Electrospun Nanofibrous Films Research Articles

Zein/polyvinyl alcohol‐based electrospun nanofibrous films reinforced with nano‐hydroxyapatite for efficient Cu(II) adsorption

AbstractTo solve the problem of the presence of heavy metals in water causing water pollution, the biodegradable film based on zein/polyvinyl alcohol (PVA) with the incorporation of nano‐hydroxyapatite (nHAP) was fabricated through an electrospinning technique. The copper ion was taken as the representative of heavy metal ions in this study. The result showed that the incorporated nHAP nanoparticles were dispersed within the zein/PVA matrix, and strong hydrogen bonding interactions were formed between the filler and matrix, improving the hydrophobicity of the nanofibrous films and maintaining thermal stability. The adsorption mechanism was analyzed by fitting the adsorption process with pseudo‐first‐order model and pseudo‐second‐order model. Based on the ion exchange effect, electrostatic interaction, and complexation, the adsorption capacities of nanofibrous films for Cu(II) were significantly increased after adding nHAP. When the nHAP content was 20 wt.%, the Cu(II) adsorption capacity reached up to 23.86 mg/g, and the adsorption efficiency was 13.94% higher than that of neat zein/PVA nanofibers. This work suggests the potential of the electrospun zein/PVA/nHAP nanofibrous films as desirable eco‐friendly materials in metal removal applications.

Nanoplasmonic biosensors for multicolor visual analysis of acetylcholinesterase activity and drug inhibitor screening in point-of-care testing

The monitoring of acetylcholinesterase (AChE) activity and the screening of its inhibitors are significance of the diagnosis and drug therapy of nervous diseases. A metal ions-mediated signal amplification strategy was developed for the highly sensitive and multicolor assay of AChE activity and visually screening its drug inhibitors. After the specific reaction between AChE and acetylthiocholine (ATCh), the hydrolysis product thiocholine (TCh) can directly and decompose the α-FeOOH nanorods (NRs) to release amounts of Fe2+, which was regarded as Fenton reagent to efficiently catalyze H2O2 to produce ·OH. Then, the as-formed ·OH can further largely shorten the gold nanobipyramids (Au NBPs), generating a series of palpable color variations. The linear range for AChE activity was 0.01–500.0 U/L with the limit of detection as low as 0.0074 U/L. The vivid visual effects could be easily distinguished for the multicolor assay of AChE activity by naked eye in visible light. To achieve the point-of-care testing, Au NBPs were further assembled on polymeric electrospun nanofibrous films (ENFs) surface as test strips for the easy-to-use test of AChE activity by RGB values with a smartphone. Fascinatingly, this proposed strategy can be used for the visual screening AChE inhibitors or non-inhibitors. Comparing with the clinical drugs (rivastigmine tartrate, and donepezil), some natural alkaloids such as evodiamine, caffeine, camptothecin, and berberine hydrochloride were selected as inhibitor modes to confirm the drug screening capability of this method. This proposed strategy may have great potential in the other disease-related enzymatic biomarkers assay and the rapid screening of drug therapy.

Preparation of color‐tunable electrospun cellulose acetate‐polycaprolactone nanofibrous film for information encryption

AbstractNovel photochromic and long‐persistent photoluminescent electrospun nanofibrous films were developed for anticounterfeiting applications. The inclusion of rare‐earth activated strontium aluminum oxide (RSAO) nano‐scaled particles into nanofibers of cellulose acetate‐polycaprolactone (CA‐PCL) composite facilitated the development of a simple method for creating an organic–inorganic photoluminescent nanocomposite. Upon excitation at 365 nm, the luminescent nanofibrous films showed an emission band of 516 nm. The current from photochromic films change color to green when illuminated with ultraviolet light as proved by absorption and fluorescence analyses, and CIE Lab parameters. Both mechanical and hydrophobic properties of the electrospun films were found to improve with raising RSAO content in CA‐PCL. Improved hydrophobic performance was monitored without any compromise to their other desirable properties. The morphology of the synthesized phosphor nanoparticles was investigated to indicate particle diameter of 2–12 nm, whereas the morphology of the electrospun nanofibers displayed diameters of 200–300 nm. The cytotoxicity of RSAO was also explored using the MTT proliferation assay. When exposed to UV, the nanofibrous films showed reversible photochromism without fatigue

Target-induced tripedal G-quadruplex DNAzyme for multicolor visual point-of-care testing of biomarkers using Au nanorods-decorated electrospun nanofibrous films

