Controlled release of doxorubicin from electrospun MWCNTs/PLGA hybrid nanofibers

In this study, multiwalled carbon nanotubes (MWCNTs) were used to encapsulate a model anticancer drug, doxorubicin (Dox). Then, the drug-loaded MWCNTs (Dox/MWCNTs) with an optimized drug encapsulation percentage were mixed with poly(lactide-co-glycolide) (PLGA) polymer solution for subsequent electrospinning to form drug-loaded composite nanofibrous mats. The structure, morphology, and mechanical properties of the formed electrospun Dox/PLGA, MWCNTs/PLGA, and Dox/MWCNTs/PLGA composite nanofibrous mats were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and tensile testing. In vitro viability assay and SEM morphology observation of mouse fibroblast cells cultured onto the MWCNTs/PLGA fibrous scaffolds demonstrate that the developed MWCNTs/PLGA composite nanofibers are cytocompatible. The incorporation of Dox-loaded MWCNTs within the PLGA nanofibers is able to improve the mechanical durability and maintain the three-dimensional structure of the nanofibrous mats. More importantly, our results indicate that this double-container drug delivery system (both PLGA polymer and MWCNTs are drug carriers) is beneficial to avoid the burst release of the drug and able to release the antitumor drug Dox in a sustained manner for 42 days. The developed composite electrospun nanofibrous drug delivery system may be used as therapeutic scaffold materials for post-operative local chemotherapy.     

Preparation and characterization of poly(lactic‐co‐glycolic acid)/chitosan electrospun membrane containing amoxicillin‐loaded halloysite nanoclay

The main attitude of new wound dressings with biocompatible natural or synthetic polymers is improving and accelerating the healing process. In this study, halloysite nanotubes (HNTs) loaded with a model antibiotic drug, amoxicillin (AMX), were incorporated within poly(lactic‐co‐glycolic acid) (PLGA) solution that were electrospun with hydrophilic chitosan nanofibers simultaneously in two different syringes to make composite nanofibrous mat. The morphology, homogeneity, and fiber diameter of electrospun (PLGA/HNTs/AMX/chitosan) composite nanofibers were investigated by scanning electron microscopy and image J software. To evaluate the chemical structure, mechanical property, contact angle, and water absorption of samples, Fourier transform infrared spectroscopy, tensile testing, water contact angle, and immersion in phosphate buffer saline were utilized, respectively. Results indicated that incorporation of HNTs does not significantly alter nanofibers' morphology but rather increases their diameter, while the mechanical properties are improved because of its high modulus. Also, addition of natural hydrophilic polymer nanofibers (chitosan) enhanced the hydrophilicity property of samples. According to high‐performance liquid chromatography drug release analysis, HNTs as a good nanocarrier decreased initial burst release and showed controlled release behavior. MTT assay determined biocompatibility of PLGA/HNTs/AMX/chitosan. Copyright © 2016 John Wiley & Sons, Ltd.     

A nanofibrous composite membrane of PLGA-chitosan/PVA prepared by electrospinning

Tissue engineering scaffolds produced by electrospinning feature a structural similarity to the natural extracellular matrix. In this study, poly(lactide-co-glycolide) (PLGA) and chitosan/poly(vinyl alcohol) (PVA) were simultaneously electrospun from two different syringes and mixed on the rotating drum to prepare the nanofibrous composite membrane. The composite membrane was crosslinked by glutaraldehyde vapor to maintain its mechanical properties and fiber morphology in wet stage. Morphology, shrinkage, absorption in phosphate buffered solution (PBS) and mechanical properties of the electrospun membranes were characterized. Fibroblast viability on electrospun membranes was discussed by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay and cell morphology after 7 days of culture. Results indicated that the PBS absorption of the composite membranes, no matter crosslinked or not, was higher than the electrospun PLGA membrane due to the introduction of hydrophilic components, chitosan and PVA. After crosslinking, the composite membrane had a little shrinkage after incubating in PBS. The crosslinked composite membrane also showed moderate tensile properties. Cell culture suggested that electrospun PLGA-chitosan/PVA membrane tended to promote fibroblast attachment and proliferation. It was assumed that the nanofibrous composite membrane of electrospun PLGA-chitosan/PVA could be potentially used for skin reconstruction.     

