Chitosan-poly Ethylene Oxide Research Articles

Anti-adhesive and antibacterial chitosan/PEO nanofiber dressings with high breathability for promoting wound healing

Wound dressings are crucial for wound healing. Ideal wound dressings should possess many functions such as wettability, antibacterial activity and anti-adherent property to promote wound healing. In the present study solution blown spinning (SBS) technology was applied to prepare chitosan/polyethylene oxide (CS/PEO) nanofiber dressings in high efficiency. The obtained nanofiber dressings were treated with anhydrous ethanol to improve the fiber structure and enhance the functionality of the fiber dressings. The results show that the treated nanofibers had higher crystallinities and higher CS contents. The CS/PEO nanofiber dressings fabricated by using no additives and crosslinking had excellent wettability, water stability and antibacterial activity against Escherichia coli and Staphylococcus aureus reached to over 99.99 %. In addition, the CS/PEO nanofiber dressings exhibited high breathability, antioxidant activity and anti-adhesion function. The in vivo animal experiment confirmed that the nanofiber dressings enhanced cell proliferation and significantly accelerated the wound healing within 10 days. The developed CS/PEO nanofiber dressings have great potential in the clinical field of wound healing.

Chitosan-polyethylene oxide/clay-alginate nanofiber hydrogel scaffold for bone tissue engineering: Preparation, physical characterization, and biomimetic mineralization

This study aimed to prepare a novel organic-mineral nanofiber/hydrogel of chitosan-polyethylene oxide (CS-PEO)/nanoclay-alginate (NC-ALG). The effects of NC particles on the mineralization and biocompatibility of the scaffold were investigated. A layer-by-layer scaffold composed of CS-PEO and NC-ALG was prepared. The morphological properties, swelling, biodegradation, and mechanical behaviors of the scaffolds were evaluated. Furthermore, scaffolds were characterized by the Fourier Transform Infrared (FTIR), the Field Emission Scanning Electron Microscope (FE-SEM), and X-Ray Diffraction (XRD) techniques. Bone-like apatite formation ability of the scaffolds was determined by the mineralization test in a simulated body fluid (M-SBF). In addition, the crystalline phase of bone-like apatite precipitates was investigated by XRD analysis. The cell compatibility of the scaffolds was also studied with osteoblastic cell line MC3T3-E1 by MTT assay. Notably, the incorporation of NC particles in CS-PEO/ALG scaffolds is suitable for bone tissue regeneration which enhances bone-like apatite formation. Further, the hemolysis and MTT assays demonstrated that CS-PEO/NC-ALG scaffold was compatible and safe for MC3T3 cells.

Improving the optical, dielectric properties and antimicrobial activity of Chitosan–PEO by GO/MWCNTs: Nanocomposites for energy storage and food packaging applications

This work is an attempt to improve the multifunctionality of chitosan–polyethylene oxide (Ch.–PEO) blend for different industrial applications including energy storage and food packaging applications. Graphene oxide (GO)/blend and multi-walled carbon nanotubes (MWCNTs)/GO/blend films were prepared by the solution casting method. FTIR analysis indicated the existence of Ch. and PEO functional groups and the positive interaction between the added nanofillers and the blend chains. XRD data confirmed interfacial compatibility between PEO and Ch. and showed that the semicrystalline nature of the blend was decreased after the incorporation of the filler. SEM analysis displayed that the blend surface is homogenous and crack-free, and the MWCNTs/GO were well-dispersed and uniformly distributed on the surface. The blend showed transmittance in the visible and NIR regions in the range of 76–91%. Loading MWCNTs/GO reduced this range and significantly increased the extinction coefficient of the blend. The indirect/direct band gap decreased from 4.3/5.2 eV to 3.0/3.8 eV with increasing fillers content. Moreover, the optical constants of the blend and nanocomposite films were determined. The dielectric measurements revealed that MWCNTs/GO doping increases the defects and results in a larger number of dipoles inside the blend and hence increases the dielectric constant of the blend. In addition, tan (δ) for all films is very small (˂ 0.05) and MWCNTs/GO/blend exhibits conductivity four times greater compared with the pure blend. The conduction mechanism, dielectric modulus, and Cole-Cole plots in the temperature range of 30–110 °C and frequencies in the range of 10−2 Hz–10 MHz were reported. The thermal analyses (TGA and DSC) for the blend and nanocomposite films were performed in the temperature range of 25–550 °C. TGA and DTG revealed three distinct weight-loss events for the samples; 25–122 °C, 229–360 °C, and 365–440 °C. The doped samples were more thermally stable where the blend lost 20% of its weight at 180.9 °C, while after doping with GO and codoping with MWCNTs, this temperature increased to 190.5 and 210.2 °C, respectively. The blend and nanocomposite solutions showed a wide antimicrobial activity against gram-positive and gram-negative bacteria, yeast, and fungi. Specifically, both GO/Ch.–PEO and 0.004%MWCNTs/GO/Ch.–PEO represented the highest antimicrobial against all tested microbes. Staphylococcus aureus ATCC 8095 was founded to be the most sensitive among the examined microbes. Additionally, the least sensitivity to studied solutions was recorded by Penicillium roqueforti. The improvements in the optical and dielectric properties make the prepared nanocomposites suitable for energy storage devices, while the antimicrobial activity suggests the use of GO/Ch.–PEO and MWCNTs/GO/Ch.–PEO nanocomposites for food packaging applications.