A target-induced tripedal G-quadruplex DNAzyme (TGD) for visual point-of-care testing (POCT) of PSA proteins by using solid Au nanorods (Au NRs)-decorated electrospun nanofibrous films was constructed. The TGD was formed by the recycling amplification cascades of target-triggered catalytic hairpin assembly (CHA), which exhibited superior horseradish peroxidase (HRP) mimicking activity to facilitate the degradation of H2O2 into hydroxyl radicals (·OH). The ·OH oxidized the 3,3′,5,5′-tetramethylbenzidine (TMB) into TMB+. Then, the TMB+ was converted into TMB2+ in the acidic environment, which can etch the Au NRs for further promoting the blue shift of their longitudinal surface plasmon resonance (LSPR) absorption peak. Thereby, with the increasing PSA concentrations, the proposed strategy presented palpable color variations from green, cyan, violet, and red by naked eyes. Significantly, the cutoff values near 4.0 and 10.0 ng/mL of PSA in human blood serum could be discriminated with naked eyes, which could provide a semi-quantitative process for the early diagnosis and prognosis evaluation. In addition, this portable, and label-free TDG biosensor exhibited remarkable improvements in sensitivity with a low detection limit of 61.1 fg/mL for PSA protein. This strategy showed the great versatility and potential for the visual biomedical detection with portable type and early diagnosis of diseases.

Biodegradable electrospun nanofibrous platform integrating antiplatelet therapy-chemotherapy for preventing postoperative tumor recurrence and metastasis

The perioperative trauma-related platelet recruitment and activation severely affect tumor recurrence and metastasis. Therefore, efficiently killing residual tumor cells and simultaneously inhibiting platelet activation to block platelet-cancer cell interaction might be a promising strategy to prevent postoperative tumor recurrence and metastasis.Methods: Biodegradable PLGA electrospun nanofibrous films co-delivering doxorubicin-loaded tumor repopulating cell-derived microparticles (DOX-MPs) and aspirin (ASA) were developed as the implant materials (DOX-MPs/ASA@NF) for postoperative in-situ treatment. The characterization, cytotoxicity against tumor cells, inhibition in platelet activation-triggered proliferation, migration and metastasis of tumor cells and in vivo anti-recurrence and anti-metastasis activity induced by DOX-MPs/ASA@NF were systematically evaluated.Results: PLGA nanofibrous films facilitate the enhanced distribution of DOX-MPs as well as DOX-MPs and ASA release in a time-programmed manner within the tumor resection cavity. The released DOX-MPs efficiently kill the residual tumor cells, while ASA decreases platelet activation and inhibits platelet-promoted proliferation, migration and metastasis of tumor cells, resulting in the remarkable inhibition of postoperative tumor recurrence and metastasis.Conclusions: DOX-MPs/ASA@NF may be a promising candidate to prevent the recurrence and metastasis of resectable tumors.

Preparation and functional properties of poly(vinyl alcohol)/ethyl cellulose/tea polyphenol electrospun nanofibrous films for active packaging material

In this study, the blending electrospinning technique was successfully used to prepare poly (vinyl alcohol)/ethyl cellulose/tea polyphenol (PVA/EC-TP) nanofibrous films for the first time. The morphology observation showed that the fiber diameter ranged from 213 ± 40 nm to 432 ± 78 nm. The thermal analysis indicated that PVA/EC-TP composite nanofibrous films had superior thermal stability to pure PVA nanofibrous film. The wettability test showed that the water contact angle of composite nanofibrous films was significantly increased from 22° to 109°. Water stability and water barrier ability analyses indicated the water solubility of composite nanofibrous films was significantly decreased from 100% to 17%, and the water vapor permeability was reduced from 0.71 to 0.42 g⋅mm/m2⋅h⋅kPa. Meanwhile, the PVA/EC-TP composite nanofibrous films exhibited good antioxidant and antimicrobial activity. The application assay showed that the PVA/EC-TP nanofibrous films with high TP content could effectively extend the shelf life of pork by 3 days.

