showing how the particle filler affects the rheological and mechanical behaviors of the resulting hydrogels. In this research, hydroxyapatite (HAp) bioceramics with definable morphologies were synthesized in order to reveal their effects on the resulting properties of HAp/polymer composite hydrogels. HAp particles with spherical, sheet-like and rod-like shapes were prepared with assistance by adding amphiphilic surfactant, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) in synthesis. Thermosensitive composite hydrogels with controllable rheological and mechanical properties were thus developed by incorporating HAp particles into poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PEG-PLGA) hydrogel. Experimental results revealed that the rheological and mechanical properties of the resultant HAp/PEG-PLGA composite hydrogel not only influenced by the added HAp particle amount, but also by the particle morphology and interactions between particles and hydrogels. The findings from this research provide a critical guideline for designing thermosensitive composite hydrogels with required rheological and mechanical properties.

The development of efficient chemical methods for total synthesis or semisynthesis of integral membrane proteins is an important challenge at the interface between chemistry and biology. This review outlines the recent advances in the synthesis of integral membrane proteins, with particular focus on the methods for difficult peptide synthesis, purification, and enhancement of peptide solubility under the ligation conditions. The applications of these methods to the synthesis of integral membrane proteins with one or multiple transmembrane domains are also described.

This chapter introduces a simple, cost-effective TopDown one-step gene synthesis method, which is suitable for the sequence assembly of fairly long DNA. This method can be distinguished from conventional gene synthesis methods by two key features: (1) the melting temperature of the outer primers is designed to be ∼8°C lower than that of the assembly oligonucleotides, and (2) different annealing temperatures are utilized to selectively control the efficiencies of oligonucleotide assembly and full-length template amplification. This method eliminates the interference between polymerase chain reactions (PCR) assembly and amplification in one-step gene synthesis. Additionally, the TopDown gene synthesis has been combined with the LCGreen I DNA fluorescence dye in a real-time gene synthesis approach for investigating the stepwise efficiency and kinetics of PCR-based gene synthesis. The obtained real-time fluorescence signals are compared with gel electrophoresis results to optimize gene synthesis conditions.

Protein phosphorylation plays a pivotal role in the regulation of many cellular events; increasing evidences indicate that this post-translational modification is involved in plant response to various abiotic and biotic stresses. Since phosphorylated proteins may be present at low abundance, enrichment methods are generally required for their analysis. We here describe the quantitative changes of phosphoproteins present in Arabidopsis thaliana leaves after challenging with elicitors or treatments mimicking biotic stresses, which stimulate basal resistance responses, or oxidative stress. Phosphoproteins from elicited and control plants were enriched by means of metal oxide affinity chromatography and resolved by 2D electrophoresis. A comparison of the resulting proteomic maps highlighted phosphoproteins showing quantitative variations induced by elicitor treatment; these components were identified by MALDI-TOF peptide mass fingerprinting and/or nanoLC-ESI-LIT-MS/MS experiments. In total, 97 differential spots, representing 75 unique candidate phosphoproteins, were characterized. They are representative of different protein functional groups, such as energy and carbon metabolism, response to oxidative and abiotic stresses, defense, protein synthesis, RNA processing and cell signaling. Ascertained protein phosphorylation found a positive confirmation in available Arabidopsis phosphoproteome database. The role of each identified phosphoprotein is here discussed in relation to plant defense mechanisms. Our results suggest a partial overlapping of the responses to different treatments, as well as a communication with key cellular functions by imposed stresses.

We report the positive dielectrophoretic (pDEP) characterization of wild-type and ethambutol-treated Mycobacterium smegmatis populations via automated pDEP cell trapping experiments. The automated technique was validated by measurements of carboxylate-modified polystyrene microspheres and Escherichia coli . The characterization of M. smegmatis identifies a key frequency regime where the membrane-specific action of ethambutol leads to a change in the cellular dielectrophoretic response. This work represents the first such characterization of Mycobacteria and highlights the potential for DEP measurements to measure changes in mycobacterial membrane properties associated with chemical treatments or genetic mutation.

The aim of this work was to evaluate the use of thermosensitive hydrogels for intravesical cisplatin delivery into the bladder. Poly(N-isopropylacrylamide) (PNIPAM) was grafted onto hyaluronic acid (HA) to synthesize an HPN copolymer, which was further grafted with gelatin to form an HPNG copolymer. A 3% concentration of HPN and HPNG was sufficient to exert a thermosensitive response, whereas a concentration of 8% was needed for PNIPAM to form the hydrogel. The physicochemical and drug delivery properties were examined by scanning electron microscopy (SEM), the lower critical solution temperature (LCST), hydration ratio, and in vitro cisplatin release. The incorporation of HA and gelatin produced a different microstructure compared to the parent PNIPAM hydrogel. Gelatin conjugation increased the fibrous structure in the matrix. The LCSTs of PNIPAM, HPN, and HPNG were 32.3, 32.0, and 30.7°C, respectively. The copolymers showed an eightfold increase in the hydration capacity compared to PNIPAM, with no significant difference in values between HPN and HPNG. The release of cisplatin from an aqueous solution (control) was nearly complete after 8 h, compared to 85, 80, and 52% release from PNIPAM, HPN, and HPNG, respectively. In vivo evaluation of cisplatin levels in bladder tissues was performed following intravesical instillation in rats. When the dwell time was extended to 6 h, PNIPAM showed a sevenfold enhancement in the drug concentration in the bladder wall. HPNG also showed a twofold increase in the drug concentration. The administration of cisplatin by the HPN carrier did not change the drug accumulation compared to the control. Confocal laser scanning microscopic results confirmed the trend of drug absorption from various systems. A histological examination showed no adverse change in the urothelium with HPN or HPNG application. PNIPAM caused partial desquamation of umbrella cells. The thermosensitive hydrogels prepared in this study may be promising carriers for targeted drug delivery to the bladder.

