首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
This study presents and evaluates an approach for fabricating poly(lactic acid) (PLA)/chitosan (CS)/tricalcium phosphate (TCP) electrospun scaffolds for guided bone regeneration, a dental procedure that uses membranes to direct and delineate regions of osteogenesis. Biomaterials were pre‐processed using cryomilling, a solid‐state grinding technique that facilitates the generation of powdered biocomposites conducive to electrospinning. X‐ray diffraction (XRD) confirmed the generation of cryomilled blends consisting of PLA, CS, and TCP. Results from the differential scanning calorimetry showed an upward shift in glass transition temperature and an increase in crystallinity with the inclusion of TCP reinforcing the observations from XRD. Murine macrophages were used to confirm the biocompatibility of the cryomilled powders and was evaluated using CellTiter‐Blue (CTB) cell viability assay and brightfield microscopy. Scanning electron microscopy was used to examine the morphology of the fibers produced via electrospinning, while Raman spectroscopy confirmed material homogeneity. In vitro studies with MG‐63 cells validated the capacity of composite scaffolds to encourage proliferation, while Coherent anti‐Stokes Raman scattering and fluorescence microscopies provided visual evidence of cell proliferation. CTB assay revealed that cells maintain viability and metabolic activity at 3 and 7 days after seeding, demonstrating the potential of the biocomposite membranes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46692.  相似文献   

2.
In this study, electrospun biocompatible nanofibers with random orientation were prepared by physically blending poly(vinyl alcohol)‐stilbazol quaternized (PVA‐SbQ) with zein in acetic acid solution for wound healing. PVA‐SbQ was used as the foundation polymer as well as crosslinking agent, blended with zein to achieve desirable properties such as improved tensile strength, surface wettability, and in vitro degradable properties. Moreover, vaccarin drug was incorporated in situ into electrospun nanofibrous membranes for cell viability and cell attachment. The addition of vaccarin showed great effects on the morphology of nanofiber and enhanced cell viability and proliferation in comparison with composite nanofibers without drug. The presence of PVA‐SbQ, zein, and vaccarin drug in the nanofibrous membranes exhibited good compatibility, hydrophilicity, and biocompatibility and created a moist environment to have potential application for wound healing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42565.  相似文献   

3.
Scaffolds fabricated from polymers have imprinted its wide applicability in the field of tissue engineering. The surface of electrospun poly(lactic acid) (PLA) nanofibers was modified to improve their compatibility with living medium. PLA film were treated with alkali solution to introduce carboxyl groups on the surface followed by covalent grafting of gelatin using Xtal Fluoro‐E as coupling agent. The gelatin g‐PLA polymer synthesized via ‘graft‐onto’ method exhibit fascinating properties as studied by contact angle measurement, fourier transformed infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, water vapor transmission rate(WVTR), swelling studies and differential scanning calorimetry. The fabricated gelatin g‐PLA scaffolds were further characterized to conduct the study on hydrolytic degradation, and extent of biodegradation at ambient temperature. It was observed from the in‐vitro analysis that the gelatin g‐PLA nanofiber (with hemolytic percentage, 0.56 ± 0.13%) was cytocompatible with fibroblast cell and does not impair cell growth. The WVTR obtained for the electrospun mat around 2900 ± 100 g/m2. 24 h signifies the optimal moist environment required for tissue engineering especially wound healing. Notably, many of these strategies resulted in porous hydrophilic scaffolds with human cell growth and proliferation for medical applications of various types. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46056.  相似文献   

4.
The electrospinning of polyglycolide (PGA), poly(L ‐lactide) (PLA), and poly(lactide‐co‐glycolide) (PLGA; L ‐lactide/glycolide = 50/50) was performed with chloroform or 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) as a spinning solvent to fabricate their nanofiber matrices. The morphology of the electrospun PGA, PLA, and PLGA nanofibers was investigated with scanning electron microscopy (SEM). The PLGA nanofibers, electrospun with a nonpolar chloroform solvent, had a relatively large average diameter (760 nm), and it had a relatively broad distribution in the range of 200–1800 nm. On the other hand, the PGA and PLA fibers, electrospun with a polar HFIP solvent, had a small average diameter (~300 nm) with a narrow distribution. This difference in the fiber diameters may be associated with the polarity of the solvent. Also, the in vitro degradation of PGA, PLA, and PLGA nanofiber matrices was examined in phosphate buffer solutions (pH 7.4) at 37°C. The degradation rates of the nanofiber matrices were fast, in the order of PGA > PLGA ? PLA. Structural and morphological changes during in vitro degradation were investigated with differential scanning calorimetry and wide‐angle X‐ray diffraction. For the PGA matrix, a significant increase in the crystallinity during the early stage was detected, as well as a gradual decrease during the later period, and this indicated that preferential hydrolytic degradation in the amorphous regions occurred with cleavage‐induced crystallization, followed by further degradation in the crystalline region. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 193–200, 2005  相似文献   

