Molecular layer‐by‐layer deposition of highly crosslinked polyamide films

A molecular layer‐by‐layer (mLbL) deposition process is demonstrated to synthesize conformal coatings of crosslinked polyamide. This process controls the rapid reaction of trimesoyl chloride and m‐phenylene diamine, unlike interfacial polymerization techniques which produce rough films and poorly defined network structure. Layer‐by‐layer polyamide films appear structurally similar to interfacially polymerized films with a linear film growth rate of ≈0.9 nm per cycle. Films made by mLbL deposition show a 70‐fold decrease in surface roughness as compared to a commercial, interfacially polymerized polyamide. Surface chemistry could be controlled based on which reaction step was performed last, leading to amine or carboxylic acid rich surfaces. With the ability to control chemical structure throughout the crosslinked network, this technique provides new routes to build polyamide films and improve analysis techniques for commercial applications such as reverse osmosis membranes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Encasement of metallic cardiovascular stents with endothelial cell‐selective copolyetheresterurethane microfibers

Cardiovascular metallic stents established in clinical application are typically coated by a thin polymeric layer on the stent struts to improve hemocompatibility, whereby often a drug is added to the coating to inhibit neointimal hyperplasia. Besides such thin film coatings recently nano/microfiber coated stents are investigated, whereby the fibrous coating was applied circumferential on stents. Here, we explored whether a thin fibrous encasement of metallic stents with preferentially longitudinal aligned fibers and different local fiber densities can be achieved by electrospinning. An elastic degradable copolyetheresterurethane, which is reported to selectively enhance the adhesion of endothelial cells, while simultaneously rejecting smooth muscle cells, was utilized for stent coating. The fibrous stent encasements were microscopically assessed regarding their single fiber diameters, fiber covered area and fiber alignment at three characteristic stent regions before and after stent expansion. Stent coatings with thicknesses in the range from 30 to 50 µm were achieved via electrospinning with 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFP)‐based polymer solution, while a mixture of HFP and formic acid as solvent resulted in encasements with a thickness below 5 µm comprising submicron sized single fibers. All polymeric encasements were mechanically stable during expansion, whereby the fibers deposited on the struts remained their position. The observed changes in fiber density and diameter indicated diverse local deformation mechanisms of the microfibers at the different regions between the struts. Based on these results it can be anticipated that the presented fibrous encasement of stents might be a promising alternative to stents with polymeric strut coatings releasing anti‐proliferative drugs. Copyright © 2015 John Wiley & Sons, Ltd.     

Sol‐Gel Related Solvothermal Procedure to Prepare Iron Oxide Fibers

A sol‐gel‐related solvothermal process is developed to prepare iron oxide fibers. Continuous iron oxide gel fiber was drawn from spinnable sol using ferric alkoxide as the precursor, and hollow hematite fiber was obtained after the gel fiber was treated by hydroncarbon thermal reaction. The as‐prepared hollow fiber was several millimeters in length, 4～15 µm in outer diameter, and ～3 µm in wall thickness. Substituting the hydrocarbon with triethylamide, Fe₃O₄ solid fiber composed of nanorods can be obtained. Incubated at 200°C in air for only 1 hour, Fe₃O₄ was oxidated to γ‐Fe₂O₃ fiber. Possible mechanisms involved in formation of these nanostructured iron oxide fibers also are discussed.     

Polyaniline/poly(methyl methacrylate) coaxial fibers: The fabrication and effects of the solution properties on the morphology of electrospun core fibers

Electrically conductive polyaniline (PANi)/poly(methyl methacrylate) (PMMA) coaxial fibers were prepared through the chemical deposition of PANi onto preformed PMMA fibers via in situ polymerization. PMMA fibers were prepared as core materials via electrospinning. Spectral studies and scanning electron microscopy observations indicated the formation of PANi/PMMA coaxial fibers with a diameter of approximately 290 nm and a PANi layer thickness of approximately 30 nm. The conductivity of the PANi/PMMA coaxial fibers was significantly higher than that of electrospun fibers of PANi/poly(ethylene oxide) blends and blend cast films of the same PANi composition. To reproducibly generate uniform‐core polymer fibers, the organic solution properties that affected the morphology and diameter of the electrospun fibers were investigated. The polymer molecular weight, solution concentration, solvent dielectric constant, and addition of soluble organic salts were strongly correlated to the morphology of the electrospun fiber mat. In particular, the dielectric constants of the solvents substantially influenced both the fiber diameter and bead formation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3934–3942, 2004     

