Fabrication of antibacterial silver nanoparticle‐modified chitosan fibers using Eucalyptus extract as a reducing agent

Green chemical method could be a promising route to achieve large scale synthesis of nanostructures for biomedical applications. Here, we describe a green chemical synthesis of silver nanoparticles (Ag NPs) on chitosan‐based electrospun nanofibers using Eucalyptus leaf extract. A series of silver salt (AgNO₃) amounts were added to a certain composition of chitosan/polyethylene oxide aqueous acetic acid solution. The solutions were then electrospun to obtain nanofibrous mats and then, morphology and size of nanofibers were analyzed by scanning electron microscopy (SEM). Incubation of AgNO₃‐containing mats into Eucalyptus leaf extract led to the formation of Ag NP clusters with average diameter of 91 ± 24 nm, depicted by SEM and transmission electron microscopy. Surface enhanced Raman spectroscopy also confirmed formation of Ag NPs on the nanofibers. The mats also showed antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria with bigger inhibition zone for extract‐exposed mats against S. aureus. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42133.     

Photocatalytic degradation of dairy effluent using AgTiO2 nanostructures/polyurethane nanofiber membrane

Dairy effluent (DE) is environmentally toxic and needs special attention. Photocatalytic degradation of DE was studied using novel polyurethane (PU)-based membranes. Typically, silver–titanium dioxide nanofibers (AgTiO₂ NFs) and silver–titanium dioxide nanoparticles (AgTiO₂ NPs) were individually incorporated in PU electrospun nanofibers to overcome the mandatory sophisticated separation of the nanocatalysts, which can create a secondary pollution, after the treatment process. These nanomembranes were characterized in SEM, TEM, XRD and UV studies. The polymeric electrospun nanofibers were smooth and continuous, with an average diameter of about 550 nm, and held their nanofibrous morphology even after more than 2 h of photocatalytic degradation of DE, due to the good stability of PU in the aqueous solutions, which indicates good imprisoning of the functional photocatalysts. The PU–AgTiO₂ NPs and PU–AgTiO₂ NFs were effective materials for degradation of DE, even after two successive cycles. PU–AgTiO₂ NPs and PU–AgTiO₂ NFs showed a maximum degradation of 75% and 95%, respectively after 2 h. The significant enhancement of degradation in the PU–Ag–TiO₂ NPs and PU–Ag–TiO₂ NFs is attributed to the photoactivity of Ag–TiO₂ material under visible light irradiation.     

Antibacterial polycaprolactone electrospun fiber mats prepared by soluble eggshell membrane protein–assisted adsorption of silver nanoparticles

Antibacterial polycaprolactone (PCL) electrospun fiber mats were prepared by coelectrospinning PCL with soluble eggshell membrane protein (SEP) in 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP), followed by adsorption of silver nanoparticles (Ag NPs) through hydrogen‐bonding interaction between the amide groups of SEP and the carboxylic acid groups capped on the surfaces of Ag NPs. The PCL/SEP fiber mat was characterized by X‐ray photoelectron spectroscopy, indicating the presence of some SEP on the fiber surface. The adsorption of Ag NPs was confirmed by transmission electron microscopy and quantitatively characterized by thermogravimetric analysis. The pH value of the silver sol used for adsorption is very important in view of the amount and dispersion state of Ag NPs adsorbed on the fibers. The Ag NP–decorated PCL/SEP fiber mats prepared at pH 3–5 exhibit strong antibacterial activity against both gram‐negative Escherichia coli and gram‐positive Bacillus subtilis. Antibacterial PCL fiber mats were also obtained similarly with the assistance of collagen (another protein) instead of SEP, showing that protein‐assisted adsorption of Ag NPs is a versatile method to prepare antibacterial electrospun fiber mats. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43850.     