5.
In the present study, polylactic acid (PLA)/polyethylene glycol (PEG)/multiwalled carbon nanotube (MWCNT) electrospun nanofibrous scaffolds were prepared via electrospinning process and their applications for the anticancer drug delivery system were investigated. A response surface methodology based on Box–Behnken design (BBD) was used to evaluate the effect of key parameters of electrospinning process including solution concentration, feeding rate, tip–collector distance (TCD) and applied voltage on the morphology of PLA/PEG/MWCNT nanofibrous scaffolds. In optimum conditions (concentration of 8.15%, feeding rate of 0.2 mL/h, voltage of 18.50 kV and TCD of 13.0 cm), the minimum experimental fiber diameter was found to be 225 nm which was in good agreement with the predicted value by the BBD analysis (228 nm). In vitro drug release study of doxorubicin (DOX)‐loaded nanofibrous scaffolds, higher drug content induced an extended release of drug. Also, drug release rate was not dependent on drug/polymer ratio in different electrospun nanofibrous formulations. The equation of Mt = c0 + kt0.5was used to describe the kinetic data of DOX release from electrospun nanofibers. The cell viability of DOX‐loaded nanofibrous scaffolds was evaluated using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide, a tetrazole assay on lung cancer A549 cell lines. We propose that DOX‐incorporated PLA/PEG/MWCNT nanofibrous scaffold could be used as a superior candidate for antitumor drug delivery. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41286.  相似文献   

6.
Polylactic acid (PLA) films were surface modified by gamma ray irradiation‐induced grafting of N‐vinyl pyrrolidone (NVP). The in vitro degradation behavior of polylactic acid grafting N‐vinyl pyrrolidone (PLA‐g‐PVP) copolymer was analyzed in terms of weight loss, molecular weight, and thermal properties. Grafting NVP significantly accelerated the degradation of PLA. The mass losses of the copolymers, which were less than that of pure PLA at the beginning of the degradation period, sharply accelerated with increasing degradation time. Moreover, the crystallization temperature decreased with increasing degradation time in the same graft ratio, and the degree of crystallinity increased. Cytotoxicity experiments and animal experiments in vivo were carried out to evaluate the biocompatibility of PLA‐g‐PVP copolymer. Varying graft ratios of PVP could control the degradation rate of copolymers, and thus broadening the applications of this material, such as in tissue engineering scaffolds, drug delivery, and prevention of postsurgical adhesion. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

7.
A cholic acid (CA)‐containing biodegradable hydrogel (PLA‐PEG‐PLA‐co‐MACAH) was synthesized from the photoinduced copolymerization of a CA‐modified methacrylate monomer (MACAH), bearing a spacer of hexane‐1,6‐diol spacer between the methacryloyl and the cholanoate moieties, and a macromonomer (PLA‐PEG‐PLA‐DA), bearing two acryloyl end groups derived from a poly(lactic acid)‐b‐poly(ethylene glycol)‐b‐poly(lactic acid) triblock copolymer. The structure of MACAH was confirmed by FTIR, 1H‐NMR, and MS. The hydrogel PLA‐PEG‐PLA‐co‐MACAH was characterized by scanning electron microscopy and X‐ray diffraction. The experiment results showed that the swelling ratios of the hydrogels decreased with the increase of the CA fraction. The investigation on the in vitro degradation of the hydrogel showed that the CA‐containing hydrogels degraded much slower than the hydrogels without CA component. The bioactivity of the synthesized hydrogels was assessed by the simulated body fluid method. The observed formation of hydroxyapatite on the scaffold of the hydrogels indicated that the hydrogels possess good bioactivity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

8.
Poly(vinylidene fluoride) (PVDF) was electrospun into ultrafine fibrous membranes from its solutions in a mixture of N,N‐dimethylformamide and acetone (9:1, v/v). The electrospun membranes were subsequently treated by continuous hot‐press at elevated temperatures up to 155°C. Changes of morphology, crystallinity, porosity, liquid absorption, and mechanical properties of the membranes after hot‐press were investigated. Results of scanning electron microscopy showed that there were no significant changes in fibrous membrane morphology when the hot‐press temperature varied from room temperature to 130°C, but larger pores were formed because of fibers melting and bonding under higher temperatures. Analyses of X‐ray diffraction and differential scanning calorimeter exhibited that the crystalline form of PVDF could transfer from β‐type to α‐type during hot‐press at temperatures higher than 65°C. Tensile tests suggested that the mechanical properties of the electrospun PVDF membranes were remarkably enhanced from 25 to 130°C, whereas the porosity and the liquid absorption decreased. The hot‐press at 130°C was optimal for the electrospun PVDF membranes. The continuous hot‐press post‐treatment could be a feasible method to produce electrospun membranes, not limited to PVDF, with suitable mechanical properties as well as good porosity and liquid absorption for their applications in high‐quality filtrations or battery separators. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers  相似文献   

