Chitosan Nanofibers Research Articles

Filtration-processed biomass nanofiber electrodes for flexible bioelectronics

An increasing demand for bioelectronics that interface with living systems has driven the development of materials to resolve mismatches between electronic devices and biological tissues. So far, a variety of different polymers have been used as substrates for bioelectronics. Especially, biopolymers have been investigated as next-generation materials for bioelectronics because they possess interesting characteristics such as high biocompatibility, biodegradability, and sustainability. However, their range of applications has been restricted due to the limited compatibility of classical fabrication methods with such biopolymers. Here, we introduce a fabrication process for thin and large-area films of chitosan nanofibers (CSNFs) integrated with conductive materials. To this end, we pattern carbon nanotubes (CNTs), silver nanowires, and poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) by a facile filtration process that uses polyimide masks fabricated via laser ablation. This method yields feedlines of conductive material on nanofiber paper and demonstrates compatibility with conjugated and high-aspect-ratio materials. Furthermore, we fabricate a CNT neural interface electrode by taking advantage of this fabrication process and demonstrate peripheral nerve stimulation to the rapid extensor nerve of a live locust. The presented method might pave the way for future bioelectronic devices based on biopolymer nanofibers.

Silver and zinc enriched chitosan nanofibers as an antimicrobial wound dressing

Silver and zinc enriched chitosan nanofibers as an antimicrobial wound dressing

Electrospinning and Photocrosslinking of Highly Modified Fungal Chitosan

AbstractThe main focus of this study is to elucidate and optimize the electrospinning process for highly modified fungal chitosan. An efficient one‐step process for functionalization of chitosan with arylazide and other desired functional groups via amidation is used for synthesis. Critical electrospinning process parameters, namely, molecular weight, concentration, and ratio of chitosan and additive poly(ethylene oxide) as well as degree of substitution of chitosan are identified by systematic parameter variation following design‐of‐experiment guidelines. Their influence on the viscoelastic properties of spinning solutions is studied and attributed to changes in chain entanglements. These changes result in drastic shifts in the electrohydrodynamic jet behavior and the resulting fiber morphologies. When the viscosity is increased above a critical limit, complete cancellation of whipping instabilities is observed, resulting in a stable linear jet and highly aligned but partly coalescing microfibers. It is shown how this process conditions can be avoided and how the production of uniform and defect‐free nanofibers from highly functional chitosan can be carried out. In addition, a new photocrosslinking method for generation of water and acid stable chitosan nanofiber meshes is established.

Electrospun Chitosan Nanofibres and its Application

Abstract: Chitosan is a biopolymer that has been widely used in medical, pharmaceutical, agricultural, cosmetics, food as well as textile and paper industries due to its biocompatibility, biodegradability, non-toxic and less allergenic nature. In recent times, chitosan has gained much attention for its application in the form of nanofibres. Nanofibres have diameters in the range of 1 to 100 nanometres. Various processing techniques like drawing, template synthesis, phase separation, meltblown technology, bicomponent extrusion, self-assembly and electro spinning are involved in the fabrication of nanofibres. Among these techniques, electro spinning is the most widely and commonly used technique as it generates ultra-thin nanofibres and has the capacity of mass production. This article reviews the process of electro spinning and applications of the nanofibres containing chitosan in the areas of enzyme immobilization, filtration, wound dressing, tissue engineering, drug delivery, catalysis and as analytical system, biosensor and diagnostic aid in detail.

Effectiveness of cellulose and chitosan nanomaterial coatings with essential oil on postharvest strawberry quality