Sea‐island polyurethane/polycarbonate composite nanofiber fabricated through electrospinning

Sea‐island polyurethane (PU)/polycarbonate (PC) composite nanofibers were obtained through electrospinning of partially miscible PU and PC in 3 : 7 (v/v) N,N‐dimethylformamide (DMF) and tetrahydrofuran (THF) mixture solvent. Their structures, mechanical, and thermal properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG), and differential scanning calorimetry (DSC). The structures and morphologies of the nanofibers were influenced by composition ratio in the binary mixtures. The pure PC nanofiber was brittle and easy to break. With increasing the PU content in the PU/PC composite nanofibers, PU component not only facilitated the electrospinning of PC but improved the mechanical properties of PU/PC nanofibrous mats. In a series of nanofibrous mats with varied PU/PC composition ratios, PU/PC 70/30 showed excellent tensile strength of 9.60 Mpa and Young's modulus of 55 Mpa. After selective removal of PC component in PU/PC composite nanofibers by washing with acetone, the residual PU maintained fiber morphology. However, the residual PU nanofiber became irregular and contained elongated indents and ridges along the fiber surface. PU/PC composite fibers showed sea‐island nanofiber structure due to phase separation in the spinning solution and in the course of electrospinning. At PC content below 30%, the PC domains were small and evenly dispersed in the composite nanofibers. As PC content was over 50%, the PC phases became large elongated aggregates dispersed in the composite nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of ampicillin‐incorporated electrospun polyurethane scaffolds for wound healing and infection control

Electrospinning is a desired method to produce interconnected flexible nanofibrous structures suitable for tissue engineering, drug delivery, and wound healing. Ampicillin‐loaded polyurethane (PU) nanofiber mats were electrospun with the antibiotic dispersed in well‐oriented nanofibers. The identification of functional groups, molecular interactions and surface morphology of the fibers were analyzed using Infrared, Raman, ¹H NMR, SEM, and TEM. Weak interactions exist between the functional groups of ampicillin and PU in electrospun fibers at ratios 1:10, 1.5:10, and 2:10. The effect of β‐lactam antibiotic ampicillin on the characteristics of electrospun PU was studied using XRD, TGA, and DSC. Their antibacterial property is proved by good zone of inhibition against Staphylococcus aureus and Klebsiella pneumonia. Cytotoxicity tests on the electrospun scaffolds were performed with normal human keratinocyte cells (HaCaT cells). Results indicate that ampicillin‐incorporated PU scaffolds are well suited for applications in wound healing and infection control. POLYM. ENG. SCI., 55:541–548, 2015. © 2014 Society of Plastics Engineers     

Electrospun polyurethane patch in combination with cedarwood and cobalt nitrate for cardiac applications

The growth in nanotechnology led to the fabrication of scaffold at a low cost with high productivity and high surface area. The present research aims to fabricate a novel cardiac scaffold utilizing polyurethane (PU) added with cedarwood (CW) and cobalt nitrate (CoNO₃) nanofibers. Morphological analysis showed that the mean fiber diameter of the PU nanofibers was reduced owing to the incorporation of CW and CoNO₃. Infrared and thermal analysis revealed the interaction of PU with CW and CoNO₃. Contact angle studies showed that the electrospun PU/CW displayed hydrophobic nature while PU/CW/CoNO₃ showed hydrophilic behavior compared to the pristine PU. The tensile strength of PU nanofibers increased with CW and CoNO₃ addition. Atomic force microscopy analysis depicted that the PU/CW was rougher while the PU/CW/CoNO₃ as smoother surfaces than the pristine PU. According to the coagulation assay data, the blood compatibility of the electrospun composites was enhanced compared to the pristine PU. In addition, PU and its composite nanofibers exhibited non-toxic to human dermal fibroblast cells and improved cell proliferation rates compared to the control plates. To conclude, the improved physicochemical and biological response of the electrospun composites would be putative for cardiac tissue engineering. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48226.     

Effects of Fe2+ ions on morphologies,microstructures and mechanical properties of electrospun nylon‐6 nanofibers

In this study, nylon‐6 nanofiber mats containing Fe²⁺ ions were fabricated via electrospinning. The resultant electrospun nylon‐6/FeCl₂ nanofiber mats were characterized by SEM, TEM, Fourier transform IR spectroscopy, wide angle XRD and DSC. Unique morphological features, such as spider's‐web‐like morphologies, were observed and became evident with increasing additive Fe²⁺ ions. The metastable γ form was predominant in the as‐spun nylon‐6 nanofibers. The relative intensity of such γ form gradually decreased with increasing additive Fe²⁺ ions, indicative of transformation of the crystalline structure in the electrospun nylon‐6/FeCl₂ nanofibers due to strong molecular interactions between the nylon‐6 backbone and the additive Fe²⁺ ions. The effects of additive Fe²⁺ ions on the mechanical properties of both nonwoven nanofiber mats and single nanofibers were investigated. In particular, Young's modulus of nylon‐6/FeCl₂ single nanofibers gradually increased from 1.46 to 5.26 GPa with increasing additive Fe²⁺ ions. © 2013 Society of Chemical Industry     