9.
Biodegradable polymers are good candidates for a wide range of applications in tissue engineering and drug delivery because of their biocompatibility, their degradation, mechanical properties, and offer a sustained release of encapsulated drugs. The electrospun polymer nanofibrous materials can be used as carriers for hydrophobic and hydrophilic drugs. This research work focused on poly(lactic acid) (PLA) and blends of PLA with poly (ε‐caprolactone) (PCL) that are reinforced with different concentrations of halloysite nanotubes (HNTs) and various cosolvents for electrospinning including chloroform : acetone, chloroform : methanol, and dichloromethane (DCM) : N,N, dimethylformamide (DFM). The fibers produced from the DCM : DMF system without HNTs were more uniform resulting in smaller fiber diameters as compared to the chloroform: methanol system due to the increased solution conductivity. The addition of HNT nanoparticles produced electrospun fibers with large diameters because the viscosity of the solution increased. Cosolvent was important in determining fiber diameters because it strongly influenced the solution viscosity and conductivity. HNTs had relatively small impact on the growth of a crystalline morphology in PCL–HNT composites. The solvent mixture of chloroform : methanol was better for PLA‐based systems since PLA was found to have slightly higher crystallinity and larger enthalpy value indicating the improved structural orderness in the PLA polymer matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

10.
BACKGROUND: Electrospinning of natural polymers offers a promising approach to generate nanofibers with a similar fibrillar structure to that of native extracellular matrix. In the present work, zein/silk fibroin (SF) blends were electrospun with formic acid as solvent to fabricate bicomponent nanofibrous scaffolds for biomedical applications. RESULTS: The zein/SF electrospun nanofibers had a smaller diameter and narrower diameter distribution than pure zein nanofibers, and the average diameter gradually decreased from 265 to 230 nm with increasing SF content in the blend. The predominant presence of α‐helix zein structure and random coil form of silk I in blend fibrous membranes was confirmed from Fourier transform infrared spectral and wide‐angle X‐ray diffraction data, while conversion to the β‐sheet structure of SF was also detected. The tensile strength of the zein/SF fibrous membranes was improved as the content of SF in the blend fibers increased. A preliminary study of in vitro degradation and cytotoxicity evaluated by MTT assay indicated that biodegradable zein/SF fibrous membranes did not induce cytotoxic effects in an L929 mouse fibroblast system. CONCLUSION: Biodegradable zein/SF fibrous membranes with good mechanical properties and cytocompatibility combine the beneficial characteristics of the individual components and may be useful for biomedical applications. Copyright © 2009 Society of Chemical Industry  相似文献   

11.
Non-woven biodegradable membranes fabricated by electrospinning have recently attracted a great deal of attention for biomedical applications. In this study, microstructure, morphology and texture of electrospun poly(glycolide-co-lactide) (GA/LA: 90:10, PLA10GA90) non-woven membranes were investigated after post-draw and thermal treatments to tailor the degradation and mechanical properties. As-prepared electrospun PLA10GA90 membranes exhibited a low degree of crystallinity. When annealed at elevated temperatures without drawing, the membrane showed a higher degree of crystallinity with distinct lamellar structure but no overall orientation. The crystal orientation improved significantly when the membrane was drawn and annealed. As the elongation ratio increased, the degree of orientation and the tensile strength were increased. The corresponding tensile retention time was also increased from 2 to 12 days during in vitro degradation. Post-drawn and annealed membranes exhibited a slower degradation rate in the beginning of incubation, but a faster rate after two weeks of degradation when compared to as-spun membranes.  相似文献   