Polysaccharide materials, including bagasse cellulose nanocrystals (BCNCs), chitosan nanofibers (ChNFs), and sodium alginate (SA), were blended with oregano essential oil (OEO) to make single- and multi-polysaccharide edible coating suspensions. The prepared suspensions were spray-coated on strawberry surface to form thin films with thickness varying from about 570 to 790 nm for single-polysaccharide coatings and 690–930 nm for multi-polysaccharide coatings. The coatings made with multi-polysaccharide were more effective in inhibiting fungal growth compared with single-polysaccharide coatings. Strawberry treated with SA/BCNC/ChNF/OEO formulation had only 10.8 % weight loss after nine days of storage. In contrast, uncoated and single-polysaccharide coated strawberries had >37.0 % and 28.6 % weight loss, respectively. In addition, the SA/BCNC/ChNF/OEO coating retained desired moisture, respiration rate, stiffness, firmness, and appearance properties of strawberry due to its gas barrier properties resulting from the entangled matrix structure. These results suggest that the multi-polysaccharide suspensions with OEO have a high potential for application as edible coatings for retarding senescence of strawberries.

Loofah-chitosan and poly (−3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) based hydrogel scaffolds for meniscus tissue engineering applications

The meniscus is a fibrocartilaginous tissue that is very important for the stability of the knee joint. However, it has a low ability to heal itself, so damage to it will always lead to articular cartilage degeneration. The goal of this study was to make a new type of meniscus scaffold made of chitosan, loofah mat, and PHBV nanofibers, as well as to describe hydrogel composite scaffolds in terms of their shape, chemical composition, mechanical properties, and temperature. Three different concentrations of genipin (0.1, 0.3, and 0.5 %) were used and the optimal crosslinker concentration was 0.3 % for Chitosan/loofah (CL) and Chitosan/loofah/PHBV fiber (CLF). Scaffolds were seeded using undifferentiated MSCs and incubated for 21 days to investigate the chondrogenic potential of hydrogel scaffolds. Cell proliferation analyses were performed using WST-1 assay, GAG content was analyzed, SEM and fluorescence imaging observed morphologies and cell attachment, and histological and immunohistochemical studies were performed. The in vitro analysis showed no cytotoxic effect and enabled cells to attach, proliferate, and migrate inside the scaffold. In conclusion, the hydrogel composite scaffold is a promising material for engineering meniscus tissue.

Agrimonia Eupatoria L.-Incorporated Electrospun Nanofibers and Cotton Composite for Antibacterial Wound Dressing Applications

Composite wound dressings which combine the suitable properties of distinct materials into one dressing are currently being explored, in combination with different types of bioactive compounds, to enhance the healing process and avoid skin infections. In the present work, poly(vinyl alcohol) and chitosan nanofibers containing Agrimonia eupatoria L. were fabricated using a needleless electrospinning method (through Nanospider technology) and deposited on top of a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cotton textile dressing. The negatively charged carboxyl groups on the cotton fibers interacted with the positively charged amino groups of chitosan, which was previously blended with poly(vinyl alcohol) and Agrimonia eupatoria L. to produce the nanofiber layer. The properties of the produced composite materials were analyzed to determine the dressing’s potential for antimicrobial wound dressing applications.
 Keywords: cotton, textile dressing, electrospun nanofibers, Agrimonia eupatoria L., antibacterial composite wound dressings

Cell loaded hydrogel containing Ag-doped bioactive glass-ceramic nanoparticles as skin substitute: Antibacterial properties, immune response, and scarless cutaneous wound regeneration.

An ideal tissue‐engineered dermal substitute should possess angiogenesis potential to promote wound healing, antibacterial activity to relieve the bacterial burden on skin, as well as sufficient porosity for air and moisture exchange. In light of this, a glass–ceramic (GC) has been incorporated into chitosan and gelatin electrospun nanofibers (240–360 nm), which MEFs were loaded on it for healing acceleration. The GC was doped with silver to improve the antibacterial activity. The bioactive nanofibrous scaffolds demonstrated antibacterial and superior antibiofilm activities against Gram‐negative and Gram‐positive bacteria. The nanofibrous scaffolds were biocompatible, hemocompatible, and promoted cell attachment and proliferation. Nanofibrous skin substitutes with or without Ag‐doped GC nanoparticles did not induce an inflammatory response and attenuated LPS‐induced interleukin‐6 release by dendritic cells. The rate of biodegradation of the nanocomposite was similar to the rate of skin regeneration under in vivo conditions. Histopathological evaluation of full‐thickness excisional wounds in BALB/c mice treated with mouse embryonic fibroblasts‐loaded nanofibrous scaffolds showed enhanced angiogenesis, and collagen synthesis as well as regeneration of the sebaceous glands and hair follicles in vivo.

