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Floods are recognized as lethal natural events, which result in devastating natural and human losses. So, identifying flood susceptible zones is crucial to adopt necessary mitigation strategies beforehand. With the advent of GIS tools and modelling techniques, mapping of such zones has become easier and more precise; yet, flood prone countries like Nepal have not been able to embrace such tools for flood risk management. With a compelling need to address this situation, this paper employs Frequency Ratio model to analyze flood susceptibility in the West Rapti River Basin. The model, created with the help of 77 flood points and tested with 30 points to obtain 80.7% accuracy, maps the flood hazard zones in the area and identifies the lower Terai and settlement regions as high-risk areas. With the increasing threat of changing climate in the future, this study also propounds better preparation of flood inventory maps in the future for more precise susceptibility analysis models and better flood risk management.

Supplementary Figures 1-9, Methods from Specific Targeting of Brain Tumors with an Optical/Magnetic Resonance Imaging Nanoprobe across the Blood-Brain Barrier

Respiratory diseases are the leading cause of death in the world according to reports from the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO: third, chronic obstructive pulmonary disease; fourth, lower respiratory infections; and sixth, trachea, bronchus and lung cancers[1]. These astounding statistics are attributed to certain risk factors that include but are not limited to air pollution and first to third-hand smoke. In addition, marijuana, the most commonly used illicit drug in the US, is becoming legal in certain states for recreational use. However, with the increase in use, the question of long-term respiratory health effects becomes crucial. In addition, evidence has emerged that US military personnel deployed to Iraq and Afghanistan may be at risk for developing respiratory symptoms and, in some cases, disabling chronic lung diseases including chronic bronchitis, emphysema, asthma, and constrictive bronchiolitis. Because of this public health concern, there seems to have a necessity for effective respiratory toxicology in vitro models. While still valuable, two-dimensional (2D) methods are simplistic and overlook important biological parameters that influence cellular behavior. The purpose of this study is to elucidate the efficacy of bronchial epithelial cells (Beas-2B) in a novel alginate-based spheroid as a three-dimensional (3D) cytotoxicity testing model. Toxicants including gun range dust and Δ9- tetrahydrocannabinol (Δ9 THC) were used to verify if this model can be used for cytotoxicity testing. Viability of encapsulated Beas-2B cells was analyzed following exposure to gun range dust extract and Δ9- tetrahydrocannabinol THC. This study established that Beas-2B cells encapsulated in a novel alginate-chitin nanofiber hydrogel spheroid is an effective three-dimensional cytotoxicity testing model.

Quantification of iron in different pharmaceuticals can be performed by different analytical methods. In this study, a rapid, sensitive and simple spectrophotometric method was used for the determination of iron (II) in different iron tablets. A spectrophotometric method is based on the reaction of iron (II) with 1,10-phenanthroline to form an orange-red chelating complex in an acidic medium. The maximum absorbance of the chelating complex was measured at 510 nm. The Beer Lambert’s law was found to be obeyed in the range of 0.4-4.0 mg/L of iron (II). Out of ten samples analyzed, the observed amount of iron (II) in nine samples were range from 105 to 96 mg whereas in one sample it was observed only 81 mg per 100 mg of the labeled amount of iron(II) by the manufacturer. Thus the results obtained by the spectrophotometric method using 1,10-phenanthroline as a color developing agent were nearly equal to the claimed values of iron (II) in different iron tablets from manufacturing companies.

Energy transformation and sustainability have become a challenge, especially for developing countries, which face broad energy-related issues such as a wide demand-supply gap, extensive fossil fuel dependency, and low accessibility to clean energy. Globally, smart grid technology has been identified to address these affairs and enable a smooth transition from traditional to smart energy systems, ensuring energy security. This paper studies the critical role in strengthening the power system, integrating renewable sources, electrifying the transport sector, and harnessing bioenergy. Evaluating the current energy scenario in Nepal, this article presents the smart grid as a solution to existing and future energy issues and the associated challenges during its implementation, urging concerned authorities to launch initiatives to promote it. Moreover, this study also lays the foundation for future research into the smart grid's potential to reform the power sector in other developing nations with abundant renewable energy sources and similar energy-related barriers.