Bimetallic Zn/Ag doped polyurethane spider net composite nanofibers: A novel multipurpose electrospun mat

The objective of this study was to develop a new class of bimetallic ZnO/Ag embedded polyurethane multi-functional nanocomposite by a straightforward approach. Bimetallic nanomaterials, composed of two unlike metal elements, are of greater interest than the monometallic materials because of their improved characteristics. In the present study the bimetallic composite was prepared using sol–gel via the facile electrospinning technique. The utilized sol–gel was composed of zinc oxide, silver and poly(urethane). The physicochemical properties of as-spun composite mats were determined by X-ray diffraction pattern, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. The antibacterial activity was tested using Escherichia coli as model organism. The antibacterial test showed that ZnO:Ag/polyurethane composite possesses superior antimicrobial activity than pristine PU and ZnO/PU hybrids. Furthermore, our results illustrate that the synergistic effect of ZnO and Ag resulted in the advanced antimicrobial action of bimetallic ZnO/Ag composite mat. The viability and proliferation properties of NIH 3T3 mouse fibroblast cells on the ZnO:Ag/polyurethane composite nanofibers were analyzed by in vitro cell compatibility test. Our results indicated the non-cytotoxic behavior of bimetallic ZnO:Ag/polyurethane nanofibers towards the fibroblast cell culture. In summary, novel ZnO:Ag/polyurethane composite nanofibers which possess large surface to volume ratio with excellent antimicrobial activity were fabricated. The unique combination of ZnO and Ag nanoparticles displayed potent bactericidal effect due to a synergism. Hence the electrospun bimetallic composite indicates the huge potential in water filtration, clinical and biomedical applications.     

Electrospun antibacterial nylon nanofibers through in situ synthesis of nanosilver: preparation and characteristics

A new method for production of nylon nanofibers with antibacterial properties containing silver nanoparticles (nylon nanofibers/Ag NPs) is introduced via in situ synthesis of nano-silver by reduction of silver nitrate in the polymer solution prior to electrospinning. The properties of the electrospinning solutions and the structures of the electrospun fibers were studied using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), UV?Cvis spectrophotometer and reflection spectrophotometer. Further, the antibacterial properties of the nanofibers were investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. Interestingly, an antibacterial properties has been found on nylon 6 nanofibers while the nylon nanofibers/Ag NPs showed excellent antibacterial activities against both tested bacteria. The produced nylon nanofibers/Ag NPs can be a good candidate for biomedical applications, water and air filtration.     

Preparation of antimicrobial poly(ϵ‐caprolactone) electrospun nanofibers containing silver‐loaded zirconium phosphate nanoparticles

Antimicrobial nanofibers of poly(?‐caprolactone) (PCL) were prepared by electrospinning of a PCL solution with small amounts of silver‐loaded zirconium phosphate nanoparticles (nanoAgZ) for potential use in wound dressing applications. The electrospun nanoAgZ‐containing PCL nanofibers were characterized using field emission scanning electron microscopy, energy dispersive X‐ray spectrum (EDX), X‐ray diffraction analysis (XRD), antimicrobial tests, and biocompatibility tests. The SEM, EDX, and XRD investigations of the electrospun fibers confirmed that silver‐containing nanoparticles were incorporated and well dispersed in smooth and beadless PCL nanofibers. The results of the antimicrobial tests showed that these fibers have maintained the strong killing abilities of Ag⁺ existed in the nanoAgZ against the tested bacteria strains and discoloration has not been observed for the nanofibers. To test the biocompatibility of nanofibers as potential wound dressings, primary human dermal fibroblasts (HDFs) were cultured on the nanofibrous mats. The cultured cells were evaluated in terms of cell proliferation and morphology. The results indicated that the cells attached and proliferated as continuous layers on the nanoAgZ‐containing nanofibers and maintained the healthy morphology of HDFs. The earlier results suggested that nanoAgZ‐containing fibers may be expected to be a novel material for potential wound dressing applications because of the significant bacteriostatic activities and good biocompatibility. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Fabrication of protein‐doped PLA composite nanofibrous scaffolds for tissue engineering