Electrospun α-mangosteen–chitosan–poly(ethylene oxide) nanofibers

In this study, electrospun α-mangosteen–chitosan–polyethylene oxide (PEO) nanofibers were produced via electrospinning process. The structure and morphology of nanofibers were evaluated through a field emission scanning electron microscope (FESEM) and Fourier-transform infrared (FTIR) spectroscopy. The FE-SEM demonstrated that the average diameter of electrospun α-mangosteen–chitosan–PEO nanofibers were 125.5 ± 33.6 nm, 91.8 ± 27.1 nm, and 111.7 ± 39.8 nm for 0.025, 0.05, and 0.075% (w/v) α-mangosteen concentration, respectively, meanwhile the average diameter of electrospun chitosan–PEO nanofibers and electrospun α-mangosteen–PEO nanofibers was 124.8 ± 52.8 nm and 153.5 ± 49 nm, respectively. The FE-SEM image of electrospun α-mangosteen–chitosan–PEO nanofibers shows that the higher concentration of PEO resulted in smooth morphology, no beads, and continuous fibers. The morphology of electrospun α-mangosteen–chitosan–PEO nanofibers resulted in a better preservative than the morphology of electrospun α-mangosteen–PEO nanofibers. The FTIR spectra of the electrospun nanofibers demonstrate the presence of characteristic peaks of α-mangosteen, chitosan, and PEO and indicate intermolecular interactions via hydrogen bonds. The average diameter of the electrospun α-mangosteen–chitosan–PEO nanofibers are within the size range of the extracellular matrix of the natural structure. Therefore, the electrospun α-mangosteen–chitosan–PEO nanofibers are the potential for biomedical applications.

Antibacterial activity of chitosan-polyethylene oxide nanofibers containing silver nanoparticles against aerobic and anaerobic bacteria