Electrospun nanofiber (EN) technology has been used in the past to generate electrostatically charged multilayer-nanofibers. This platform offers versatile applications including in tissue engineering, drug delivery, wound dressings, and high-efficiency particulate air filters. In this study, we synthesized for the first time nanonet-nanofiber electrospun meshes (NNEMs) of polycaprolactone (PCL)-chitosan (CH) using EN technology. The fabricated NNEMs were utilized for high payload delivery and controlled release of a water-soluble drug. Diclofenac Sodium (DS), a hydrophilic anti-inflammatory drug, was selected as a model drug because of its high aqueous solubility and poor compatibility with insoluble polymers. Various compositions of DS drug-loaded NNEMs (DS-NNEMs) were synthesized. The physicochemical properties such as structure, morphology, and aqueous stability and the chemical properties of DS-NNEMs were evaluated. High drug entrapment efficiency and concentration-dependent drug release patterns were investigated for up to 14 days. Furthermore, the biocompatibility of the DS-NNEMs was tested with NIH 3T3 cells. The physicochemical characterization results showed that the DS drug is a key contributing factor in the generation of nanonet-nanofiber networks during electrospinning. DS-NNEMs also enhanced 3T3 cell adhesion, viability, and proliferation in the nanonet-nano fiber network through the controlled release of DS. The presented EN technology-based biodegradable NNEM material is not only limited for the controlled release of hydrophilic anti-inflammatory drugs, but also can be a suitable platform for loading and release of antiviral drugs.

Nano-in-micro (NIM) system is a promising approach to enhance the performance of devices for a wide range of applications in disease treatment and tissue regeneration. In this study, polymeric nanofibre-integrated alginate (PNA) hydrogel microcapsules were designed using NIM technology. Various ratios of cryo-ground poly (lactide-co-glycolide) (PLGA) nanofibres (CPN) were incorporated into PNA hydrogel microcapsule. Electrostatic encapsulation method was used to incorporate living cells into the PNA microcapsules (~500 µm diameter). Human liver carcinoma cells, HepG2, were encapsulated into the microcapsules and their physio-chemical properties were studied. Morphology, stability, and chemical composition of the PNA microcapsules were analysed by light microscopy, fluorescent microscopy, scanning electron microscopy (SEM), Fourier-Transform Infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The incorporation of CPN caused no significant changes in the morphology, size, and chemical structure of PNA microcapsules in cell culture media. Among four PNA microcapsule products (PNA-0, PNA-10, PNA-30, and PNA-50 with size 489 ± 31 µm, 480 ± 40 µm, 473 ± 51 µm and 464 ± 35 µm, respectively), PNA-10 showed overall suitability for HepG2 growth with high cellular metabolic activity, indicating that the 3D PNA-10 microcapsule could be suitable to maintain better vitality and liver-specific metabolic functions. Overall, this novel design of PNA microcapsule and the one-step method of cell encapsulation can be a versatile 3D NIM system for spontaneous generation of organoids with in vivo like tissue architectures, and the system can be useful for numerous biomedical applications, especially for liver tissue engineering, cell preservation, and drug toxicity study.

Domestic wastewater and wastewater treatment plants (WWTPs) are key emitters of greenhouse gases (GHGs). Quantifying these emissions in the present and future is crucial to tackle global climate change issues. As a developing country with few rural and urban wastewater treatment facilities, Nepal may have a unique opportunity to reduce future GHGs emissions by a proper selection of wastewater treatment technology. In this paper, the authors used Python programming to estimate the GHGs emissions from the domestic wastewater sector in Nepal under various technological development scenarios for 2020 to 2040 using the refined 2019 estimation methodology developed by Inter-governmental Panel on Climate Change (IPCC). Results show total equivalent CO

Coumarins are found in higher plants like Rutaceae and Umbelliferae and essential oils of cinnamon bark, cassia leaf, and lavender oil. Coumarin compounds show different biological properties, viz antimicrobial, antibacterial, antifungal, antioxidant, antitumor, anti-HIV, antihypertension, anticoagulant, anticancer, antiviral, anti-inflammatory, analgesics, antidiabetic, anti-depressive, and other bioactive properties. Coumarin and its derivatives possess anticancer activity against different types of cancers such as prostate, renal, breast, laryngeal, lung, colon, CNS, leukemia, malignant melanoma. In this review, current developments of coumarin-based anticancer agents viz simple coumarin, furanocoumarin, pyranocoumarin, pyrone-substituted coumarin, and their important derivatives have been discussed. The coumarin-triazole, coumarin-chalcone, coumarin-thiosemicarbazone derivatives, and coumarin-metal complexes have been found more potent than coumarin. Hence, further study and structural improvement on coumarin and its derivatives may lead to the design and development of more potent anticancer agents.