BACKGROUND: Electrospinning is known as a novel fabrication method to form nanofibrous scaffolds for tissue‐engineering application. Previously, many natural biopolymers of protein have been electrospun. However, keratin has not attracted enough attention. In this study, keratin and gelatin were co‐electrospun with polylactide (PLA), respectively. RESULTS: The resulting nanofibers were characterized by a field emission scanning electron microscope (FE‐SEM), an attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR), and an electron spectroscopy for chemical analysis (ESCA). The biodegradation of mats in the presence of trypsin solution was studied. Cell attachment experiments showed that NIH 3T3 cells adhered more and spread better onto the PLA/keratin and PLA/gelatin nanofibrous mats than that onto the blank PLA mats. MTT and BrdU assay showed that PLA/keratin and PLA/gelatin nanofibrous mats could both accelerate the viability and proliferation of fibroblast cells as compared to PLA nanofibrous mats. CONCLUSION: The present study suggests that the introduction of gelatin and keratin can both improve cell‐material interaction, especially, the former is more effective. Copyright © 2008 Society of Chemical Industry     

Studies on the synthesis of electrospun PAN‐Ag composite nanofibers for antibacterial application

We have successfully synthesized polyacrylonitrile (PAN) nanofibers impregnated with Ag nanoparticles by electrospinning method at room temperature. Briefly, the PAN‐Ag composite nanofibers were prepared by electrospinning PAN (10% w/v) in dimethyl formamide (DMF) solvent containing silver nitrate (AgNO₃) in the amounts of 8% by weight of PAN. The silver ions were reduced into silver particles in three different methods i.e., by refluxing the solution before electrospinning, treating with sodium borohydride (NaBH₄), as reducing agent, and heating the prepared composite nanofibers at 160°C. The prepared PAN nanofibers functionalized with Ag nanoparticles were characterized by field emission scanning electron microscopy (FESEM), SEM elemental detection X‐ray analysis (SEM‐EDAX), transmission electron microscopy (TEM), and ultraviolet‐visible spectroscopy (UV‐VIS) analytical techniques. UV‐VIS spectra analysis showed distinct absorption band at 410 nm, suggesting the formation of Ag nanoparticles. TEM micrographs confirmed homogeneous dispersion of Ag nanoparticles on the surface of PAN nanofibers, and particle diameter was found to be 5–15 nm. It was found that all the three electrospun PAN‐Ag composite nanofibers showed strong antibacterial activity toward both gram positive and gram negative bacteria. However, the antibacterial activity of PAN‐Ag composite nanofibers membrane prepared by refluxed method was most prominent against S. aureus bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and properties of silver‐containing nylon 6 nanofibers formed by electrospinning

Nylon 6 nanofibers containing silver nanoparticles (nylon 6/silver) were successfully prepared by electrospinning. The structure and properties of the electrospun fibers were studied with the aid of scanning electron microscopy, transmission electron microscopy, energy‐dispersive spectroscopy, and X‐ray diffraction. The structural analysis indicated that the fibers electrospun at maximum conditions were straight and that silver nanoparticles were distributed in the fibers. Finally, the antibacterial activities of the nylon 6/silver nanofiber mats were investigated in a broth dilution test against Staphylococcus aureus (Gram‐positive) and Klebsiella pneumoniae (Gram‐negative) bacteria. It was revealed that nylon 6/silver possessed excellent antibacterial properties and an inhibitory effect on the growth of S. aureus and K. pneumoniae. On the contrary, nylon 6 fibers without silver nanoparticles did not show any such antibacterial activity. Therefore, electrospun nylon 6/silver nanocomposites could be used in water filters, wound dressings, or antiadhesion membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Spider-net within the N6, PVA and PU electrospun nanofiber mats using salt addition: Novel strategy in the electrospinning process