Bacterial wound infection is one of the foremost prevalent nosocomial infections. The overuse of antibiotics leads to the growing proliferation of antibiotic-resistant microorganisms, a specialty challenging to establish in anaerobic infections and even more so in mixed anaerobic-aerobic disorders. Consequently, alternate munitions are urgently needed to expedite wound healing and bactericidal impacts. Considering this, we determined the properties of antibacterial nanofibers (NFs) generated from electrospun chitosan/polyethylene oxide nanofibers (CS-PEO NFs) integrated with 1% (w/w) silver nanoparticles (SNPs). SNPs were efficiently produced via chemical reduction synthesis and confirmed by color changing to light brown during sonication. SNPs had no discernible influence on the morphology of CS-PEO NFs. Surface Plasmon resonance (SPR) investigated SNPs' size. This technique analyzed that increasing the sonication time to 30 min results in SNP formation with the proper size (4 nm). Following these procedures, the nanofibers' characteristics were assessed using physical and mechanical parameters, viscosity, Field Emission-Scanning Electron Microscopy (FESEM), and Fourier transform-infrared spectroscopy (FT-IR). Transmission electron microscopy (TEM) micrographs demonstrated that SNPs produced in chitosan had adequate dispersion.Moreover, in vitro SNP release and encapsulation efficiency were measured, showing a rapid release of up to 36% in the first two hours, and also the effect of CS-PEO NFs and CS-PEO/SNP NFs on the survival of human dermal fibroblast (HDF) and a normal fibroblast cell line (L929) were investigated by MTT colorimetric assay demonstrated the biocompatibility of cells with CS-PEO/SNP NFs. The nanofibers' antibacterial properties were compared to evaluate the antibacterial effects of SNPs in the form of CS-PEO/SNP NFs against aerobic and anaerobic bacteria. Antibacterial effect against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus was measured as aerobic microorganisms. Although a significant activity against Pseudomonas aeruginosa was observed, it was effective lesser against E. coli and Staphylococcus aureus. Pseudomonas aeruginosa also had an antibacterial impact against anaerobic bacteria such as Streptococcus mutans, Streptococcus sobrinus, and Streptococcus sanguis. CS-PEO/SNP NFs are smashing candidates for wound healing and mixed aerobic-anaerobic infections due to their natural origin and favorable results.

Facile and Green Synthesis of Silver Quantum Dots Immobilized onto a Polymeric CTS-PEO Blend for the Photocatalytic Degradation of p-Nitrophenol.

Immobilization of inorganic metal quantum dots (especially, noble transition metals) onto organic polymers to synthesize nanometal–polymer composites (NMPCs) has attracted considerable attention because of their advanced optical, electrical, catalytic/photocatalytic, and biological properties. Herein, novel, highly efficient, stable, and visible light-active NMPC photocatalysts consisting of silver quantum dots (Ag QDs) immobilized onto polymeric chitosan–polyethylene oxide (CTS–PEO) blend sheets have been successfully prepared by an in situ self-assembly facile casting method as a facile and green approach. The CTS–PEO blend polymer acts as a reducing and a stabilizing agent for Ag QDs which does not generate any environmental chemical pollutant. The prepared x wt % Ag QDs/CTS–PEO composites were fully characterized through X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis, and UV/visible spectroscopy. The characterization results indicated the successful synthesis of the Ag QDs/CTS–PEO composites by the interactions and complexation between x wt % Ag QDs and CTS–PEO blend sheets. TEM images revealed small granules randomly distributed onto the CTS–PEO blend sheets, indicating the immobilization of Ag QDs onto CTS–PEO composites. The presence of a surface plasmon resonance (SPR) band and the shifting of the absorption edge toward higher wavelengths in the UV/vis spectra indicated the formation of x wt % Ag QDs/CTS–PEO composites. The Ag QDs in the polymeric blend matrix led to remarkable enhancement in the optical, thermal, electrical, and photocatalytic properties of x wt % Ag QDs/CTS–PEO composites. The photocatalytic efficiency of the prepared composites was evaluated by the photodegradation of p-nitrophenol (PNP) under simulated sunlight. The maximum photocatalytic degradation reached 91.1% efficiency within 3 h for the 12.0 wt % Ag QDs/CTS–PEO photocatalyst. Generally, the Ag QDs immobilized onto CTS–PEO blend composites significantly enhance the SPR effect and the synergistic effect and reduce the band gap, leading to a high photocatalytic activity.

Evaluation of wound healing efficiency of vancomycin-loaded electrospun chitosan/poly ethylene oxide nanofibers in full thickness wound model of rat