Our research group has exhibited a long-standing interest in the synthesis and bioassay study of a number of unique natural products containing flavonoids, camphorataimides, and benzofurans. In previous works, we have shown that tumor suppressor protein p53 and p38 MAPK (mitogen activated protein kinase) play a prominent role in the caffaic acid phenethyl ester (CAPE) induced-apoptosis of C6 glioma cells. In addition, studies on the constituents of the Chinese crude drug “Sang-bai-pi” (Morus root bark) have been recorded in books of traditional Chinese herbal medicines, which are used as an antiphlogistic, a diuretic, an expectorant, and anti-hepatitis B activity. Herein, we present the first total synthesis of morusin and himanimide D, and then show the development of the COX/LOX inhibitors by an automated docking method. Morusin, which can be isolated from Chinese herbal medicine, is achieved in which the longest linear sequence is only 13 steps in 12% overall yield from commercially available phloroglucinol. In addition, to probe accessibility of the active sites of proteins, particular COXs/LOXs, the binding affinity of protein-ligand complexes were examined by an automated docking method. Consequently, the rationally optimized LEE-BNOHDM was identified as a potent inhibitor of the arachidonate 5-lipoxygenase.

Treatment with a combination of peripheral nerve grafts and acidic fibroblast growth factor improves hind limb locomotor function after spinal cord transection. This study examined the effect of treatment on expression of arginase I (Arg I) and polyamines. Arg I expression was low in the spinal cords of normal rats but increased following spinal injury. Only fully repaired spinal cords expressed higher Arg I levels 6-14 days following repair. In 10-day repaired spinal cords, high Arg I immunoreactivity was detected in motoneurons and alternatively activated macrophages in the graft area and graft-stump edges, and high levels of the polyamine spermine were expressed by macrophages within the intercostal nerve graft. Thus, in addition to enhancing the expression of Arg I and spermine in repaired spinal cords, our treatment may recruit activated macrophages and create a more favorable environment for axonal regrowth.

Superparamagnetic iron oxide nanoparticles (SPIONs) designed to interact with tumor cells have received increasing interest in the past few years, due to their potential for applications such as magnetic resonance imaging (MRI) contrast enhancement, drug delivery, and hyperthermia. However, the stability of these nanoparticles under physiological conditions, and their ability to selectively target tumor cells are challenges which need to be addressed. In this work, SPIONs were first modified with poly(glycidyl methacrylate) (PGMA) via atom transfer radical polymerization (ATRP). The epoxy groups in PGMA were then reacted with ethylenediamine to generate amino groups, which were conjugated with different amounts of folic acid (FA) for cancer cells targeting. The as-synthesized folic acid conjugated SPIONs (SPIONs–PGMA–FA) are hydrophilic and highly stable in an aqueous medium. The targeting efficiency of the folic acid-conjugated nanoparticles was investigated with different cell lines. The uptake of SPIONs–PGMA–FA by KB (human epidermoid carcinoma) cells is about three and five times higher than that of macrophages and 3T3 fibroblasts, respectively. No significant cytotoxicity was observed when the three types of cells were incubated with nanoparticles at a concentration of 0.5 mg mL−1 or less. The nanoparticles also exhibited high MR enhancement effects with r2 and r2/r1 values of 191.4 mM−1 s−1 and 98 respectively in a 3T magnetic field. Hence, these nanoparticles can potentially be used to selectively target cancer cells for imaging as well as hyperthermia.

Magnetic nanoparticles (MNPs) have great potential as a contrast agent in magnetic resonance imaging (MRI). They can be used to label macrophages which then function as cellular probes to study inflammatory disorders such as atherosclerosis. Alternatively, they can be made to evade the reticuloendothelical system (RES) and attain a long blood circulation time to reach other target organs. The purpose of this work is to develop a polymer coating for MNPs which can be readily tuned to modulate the interaction of the MNPs with macrophages. The coating developed is based on poly(DL-lactic acid-co-malic acid) (PLMA) with adjustable polyethylene glycol (PEG) content. The physical, surface and magnetic properties, cytotoxicity and macrophage uptake of the polymer-coated MNPs were evaluated. The results indicated that a wide range of cellular iron concentration in macrophages can be achieved by changing the PEG content of the coating, the incubation time and the concentration of nanoparticles. No significant cytotoxicity was observed and the nanoparticles exhibited high magnetic resonance enhancement effects. Hence, these nanoparticles can be expected to be suitable for a wide range of MRI applications.