Improved cellular response on multiwalled carbon nanotube-incorporated electrospun polyvinyl alcohol/chitosan nanofibrous scaffolds

We report the fabrication of multiwalled carbon nanotube (MWCNT)-incorporated electrospun polyvinyl alcohol (PVA)/chitosan (CS) nanofibers with improved cellular response for potential tissue engineering applications. In this study, smooth and uniform PVA/CS and PVA/CS/MWCNTs nanofibers with water stability were formed by electrospinning, followed by crosslinking with glutaraldehyde vapor. The morphology, structure, and mechanical properties of the formed electrospun fibrous mats were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and mechanical testing, respectively. We showed that the incorporation of MWCNTs did not appreciably affect the morphology of the PVA/CS nanofibers; importantly the protein adsorption ability of the nanofibers was significantly improved. In vitro cell culture of mouse fibroblasts (L929) seeded onto the electrospun scaffolds showed that the incorporation of MWCNTs into the PVA/CS nanofibers significantly promoted cell proliferation. Results from this study hence suggest that MWCNT-incorporated PVA/CS nanofibrous scaffolds with small diameters (around 160 nm) and high porosity can mimic the natural extracellular matrix well, and potentially provide many possibilities for applications in the fields of tissue engineering and regenerative medicine.     

In-Vitro Cytotoxicity Study: Cell Viability and Cell Morphology of Carbon Nanofibrous Scaffold/Hydroxyapatite Nanocomposites

Electrospun carbon nanofibers (CNFs), which were modified with hydroxyapatite, were fabricated to be used as a substrate for bone cell proliferation. The CNFs were derived from electrospun polyacrylonitrile (PAN) nanofibers after two steps of heat treatment: stabilization and carbonization. Carbon nanofibrous (CNF)/hydroxyapatite (HA) nanocomposites were prepared by two different methods; one of them being modification during electrospinning (CNF-8HA) and the second method being hydrothermal modification after carbonization (CNF-8HA; hydrothermally) to be used as a platform for bone tissue engineering. The biological investigations were performed using in-vitro cell counting, WST cell viability and cell morphology after three and seven days. L929 mouse fibroblasts were found to be more viable on the hydrothermally-modified CNF scaffolds than on the unmodified CNF scaffolds. The biological characterizations of the synthesized CNF/HA nanofibrous composites indicated higher capability of bone regeneration.     

聚乳酸-乙醇酸/纳米氧化锌复合电纺纤维装载亲疏水药物的控释及体外细胞毒性

利用静电纺丝技术制备了负载亲水性药物阿霉素(DOX)以及疏水性药物喜树碱(CPT)的复合纳米纤维. 先用巯基封端的普朗尼克(F127)修饰纳米氧化锌(FZnO), 再将FZnO负载盐酸阿霉素(DOX@FZnO), 最后将DOX@FZnO与CPT一起纺入聚乳酸-乙醇酸(PLGA)纤维中. 体外药物释放结果表明, 复合纳米纤维能够减小亲水性药物的突释, 减缓药物释放速率, 延长药物释放时间. 体外细胞活性结果表明, 双载药复合纤维比单载药复合纤维具有更强的细胞毒性, 能够有效抑制癌细胞生长.     

A novel composite derived from a metal organic framework immobilized within electrospun nanofibrous polymers: An efficient methane adsorbent

In this study, tantalum(V) metal organic framework (Ta-MOF) nanostructure was incorporated within polyvinyl alcohol (PVA) nanofibers to prepare an electrospun porous composite as a novel CH₄ adsorbent. The crystallinity, thermodynamic behavior, and textural properties of the products were investigated using instrumental analyses techniques. The results confirmed that the developed PVA/Ta-MOF electrospun nanofibrous composite exhibits higher thermal stability, considerable porosity, and larger surface area compared to the parent Ta-MOF. A 2^k factorial design was used for systematic study of the adsorption process. The results of response surface methodology (RSM) optimization indicated that the highest methane adsorption can be achieved at 24.40 °C and 3.70 bar in 23.60 min. These nano pore sorbents showed a significant potential for CH₄ adsorption due to the presence of Ta-MOF at the surface of nanofibrous composite compared to many other conventional sorbents that have been already used. This study introduces a novel biocompatible/biodegradable nanofibrous composite material with high methane adsorption performance and potentials for other applications.     