Electrospun nanofibers are promising candidates in the nanotechnological applications due to the advantages of the nanofibrous morphology. Therefore, many attempts were reported to modify the electrospun mats to gain more beneficial properties. In the present study, we are introducing a strategy to synthesize electrospun polymeric nanofiber mats containing spider-net binding the main nanofibers. Addition with long stirring time of a metallic salt having tendency to ionize rather than formation of sol–gel in the host polymer solution reveals to synthesize a spider-net within the electrospun nanofibers of the utilized polymer. Nylon6, polyurethane and poly(vinyl alcohol) have been utilized; NaCl, KBr, CaCl₂ and H₂PtCl₆ have been added to the polymeric solutions. In the case of nylon6 and poly(vinyl alcohol), addition of the inorganic salts resulted in the formation of multi-layers spider-network within the electrospun nanofibers mats. The synthesized spider-nets were almost independent on the nature of the salt; the optimum salt concentration was 1.5 wt%. The metallic acid led to form trivial spider-nets within both of nylon6 and poly(vinyl alcohol) nanofibers. In a case of polyurethane, few spider-nets were formed after salt addition due to the low polarity of the utilized solvents. According to TEM analysis, the synthesized spider-net consisted of joints; the later issued from the main nanofibers at Taylor's cone zone. The spider-net improved the mechanical properties and the wetability of the nylon6 nanofiber mats, accordingly a mat having amphiphilic feature has been prepared.     

Preparation and characterization of electrospun polyurethane/inorganic‐particles nanofibers

To develop a novel functional fibrous scaffold, a blend‐electrospinning technique was applied to transfer polyurethane/inorganic‐particles solutions into nanofibers, in which titanium dioxide, copper, or/and silver nanoparticles were used. The resultant nanofibers were subsequently characterized by means of scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and tensile mechanical test. Furthermore, the structural change and the thermal properties of the electrospun fabrics were examined by X‐ray diffraction and differential scanning calorimetry, respectively. Antibacterial performance of the resulting nanofibrous mats on Escherichia coli and Staphylococcus aureus was also measured. Experimental results have shown that when the ratio of polyurethane solution and titanium dioxide sol was in 3.5:1, 89.55% of the Escherichia coli and 82.35% of the Staphylococcus aureus bacteria were killed under a UV‐light activation. However, the introduction of silver or/and cuprum nanoparticles into the polyurethane/TiO₂ (in the ratio of 3.5:1) nanofibers led to a significant improvement in their antibacterial ability without any photocatalysis.POLYM. COMPOS., 33:2045–2057, 2012. © 2012 Society of Plastics Engineers     

Poly(vinyl alcohol) triggers Au nanoparticles formation for near-infrared radiation-responsive gels and nanofibers

The capability of poly(vinyl alcohol) (PVA) to reduce noble metal ions and, in turn, to prepare one-step hybrid systems that exhibit near-infrared radiation (NIR) light-responsiveness has been barely explored. The aim of this work was to elucidate whether gold nanoparticles (Au NPs) could be spontaneously formed in PVA gels suitable to be used as syringeable depots or to prepare electrospun nanofibers. To check the hypothesis of that the gold counterion may play a role in the Au NPs formation process, two different gold salts (HAuCl₄ and AuAc₃) were used. Localized surface plasmon resonance bands were monitored during the incubation of PVA-gold salt gels, and the photoresponsive capability of the newly formed Au NPs inside gels was investigated during laser irradiation at 808 nm. HET-CAM assay suggested good biocompatibility. Then, the feasibility of producing electrospun hybrid PVA-based mats that exhibit light-responsive photothermal features was explored here for the first time. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48811.     

Preparation and characterization of octadecane/polyurea nanocapsule‐embedded poly(ethylene oxide) nanofibers

This article describes the preparation and characterization of latent heat storage poly(ethylene oxide) nanofibers (LHS‐PEO nanofibers) with octadecane/polyurea (PCM/PU) nanocapsules. PCM/PU nanocapsules were prepared by interfacial polycondensation from toluene 2,4‐diisocyanate and ethylene diamine in a resin‐fortified emulsion system. LHS‐PEO nanofibers were prepared using an electrospinning procedure with varying PCM/PU nanocapsules content, i.e., from 0 to 8 wt %. The PCM/PU nanocapsules were polydisperse with an average diameter of 200 nm. The melting and freezing temperatures were determined as 23.7 and 28.2°C, respectively, and the corresponding latent heats were determined as 123.4 and 124.1 kJ kg^?1, respectively. The encapsulation efficiency of the PCM/PU nanocapsules was 78.1%. The latent heat capacity of the LHS‐PEO nanofibers increased as the PCM/PU nanocapsules content increased. Defects, such as holes and disconnection of the nanofibers, were observed, particularly inside the LHS‐PEO nanofibers. For packaging applications, mats were fabricated from the nanocapsules‐embedded nanofibers with varying nanocapsule content and the mats’ surface temperatures were monitored with a thermal imaging camera. The results proved the feasibility of using the LHS‐PEO nanofibers for thermal energy storage and functional packaging materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42539.     