Flexible electrospun nanofibrous film integrated with fluorescent carbon dots for smartphone-based detection and cellular imaging application

The dose of administered chemotherapy drugs is crucial to determine due to the potential for efficient or adverse outcomes for cancer patients. To date, no user-friendly and low-cost method of doxorubicin (DOX) detection using nontoxic and biodegradable materials has been reported. For this reason, in this work, we have developed for the first time a nanofiber-based sensing platform for sensitive and on-site DOX assay in just 10 min. This is obtained thanks to printable, porosity and embeddability features of electrospun nanofibrous films (ENFFs) combined with nitrogen and sulfur co-doped carbon dots (NS-CDs) as sensing probes. The assay was done by just pipetting analyte on the hydrophilic spots of the fabricated photoluminescence water-stable ENFFs where the color intensity was being darkened. DOX quenched NS-CDs fluorescence onto ENFFs through inner filter effect. The developed sensor was either coupled with smartphone technology to provide miniaturized, portable and easy-to-use device or an ordinary spectrofluorimeter for solid-state sensing applications (detection limit of 5.4 nM). Moreover, applicability of the designed sensor was evaluated in human serum with satisfactory recoveries. It is more interesting that the fabricated NS-CDs/ENF scaffolds have a high potential to detect the intracellular DOX to enhance cell proliferation leading to be considered as a multimodal tool in biomedical research and clinical diagnostics.

Europium coordination polymer particles based electrospun nanofibrous film for point-of-care testing of copper (II) ions

Excess free copper in serum has been identified to induce neurodegenerative diseases such as Alzheimer's disease, thus it is very important to determine copper (II) ions (Cu2+) content for human health test. Herein we developed a point-of-care testing (POCT) platform through a luminescence “on-off” recognition mechanism of serum copper. Microsized europium coordination polymer particles (Eu-CPs), which was prepared with citric acid (CA) and europium nitrate hexahydrate through a hydrothermal route, were then successfully loaded with the mixture of 2,6-pyridinedicarboxylic acid (DPA) and poly(vinyl alcohol) (PVA) to form electrospun nanofibrous films (ENFFs). The as-prepared Eu-CPs/DPA/PVA ENFFs exhibited red emission at 618 nm when exciting at 280 nm, with the quantum yields of 22.2% owing to the antenna effect from DPA to Eu3+. Furthermore, the strong luminescence could be selectively quenched by Cu2+ through coordination with DPA to interrupt the antenna effect. With that, Cu2+ was successfully detected in the range of 2–45 μM with a detection of limit of 1.3 μM, well matching with the requirement of clinic test of excess free copper induced neurodegenerative diseases. As a proof of concept at last, this POCT platform was used to detect free copper in spiked serum samples with a recovery of 101.1%–105.2%, demonstrating that this platform provides significant potential for use in clinical test.

Electrospinning/Spray: The Interaction between Graphene Nanosheets and Different Nanofibers

The electrospun nanofiber/graphene composites is a promising candidate in the field of flexible strain sensors due to the synergic effect of graphene and the nanofibers. It is an effective way to synthesize a uniform graphene-embedded film by simultaneously electrospinning nanofibers and electrospraying graphene nanosheets. In this paper, we prepare two specimens of different materials to study the interaction between graphene nanosheets and nanofibers under the same process parameters, such as thermoplastic urethane (TPU), polyacrylonitrile (PAN). Then, morphology and mechanical properties are used to characterize the interaction. The mechanical test was conducted by the tensile tester, and the surface morphology of electrospun nanofibrous films was observed through a microscope. By comparing these results, the properties of the graphene nanosheets embedded to different nanofibers are explored. This study provides a good way to select an appropriate nanofiber matrix for the application in flexible strain sensors.

Characterization and physical properties of electrospun gelatin nanofibrous films by incorporation of nano-hydroxyapatite

In this study, the gelatin/nano-hydroxyapatite (n-HAP) composite nanofibrous films were fabricated by electrospinning. The gelatin/n-HAP mixtures in acetic aqueous solutions as the spinning dispersions showed a shear thinning behavior, and the apparent viscosity increased with the increasing n-HAP content. However, the average diameter of the gelatin nanofibers decreased from 516 to 510, 458 and 403 nm after the addition of 10%, 25% and 50% n-HAP, due to the decreased entanglement density. The EDS and TEM analysis indicated that n-HAP was uniformly dispersed within the nanofibers. As indicated by the FTIR results, the hydrogen bonding formed between gelatin and n-HAP resulted in the conformational transition of gelatin from β-sheet to turns. The water contact angle and XPS analysis suggested that the incorporation of n-HAP favored the wettability of the electrospun nanofibrous films, which was ascribed to the rough fiber surface and higher ratio of polar groups on the surface. The incorporation of 10% n-HAP did not affect the mechanical strength significantly, but the higher ratios of n-HAP led to the brittle and fragile property of the electrospun films. In addition, the water barrier property of the gelatin nanofibrous film was significantly improved by the addition of n-HAP. These results suggest that the surface wettability, mechanical strength and water barrier property of the electrospun gelatin nanofibrous films may be tuned by the incorporation of nano-hydroxyapatite.