Chitosan nanofibres and polypropylene meltblown substrate based multilayer respiratory filter for byssinosis prevention

Byssinosis is a chronic obstructive pulmonary disease very common in textile cotton workers due to inhalation of fine cotton dust and gram negative bacteria. A three layer composite respiratory filter was developed for Byssinosis prevention by using the combination of polypropylene (PP) based meltblown layers and chitosan nanofibres (CSNF). Filtration efficiency against fine particulates ranges from 100 nm to 2.5 μm and anti-bacterial activity against Pantoea agglomerans were investigated. Chitosan nanofibres were produced by using the electrospinning process and were sandwiched between two PP layers to improve the overall surface area of the filter as well as providing a protective barrier against bacterial pathogens. The filter sample with just 2 hour’s CSNF coating showed more than 99% filtration efficiency with a low pressure drop of 71.6 Pa and a high quality factor value 0.082. The antibacterial performance of CSNF layers achieved up to 91% against the Pantoea agglomerans. Finally, results concluded that the developed respiratory filter can potentially reduce Byssinosis in textile workers.

Studies of Protein Wastes Adsorption by Chitosan-Modified Nanofibers Decorated with Dye Wastes in Batch and Continuous Flow Processes: Potential Environmental Applications.

In this study, reactive green 19 dye from wastewater was immobilized on the functionalized chitosan nanofiber membranes to treat soluble microbial proteins in biological wastewater. Polyacrylonitrile nanofiber membrane (PAN) was prepared by the electrospinning technique. After heat treatment, alkaline hydrolysis, and chemically grafted with chitosan to obtain modified chitosan nanofibers (P-COOH-CS), and finally immobilized with RG19 dye, dyed nanofibers were generated (P-COOH-CS-RG19). The synthesis of P-COOH-CS and P-COOH-CS-RG19 are novel materials for protein adsorption that are not deeply investigated currently, with each of the material functions based on their properties in significantly improving the adsorption efficiency. The nanofiber membrane shows good adsorption capacity and great recycling performance, while the application of chitosan and dye acts as the crosslinker in the nanofiber membrane and consists of various functional groups to enhance the adsorption of protein. The dyed nanofibers were applied for the batch adsorption of soluble protein (i.e., lysozyme), and the process parameters including chitosan’s molecular weight, coupling pH, chitosan concentration, dye pH, dye concentration, and lysozyme pH were studied. The results showed that the molecular weight of chitosan was 50 kDa, pH 5, concentration 0.5%, initial concentration of dye at 1 mg/mL dye and pH 12, lysozyme solution at 2 mg/mL at pH 8, and the maximum adsorption capacity was 1293.66 mg/g at a temperature of 318 K. Furthermore, thermodynamic, and kinetic studies suggested that the adsorption behavior of lysozyme followed the Langmuir adsorption isotherm model and the pseudo-second-order kinetic model. The optimal adsorption and desorption conditions based on batch experiments were directly applied to remove lysozyme in a continuous operation. This study demonstrated the potential of dyed nanofibers as an efficient adsorbent to remove approximately 100% of lysozyme from the simulated biological wastewater.

Development and characterization of the electrospun melittin-loaded chitosan nanofibers for treatment of acne vulgaris in animal model