Functionalized electrospun carbon nanofibers for removal of cationic dye

Electrospun carbon nanofibers (ECNFs) have attracted significant attention in recent years as relatively inexpensive alternative to carbon nanotubes for adsorption organic pollutants. In this study, ECNFs were fabricated from polyacrylonitrile (PAN) using an electrospinning technique, followed by carbonization and oxidation via treatment with a H₂SO₄/HNO₃ mixture. The prepared oxidized electrospun carbon nanofibers (O-ECNFs) were characterized using scanning and transmission electron microscopy (SEM and TEM), Fourier transform infrared (FT-IR), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The O-ECNFs were used as nano-adsorbents for the adsorption of methylene blue (MB) from aqueous solution. The adsorption of MB by the O-ECNFs was studied as a function of pH, time, adsorbent dosage, MB concentration, and temperature. ECNF functionalization enhanced the adsorption capacity towards MB dye compared pristine ECNFs. Detailed analysis of the adsorption kinetics showed that the adsorption process followed a pseudo-second-order model. The adsorption isotherm was best fit by the Langmuir model. The thermodynamic results showed that MB adsorption onto the O-ECNFs was endothermic and spontaneous.     

C60(OH)n-loaded nanofibrous membranes protect HaCaT cells from ROS-associated damage

C₆₀(OH)n-loaded nanofi brous membranes were prepared by electrospinning to suppress the elevation of intracellular ROS and Ca²⁺, and to protect human keratinocyte cells from ROS-associated damage and apoptosis.     

Folic acid modified electrospun poly(vinyl alcohol)/polyethyleneimine nanofibers for cancer cell capture applications

Capture and detection of metastatic cancer cells are crucial for diagnosis and treatment of malignant neoplasm. Here, we report the use of folic acid (FA) modified electrospun poly(vinyl alcohol) (PVA)/polyethyleneimine (PEI) nanofibers for cancer cell capture applications. Electrospun PVA/PEI nanofibers crosslinked by glutaraldehyde vapor were modified with FA via a poly(ethylene glycol) (PEG) spacer, followed by acetylation of the fiber surface PEI amines. The formed FA-modified nanofibers were well characterized. The morphology of the electrospun PVA/PEI nanofibers is smooth and uniform despite the surface modification. In addition, the FA-modified nanofibers display good hemocompatibility as confirmed by hemolysis assay. Importantly, the developed FA-modified nanofibers are able to specifically capture cancer cells overexpressing FA receptors, which were validated by quantitative cell counting assay and qualitative confocal microscopy analysis. The developed FA-modified PVA/PEI nanofibers may be used for capturing circulating tumor cells for cancer diagnosis applications.     

Electrically conducting electrospun silk membranes fabricated by adsorption of carbon nanotubes

We present a simple method of obtaining electrically conducting electrospun silk non-woven membranes consisting of nanofibers with multi-walled carbon nanotubes (MWCNTs) adsorbed on their surface. Nanofibrous membranes with fibroin diameters of 460 ± 40 nm were formed from aqueous Bombyx mori fibroin solution by electrospinning. The MWCNTs adhered well to the surface of the highly porous silk nanofibrous membranes when Triton X-100 was used as the surfactant for the dispersion of the MWCNTs in aqueous media. The electrical conductivity of the membranes was 2.4 × 10⁻⁴ S/cm due to the presence of the MWCNTs on their surface. In addition, the strong interaction between the MWCNTs and nanofibers keeps them from separating each other, even after ultrasonication. The combination of the high conductivity of the membranes and the simple process used to fabricate them could lead to significant advances in the development of new materials, such as electromagnetic interference shielding or electrostatic dissipation membranes.     

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.     

Electrospun poly(aniline‐co‐ethyl 3‐aminobenzoate)/poly(lactic acid) nanofibers and their potential in biomedical applications

Poly(aniline‐co‐ethyl 3‐aminobenzoate) (3EABPANI) copolymer was blended with poly(lactic acid) (PLA) and co‐electrospun into nanofibers to investigate its potential in biomedical applications. The relationship between electrospinning parameters and fiber diameter has been investigated. The mechanical and electrical properties of electrospun 3EABPANI‐PLA nanofibers were also evaluated. To assess cell morphology and biocompatibility, nanofibrous mats of pure PLA and 3EABPANI‐PLA were deposited on glass substrates and the proliferation of COS‐1 fibroblast cells on the nanofibrous polymer surfaces determined. The nanofibrous 3EABPANI‐PLA blends were easily fabricated by electrospinning and gave enhanced mammalian cell growth, antioxidant and antimicrobial capabilities, and electrical conductivity. These results suggest that 3EABPANI‐PLA nanofibrous blends might provide a novel bioactive conductive material for biomedical applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