Preparation of Zirconia Fibers via a Simple Aqueous Sol‐Gel Method

Polycrystalline tetragonal zirconia fiber was obtained by pyrolysis of precursor fibers from citrate‐acetate‐zirconium complex solution. The viscous zirconia sol with good spinnability was prepared by aging the starting solution of ZrOCl₂ · 8H₂O (ZOC) in the presence of acetic acid (HA) and citric acid (CA). The effects of molar ratio of zirconium cation to carboxylic acid and the aging time on the formation of spinnable sol were investigated. Thermogravimetric (TG) analysis, x‐ray diffraction (XRD), infrared (IR) spectra, and scanning electron microscope (SEM) techniques were used to characterize the sintered fibers. The results show that the fibers obtained at 1400°C are crack‐free with diameter of ca. 5–10 µm.     

Electrospun fiber mats of poly(3‐hydroxybutyrate), poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate), and their blends

Electrospinning of poly(3‐hydroxybutyrate) (PHB), poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), and their blends was first carried out in chloroform at 50 °C on a stationary collector. The average diameter of the as‐spun fiber from PHB and PHBV solutions decreased with increasing collection distance and increased with increasing solution concentration and applied electrical potential. In all of the spinning conditions investigated, the average diameter of the as‐spun pure fibers ranged between 1.6 and 8.8 μm. Electrospinning of PHB, PHBV, and their blends was carried out further at a fixed solution concentration of 14% w/v on a homemade rotating cylindrical collector. Well‐aligned, cross‐sectionally round fibers without beads were obtained. The average diameter of the as‐spun pure and blend fibers ranged between 2.3 and 4.0 μm. The as‐spun fiber mats appeared to be more hydrophobic than the corresponding films and much improvement in the tensile strength and the elongation at break was observed for the blend fiber mats over those of the pure fiber ones. Lastly, indirect cytotoxicity evaluation of the as‐spun pure and blend fiber mats with mouse fibroblasts (L929) indicated that these mats posed no threat to the cells. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2923–2933, 2006     

Curcumin-Loaded Biodegradable Electrospun Fibers: Preparation,Characterization, and Differences in Fiber Morphology

This article relates curcumin incorporation into poly(latic acid) and poly(lactic-co-glycolic acid) fibers by electrospinning. The fibers were characterized by field emission scanning electron microscopy and Fourier transform-infrared spectroscopy, performed in attenuated total reflection, and the actual curcumin content was evaluated by electronic absorption spectroscopy. The poly(latic acid)/curcumin fibers were malleable, had rough surface, and an average diameter of 3.6 µm. On the other hand, poly(lactic-co-glycolic acid)/curcumin fibers were rigid and porous and had an average diameter of 123.6 nm. The bigger diameter of the poly(latic acid) fibers was responsible for a higher percentage of curcumin/milligram of fiber.     

Layer‐by‐layer ionomer films made from poly(styrene‐co‐styrenesulfonic acid) and poly(methyl methacrylate‐co‐4‐vinylpyridine) in tetrahydrofuran

Thin films were fabricated layer‐by‐layer (LbL) via ionic bonds formed between a cationic ionomer and an anionic ionomer, which were produced via proton transfer from poly(styrene‐co‐styrenesulfonic acid) to poly(methyl methacrylate‐co‐4‐vinylpyridine) in an organic solvent, tetrahydrofuran. Ionic contents of the ionomers were very low down to 5.6 mol %, much lower than usual polyelectrolytes. The build up of the LbL films was demonstrated by UV/vis spectroscopy: the absorbance of the phenyl rings in styrene residues increased with the number of depositions (thus the number of layers). Transmission electron microscopy observation of strained thin films showed unique deformation mode, involving many bands that developed both in the parallel and perpendicular directions to the stress axis. This is quite different from the deformation modes seen for ionomer blend films and for coextruded polystyrene/poly(methyl methacrylate) multilayer tapes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 50: 101–105, 2012     