Electrospun hybrid nanofibers have been extensively regarded as drug carriers. This study tries to introduce a nano fibrous wound dressing as a new strategy for a topical drug-delivery system. The vancomycin (VCM)-loaded hybrid chitosan/poly ethylene oxide (CH/PEO) nanofibers were fabricated by the blend-electrospinning process. Morphological, mechanical, chemical, and biological properties of nanofibers were examined by SEM, FTIR, release profile study, tensile assay, Alamar Blue cytotoxicity evaluation, and antibacterial activity assay. In vivo wound healing activity of hybrid CH/PEO/VCM nanofibers was evaluated in full-thickness skin wounds of rats. The hybrid CH/PEO/VCM nanofibers were successfully fabricated in a nanometer. The CH/PEO/VCM 2.5% had higher Young's Modulus, better tensile strength, smaller fiber diameter with sustained-release profiles compared to CH/PEO/VCM 5%. All nanofibers did not show any significant cytotoxicity (P < 0.05) on the normal fibroblast cells. Also, VCM-load hybrid CH/PEO nanofibers successfully inhibited bacterial growth. The wound area in the rats treated with CH/PEO/VCM 2.5% was less than CH/PEO/VCM 5% treated group. According to histological evaluation, the CH/PEO/VCM 2.5% group showed the fastest wound healing than other treatment groups. Results of this study proposed that CH/PEO/VCM nanofibers could promote the wound healing process by reducing the side effects of VCM as a topical antimicrobial agent.

Glutaraldehyde-crosslinked chitosan-polyethylene oxide nanofibers as a potential gastroretentive delivery system of nizatidine for augmented gastroprotective activity

Nizatidine (NIZ), a histamine H2-receptor antagonist, is soluble and stable in the stomach, however, it exhibits a short half-life and a rapid clearance. Therefore, chitosan (CS) and polyethylene oxide (PEO) nanofibers (NFs) at different weight ratios were prepared by electrospinning and characterized. The selected uncrosslinked and glutaraldehyde-crosslinked NFs were investigated regarding floating, solid-state characteristics, in vitro release, and in vitro cytotoxicity. The cytoprotective activity against ethanol-induced gastric injury in rats was evaluated through macroscopical, histopathological, immunohistochemical, and oxidative stress examinations. NFs based on 8:2 CS:PEO exhibited the smallest diameter (119.17 ± 22.05 nm) and the greatest mucoadhesion (22.82 ± 3.21 g/cm2), so they were crosslinked with glutaraldehyde. Solid-state characterization indicated polymers interaction, a successful crosslinking, and NIZ dispersion in NFs. Crosslinking maintained swollen mats at pH 1.2 (swelling% = 29.47 ± 3.50% at 24 h), retarded their erosion at pH 6.8 (swelling%= 84.64 ± 4.91% vs. 25.40 ± 0.79% for the uncrosslinked NFs at 24 h), augmented the floating up to 24 h vs. 10 min for the uncrosslinked NFs at pH 1.2 and prolonged the drug release (%drug released ≥ 93% at 24 h vs. 4 and 5 h for the uncrosslinked NFs at pHs 1.2 and 6.8, respectively). The viability of Caco-2 cells ≥ 86.87 ± 6.86% revealed NFs biocompatibility and unreacted glutaraldehyde removal. Crosslinking of 8:2 CS:PEO NFs potentiated the antiulcer activity (38.98 vs. 8.67 for the uncrosslinked NFs) as well as it preserved the gastric wall architecture, COX-2 expression, and oxidative stress markers levels of the normal rats.

Cerium-doped bioactive glass-loaded chitosan/polyethylene oxide nanofiber with elevated antibacterial properties as a potential wound dressing