12.
This work attempted to improve the dispersion of graphene by coating poly(lactic acid) pellets with a masterbatch before melt processing. An in situ polycondensation reaction of lactic acid oligomer was utilized to prepare the masterbatch (MB) of exfoliated graphene (GR). MB dispersed composites of poly(lactic acid) (PLA) were fabricated by melt extrusion of MB‐coated PLA. One normal coated composite without MB coating (PLA‐M‐0.2GR) was fabricated for comparing properties. X‐ray diffraction, Raman spectroscopy, and morphological studies revealed better compatibility, dispersion, and interaction of GR for the diluted‐MB composite compared to the normal coated composite. The thermal stability, crystallization properties, and mechanical properties of the composites were examined, and the effect of short PLA chains in diluted‐MB composites was observed. The melt rheology nature of the composites was examined. Cole–Cole plots and Han plots suggested a uniform distribution of graphene. The sample PLA‐MB‐0.05GR showed improved modulus and elongation at break. It also showed better dispersion of GR, comparable thermal stability, good miscibility, good chain mobility, and high activation energy. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46476.  相似文献   

13.
Even though the biodegradability of polycaprolactone (PCL) is well established, few studies have carried out on the effect of nanofillers on the in vitro degradability of electrospun PCL membranes. Thus, the authors incorporated common nanofiller zinc oxide (ZnO) nanoparticles in electrospun PCL membranes. From the study of morphological schanges as well as the changes in crystallinity, it is clear that the ZnO nanoparticles accelerated the degradation of PCL. The FTIR results ascertain that the hydrolysis of the PCL nanofibers generates free hydroxyl and carbonyl groups in the bulk of the polymer. The tensile property of the PCL/ZnO nanocomposite membranes decreased with an increase in filler loading during degradation.  相似文献   

14.
Poly(lactic acid)(PLA)/cellulose nanocrystal nanocomposite fibers were prepared by electrospinning at elevated temperature. Columbia Blue, a nonionic hydrophobic dye with a molecular weight and partition coefficient that mimics a systemic agrichemical, was incorporated into the fibers as a model compound. The release of Columbia Blue into water displayed little burst release. Diffusion‐controlled release of Columbia Blue was significantly influenced by the hydrophobicity of the electrospun PLA nanocomposite fibers and followed Fickian diffusion kinetics. The release of Columbia Blue by degradation‐controlled mechanism followed zero‐order, time‐independent Case II kinetics (n = 1.0). Increasing cellulose nanocrystal content in the fibers increased the fiber degradation rate and the Columbia Blue release rate. The plasticizing effect of Columbia Blue on the thermal properties of the electrospun nanocomposite fibers showed the miscibility of Columbia Blue inside the electrospun nanocomposite fibers. A greenhouse trial confirmed the anticipated trends of higher pesticide dosage causing higher whitefly mortality percentage. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013  相似文献   

15.
Ultrafine fibrous webs of poly(lactide‐co‐glycolic acid) (PLGA) containing the bactericidal antibiotic drug rifampin were prepared by electrospinning, and their properties were investigated for wound‐dressing applications. Because PLGA is a biodegradable and biocompatible polymer, it is one of the best materials for the preparation of wound‐dressing substrates. Through this investigation of PLGA/rifampin electrospun webs, we found that the in vitro degradation reached approximately 60% in 10 days, and the drug release from the webs showed a fast and constant profile suitable for wound‐dressing applications. Also, we observed that both the web‐degradation rate and the drug‐release rate increased as the drug concentration in the PLGA/rifampin electrospun webs and the content level of glycolide units in the PLGA polymer matrix increased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

16.
Electrospinning nanotechnology has recently attracted lots of attention in different kinds of applications. Poly(butylene terephthalate) random‐segment copolymers, named poly[(butylene terephthalate)‐co‐(1,4‐cyclohexanedimethanol terephthalate)]‐b‐poly(tetramethylene glycol) (P(BT‐co‐CT)‐b‐PTMG), were synthesized in this study. On the basis of the new thermoplastic polyester elastomers (TPEEs), the fiber membranes were subsequently electrospun. With the aid of a cosolvent of trifluoroacetic acid and dichloromethane, the resulting solutions with a concentration between 24 and 32% w/v were electrospun into fibers without beads. The results also show a good spinnability for the copolymer solution in a range of voltages from 16 to 24 kV. When the molar ratio of 1,4‐cyclohexanedimethanol to 1,4‐butanediol was 10 : 90, the electrospun membrane prepared by the corresponding copolymers had a higher elastic modulus than the commercial TPEE (Hytrel 4056, 4.51 ± 0.35 MPa). Differential scanning calorimetry and X‐ray diffraction showed that a crystalline phase existed in the electrospun poly[(butylene terephthalate)‐co‐(1,4‐cyclohexanedimethanol terephthalate)]‐b‐poly(tetramethylene glycol) (P(BT‐co‐CT)‐b‐PTMG) copolymer fiber membranes. The melting point of the electrospun fibers was approximately less than that of the corresponding copolymers © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