Particle formation by infrared laser ablation of MALDI matrix compounds

The concentration and size distribution of particles ablated from the infrared matrix‐assisted laser desorption/ionization matrix compounds succinic acid (butanedioic acid), α‐cyano‐4‐hydroxycinnamic acid, and glycerol were measured using an aerodynamic particle sizer combined with a scanning mobility particle sizer. The two sizing instruments together had a sizing range to from 10 nm to 20 µm. Thin layers of the matrix compounds were irradiated with fluences between 6.0 and 9.5 kJ/m² and wavelengths between 2.8 and 3.0 µm. The distribution of particles was characterized by a large concentration of clusters in the 20‐nm‐diameter range and large component of mass in the range of coarse particle with diameters greater than 1 µm. The wavelength dependence revealed a blue shift for the maximum particle production that is attributed to heating and disruption of the hydrogen bonds in the matrix that shifts the absorption to shorter wavelengths. This blue shift has been observed previously in infrared matrix‐assisted laser desorption/ionization. Copyright © 2014 John Wiley & Sons, Ltd.     

Electropolymerization of layer‐by‐layer precursor polymer films

The layer‐by‐layer (LbL) self‐assembly has been used to fabricate polymer thin films on any solid substrates. The multilayer polymer thin films are constructed by alternating adsorption of anionic and cationic polymers. Polyelectrolyte multilayer ultrathin films containing anionic poly[2‐(thiophen‐3‐yl)ethyl methacrylate‐co‐methacrylic acid]; P(TEM‐co‐MA) and cationic poly[4‐(9H‐carbazol‐9‐yl)‐N‐butyl‐4‐vinyl pyridium bromide]; P4VPCBZ, were fabricated. The growth of multilayer ultrathin films was followed by UV–Vis absorption spectrophotometer and surface plasmon resonance spectroscopy (SPR). The deposition of P(TEM‐co‐MA)/P4VPCBZ as multilayer self‐assembled ultrathin films regularly grow which showed linear growth of absorbance and thickness with increasing the number of layer pair. Cross‐linking of the layers was verified by cyclic voltammetry (CV), UV–Vis spectrophotometry and electrochemical surface plasmon resonance (EC‐SPR) spectroscopy with good electro‐copolymerizability. This was verified by spectroelectrochemistry. The SPR angular‐reflectivity measurement resulted in shifts to a higher reflectivity according to the change in the dielectric constant of the electropolymerized film. Copyright © 2011 John Wiley & Sons, Ltd.     

Layer‐by‐layer self‐assembly of a novel covalent organic frameworks microextraction coating for analyzing polycyclic aromatic hydrocarbons from aqueous solutions via gas chromatography

In this study, a new covalent organic framework, consisting of tetra(4‐aminophenyl)porphyrin and tris(4‐formyl phenyl)amine, was layer‐by‐layer immobilized on stainless‐steel wire as a coating for microextraction. The fabrication process was easy and controllable under mild conditions. The as‐grown fiber was applied to extract polycyclic aromatic hydrocarbons in aqueous solution via head‐space solid‐phase microextraction. Furthermore, it was analyzed by gas chromatography with a flame ionization detector. A wide linear range (0.1–50 µg/L), low limits of detection (0.006–0.024 µg/L, signal‐to‐noise ratio = 3), good repeatability (intra‐fiber, n = 6, 3.1–8.50%), and reproducibility (fiber to fiber; n = 3, 5.79–9.98%), expressed as relative standard deviations, demonstrate the applicability of the newly developed coating. This new material was successfully utilized in real sample extraction with a satisfactory result. Potential parameters affecting the extraction efficiency, including extraction temperature and extraction time, salt concentration, agitation speed, sample volume, desorption temperature, and time, were also optimized and discussed.     