Surface modification of patterned electrospun nanofibrous films via the adhesion of DOPA-bFGF and DOPA-ponericin G1 for skin wound healing

Combining biodegradable materials with bioactive factors for skin wound healing has been receiving significant attention. This study was inspired by the adhesion mechanism of a marine organism, the mussel. 3,4-Dihydroxyphenylalanine (DOPA) was introduced to basic fibroblast growth factor (bFGF) and ponericin G1 (PonG1) using tyrosine hydroxylation, which are expected to have strong binding affinities to the surfaces of materials. DOPA-bFGF and DOPA-PonG1 were applied for the surface modification of patterned poly(lactic-co-glycolic acid) (PLGA) electrospun nanofibrous films for skin wound healing. The DOPA-bFGF- and DOPA-PonG1-modified patterned PLGA nanofibrous films were analysed using scanning electron microscopy (SEM), contact angle, and materials testing machine. Then, the immobilization efficiencies and antibacterial abilities of the different films were examined. The results show that the DOPA-bFGF- and DOPA-PonG1-modified PLGA nanofibrous films exhibited bionic performance, improved tensile strength, and hydrophilicity. DOPA-bFGF and DOPA-PonG1 exhibited stronger binding abilities to films compared with bFGF and PonG1. DOPA-bFGF and DOPA-PonG1 films can significantly promote BALB/c 3T3 cell attachment, proliferation and tissue repair-related gene expression. In vivo experiments indicated that DOPA-PonG1/DOPA-bFGF@PLGA nanofibrous films shortened the wound healing time, accelerated epithelialization and promoted skin remodelling.

Fast-dissolving electrospun nanofibrous films of paracetamol/cyclodextrin inclusion complexes

Abstract The free-standing and fast-dissolving nanofibrous films from inclusion complexes (ICs) of paracetamol with two different cyclodextrins, hydroxypropyl-beta-cyclodextrin (HPβCD) and sulfobutylether-beta-cyclodextrin (SBE-β-CD) were produced through electrospinning without using polymer matrix. The morphology of the nanofibers (NFs) was uniform and bead-free as confirmed by scanning electron microscopy imaging. The chemical, structural and thermal characteristics of the electrospun paracetamol/CD-IC NFs were investigated by X-ray diffractometry, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analyzer and proton nuclear magnetic resonance. The aforementioned methods indicated the successful formation of ICs of paracetamol with both CD types (HPβCD and SBE-β-CD). Besides, paracetamol/CD-IC NFs exhibited different features and properties from pristine paracetamol. For instance, the crystalline state of pristine paracetamol was transformed into amorphous state by CD-IC NFs formation which is important for the water-solubility increment of the drug molecules. Moreover, thermal studies indicated that paracetamol became thermally more stable in CD-IC NFs. The molar ratio of paracetamol:CD was found as ~0.85:1.00 for paracetamol/HPβCD-IC NFs and ~0.80:1.00 for paracetamol/SBE-β-CD-IC NFs. The dissolution behavior of paracetamol/CD-IC nanofibrous films was examined by exposing them to water. The electrospun paracetamol/CD-IC nanofibrous films showed fast-dissolving character in water due to the CD-ICs formation and high surface area of nanofibrous structure.

Nanomechanical, Mechanical Responses and Characterization of Piezoelectric Nanoparticle-Modified Electrospun PVDF Nanofibrous Films

Limitless implementations of nanofibrous membrane show the importance of understanding the nanomechanical responses for water purification and piezoelectric nanogenerator applications. Here, the polyvinylidene fluoride (PVDF) electrospun nanofibrous films doped by 0.01, 0.05 and 0.1 wt% of ZnO nanoparticles were prepared in the method of electrospinning. Characterizations of PVDF nanocomposite fibrous films were inspected using field emission scanning electron microscope, thermogravimetric analysis, water contact angle, uniaxial tensile test and nanoindentation technique. The influence of minimal concentration of piezoelectric nanoparticles on the morphological, water contact angle, dynamic water contact angle, piezoelectric, thermal and mechanical stabilities of nanocomposite fibrous films was examined. The nanoscale mechanical properties of the PVDF/ZnO nanofibrous films were performed by nanoindentation technique at different spots of nanofibrous mat to examine the elastic–plastic behavior of membranes. The eventual ZnO nanoparticle-modified nanofibrous membranes have been shown nano-level fibers, considerable hydrophilicity and preferable thermal, mechanical and piezoelectric properties. The doping of polymer by 0.1 wt% of ZnO nanoparticles exposed significant enhancement of thermal, mechanical and nanomechanical responses of the melting temperature 2% (170– $$173\,^{\circ }\hbox {C}$$ ), tensile strength 20% (2.418 MPa), elastic modulus 18% (2.418 GPa) and hardness 60% (235 MPa) and piezoelectric coefficient 13.42 pC/N of the nanofibrous films. These understandings of nanoscale properties are highly promising in the development of sensor and actuators, biomedical, energy harvesting and water filtration devices.