In this study, 5 different electrospun chitosan-based scaffolds were fabricated for wound healing applications using benign solvents. Researchers have reported that chitosan/PEO scaffolds are generally unstable in aqueous solutions and have poor mechanical properties particularly in wet conditions, therefore we had to tackle these problems by modifying the scaffolds. The ratio of chitosan to PEO was equal in all of our scaffolds but they contained different amounts of cerium doped bioactive glass (Ce-BG). In a previous study performed by the same authors of this study, the morphology, structure, chemical bonding, cell biocompatibility, and cell cultures of the five scaffolds were analyzed. Meanwhile, the parameters studied in this study were antibacterial activity against gram-positive and gram-negative bacteria cells, mechanical properties, ion release behavior, and swelling properties. Results indicated that although increasing Ce-BG/CH (w/w) ratio up to 20% (w/w) improved the swelling degree and mechanical properties of the scaffolds significantly, increasing the ratio beyond 20% (w/w) reduced the useful effects of Ce-BG on the mentioned properties. The latter phenomenon was probably due to the agglomeration of Ce-BG nanoparticles. Even though the agglomeration of Ce-BG nanoparticles had some adverse effects, it did not affect the antibacterial activity and ion release behavior of the scaffolds. In fact, those properties continued to improve up to a ratio of Ce-BG/CH = 40% (w/w). It is worth noting, however, that increasing the Ce-BG/CH (w/w) ratio to 40% significantly improved the antibacterial activity of the scaffolds against gram-negative E. coli bacteria cells, but not against gram-positive S. aureus. Since none of the as-electrospun scaffolds had satisfactory mechanical properties in wet conditions, a modified sample was fabricated to enhance those properties. The modifications involved coating Ce-BGs nanoparticles with chitosan before inserting them into chitosan-polyethylene oxide electrospinning solutions. In the dried state, the modified sample had a 287% and 889% increase in tensile strength and an 88% and 330% increase in peak strain compared to the unmodified version of the sample and the base scaffold, respectively. Overall, the modified scaffold in its wet state had mechanical properties very close to the skin and its elongation at break was 28.6%, which was only 20% less than the required elongation at break for skin tissue scaffolds.

Synthesis of silver nanoplates on electrospun fibers via tollens reaction for SERS sensing of pesticide residues.

Silver nanoplates were for the first time synthesized on electrospun chitosan/polyethylene oxide (CS/PEO) fibers via tollens reaction. Ag nanoplates/CS/PEO fibers were used as the SERS-active substrates for quantitative evaluation of 2-naphthylthiol, with an enhancement factor (1.41± 0.07)× 106. The SERS-active substrates are flexible, stable, and easy for transportion and preservation, and act as the SERS platform for sensitive detection of the target. Thiram and thiabendazole as the representatives of pesticide residues were identified and detected by the Ag nanoplates/CS/PEO fibers, exhibiting linear response ranges from 10-11 to 10-7M with a detection limit of 10-11 M. The Ag nanoplates/CS/PEO fibers meet the requirement of thiram detection in practical samples, such as apple, pear, tomato, and cucumber juices. The strategy revealed the feasibility of fabrication of Ag nanoplates on electrospun fibers via tollens reaction and SERS sensing of pesticides in real samples. Ag nanoplates/CS/PEO fibers were fabricated by tollens reaction and electrospinning for SERS sensing of pesticide residues with high sensitivity.

Chitosan-PEO nanofiber mats for copper removal in aqueous solution using a new versatile electrospinning collector

Electrospun chitosan–polyethylene oxide nanofiber mats were fabricated using a new collector design. Besides being reusable, it allows to assess the desired morphology of the mat in a quicker way. To test its efficiency, nonwoven mats designed for water treatment applications were prepared using conditions never been reported before. Under these conditions, continuous and flawless nanofibers of 151 ± 36 nm in diameter were achieved. Adsorption capacity of the mats for copper ions in aqueous solutions were investigated. Results showed that sorption equilibrium was achieved within 150 min with a homogenous distribution of copper ions within the nanofibrous mats. The pseudo-second order kinetic model best fitted the experimental data. The Langmuir isotherm best described the sorption process with a maximum adsorption capacity of 124 mg/g for trial temperatures ranging from 25 to 60 °C. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) demonstrate that the adsorption was feasible, endothermic and spontaneous. The desorption potential and mat’s reusability were also studied. Results reveal that the electrospun chitosan mats can be desorbed and reused up to 5 cycles without significant loss in adsorption performance.

Anti-Leishmanial Effects of Chitosan-Polyethylene Oxide Nanofibers Containing Berberine: An Applied Model for Leishmania Wound Dressing.