17.
In vitro degradation behavior of dry‐jet‐wet spun poly(lactic acid) (PLA) monofilament and knitted scaffold were studied at three different pH i.e., at 4.6, 7.4, and 8.0 at 37°C for 20 weeks. Characterization of PLA by intrinsic viscosity, thermal properties, and scanning electron microscopy (SEM) was carried out. It is observed that the pH of the medium has significant role on degradation behavior of PLA. The degradation at pH 4.6 is observed to be maximum, which is confirmed by the drop of 52% in intrinsic viscosity. The degradation process has effect on the hydrophobicity of the PLA. The decrease in contact angle from 73° to 48° indicates that the PLA surface tends to become more hydrophilic as the degradation proceeds. The SEM analysis showed that with the degradation, surface deterioration takes place. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2006–2012, 2007  相似文献   

18.
The objectives of this work were to seek a simple method for preparation of poly(lactic acid) (PLA) foams and evaluate properties of these foams for scaffold application. Using a typical blowing agent and compression molding, biocomposite foams were successfully prepared from a PLA/rubber wood sawdust (PLA/RWS) blend. Selection of RWS for the biocomposites was based on particle size. RWS particles in two size ranges were used: 212–600 μm and ≤75 μm. Alkaline and silane treatments were applied to the RWS before blending with PLA. The tensile properties, Izod impact strength, foam morphology, and thermal degradation of the biocomposite foams were evaluated. Cytotoxicity and in vitro degradation were tested to determine the potential of the biocomposite foam for use as a scaffold in tissue engineering. Silane treatment improved mechanical properties by increasing the interfacial adhesion between PLA and RWS. The density and void fraction of the foam samples had a greater effect on mechanical properties than pore size. Proliferation of MG-63 cells increased with culture time, indicating that the foam samples were not cytotoxic. Promising samples were tested for degradation in a lysozyme/phosphate-buffered saline and showed a slow rate of in vitro degradation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48259.  相似文献   

19.
Electrospinning of a biodegradable polymer blend of poly(lactic acid) (PLA) and poly(butylene adipate‐co‐terephthalate) (PBAT) is reported for the first time. Effects of several solution parameters on electrospinning are explored, including types of single and binary solvents, binary solvent mixing ratio, polymer blend concentration, polymer blending ratio, and loading content of tetrabutyl titanate as a compatibilizer. An electrospinnability–solubility map of the PLA/PBAT blend is firstly developed for the facile selection of a suitable binary solvent system, thus simplifying the laborious, time‐consuming, trial‐and‐error process. A particular binary solvent system derived from good and non‐solvent serves as the most suitable medium for the successful preparation of homogeneous bead‐free electrospun PLA/PBAT nanofibers. It is revealed that the compatibilizer acts not only as a diameter size tuner for the PLA/PBAT fibers but also as a mechanical property enhancer for the immiscible PLA/PBAT electrospun mats. Moreover, the antibacterial activity of the drug‐loaded PLA/PBAT fibrous mats suggests their potential application as antibiotic‐carrier mats. Preparation of the composite mats comprising bead‐free fibers with an average size at sub‐micrometer scale is also demonstrated, additionally promoting the possibility of using the PLA/PBAT‐based electrospun mats as a matrix of various additives for a wide range of applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46486.  相似文献   

20.
Poly(lactic acid) (PLA) was reinforced halloysite nanotubes (HNTs) in this study. To improve dispersion and interfacial adhesion of HNTs within the PLA matrix, HNTs were surface modified with 3‐aminopropyltriethoxysilane (ASP) prior to compounding with PLA. PLA/ASP‐HNTs nanocomposites were characterized by differential scanning calorimetry (DSC), Fourier transfer infrared spectroscopy (FTIR), surface wettability, thermogravimetric analysis, transmission electron microscopy (TEM), and tensile testing. The hemocompatibility and cytocompatibility of PLA and PLA composites were investigated and the in vitro degradation process of PLA/ASP‐HNTs composites was investigated for a period of 6 months by gel permeation chromatography, FTIR, weight loss measurement, DSC, and tensile testing. PLA and all PLA composites were blood compatibile and non‐cytotoxic. TEM analysis revealed that HNTs agglomeration in PLA matrix was reduced by surface treatment with ASP. ASP‐HNTs had better reinforcing effect than unmodified HNTs evidenced by tensile testing. ASP‐HNTs appeared to increase the hydrolytic degradation process as measured by weight measurement. PLA/ASP‐HNTs composites displayed 12.1% weight loss and 30.6% average molecular weight reduction while retaining 74% of Young's modulus by the 24th week of degradation. Based on this data, the reinforcement of PLA using ASP‐HNTs may prove beneficial for applications such as biodegradable stents. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46521.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号