Comparing the performance of electrospun and cast nanocomposite film of polyamide-6 reinforced with multi-wall carbon nanotubes

This study aims at fabrication and characterization of two different structures of electrically conductive polyamide 6/multi-wall carbon nanotube nanocomposite films at different multi-wall carbon nanotube concentrations including electrospun nanofibrous and cast films. Morphology, embedded multi-wall carbon nanotubes into nanofiber, thermal behavior, electrical conductivity and wettability of films were characterized. Scanning electron microscopy images depicted that the nanofiber diameter decreased with increased nanofillers. Enhancement of crystallinity, electrical and tensile properties, and simultaneously achieving a low percolation threshold confirmed good nanotube dispersion by employing a polymeric emulsifier, polyvinylpyrrolidone. The electrospun film crystalline content increased 18.5% and the cast ones increased 46.8% at 7 wt.% multi-wall carbon nanotubes loading. The electrospun and cast membrane electrical conductivity increased by 10 and 12 orders of magnitude. These results demonstrated higher values compared to previously reported data for polyamide 6/multi-wall carbon nanotube nanocomposites. The electrospun film Young’s modulus increased 93% and that of casted one increased 267%, due to the increased crystallinity after adding carbon nanotubes into the films.

Ratiometrically Fluorescent Electrospun Nanofibrous Film as a Cu2+-Mediated Solid-Phase Immunoassay Platform for Biomarkers.

Increasing demands for the sensitive, selective, visual, conveniently solid-phase-sensing film for disease-related biomarkers, electrospun nanofibrous films (ENFFs) are a novel sensing paltform because of the high surface area ratios, networked structures, and facile functionalization. In this research, carbon dots (CDs) and quantum dots (QDs) were doped inside and electrostatically assembled on electrospun nanofibers (ENFs), affording ratiometrically dual-emitting fluoresecent films. Because of the FRET process between CDs and QDs on NFs and the strong quenching response of QDs to Cu2+, the as-prepared NFs can visually detect Cu2+ with high sensitivity and selectivity based on ratiometric fluorescent signals. By exploiting the release of numerous Cu2+ from CuO nanoparticles (NPs) under acidic conditions, a sandwich-type immunoassay with CuO NPs-labeled antibody was developed for the detection of biomarker proteins via the response of dual-emitting and FRET-based NFs to different Cu2+ concentrations. Taking advantage of the ratiometrically fluorescent property of these ENFFs as well as the Cu2+-mediated signal amplification strategy, alpha fetoprotein can be detected with high sensitivity (detection limit of 8.3 pg/mL) and selectivity. This strategy demonstrates a promising candidate with a point-of-care assay for clinical diagnostics and biomedical research.

Investigating the structural effect of electrospun nano-fibrous polymeric films on water vapor transmission

Abstract Electrospun polymers have many applications in the industry. However, the structure of these polymers has been less widely considered by researchers. In this work, the structural effect of electrospun and casted films of polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) polymers on water vapor transmission were investigated. Sorption of water vapor was measured at 35, 60 and 80 °C and different relative humidities. The diffusion coefficients were calculated based on mass changes of the polymer sample. The water vapor transmission rate (WVTR) was also measured at 35 °C and 90% relative humidity. The results indicated that electrospun nano-fibrous polymers (ESNPs) absorb much higher water vapor compared to non-porous casted polymers. The interaction of water molecules with mentioned polymers was investigated based on Flory-Huggins theory. The Flory-Huggins interaction parameter of electrospun films was less than casted films, suggesting much better interaction of water molecules with electrospun films. It was also found that electrospun films have anomalous kinetic behavior and do not obey the Fickian diffusion model. Finally, it was revealed that ESNPs show less resistance to water vapor transmission and they are good candidates for the applications of water vapor separation using membranes.