Background: Leishmaniasis is the most important parasitic disease in Iran and is the third highest rate of rural cutaneous leishmaniasis in the world. Chitosan-polyethylene oxide nanocomposite fibers can be a suitable replacement for ordinary bandages. For the first time, in the absence of any published reports, the present in vitro study aimed to evaluate the anti-leishmanial effects of chitosan (CS)-polyethylene oxide (PEO)-berberine nanofibers on Leishmania major.Methods: The present experimental study was conducted in 2018 in Tehran, Iran. The CS-PEO nanofibers containing berberine, as a natural anti-parasitic agent, were prepared using the electrospinning technique. Biocompatibility and fibroblast proliferation on nanofibers were investigated. In addition, the anti-leishmanial activity of CS-PEO nanofibers in both the promastigote and amastigote stages of Leishmania major was evaluated after parasite vital staining and MTT assay and compared to a control group. Statistical analysis was performed using SPSS software (version 18.0). Statistically significant differences were determined using the one-way ANOVA. The Duncan and Dunnett post hoc tests were used for within-group comparisons. P<0.05 was considered statistically significant.Results: The results showed that nanofiber scaffolds with a mean diameter of 77.5±19.5 nm were perfect, regular, bead-free, and non-toxic, on which fibroblast cells grew well and proliferated. In addition, the optical density indicated that berberine 20% (w/v) significantly prevented promastigotes growth (IC50=0.24 μg/mL) and amastigotes death (IC50=0.91 μg/mL) compared with other concentrations and the control group.Conclusion: The study on the cytotoxic effects showed that CS-PEO-berberine nanofibers had strong lethal effects on Leishmania major in promastigote and amastigote stages in vitro. Further studies are required to investigate the effects of this nanofiber on leishmanial ulcers in laboratory animals and clinical cases.

Stabilization of chitosan-polyethylene oxide electrospun nanofibrous containing Colocasia esculenta tuber protein

In this study, protein in Colocasia esculenta tuber (CET) combined with polyethylene oxide (PEO) and chitosan were fabricated by electrospinning, which could be further stabilized by heat treatment and compared with glutaraldehyde vapor. CET’s protein containing 6.6% protein with molecular weight 53.5, 42, 24.4, 11.8, and 9.8 kDa shows no cytotoxicity and has the potential growth-stimulatory activities on NIH-3T3 fibroblast cell. The 10% (v/v) acetic acid was found as an appropriate solvent to electrospun the CET’s protein-chitosan-PEO solution. The influence of conductivity, surface tension, and viscosity in the solution of CET’s protein, chitosan, and PEO on nanofibers morphology was successfully demonstrated. The scanning electron microscope shows that the average diameter of the CET’s protein-chitosan-PEO nanofibers decreased with the increased of chitosan and CET’s protein content. The chemical and physical stabilization of nanofibers exhibits an increase in the fiber diameter up to 157%. The presence of 1% (w/v) chitosan resulted in a better preservative of the nanofibrous structure after the stabilization process. By the confirmation using Fourier transform infrared spectroscopic data, it is concluded that stabilization techniques applied in this study are promising to improve the value of CET’s protein-chitosan-PEO nanofiber in medical purposes.

Fabrication of triple layer composite membrane and its application in membrane distillation (MD): Effect of hydrophobic-hydrophilic membrane structure on MD performance

Electrospinning is a notable technique to prepare nanofibrous membranes with remarkable features required for membrane distillation (MD). However, hydrophobic membrane fabricated by electrospinning alone could hardly ensure a high flux. In this study, triple layer membrane that is composed of a PVDF-PTFE hydrophobic layer, a PET support layer, and a chitosan-polyethylene oxide (CS-PEO) hydrophilic layer, was fabricated by electrospinning. Firstly, the PVDF-PTFE and CS-PEO layers were optimized, whose contact angles and thicknesses were 144.3°, 55 μm and 20°, 75 μm, respectively. Then, the triple layer membrane (TL-M), dual layer membrane without hydrophilic layer (DL-M) were fabricated and tested in a DCMD process using 3.5 wt% NaCl as the feed to illustrate the effect of hydrophilic layer. The triple layer composite membrane (average flux: 19 kg/m−2 h−1, rejection rate: 99.92%) showed better performance in comparison to the dual-layer membrane (average flux: 15 kg/m−2 h−1, rejection rate: 99.88%). In addition, the driving forces of TL-M (from 14.34 to 14.16 kPa) and DL-M (from 13.26 to 12.88 kPa) were calculated. Results suggested the incorporation of hydrophilic layer could increase the driving force, and largely enhance the membrane flux which could ensure the triple layer membrane possesses a good potential for DCMD application.