Lysozyme coated DNA and DNA/SWNT fibers by solution spinning

DNA fibers were prepared by solution spinning of DNA in a lysozyme (LSZ) coagulation/gelation bath. Strong positive charges carried by LSZ protein condensed the DNA (strong negative charged) molecules resulting in self‐assembly and the formation of fibrillar structures in a gel‐like network. DNA/LSZ fibril formation was found to be dependent on the ratio of DNA to LSZ. A minimum 0.1 wt.‐% of LSZ was necessary to condense 0.1 wt.‐% of DNA into micro‐fibrils. Macroscopic fiber spinning was possible by introducing a 0.1 wt.‐% DNA aqueous solution into a 0.2 wt.‐% LSZ coagulation bath which resulted in fibers with ≈20 µm diameter. Single‐walled carbon nanotubes (SWNT) were also incorporated into these fibers to explore the possibility for creating hybrid materials. All DNA‐based fibers exhibit strong birefringence confirming molecular orientation along the fiber axis. Due to the presence of LSZ, the fibers exhibit antimicrobial activity against bacteria like Micrococcus lysodeikticus.

     

Morphology and pH Sensing Characteristics of New Luminescent Electrospun Fibers Prepared from Poly(phenylquinoline)‐block‐Polystyrene/Polystyrene Blends

New luminescent electrospun (ES) fibers for pH‐tunable colorimetric sensors were prepared from binary blends of poly(phenylquinoline)‐block‐polystyrene (PPQ‐b‐PS)/polystyrene (PS) with a single‐capillary spinneret. The PPQ‐b‐PS aggregated domain sizes in the ES fibers prepared from dichloromethane (CH₂Cl₂), chlorobenzene (CB) and chloroform (CHCl₃) were 1.5 ± 0.5, 2.2 ± 0.4 and 4.1 ± 1.1 µm, respectively. Such variation on the aggregation size led to the red‐shifting photoluminescence spectra changing from green, to yellow, and orange. ES fibers prepared from CH₂Cl₂ exhibited pH‐tunable photoluminescence and the emission maximum varied from 532 to 560 nm as the pH value changed from 7 to 1. The study demonstrated that the ES fibers prepared could have potential applications for sensory devices.

     

Electrospun fibers of poly(ethylene terephthalate) blended with poly(lactic acid)

Fibrous blends of polyethylene terephthalate (PET) and polylactic acid (PLA) were fabricated by electrospinning (ES) from a common solvent, at concentrations of PET/PLA = 100/0, 70/30, 50/50, 30/70, and 0/100. Oriented fiber mats were studied either as-spun, or after a cold-crystallization treatment. Scanning electron microscopy of as-spun amorphous fibers showed that addition of PLA into the ES solution prevents occurrence of beads. In some compositions, two glass transitions were observed by temperature-modulated differential scanning calorimetry indicating that the two components in the ES fibers were phase separated. Thermogravimetric analysis was used to study thermal degradation at high temperatures. PLA degrades at a temperature about 100 °C lower than that of PET, and holding or cycling the blends to high temperature can result in the degradation of PLA. Degree of crystallinity was determined using DSC for as-spun and cold-crystallized ES blend fibers. The degree of crystallinity of each blend component is reduced by the presence of the other blend component, and the overall crystallinity of the blend fibers is less than that of the homopolymer fibers. Wide-angle X-ray scattering results show that oriented crystals were formed in the blended electrospun fibers collected on a rotating collector. The cold-crystallization process leads to both PET and PLA crystallizations. Oriented crystallites form even when the fiber is crystallized with its ends free to shrink.     

Modulation of Foreign Body Reaction against PDMS Implant by Grafting Topographically Different Poly(acrylic acid) Micropatterns

The surface of poly(dimethylsiloxane) (PDMS) is grafted with poly(acrylic acid) (PAA) layers via surface‐initiated photopolymerization to suppress the capsular contracture resulting from a foreign body reaction. Owing to the nature of photo‐induced polymerization, various PAA micropatterns can be fabricated using photolithography. Hole and stripe micropatterns ≈100‐µm wide and 3‐µm thick are grafted onto the PDMS surface without delamination. The incorporation of PAA micropatterns provides not only chemical cues by hydrophilic PAA microdomains but also topographical cues by hole or stripe micropatterns. In vitro studies reveal that a PAA‐grafted PDMS surface has a lower proliferation of both macrophages (Raw 264.7) and fibroblasts (NIH 3T3) regardless of the pattern presence. However, PDMS with PAA micropatterns, especially stripe micropatterns, minimizes the aggregation of fibroblasts and their subsequent differentiation into myofibroblasts. An in vivo study also shows that PDMS samples with stripe micropatterns polarized macrophages into anti‐inflammatory M2 macrophages and most effectively inhibits capsular contracture, which is demonstrated by investigation of inflammation score, transforming‐growth‐factor‐β expression, number of macrophages, and myofibroblasts as well as the collagen density and capsule thickness.     