Nanoparticle (NP) toxicity assessment is a critical step in assessing the health impacts of NP exposure to both consumers and occupational workers.

The ability to produce composite nanofibers of inorganic particles and synthetic polymers represents a significant advancement in the development of composite materials for potential biomedical applications. In this study, composite nanofibers of magnesium oxide (MgO), poly(e-caprolactone) (PCL) and chitosan (CS) with diameters in the range of 0.7–1.3 µm were fabricated by electrospinning their blend solutions in trifluroethanol and water. To support the potential use of these nanofibrous membranes for biomedical applications their physicochemical properties such as morphology, mechanical strength, and integrity in aqueous medium, were studied. Cellular compatibility was determined using cell viability assays and microscopy imaging, with the results showing that the nanofibrous membranes support 3T3 cell viability and attachments. The new composite nanofibrous membranes developed in this study have the ability to mimic the physical structure and function of tissue extracellular matrix (ECM) and thus have potential for many tissue engineering applications.

Real-time dose-response curves for fructose have been non-invasively determined in primary rat hepatocyte alginate spheroids cultured in a NMR-compatible fluidized-bed bioreactor. Using 13C-labeled glucose and glycine culture medium, fructose dose was compared to glucose uptake and glycogen synthesis rate using 13C NMR spectroscopy, and to ATP and fructose-1-phosphate concentration using 31P NMR spectroscopy. A highly efficient multicoaxial perfusion system maintains high density 3-D hepatocyte cultures, permitting 13C and 31P NMR spectral time courses with 1min time points. The perfusion system was turned off to demonstrate its efficiency and effect on the metabolites. Within 16min, glycogen plummeted, lactate became the largest 13C-glucose metabolite via anaerobic glycolysis, while glutathione was the largest 13C-glycine metabolite. ATP depletion and fructose-1-phosphate formation demonstrated a dose response with a 3h EC50 of 19mM±8.9mM and 17.4mM±3.7mM, respectively. Computational modeling of mass transfer corroborated experimental results and helped determine the optimal bioreactor loading densities, oxygen concentration, and perfusion rates to maintain physiologically-relevant nutrient levels. The total bioreactor plus perfusion loop has a dead volume of 2ml, and contains 5 million hepatocytes. Due to the non-invasive measurements, there is a reduction of animal tissue by an order-of-magnitude, depending on the number of time points in an experiment. This dynamic flux approach may have generic utility for dose-response studies monitoring multiple metabolic reactions in other primary mammalian cells, such as human, that have strict oxygen demands.

Guided tissue regeneration (GTR) is a widely used method in dental surgical procedures that utilizes a barrier membrane to exclude migration of epithelium and ensure repopulation of periodontal ligament cells at the sites having insufficient gingiva. Commercial GTR membranes are typically composed of synthetic polymers that have had mild clinical success mostly because of their lack of proper bioactivity and appropriate degradation profile. In this study, a natural polymer, aloe vera was blended with polycaprolactone (PCL) to create nanofibrous GTR membranes by electrospinning. Aloe vera has proven anti-inflammatory properties and enhances the regeneration of periodontium tissues. PCL, a synthetic polymer, is well known to produce miscible polyblends nanofibers with natural polymers. Nanofibrous membranes with varying composition of PCL to aloe vera were fabricated, and several physicochemical and biological properties, such as fiber morphology, wettability, chemical structure, mechanical strength, and cellular compatibility of the membranes were analyzed. PCL/aloe vera membranes with ratios from 100/00 to 70/30 showed good uniformity in fiber morphology and suitable mechanical properties, and retained the integrity of their fibrous structure in aqueous solutions. Experimental results, using cell viability assay and cell attachment observation, showed that the nanofibrous membranes support 3T3 cell viability and could be a potential candidate for GTR therapy.