Enhanced performance of Aloe vera incorporated chitosan-polyethylene oxide electrospun wound scaffold produced using novel Spirograph based collector assembly

Spirograph is a geometric drawing that produces mathematical roulette curves of the variety technically known as hypotrochoids and epitrochoids. This paper presents a research on a novel Spirograph Based Mechanical System (SBMS) meant for the production of electrospun mat with near uniform characteristics for wound dressing applications. A combination of natural (Chitosan) and artificial (Polyethylene oxide) polymer, along with Aloe vera plant extract has been evaluated as a material for wound dressing application. The improvement in the mechanical property, in vitro and in vivo studies indicate developed SBMS compared to the typical collectors has been found suitable for producing electrospun mat for wound dressing applications.

Sandwich-Like Nanofibrous Scaffolds for Bone Tissue Regeneration.

Advanced bone healing approaches included a wide range of biomaterials that mainly mimic the composition, structure, and properties of bone extracellular matrix with osteogenic activity. The present study aimed to develop a sandwich-like structure of electrospun nanofibers (NFs) based on polycaprolactone (PCL) and chitosan/polyethylene oxide (CS/PEO) composite to stimulate bone fracture healing. The morphology of the fabricated scaffolds was examined using scanning electron microscopy (SEM). Apatite deposition was evaluated using simulated body fluid (SBF). The physicochemical and mechanical properties of samples were analyzed by Fourier transform infrared, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and universal testing machine. SEM images exhibited a porous three-dimensional structure with NF diameters of 514-4745 nm and 68-786 nm for PCL NFs layer and the sandwich-like NFs scaffolds, respectively. Deposition of apatite crystal on scaffolds started at week 2 followed by heavy deposition at week 8. This was confirmed by measuring the consumption of calcium and phosphorous ions from SBF. Thermal stability of scaffolds was confirmed using DSC and TGA. Moreover, the PCL NF layer in the middle of the developed sandwich structure reinforced the scaffolds with bear load up to 12.224 ± 1.12 MPa and Young's modulus of 17.53 ± 3.24 MPa. The scaffolds' porous structure enhanced both cell propagation and proliferation. Besides, the presence of CS in the outer NF layers of the scaffolds increased the hydrophilicity, as evidenced by the reduction of contact angle from 116.6 to 57.6°, which is essential for cell attachment. Cell viability study on mesenchymal stem cells proved the cytocompatibility of the fabricated scaffolds. Finally, in vivo mandibular bone defect rabbit model was used to confirm the regeneration of a new healthy bone within 28 days. In conclusion, the developed scaffolds could be a promising solution to stimulate bone regeneration.

Application of polycaprolactone, chitosan, and collagen composite as a nanofibrous mat loaded with silver sulfadiazine and growth factors for wound dressing.

Fabrication of nanofibrous biomaterials composed of natural and synthetic materials that incorporated with antibiotic and growth factors with controlled release manner is an attractive topic in wound healing. The purpose of this study was to prepare optimal composite of materials as biomimetic nanofibrous mats for application in wound healing. The mat was prepared of polycaprolactone (PCL) in the bottom, chitosan/poly ethylene oxide (Cs/PEO) in the middle, and PCL/collagen (PCL/Coll) in the top layer. A panel of standard characterization tests of nanofibrous mat was performed and its compatibilities in strength and integration were confirmed. Middle layer was loaded with epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), and silver sulfadiazine (SSD) was incorporated in the bottom layer as an anti-infection factor. Then, on the dorsum of rats, a 400-mm2 wound was created and surrounded by a silicone ring to control the usual tissue contractions. Nanofibrous mats with or without growth factors were applied as wound dressings and at day 14, the healing process was evaluated. At day 14, the treated group by designed mat showed faster epithelialization and angiogenesis. Silicone ring in the test group was desirable in wound closure compared to the control group. Reformation of skin tissue was manifested in a shorter time. This composite nanofibrous mat could be introduced as a dynamic and effective candidate for wound dressing.