Fabrication of well‐aligned electrospun nanofibrous membrane based on fluorinated polyimide

We have fabricated novel nanofibrous fluorinated polyimide membranes on a specially designed collector, which is composed of conductive aluminum plates and glass insulator materials and can be removed from the apparatus, using an electrospinning method. We describe the structure and water flux properties of the nanofibrous fluorinated polyimide membranes. The electrospun nanofibers were deposited across the plates and uniaxially aligned to the collector. In addition, the multi‐layer stacked nanofibrous membranes, consisting of three‐dimensionally ordered nanopores, were produced. The pure water fluxes for the stacked membranes were measured, using a stirred dead‐end filtration cell, and were linearly decreased with an increasing deposition time, indicating that the nanopores formed in the nanofibrous membrane were further narrowed due to the regularly accumulated nanofibers. Copyright © 2009 John Wiley & Sons, Ltd.     

Photocrosslinked methacrylated chitosan-based nanofibrous scaffolds as potential skin substitute

Nanofibers based on natural polymers have recently been attracting research interest as promising materials for use as skin substitutes. Here, we prepared photocrosslinked nanofibrous scaffolds based on methacrylated chitosan (MACS) by photocrosslinking electrospun methacrylated chitosan/poly (vinyl alcohol) (PVA) mats and subsequently removing PVA from the nanofibers. We comprehensively investigated the solution properties of MACS/PVA precursors, the intermolecular action between MACS and PVA components, and the morphology of MACS/PVA nanofibers. Results indicated that the fiber diameter and morphology of the photocrosslinked methacrylated chitosan-based nanofibrous scaffolds were controlled by the MACS/PVA mass ratio and showed highly micro-porous structures with many fibrils. In vitro cytotoxicity evaluation and cell culture experiments confirmed that MACS-based mats with micro-pore structure were biocompatible with L929 cells and facilitated cellular migration into the 3D matrix, demonstrating their potential application as skin replacements for wound repair.     

Fabrication of novel thermo-responsive electrospun nanofibrous mats and their application in bioseparation

To fulfill the development of biotechnology and biomedicine, environmental-responsive polymer materials are wanted for isolation and purification of biomolecules. Herein, a novel thermo-responsive poly(methyl methacrylate) (PMMA)/poly(N-isopropylacrylamide) (PNIPAM) blend nanofibrous mat was developed, which can adsorb and release a model solute, bovine serum albumin (BSA), through the way of hydrophilicity–hydrophobicity transition behavior of PNIPAM. The uniform bead-free electrospun nanofibers were obtained from the homogeneous PMMA solution in the presence of different amount of PNIPAM. Scanning electron microscopy (SEM) analysis showed that the electrospinnability of PMMA was improved by the addition of PNIPAM, and the diameter of resultant nanofibers could be modulated by controlling the amount of PNIPAM. The thermo-responsive swelling behavior of the blend nanofibrous mats was reversible and reproducible by changing environmental temperature across the lower critical solution temperature (LCST) of PNIPAM. Moreover, the separation property of the blend nanofibrous mats was found to be related to the amount of PNIPAM as well as the concentration of BSA. As for a better separation effect, the nanofibers with higher content of PNIPAM were favorable.     

Progresses on electrospun metal–organic frameworks nanofibers and their wastewater treatment applications