Acne is an inflammatory disease of the sebaceous glands. Melittin (Mel) is one of the principal toxic components of bee venom that can cause antibacterial and anti-inflammatory effects. Chitosan is a biodegradable polysaccharide has anti-inflammatory, antimicrobial, and regenerative properties. In this study, chitosan (Ch)/Mel 0.001 and 0.003% nanofibers were fabricated for topical treatment of acne vulgaris. Physicochemical properties of Ch/Mel were evaluated using FTIR and FESEM. Furthermore, encapsulation efficiency, tensile strength, water absorption capacity, enzymatic activity, drug release, antimicrobial, and cell cytotoxicity were assayed. Animal models were exerted to study the impact of Ch/Mel nanofibers on the treatment of Propionibacterium acnes. The FESEM results showed that nanofibers were successfully prepared in nano-scale fiber diameter. The FTIR confirmed the presence of Mel in structures. The addition of melittin to the polymer solution reduced electrical conductivity, induced viscosity and tensile strength of the fibers, and decreased the percentage of the swelling. The Mel loading into Ch/Mel 0.003% was reported at 86.74±1%. This Mel releasing process (89.65%) of Ch/Mel 0.003% was slowly completed during 72 h. The Mel retained its hemolytic activity after being loaded into the polymer structure. The drug toxicity study displayed the lack of any significant toxicity from Ch/Mel nanofibers on normal Human Dermal Fibroblasts (HDF). The Ch/Mel 0.003% achieved the highest growth inhibition in P. acnes in vitro and animal studies, this group showed the greatest reduction in inflammation and redness. The Ch/Mel 0.003% structure is proposed as a suitable topical drug delivery system for treating acne vulgaris.

Anisotropic chitosan/tunicate cellulose nanocrystals hydrogel with tunable interference color and acid-responsiveness

A robust chitosan/tunicate cellulose nanocrystals (TCNCs) anisotropic hydrogel with bright interference colors was fabricated via combining the prestretching orientation method and chemically-physically dual cross-linking. The oriented regenerated chitosan nanofibrous network enabled the TCNCs alignment by covalent interaction and hydrogen bonding. The stretching alignment endows the chitosan/TCNCs hydrogel with enhanced tensile strength, from 0.63 MPa (draw ratio 1.0) to 2.06 MPa (draw ratio 3.5). Moreover, the orientation of chitosan nanofibers led to birefringence appearance, which could be regulated with the TCNCs introduction or draw ratios. The hydrogel swelled completely in 2 min in pH = 3 solution and the interference color disappeared. The oriented chitosan/TCNCs hydrogels showed distinct color change under acid stimulation, which could be quantitatively measured or directly observed under crossed polarizers. This work demonstrated a strategy for fabricating the interference color regulatable hydrogels with acid-response property for sensors and environmental monitoring.

Drying-Induced Surface Wrinkles Generated on Chitosan Films Having Polyion Complex Skin Layers: Effects of Physical Properties of Skin Layers and Substrates on Surface Wrinkling upon Drying

Abstract The effects of the physical properties of skin layers and substrates on drying-induced surface wrinkling are investigated with a system using chitosan films having polyion complex (PIC) skin layers. The PIC layers are fabricated with diverse anionic polymers having similar molecular weights on a chitosan (CS) film surface, and the films are dried. In all cases, surface wrinkles form but their sizes vary widely depending on the molecular structure. In particular, wrinkles formed with ligninsulfonate are much larger than those formed with the others. The skin layers differ significantly in surface hardness but not in thickness, indicating that wrinkle sizes induced by PIC skin layers are predominately determined by the hardness of the layers or by physical properties affected by hardness, such as shrinkage volume. The effects of the elastic moduli and shrinkage volume of the substrates are evaluated with higher molecular weight CS and surface-deacetylated chitin nanofiber composite CS films that have different elastic moduli but show very similar swelling–drying behaviors. The wrinkle sizes and skin layer thicknesses also suggest that wrinkle size in this system depends on the hardness of the skin layers or on the physical properties affecting the hardness.

Characterization of Tilapia collagen-loaded chitosan nanofibers synthesized by electrospinning method for wound dressing

Burns are traumatic injuries that require intensive therapy. Tilapia skin is known to contain high collagen properties and was developed for wound dressing. This study aimed to investigate the characterization of Tilapia collagen-loaded chitosan nanofibers synthesized by electrospinning for wound dressing. This study evaluated three group materials, i.e. (G1) chitosan, (G2) Tilapia collagen, and (G3) Tilapia collagen-loaded chitosan. The electrospun method was performed by alloy the chitosan nanofibers containing 8% w/v Tilapia collagen. The mix solution was characterized using scanning electron microscopy (SEM), Fourier- transform infrared (FTIR) spectroscopy, pH level, swelling test, water capacity test, and cytotoxicity test. As result, Tilapia collagen-loaded chitosan showed the better swelling test, water capacity test, cytotoxicity test, and FTIR evaluation compared to the collagen or chitosan group. However, all group materials showed similarities in pH level and SEM evaluation. In conclusion, Tilapia collagen-loaded chitosan nanofibers could be considered as a wound dressing based on positive results during characterization.