Magnesium (Mg) metal is of great interest in biomedical applications, especially in tissue engineering. Mg exhibits excellent in vivo biocompatibility, biodegradability and, during degradation, releases Mg ions (Mg2+) with the potential to improve tissue repair. We used electrospinning technology to incorporate Mg particles into nanofibers. Various ratios of Mg metal microparticles ( Statement of Significance The biodegradable metal, magnesium, safely biodegrades in the body, releasing beneficial byproducts. To improve tissue delivery, magnesium metal particles were incorporated into electrospun nanofiber meshes composed of a biodegradable, biocompatible polymer, polycaprolactone (PCL). Magnesium addition, at several concentrations, did not alter PCL chemistry, but did alter physical properties. Under cell culture conditions, meshes released magnesium ions and hydrogen gas and were not cytotoxic for two cell types. After implantation in mice, the mesh with magnesium resulted in earlier appearance of M2-like, reparative macrophages and improved tissue healing versus mesh alone. This is in agreement with other studies showing beneficial effects of magnesium metal and provides a new type of scaffold material that will be useful in clinically relevant tissue engineering applications.

The goal of this study was to fabricate and investigate the chitosan coated poly(lactic- co -glycolic acid) (PLGA) microspheres for the development of controlled release magnesium delivery system. PLGA based microspheres are ideal vehicles for many controlled release drug delivery applications. Chitosan is a naturally occurring biodegradable and biocompatible polysaccharide, which can coat the surface of PLGA to alter the release of drugs. Magnesium gluconate (MgG) was encapsulated in the PLGA and PLGA/chitosan microspheres by utilizing the double emulsion solvent evaporation technique for controlled release study. The microspheres were tested with respect to several physicochemical and biological properties, including morphology, chemical structure, chitosan adsorption efficiency, magnesium encapsulation efficiency, in vitro release of magnesium ions, and cellular compatibility using both human adipose-derived stem cells (ASCs) and PC12 cells. Chitosan coated PLGA microspheres can significantly control the release of magnesium ions compared to uncoated PLGA microspheres. Both coated and uncoated microspheres showed good cellular compatibility.

Polymeric nanofibers are of great interest in biomedical applications, such as tissue engineering, drug delivery and wound healing, due to their ability to mimic and restore the function of natural extracellular matrix (ECM) found in tissues. Electrospinning has been heavily used to fabricate nanofibers because of its reliability and effectiveness. In our research, we fabricated poly(ε-caprolactone)-(PCL), magnesium oxide-(MgO) and keratin (K)-based composite nanofibers by electrospinning a blend solution of PCL, MgO and/or K. The electrospun nanofibers were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), mechanical tensile testing and inductively-coupled plasma optical emission spectroscopy (ICP-OES). Nanofibers with diameters in the range of 0.2–2.2 µm were produced by using different ratios of PCL/MgO and PCL-K/MgO. These fibers showed a uniform morphology with suitable mechanical properties, ultimate tensile strength up to 3 MPa and Young’s modulus 10 MPa. The structural integrity of nanofiber mats was retained in aqueous and phosphate buffer saline (PBS) medium. This study provides a new composite material with structural and material properties suitable for potential application in tissue engineering.

Composite nanofibers of biopolymers and inorganic materials have been widely explored as tissue engineering scaffolds because of their superior structural, mechanical and biological properties. In this study, magnesium ferrite (Mg-ferrite) based composite nanofibers were synthesized using an electrospinning technique. Mg-ferrite nanoparticles were first synthesized using the reverse micelle method, and then blended in a mixture of polycaprolactone (PCL), a synthetic polymer, and Aloe vera, a natural polymer, to create magnetic nanofibers by electrospinning. The morphology, structural and magnetic properties, and cellular compatibility of the magnetic nanofibers were analyzed. Mg-ferrite/PCL/Aloe vera nanofibers showed good uniformity in fiber morphology, retained their structural integrity, and displayed magnetic strength. Experimental results, using cell viability assay and scanning electron microscopy imaging showed that magnetic nanofibers supported 3T3 cell viability. We believe that the new composite nanofibrous membranes developed in this study have the ability to mimic the physical structure and function of tissue extracellular matrix, as well as provide the magnetic and soluble metal ion attributes in the scaffolds with enhanced cell attachment, and thus improve tissue regeneration.