Effect of engineered PLGA‐gelatin‐chitosan/PLGA‐gelatin/PLGA‐gelatin‐graphene three‐layer scaffold on adhesion/proliferation of HUVECs

A three‐layered fibrous scaffold composed of fibers of different diameters in each layer was fabricated in correspondence with the structure of the blood vessels. Effect of solution and electrospinning parameters on morphology and diameters of the fibers were investigated by scanning electron microscopy (SEM), for each layer. The SEM images showed that 18% poly (lactic‐co‐glycolic acid) (PLGA)‐gelatin‐chitosan in 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP)/acid acetic solution resulted in bead‐free fibers for the outer layer. For the middle layer, 18% PLGA‐gelatin in HFIP at 13 kV with 13 cm needle to collector distance was chosen as the optimum condition. SEM imaging demonstrated that by increasing graphene content from 0.5 to 2 wt% in the inner layer (as an electrically conductive/platelet anti‐adhesion material), the fiber diameter decreased from 324.01 ± 58.90 to 288.59 ± 70.77 nm. The effect of gelatin crosslinking on the microstructure of the fibers was also examined. Shrinkage ratio decreased from 57 to below 21% upon crosslinking of the three‐layered scaffold in exposure to vapor of 50% glutaraldehyde solution for 2 hours. Mechanical test showed that tensile strength of the crosslinked three‐layer scaffold in the longitudinal direction was 2.90 MPa which is comparable to that of the vein and artery. The MTT [3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide] assay displayed cell viability of above 96% for the PLGA‐gelatin containing 2 wt% graphene. SEM analysis revealed that the addition of graphene to PLGA‐gelatin (up to 2%) causes a remarkable improvement in cell adhesion.     

Corrosion and tribocorrosion behaviour of super‐thick diamond‐like carbon films deposited on stainless steel in NaCl solution

Super‐thick diamond‐like carbon (DLC) film is a potential protective coating in corrosive environments. In the present work, three kinds of DLC films whose thickness and modulation periods are 4 µm and 3, 21 µm and 17 and 21 µm and 7, respectively, were fabricated on stainless steel. The effect of different thickness and modulation periods on corrosion and tribocorrosion behaviour of the DLC‐coating stainless steel was investigated in 3.5 wt% NaCl aqueous solution by a ball‐on‐flat tribometer equipped with a three‐electrode electrochemical cell. The DLC‐coating stainless steel served as a working electrode, and its OCP and potentiodynamic polarization were monitored before and during rubbing. The wear–corrosion mechanism of the DLC films was investigated by SEM. The results showed that the increasing thickness can prolong significantly lifetime of DLC films in NaCl aqueous solution. In particular, the modulation period has a significant impact on the tribocorrosion resistance of the DLC super‐thick films. The study suggested that the increasing thickness of compressive stress layer could suppress film damage by reducing crack propagation rate. Thus, the super‐thick DLC film with thickness of 21 µm and 7 periods presented the best tribocorrosion resistance among all studied films. Copyright © 2016 John Wiley & Sons, Ltd.     

Full color light‐emitting electrospun nanofibers prepared from PFO/MEH‐PPV/PMMA ternary blends