Fabrication of Silver Nanoparticles / Chitosan Nanofibers Composite Material Using a High-Pressure Wet-Type Jet Mill and their Antibacterial Properties

Fabrication of Silver Nanoparticles / Chitosan Nanofibers Composite Material Using a High-Pressure Wet-Type Jet Mill and their Antibacterial Properties

Effectiveness of wound coatings with chitosan nanofibers in combination with necrectomy in frostbite treatment in experiment

The problem of treatment of the patients with deep frostbite is still relevant due to its great social and economic significance, which necessitates further research. In general injuries structure, the proportion of cold injury can reach 10 %. The variety of the pathophysiological cryotrauma mechanisms explains the treatment complexity, which leads to frequent complications and significant disability of patients, among them the persons of working age are predominate. However, the generally accepted practice of managing patients with deep frostbite has not yet been developed, for example, the effectiveness of various drugs for local treatment has not been substantiated, the timing and scope of surgical benefits have not been determined. The aim of the study was to examine the effectiveness of wound coatings with chitosan nanofibers in combination with necrectomy on the 5th day during deep contact frostbite treatment. On the 5th day after modeling the standard deep experimental frostbites in 45 laboratory rats, the non-viable tissues in the cryopreservation zone were removed. For treatment of wound defects, the Mekol ointment, sterile gauze napkins, and wound coatings with chitosan nanofibers “Hitomed-wound healing” were used. Reparative processes in the frostbite area were assessed histologically, morphometrically, and statistically. The effectiveness of wound coatings with chitosan nanofibers in combination with necrectomy of the cryoinjured zone on the 5th day in the deep frostbite treatment was established.

Extracellular matrix-mimicking nanofibrous chitosan microspheres as cell micro-ark for tissue engineering

In the present study, extracellular matrix (ECM)-mimicking nanofibrous chitosan microspheres (NCM) were developed via thermal induction of chitosan molecular chain from alkaline/urea aqueous solution. The regeneration of NCM from chitosan was proved to be physical process. The morphology of NCM could be precisely controlled by adjusting the initial solution concentration and the reaction temperature. The NCM possessed desirable in vitro/vivo biocompatibility and biodegradability. The excellent cell adhesion capability of NCM facilitated the formation of large-sized 3D geometric constructs in vitro. The NCM promoted in vitro osteogenic differentiation of rat bone marrow stem cells (rMSCs). Finally, pre-differentiated rMSCs-NCM constructs obviously enhanced in vivo bone healing of rat calvarial defects. This work opened up a new avenue for the construction of chitosan microspheres with ECM-like nanofibrous structure, indicated the great potential of the NCM as micro-Noah's Ark for stem cells to anchor, proliferate, and pre-differentiate for tissue engineering.

Solution blow spinning of highly deacetylated chitosan nanofiber scaffolds for dermal wound healing.