Keratin-based composite nanofibers have been fabricated by an electrospinning technique. Aqueous soluble keratin extracted from human hair was successfully blended with poly(e-caprolactone) (PCL) in different ratios and transformed into nanofibrous membranes. Toward the potential use of this nanofibrous membrane in tissue engineering, its physicochemical properties, such as morphology, mechanical strength, crystallinity, chemical structure, and integrity in aqueous medium were studied and its cellular compatibility was determined. Nanofibrous membranes with PCL/keratin ratios from 100/00 to 70/30 showed good uniformity in fiber morphology and suitable mechanical properties, and retained the integrity of their fibrous structure in buffered solutions. Experimental results, using cell viability assays and scanning electron microscopy imaging, showed that the nanofibrous membranes supported 3T3 cell viability. The ability to produce blended nanofibers from protein and synthetic polymers represents a significant advancement in development of composite materials with structural and material properties that will support biomedical applications. This provides new nanofibrous materials for applications in tissue engineering and regenerative medicine.

This chapter presents an overview of the electrospinning of chitosan. The properties of chitosan solutions relevant to electrospinning are discussed, followed by a summary of studies on electrospinning of unmodified and modified chitosan and experimental setups to produce core–shell and aligned nanofibers from chitosan. Finally, some highlights on applications of electrospun chitosan are presented.

Electrospun chitosan fibers are of great interest for various biomedical applications such as tissue engineering scaffolds, drug delivery, implant coatings, and wound dressings. Chitosan, a naturally occurring positively charged polysaccharide, is advantageous for biomedical applications due to several material characteristics including biodegradability, biocompatibility, and bacteriostatic properties. Electrospinning techniques have been widely used to create nanofibers from this natural polymer. Due to high porosity, which results in large surface area, these nanofibers have novel applications in biomedical fields. This chapter will emphasize the challenges and success in the production of electrospun chitosan nanofibers, its processing parameters, and its potential applications in clinical and industrial fields.

Magnesium injection is a suitable approach for replenishment of its ions (Mg++) during neural or tissue injury and stroke to avoids risks associated with abnormally low level of Mg++ in blood. In this study, alginate encapsulated magnesium sulfate microbeads were fabricated by the electrospraying technique for Mg++ delivery. Microbeads were evaluated for particle size and surface morphology using inverted optical microscopy and scanning electron microscopy (SEM) respectively. Average particle size of 200–500 μm for hydrated and 50–200 μm for dry beads were observed. An in vitro release study of Mg++ was performed; revealing a cumulative release of ∼50% within first 24 h. This strategy can potentially be useful for the targeted local delivery of magnesium at required concentrations and subsequently enhance the therapeutic efficacy of magnesium in treating tissue injury or stroke.

Bone is a living tissue that constantly remodels and adapts to the stresses imposed upon it. Bone disorders are of growing concern as the median age of our population rises. Healing and recovery from fractures requires bone cells to have a 3-dimensional (3D) structural base, or scaffold, to grow out from. In addition to providing mechanical support, the scaffold, an extracellular matrix (ECM) assembly, enables the transport of nutrients and oxygen in and removal of waste materials from cells that are growing into new tissue. In this research, a 3D scaffold was synthesized with chitosan (CS), carboxymethyl chitosan (CMC), calcium phosphate monobasic and magnesium oxide (MgO). CS is a positiviely-charged natural bioactive polymer. It is combined with its negatively-charged derivative, CMC, to form a complex scaffold. Magnesium phosphate biocement (MgP), formed by reacting calcium phosphate monobasic and MgO, was incorporated into CMC solution before adding CS solution. Scaffolds were prepared by casting, freezing and lyophilization. The scaffolds were characterized in terms of pore microstructures, surface topography, water uptake and retention abilities, and crystal structure. The results show that the developed scaffolds exhibit highly interconnected pores and present the ideal pore size range (100–300 μm) to be morphometrically suitable for the proposed bone tissue engineering applications. These scaffolds not only mimic the nanostructured architecture and the chemical composition of natural bone tissue matrices but also serve as a source for soluble ions of magnesium (Mg++) and calcium (Ca++) that are favorable to osteoblast cells. The scaffolds thus provide a desirable microenvironment to facilitate biomineralization. These observations provide a new effective approach for preparing scaffold materials suitable for bone tissue engineering.