In this study, luminescence electrospun (ES) nanofibers based on ternary blends of poly(9,9‐dioctylfluoreny‐2,7‐diyl) (PFO)/poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV)/poly(methyl methacrylate) (PMMA) were prepared from chloroform solutions using a single capillary spinneret. Effects of PFO/MEH‐PPV ratio on the morphology and photophysical properties were studied while the PMMA weight percentage was fixed at 90 wt %. The morphologies of the prepared ES fibers were characterized by FE‐SEM and fluorescence microscopy. The obtained fibers had diameters around a few hundred nm and pore sizes in the range of 30–35 nm. The emission colors of the PFO/MEH‐PPV/PMMA blend ES fibers changed from blue, white, yellowish‐green, greenish‐yellow, orange, to yellow, as the MEH‐PPV composition increased. In contrast, the emission colors of the corresponding spin‐coated films were blue, orange, pink‐red, red, and deep‐red. Based on the values of solubility parameters, the PFO and MEH‐PPV are miscible to each other and trapped in the PMMA matrix. Hence, energy transfer between these two polymers is possible. The smaller aggregated domains in the ES fiber compared to those of spin‐coated films possibly reduce the efficiency of energy transfer, leading to different emission colors. Also, the prepared ES fibers had higher photoluminescence efficiencies than those of the spin‐coated films. Pure white light‐emitting fibers prepared from the PFO/MEH‐PPV/PMMA blend ratio of 9.5/0.5/90 had the Commission Internationale de L'Eclairage (CIE) coordinate of (0.33, 0.31). Our results showed that different color light‐emitting ES fibers were produced through optimizing the composition of semiconducting polymer in the transparent polymer matrix. This type of ES fibers could have potential applications as new light sources or sensory materials for smart textiles. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 463–470, 2009     

Effects of raster angle on the mechanical properties of PLA and Al/PLA composite part produced by fused deposition modeling

This paper studies the mechanical properties of polylactic acid (PLA) and aluminum fiber–reinforced PLA composite (Al/PLA) specimens fabricated by fused deposition modeling (FDM) process. The effect of raster angle (0°, 90°, 45°, 0°/90°, and ± 45°) on dynamic mechanical thermal property and tensile property of FDM‐printed PLA and Al/PLA has been studied. The results show reduced tensile strength and Young's modulus in Al/PLA composite specimen in comparison with pure PLA specimen. However, the elongation‐at‐break increases, which is due to Al fiber with the higher elasticity and lower tensile strength than PLA. The addition of Al fibers improves the dynamic mechanical thermal property of pure PLA because of the good interaction of the PLA matrix with the surrounding Al fibers. Raster angle plays an important role in FDM process. All specimens printed with 0° raster angle show highest tensile strength and dynamic mechanical properties, while specimens printed with 90° raster angle have the lowest values. Fractured surfaces indicate that the failure of the specimen with 0° raster angle is due to breaking of individual layers, while for 90° raster angle, specimen fails under separation of the adjacent raster layers.     

S‐Nitrosoglutathione‐Based Nitric Oxide‐Releasing Nanofibers Exhibit Dual Antimicrobial and Antithrombotic Activity for Biomedical Applications

The novel use of nanofibers as a physical barrier between blood and medical devices has allowed for modifiable, innovative surface coatings on devices ordinarily plagued by thrombosis, delayed healing, and chronic infection. In this study, the nitric oxide (NO) donor S‐nitrosoglutathione (GSNO) is blended with the biodegradable polymers polyhydroxybutyrate (PHB) and polylactic acid (PLA) for the fabrication of hemocompatible, antibacterial nanofibers tailored for blood‐contacting applications. Stress/strain behavior of different concentrations of PHB and PLA is recorded to optimize the mechanical properties of the nanofibers. Nanofibers incorporated with different concentrations of GSNO (10, 15, 20 wt%) are evaluated based on their NO‐releasing kinetics. PLA/PHB + 20 wt% GSNO nanofibers display the greatest NO release over 72 h (0.4–1.5 × 10^?10 mol mg^?1 min^?1). NO‐releasing fibers successfully reduce viable adhered bacterial counts by ≈80% after 24 h of exposure to Staphylococcus aureus. NO‐releasing nanofibers exposed to porcine plasma reduce platelet adhesion by 64.6% compared to control nanofibers. The nanofibers are found noncytotoxic (>95% viability) toward NIH/3T3 mouse fibroblasts, and 4′,6‐diamidino‐2‐phenylindole and phalloidin staining shows that fibroblasts cultured on NO‐releasing fibers have improved cellular adhesion and functionality. Therefore, these novel NO‐releasing nanofibers provide a safe antimicrobial and hemocompatible coating for blood‐contacting medical devices.