Biocompatible fibrous scaffolds based on highly deacetylated chitosan were fabricated using high-throughput solution blow spinning. Scanning electron microscopy analysis revealed that the chitosan nanofiber scaffolds had ultrafine and continuous fibers (300-1200nm) with highly interconnected porous structures (30-75% porosity), mimicking some aspects of the native extracellular matrix in skin tissue. Post-treatment of as-spun nanofibers with aqueous potassium carbonate solution resulted in a fibrous scaffold with a high chitosan content that retained its fibrous structural integrity for cell culture. Analysis of the mechanical properties of the chitosan nanofiber scaffolds in both dry and wet conditions showed that their strength and durability were sufficient for wound dressing applications. Significantly, the wet scaffold underwent remarkable elastic deformation during stretch such that the elongation at break dramatically increased to up to 44% of its original length, showing wavy fiber morphology near the break site. The culture of normal human dermal fibroblast cells onto scaffolds for 1-14days demonstrated that the scaffolds were highly compatible and a suitable platform for cell adhesion, viability, and proliferation. Secretion profiles of wound healing-related proteins to the cell culture medium demonstrated that chitosan fibers were a promising scaffold for wound healing applications. Overall, the dense fibrous network with high porosity of the chitosan nanofiber scaffold and their mechanical properties indicate that they could be used to design and fabricate new materials that mimic the epidermis layer of natural skin.

Impact of Electrospinning Parameters and Post-Treatment Method on Antibacterial and Antibiofilm Activity of Chitosan Nanofibers.

Chitosan, a natural biopolymer, is an ideal candidate to prepare biomaterials capable of preventing microbial infections due to its antibacterial properties. Electrospinning is a versatile method ideally suited to process biopolymers with minimal impact on their physicochemical properties. However, fabrication parameters and post-processing routine can affect biological activity and, therefore, must be well adjusted. In this study, nanofibrous membranes were prepared using trifluoroacetic acid and dichloromethane and evaluated for physiochemical and antimicrobial properties. The use of such biomaterials as potential antibacterial agents was extensively studied in vitro using Staphylococcus aureus and Escherichia coli as test organisms. The antibacterial assay showed inhibition of bacterial growth and eradication of the planktonic cells of both E. coli and S. aureus in the liquid medium for up to 6 hrs. The quantitative assay showed a significant reduction in bacteria cell viability by nanofibers depending on the method of fabrication. The antibacterial properties of these biomaterials can be attributed to the structural modifications provided by co-solvent formulation and application of post-treatment procedure. Consequently, the proposed antimicrobial surface modification method is a promising technique to prepare biomaterials designed to induce antimicrobial resistance via antiadhesive capability and the biocide-releasing mechanism.

Fabrication of Chitosan Nanofibers Containing Some Steroidal Compounds as a Drug Delivery System.

A novel drug delivery system based on chitosan nanofibers containing some steroidal derivatives was developed using an electrospinning process. Oxazolines and aziridines from the cholestane series of steroidal epoxides were successfully synthesized and characterized by elemental analysis, Fourier transforms infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1HNMR), and mass spectroscopy (MS). Steroidal-compound-loaded chitosan (ST-CH) nanofibers were fabricated using the electrospinning technique in the presence of polyvinylpyrrolidone (CH/PVP). The electrospun nanofibers were characterized by scanning electron microscopy (SEM). The swelling degree of the electrospun nanofibers and their steroidal compound release performance were studied as well. Furthermore, their antibacterial activity against gram-positive (Staphylococcus aurous) and gram-negative bacteria (Escherichia coli) was evaluated. The experimental data revealed that identical and bead-free nanofiber mats loaded with 10 Wt. % of synthesized steroidal derivatives had been obtained. The FTIR spectrum proved that no change occurred in the chitosan structure during the electrospinning process. The synthesized nanofiber mats showed a high swelling degree and a burst release of steroidal compounds after 2 h doping in phosphate buffer saline. In addition, the electrospun nanofibers containing 3β-chloro-N-amido-5α-cholestano-aziridine and those containing 3β-acetoxy-N-amido-5α-cholestano-aziridine were the most active, with activity indices of 91 and 104% in the case of S. aureus and 52% and 61% in the case of E. coli, respectively. The release mechanism by CH/PVP of the drug samples was studied based on the charge density and diffusion controlled factors. The oxazoline derivatives release mechanism from CH/PVP was evaluated by applying the suppositions of the Ritger-Peppas kinetic model and by estimating the transport exponent; the latter revealed the involvement of the solvent diffusion and chain relaxation processes. Tailored steroidal loaded-chitosan (ST-CH) nanofibers are expected to be feasible and efficient drug delivery systems.