Temperature compensation of pressure-sensitive luminescent polymer sensors

In this study, dual luminescent polymer sensors based on a pressure-sensitive palladium(II) tetraphenylporphyrin, PdTPP, and a temperature-sensitive europium(III) complex, EuDT, were newly fabricated by spray-coating or electrospinning of the solutions containing polystyrene as a matrix for the simultaneous detection of both pressure and temperature. The pressure and temperature responses were recorded as a function of the luminescence changes, and their sensitivities were carefully evaluated. The electrospun nanofibrous films exhibited a higher pressure-sensitivity than the corresponding spray-coated films, which was most likely attributed to their highly porous structures. In addition, accurate temperatures at the sample surface were determined from the luminescence intensities of the temperature-sensitive dye, which were used for the temperature correction of the surface pressure measurements. It was demonstrated that the accuracy of the pressure measurements based on the luminescence intensities of the pressure-sensitive dye was significantly improved after the temperature corrections. This is the first report of dual luminescent nanofibrous polymer sensors.

Mechanical enhancement of bi-phasic electrospun nanofibrous films by optimizing composition and configuration

An understanding of the composition, structure and property relationship is essential for engineering high performance polymer nanofibers to meet the ever-increasing demands for various applications. Here, bi-phasic polymeric fibres were prepared using electrospinning followed by thermal bonding. By controlling the softness-stiffness of the composition and configuration, the mechanical properties of bi-phasic fibrous films were improved with the strength up to eight times higher than that of single counterparts. We demonstrate that compatible interfaces, increasing alignment, supramolecular chains and connected bonding points, are jointly responsible for the mechanical enhancement except the diameter previous thought. This strategy provides new ideas and directions to design high-performance materials, especially for polymer-based fibrous material.

Effect of growth factors-coated electrospun nanofibrous films on the growth of bone marrow mesenchymal stem cells

Objective To explore the impact of growth factors-coated electrospun [poly(L-lactideco-e-caprolactone) (PLCL)]/fibrinogen nanofibrous films on the growth of rabbit bone marrow mesenchymal stem cells (BMSCs).Methods Electrospun nanofibrous films were fabricated from PLCL solution and fibrinogen solution.The nanofibrous films which were immersed into fibronectin solution and growth factors solution [vascular endothelial growth factor (VEGF),basic fibroblast growth factor (bFGF)] sequentially served as experimental group A films,those which were immersed into growth factors solution only as experimental group B films,and those without given any treatment as control group.The in vitro release results of growth factors in groups A and B were detected by using enzyme-linked immunosorbent assay (ELISA).BMSCs were obtained from rabbits by density gradient centrifugation and inoculated on the films.The adhesion and proliferation results of BMSCs on different films were detected by methyl thiazol tetrazolium (MTT) assay.Results In both experimental groups A and B,the growth factors were released in vitro for over 10 days,the released amount of the growth factor in the two groups was gradually reduced with time,and the reduction rate in group B was higher than in group A.The absorbance values in group B (0.37 ±0.06) and control group (0.35 ±0.09) were significantly lower than in group A (0.47 ±0.04) during the first 12 h (P ＜ 0.01).The cell proliferation rate was higher in group A than in group B and control group (P ＜ 0.05).Conclusion Electrospun PLCL/fibrinogen nanofibrous films,which surface is modified by fibronectin and growth factors (VEGF,bFGF) sequentially,have good performance in growth factors sustained release and cell compatibility. Key words: Bone marrow mesenchymal stem cells ; Electrospinning; Nanofibrous; Surface modification ; Tissue engineering

Aggregation states of rhodamine 6G in electrospun nanofibrous films

Novel fluorescent composite nanofibrous films of rhodamine 6G (Rh6G) and polyacrylonitrile (PAN) are first prepared by electrospinning. The aggregation states of Rh6G in electruspun nanofibrous films are studied as a function of concentrations and characterized by UV–vis absorption spectroscopy and emission and excitation fluorescence spectroscopy. We have also used casting films as reference material to compare the effect of incorporation of Rh6G in electrospun nanofibrous films and casting films. The large specific surface area of the nanofibers and fast evaporation of the solvents in the electrospinning process reduced the aggregation of Rh6G. The appearance of fluorescent J-type dimers, even at higher dye concentration in elctrospun films, demonstrates that the electrospun films are an ideal material for incorporation of fluorescent dyes.