Preparation and Evaluation of Composite Nanofibers Containing Vancomycin

Background: Electrospinning of chitosan/poly ethylene oxide (CS/PEO) and poly caprolactone (PCL)/ CS/ PEO/ solutions with the addition of vancomycin to create nanofibers with antibacterial properties were examined. Methods: Polymeric nanofibers including CS/PEO and PCL /CS/PEO/ vancomycin were produced by electrospinning method. The morphology of electrospun nanofibers was studied with use of scanning electron microscopy (SEM). Moreover, the chemical structures of the nanofibers were evaluated by FT-IR. The drug release of nanofibers was also investigated by UV-Vis spectrophotometry. The antibacterial activity of scaffolds was tested by two type bacteria including Streptococcus pyogenes and Staphylococcus aureus. Results: The SEM images indicated that the addition of vancomycin as much as 0/8wt brings about the best nanofiber. Also, the morphology of electrospun nanofiber is dependent on the viscosity of the solution and the ratio of PCL/CS /PEO/vancomycin. According to the results of vancomycin releasing from nanofibers, the best results were obtained in the presence of PCL/ CS/PEO/0/8wt vancomycin nanofibers as healing sample. Conclusion: The result of antibacterial activity of nanofiber and drug releasing showed this nanofiber can used as an antibacterial coating to prevent the spread of infections in the wound surface.

Fabrication of Chitosan-Polyethylene Oxide Polymeric Thin Film Using Electrochemical Deposition for Detection of Volatile Organic Compounds

This study focused on the fabrication of chitosan-polyethylene oxide sensitive thin film. The polyethylene oxide was used as an additive to enhance the electrical properties of chitosan towards ethanol and methanol gases. The chitosan-polyethylene oxide sensitive film was fabricated using electrochemical deposition technique to deposit a thin film of the sensitive blend on the printed circuit board surface. The sensitive blend electrical (I-V) properties were tested using a specific developed test chamber. Ethanol and methanol volatile organic compound gases were chosen in this work to study the thin sensing properties of the chitosan-polyethylene oxide film. The analyzed data demonstrated that chitosan-polyethylene oxide sensitive film was capable to detect the VOC gas molecules and showed that the sensitive blend was significantly selective to ethanol over methanol gas with output values of 0.31 µA and 0.023 µA respectively. Atomic force microscopy test was used to characterize the morphology and roughness of the pure chitosan and chitosan-polyethylene oxide sensitive films.

Controlled release of cefazolin sodium antibiotic drug from electrospun chitosan-polyethylene oxide nanofibrous Mats

Antimicrobial electrospun chitosan–polyethylene oxide (CS-PEO) nanofibrous mats containing cefazolin, fumed silica (F. silica) and cefazolin-loaded fumed silica nanoparticles (NPs) were produced for biomedical applications. The FE-SEM images revealed that the F. silica and F. silica-cefazolin NPs had average diameters of 40±10 and 60±15nm, respectively. Also, the fibers diameters were approximately 160±30, 90±20 and 70±15nm for the pure CS-PEO, CS-PEO-1% F. silica and CS-PEO-1% F. silica-0.5% cefazolin nanofibrous mats, respectively indicating addition of F. silica and cefazolin loaded F. silica NPs to the CS-PEO mat led to decreasing the nanofiber diameter. Both of the CS-PEO mats containing 2.5% cefazolin and 1% F. silica-0.50% cefazolin showed 100% bactericidal activities against both S. aureus and E. coli bacteria. The cefazolin release from mats was sharply increased within first 24 and 6hours for the CS-PEO mats including 2.5% cefazolin and 1% F. silica-0.50% cefazolin but after that the drug was released very slowly. The improved hydrophilicity, higher tensile strength and sustained drug release for CS-PEO-1% F. silica-0.50% cefazolin suggested that it was the best nanocomposite tissue/device for biomedical applications among the mats CS-PEO-2.5% cefazolin and CS-PEO-1% F. silica. The wound healing ability of the CS-PEO-F. silica-cefazolin mat was evaluated on the wounded skins of the female Wistar rats and it was shown that the wounded skins of the rats were almost entirely healed after ten days using this mat as a wound dressing scaffold.