The ability to produce aligned sub-micron fibers may open new avenues for the development of scaffolds for application in tissue engineering and regenerative medicine. An area of particular interest is functional restoration of damaged or diseased nerves where the aligned fibers serve to support cell adhesion and proliferation, and guide neurite outgrowth in the direction of fiber orientation. In this study, we developed an aligned chitosan–polycaprolactone (chitosan–PCL) fibrous scaffold and investigated how the fiber alignment influenced nerve cell organization and function in comparison with randomly oriented fibrous scaffolds and cast films of the same material. Schwann cells (SCs) were shown to attach and proliferate on all the substrates regardless of their topography, demonstrating the cellular compatibility of the chitosan–PCL material. SCs grown on the aligned chitosan–PCL fibers exhibited a bipolar morphology that oriented along the fiber alignment direction, while those on the films and randomly oriented fibers had a multipolar morphology. Similarly, the chitosan–PCL material supported neuron-like PC-12 cell adhesion, and the aligned fibers regulated the growth of PC-12 cells along the fiber orientation. Additionally, PC-12 cells cultured on the aligned fibers exhibited enhanced unidirectional neurite extension along fiber orientation and significantly higher β-tubulin gene expression than those grown on chitosan–PCL films and randomly oriented fibers. Our investigation suggested that the aligned chitosan–PCL fibers can serve as a suitable scaffold for improved nerve tissue reconstruction.

Aim: To develop and evaluate two tumor-specific nanoprobes by functionalization of a polyethylene glycol-immobilized nanoparticle with arginine–glycine–aspartic acid (RGD) or chlorotoxin ligand that targets αvβ3 integrin and matrix metalloproteinase-2 receptors, respectively. Materials & methods: The nanoprobes were made of iron oxide cores, biocompatible polymer coating, and surface-conjugated RGD or chlorotoxin peptide. The tumor-targeting specificity of the nanoprobes was evaluated both in vitro and in vivo. Results & discussion: Both nanoprobes were highly dispersive and exhibited excellent long-term stability in cell culture media. The RGD-conjugated nanoprobe displayed a strong initial accumulation near neovasculatures in tumors followed by quick clearance. Conversely, the chlorotoxin-enabled nanoprobe exhibited sustained accumulation throughout the tumor. Conclusion: These findings revealed the influence of the targeting ligands on the intratumoral distribution of the ligand-enabled nanoprobes. With flexible surface chemistry, our nanoparticle platform can be used in a modular fashion to conjugate biomolecules for intended applications.

Nanoparticle-based platforms have drawn considerable attention for their potential effect on oncology and other biomedical fields. However, their in vivo application is challenged by insufficient accumulation and retention within tumors due to limited specificity to the target, and an inability to traverse biological barriers. Here, we present a nanoprobe that shows an ability to cross the blood-brain barrier and specifically target brain tumors in a genetically engineered mouse model, as established through in vivo magnetic resonance and biophotonic imaging, and histologic and biodistribution analyses. The nanoprobe is comprised of an iron oxide nanoparticle coated with biocompatible polyethylene glycol–grafted chitosan copolymer, to which a tumor-targeting agent, chlorotoxin, and a near-IR fluorophore are conjugated. The nanoprobe shows an innocuous toxicity profile and sustained retention in tumors. With the versatile affinity of the targeting ligand and the flexible conjugation chemistry for alternative diagnostic and therapeutic agents, this nanoparticle platform can be potentially used for the diagnosis and treatment of a variety of tumor types. [Cancer Res 2009;69(15):6200–7]

Gene therapy offers the potential of mediating disease through modification of specific cellular functions of target cells. However, effective transport of nucleic acids to target cells with minimal side effects remains a challenge despite the use of unique viral and non-viral delivery approaches. Here we present a non-viral nanoparticle gene carrier that demonstrates effective gene delivery and transfection both in vitro and in vivo. The nanoparticle system (NP-CP-PEI) is made of a superparamagnetic iron oxide nanoparticle (NP), which enables magnetic resonance imaging, coated with a novel copolymer (CP-PEI) comprised of short chain polyethylenimine (PEI) and poly(ethylene glycol) (PEG) grafted to the natural polysaccharide, chitosan (CP), which allows efficient loading and protection of the nucleic acids. The function of each component material in this nanoparticle system is illustrated by comparative studies of three nanoparticle systems of different surface chemistries, through material property characterization, DNA loading and transfection analyses, and toxicity assessment. Significantly, NP-CP-PEI demonstrates an innocuous toxic profile and a high level of expression of the delivered plasmid DNA in a C6 xenograft mouse model, making it a potential candidate for safe in vivo delivery of DNA for gene therapy.