Metal–organic frameworks (MOFs) have been proven to be outstanding adsorbent materials which possess excellent pollutant removal performances in wastewater treatment. However, MOFs consumption, loss, or blockage in reactor pipelines as well as the long and complicated recycling process severely limit their practical applications. Therefore, construction of novel MOFs composites with extremely high ease-of-use property has become a research hotspot, such as two-dimensional (2D) MOFs fibrous membranes. In this review, the exploitation of MOFs nanofibrous membranes via electrospinning and their applications in wastewater treatment are summarized. The MOFs nanofibers (NFs) architectures are established systematically by five routes: (1) direct electrospinning of MOFs-polymer; (2) induced growth of MOFs on electrospun NFs containing seeds; (3) growth of MOFs on electrospun organic NFs’ (4) growth of MOFs on electrospun inorganic NFs; and (5) simultaneous electrospinning and electrospraying. Furthermore, the applications of different types of MOFs nanofibrous membranes and their derivatives in water treatment and purification are discussed, including oil-water separation, the removal of heavy metal ions, organic dyes, personal care products, non-steroidal anti-inflammatory drugs (NSAIDs) and so on. The adsorption properties and mechanisms of electrospun MOFs nanofibrous membranes towards various environmental pollutants are discussed. Finally, the challenges of electrospun MOFs NFs, the limitations of their applications, and future development trends are prospected.     

Electrospun composite nanofibrous membrane as wound dressing with good adhesion

A photopolymerizationable mimic mussel protein structure monomer, dopamine methacrylamide (DMA), was synthesized. The photopolymerization of DMA was analysed by series real time near infrared spectroscopy (SRTIR). Dopamine methacrylamide/poly (ethylene oxide) (DMA/PEO) nanofibers were successfully prepared by electrospinning of aqueous DMA/PEO solution. Biocompatible nanofibrous membrane with good adhesion was produced by photocuring from the DMA/PEO nanofibers. The surface characterization and structure of the composite nanofibrous membrane were characterized by a scanning electron microscopy (SEM) and contact angle measurements. For identifying the potential crystalline of curing, a XRD method was used through comparing diffraction data. In the cell adhesion test we utilized the mouse fibroblast (L929) to exam the various use of the nanofibrous membrane as scaffolding materials for skin regeneration.     

Stabilization of electrospun poly(vinyl alcohol) nanofibrous mats in aqueous solutions

<正>The stability ofpoly(vinyl alcohol)(PVA) nanofibrous mats in water media was improved by post-electrospinning treatments.Bifunctional glutaraldehyde(GA) in methanol was used as a crosslinking agent to stabilize PVA nanofiber,but fiber twinning was observed frequently,and the highly porous structure of PVA nanofibrous mats was destroyed when the crosslinked fiber was soaked in water.To overcome this shortcoming,chitosan(CS) was introduced into the PVA spinning solution to prepare PVA/CS composite nanofibers.Their treatment in GA/methanol solution could retain the fiber morphology of PVA/CS nanofibers and porous structure of PVA/CS nanofibrous mats even if they were soaked in aqueous solutions for 1 month.Scanning electron microscopy(SEM),X-ray diffraction(XRD),thermal gravimetric analysis(TGA) and differential scanning calorimetry(DSC) were applied to characterize the physicochemical structure and thermal properties of PVA nanofibers.It was found that the water resistance of PVA nanofibrous mats was enhanced because of the improvement of the degree of crosslinking and crystallinity in the electrospun PVA fibers after soaking in GA/methanol solution.     

MicroRNA‐2861 and nanofibrous scaffold synergistically promote human induced pluripotent stem cells osteogenic differentiation

Tissue engineering using new strategies has become a growing and promising method for treating large tissue lesions in the body. On the other hand, microRNAs (miRNAs), which are small non‐coding regulatory RNAs, are a new class of genetic materials that can have effective pharmacological roles. The combination of these two themes has created promising prospects for the treatment of diseases. Herein, human induced pluripotent stem cells (iPSCs) were transduced with miRNA‐2861 and then the osteogenic differentiation potential of transduced iPSCs and non‐transduced iPSCs was investigated while cultured on the electrospun poly lactic‐co‐glycolic acid (PLGA) nanofibrous scaffold and culture plate. MiR‐2861‐transduced iPSCs showed a significantly higher viability, mineralization, alkaline phosphatase (ALP) activity, calcium content, and bone‐related gene expression in comparison with those iPSCs that non‐transduced. The results also indicated that this increase is improved when miR‐2861 transduced iPSCs are cultured on the PLGA nanofibrous scaffold synergistically. This synergy was also confirmed by the results obtained from of Western blot analysis. It can be concluded that, miR‐2861, by negative regulation of those proteins that decrease/inhibit osteogenic differentiation and PLGA nanofibrous scaffold by preparation of a suitable artificial extracellular matrix, have a great positive impact in improving iPSCs osteogenic differentiation potential and this blend can be proposed to use in bone tissue engineering application.