Preparation and characterization of electrospun poly(ε‐caprolactone)–pluronic–poly(ε‐caprolactone)‐based polyurethane nanofibers

In this study, amphiphilic poly(ε‐caprolactone)–pluronic–poly(ε‐caprolactone) (PCL–pluronic–PCL, PCFC) copolymers were synthesized by ring‐opening copolymerization and then reacted with isophorone diisocyanate to form polyurethane (PU) copolymers. The molecular weight of the PU copolymers was measured by gel permeation chromatography, and the chemical structure was analyzed by ¹H‐nuclear magnetic resonance and Fourier transform infrared spectra. Then, the PU copolymers were processed into fibrous scaffolds by the electrospinning technology. The morphology, surface wettability, mechanical strength, and cytotoxicity of the obtained PU fibrous mats were investigated by scanning electron microscopy, water contact angle analysis, tensile test, and MTT analysis. The results show that the molecular weights of PCFC and PU copolymers significantly affected the physicochemical properties of electrospun PU nanofibers. Moreover, their good in vitro biocompatibility showed that the as‐prepared PU nanofibers have great potential for applications in tissue engineering. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43643.     

Coating of polyelectrolyte multilayer thin films on nanofibrous scaffolds to improve cell adhesion

The adhesion of L929 cells to poly(?‐caprolactone) (PCL) nanofibers was successfully improved via coating with polyelectrolyte multilayer thin films (PEMs), which enhanced the potential of this material as a scaffold in tissue engineering applications. With the electrostatic self‐assembly technique, poly(diallyldimethylammonium chloride) (PDADMAC) and poly(sodium 4‐styrene sulfonate) (PSS) were formed as four‐bilayer PEMs on electrospun PCL nanofiber mats. Because PDADMAC and PSS are strong polyelectrolytes, they provided stable films with good adhesion on the fibers within a wide pH range suitable for the subsequent processes and conditions. PDADMAC and gelatin were also constructed as four‐bilayer PEMs on top of the PDADMAC‐ and PSS‐coated nanofibers with the expectation that the gelatin would improve the cell adhesion. L929 cells from mouse fibroblasts were then seeded on both uncoated and coated scaffolds to study the cytocompatibility and in vitro cell behavior. It was revealed by the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay that both the uncoated and coated nanofiber mats were nontoxic as the cell viability was comparable to that of those cultured in the serum‐free medium that was used as a control. The MTT assay also demonstrated that cells proliferated more efficiently on the coated nanofibers than those on the uncoated ones during the 48‐h culture period. As observed by scanning electron microscopy, the cells spread well on the coated nanofibers, especially when gelatin was incorporated. The surface modification of PCL nanofiber mats described in this research is therefore an effective technique for improving cell adhesion. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and antibacterial activity of PET/chitosan nanofibrous mats using an electrospinning technique

The nanofiber deposition method, by electrospinning, was employed to introduce antibacterial activity and biocompatibility to the surface of poly (ethylene terephthalate) (PET) textiles. The polymer blends of PET and chitosan were electrospun on to the PET micro‐nonwoven mats for biomedical applications. The PET/chitosan nanofibers were evenly deposited on to the surface, and the diameter of the nanofibers was in the range between 500 and 800 nm. The surface of the nanofibers was characterized using SEM, ESCA, AFM, and ATR‐FTIR. The wettability of the PET nanofibers was significantly enhanced by the incorporation of chitosan. The antibacterial activity of the samples was evaluated utilizing the colony counting method against Staphylococcus aureus and Klebsiella pneumoniae. The results indicated that the PET/chitosan nanofiber mats showed a significantly higher growth inhibition rate compared with the PET nanofiber control. In addition, the fibroblast cells adhered better to the PET/chitosan nanofibers than to the PET nanofibers mats, suggesting better tissue compatibility. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007