This communication reports that a plasmid DNA molecule could spontaneously interact with hydroxyapatite (HA) functionalized multi-walled carbon nanotubes (MWNTs-HA) in water-solute environment. Gel electrophoresis, UV absorption, FT-IR, and Raman spectra were used to characterize MWNTs-HA/DNA complexes. AFM and TEM images revealed that DNA induces the de-aggregation of MWNTs-HA. Our preliminary study suggests that the plasmid DNA significantly interacted with MWNTs-HA, and formed the stable complex, and could find the application in nanotechnology for gene delivery system.

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of these porous nanofibers is of great interest due to their unique physiochemical properties. Here we elaborate on the fabrication of keratin containing poly (e-caprolactone) (PCL) nanofibers (i.e., PCL/keratin composite fiber). Water soluble keratin was first extracted from human hair and mixed with PCL in different ratios. The blended solution of PCL/keratin was transformed into nanofibrous membranes using a laboratory designed electrospinning set up. Fiber morphology and mechanical properties of the obtained nanofiber were observed and measured using scanning electron microscopy and tensile tester. Furthermore, degradability and chemical properties of the nanofiber were studied by FTIR. SEM images showed uniform surface morphology for PCL/keratin fibers of different compositions. These PCL/keratin fibers also showed excellent mechanical properties such as Young's modulus and failure point. Fibroblast cells were able to attach and proliferate thus proving good cell viability. Based on the characteristics discussed above, we can strongly argue that the blended nanofibers of natural and synthetic polymers can represent an excellent development of composite materials that can be used for different biomedical applications.

Synthetic grafts comprised of a porous scaffold in the size and shape of the natural tracheobronchial tree, and autologous stem cells have shown promise in the ability to restore the structure and function of a severely damaged airway system. For this specific application, the selected scaffold material should be biocompatible, elicit limited cytotoxicity, and exhibit sufficient mechanical properties. In this research, we developed composite nanofibers of polycaprolactone (PCL) and depolymerized chitosan using the electrospinning technique and assessed the properties of the fibers for its potential use as a scaffold for regenerating tracheal tissue. Water-soluble depolymerized chitosan solution was first prepared and mixed with polycaprolactone solution making it suitable for electrospinning. Morphology and chemical structure analysis were performed to confirm the structure and composition of the fibers. Mechanical testing of nanofibers demonstrated both elastic and ductile properties depending on the ratio of PCL to chitosan. To assess biological potential, porcine tracheobronchial epithelial (PTBE) cells were seeded on the nanofibers with composition ratios of PCL/chitosan: 100/0, 90/10, 80/20, and 70/30. Transwell inserts were modified with the nanofiber membrane and cells were seeded according to air-liquid interface culture techniques that mimics the conditions found in the human airways. Lactase dehydrogenase assay was carried out at different time points to determine cytotoxicity levels within PTBE cell cultures on nanofibers. This study shows that PCL/chitosan nanofiber has sufficient structural integrity and serves as a potential candidate for tracheobronchial tissue engineering.

Present study dealt an application of modified chitosan gold nanoparticles (Nac-6-Au) for the immobilization of necked plasmid DNA. Gold nanoparticles stabilized with N-acylated chitosan were prepared by graft-onto approach. The stabilized gold nanoparticles were characterized by different physico-chemical techniques such as UV-vis, TEM, ELS and DLS. MTT assay was used for in vitro cytotoxicity of the nanoparticles into three different cell lines (NIH 3T3, CT-26 and MCF-7). The formulation of plasmid DNA with the nanoparticles corresponds to the complex forming capacity and in-vitro/in-vivo transfection efficiency was studied via gel electrophoresis and transfection methods, respectively. Results showed the modified chitosan gold nanoparticles were well-dispersed and spherical in shape with average size around 10∼12 nm in triple distilled water at pH 7.4, and showed relatively no cytotoxicity at low concentration. Addition of plasmid DNA on the aqueous solution of the nanoparticles markedly reduced surface potential (50.0∼66.6%) as well as resulted in a 13.33% increase in hydrodynamic diameters of the formulated nanoparticles. Transfection efficiency of Nac-6-Au/DNA was dependent on cell type, and higher β-galactosidase activity was observed on MCF-7 breast cancer cell. Typically, this activity was 5 times higher in 4.5 mg/ml nanoparticles concentration than that achieved by the nanoparticles of other concentrations (and/or control). However, this activity was lower in in-vitro and dramatically higher in in-vivo than that of commercially available transfection kit (Lipofectin®) and DNA. From these results, it can be expected to develop alternative new vectors for gene delivery.