Structure and process relationship of electrospun bioabsorbable nanofiber membranes (original) (raw)
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Tailoring the morphology and crystallinity of poly(L-lactide acid) electrospun membranes
Science and Technology of Advanced Materials, 2011
Biodegradable poly(L-lactic acid) (PLLA) microfibers were prepared by electrospinning by varying the applied potential, solution flow rate and collector conditions. PLLA fibers with smoothly oriented and random morphologies were obtained and characterized by scanning electron microscopy. The optimum fiber orientation was obtained at 1000 rpm using a 20.3 cm diameter collecting drum, while for higher and lower drum rotation speeds, the rapid random motion of the jets resulted in a random fiber distribution. The deformation of the jet with rapid solidification during electrospinning often results in a metastable phase. PLLA electrospun fibers are amorphous but contain numerous crystal nuclei that rapidly grow when the sample is heated to 70-140 °C. In this way, the degree of crystallinity of the fibers can be tailored between 0 and 50% by annealing. Infrared transmission spectra revealed that the processing conditions do not affect the PLLA samples at the molecular level and that the crystallinity of the samples is related to the presence of α-crystals.
Journal of Nanoscience and Nanotechnology, 2012
Biodegradable poly(L-lactide acid) (PLLA) nanofiber membranes were prepared by electrospinning of PLLA and poly(ethylene oxide) (PEO). The selective removal of PEO by water allows to obtain smaller fiber diameters and to increase the porosity of the membranes in comparison to PLLA membranes obtained under the same electrospinning conditions. After removal of PEO membranes with fiber sizes of 260 nm and average porosity close to 80% are obtained. Thermal and infrared results confirm the poor miscibility of PLLA and PEO, with the PEO randomly distributed along the PLLA fibers. On the other, PLLA and PEO mixing strongly affect their respective degradation temperatures. The influence of the PEO in the electrospinning process is discussed and the results are correlated to the evolution of the PLLA fiber diameter.
Biocompatibility studies of electrospun nanofibrous membrane of PLLA-PVA blend
Journal of Applied Polymer Science, 2013
Electrospinning, self-assembly, and phase separation are some of the techniques available for the synthesis of nanofibers. Of these techniques, electrospinning is a simple and versatile method for generating ultrafine fibers from a wide variety of polymers and polymer blends. Poly L-lactide (PLLA) and Poly (vinyl alcohol) (PVA) are biodegradable and biocompatible polymers which are mainly used for biomedical applications. Nanofibrous membranes with 1:9 ratio of PLLA to PVA (8 to 10 wt % and 10 wt %) were fabricated by electrospinning. The percentage porosity and contact angle of PVA in the PLLA-PVA nanofibrous mat increased from 80 to 83% and from 39 6 3 to 55 6 3 , respectively. The water uptake percentage of PVA nanofibers decreased from 190 to 125% on the addition of PLLA to PVA in the PLLA-PVA nanofibrous mat. The nanofiber morphology, structure and crystallinity were studied by Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), respectively. The thermal properties were studied by thermogravimetric analysis (TGA) and differential scanning calorimetery (DSC). The biocompatibility studies of PLLA-PVA blend were performed using fibroblast cells (NIH 3T3
Electrospun Polylactic Acid Based Nanofibers for Biomedical Applications
Material Science Research India
Electrospinning technique has excellent advantages such as tunable functionality, thin fibers with large surface areas, ease of processing and good physical properties. Electrospinning provides wide usage area with these advantages in biomedical applications. Polylactic acid (PLA) is a biodegradable and biocompatible polymer, so it can be used in various biomedical applications. PLA can be easily electrospun from solution by using different kinds of conventional solvents. Electrospun PLA based nanofibers are used in many biomedical applications such as drug delivery, scaffold for tissue engineering, dressings for wound healing, dental applications etc. This review focuses on electrospun PLA based nanofibers used in biomedical applications in recent years. Future perspectives of electrospun PLA based fibers are also discussed in the last part.
Optimisation of electrospinning parameter for Poly(L-lactic) acid (PLLA) electrospun nanofiber
MATEC Web of Conferences, 2016
Poly (L-lactic) Acid (PLLA) ia one of the biodegradable polymer that normally used in the biomedical application. In this work it is shown that electrospinning of PLLA electrospun fibre was affected by electrospinning processing parameters such as the solvent systems selection, polymer solution concentration, flow rate and acceleratingvoltage. Optimisation of these parameters is necessary to obtain a beadless and submicron diameter fibre as desired in this research.
International Journal of Biological Macromolecules, 2019
Poly(L-lactic acid-co-succinic acid-co-1,4-butane diol) (PLASB) was synthesized by direct condensation copolymerization of L-lactic acid (LA), succinic acid (SA), and 1,4-butanediol (BD) in the bulk using titanium(IV) butoxide as a catalyst. The weight-average molecular weight of PLASB was 2.1Ý 10 5 when the contents of SA and BD were each 0.5 mol/100 mol of LA. Electrospinning was used to fabricate porous membranes from this newly synthesized bioabsorbable PLASB dissolved in mixed solvents of methylene chloride and dimethylformamide. Scanning electron microscopy (SEM) images indicated that the fiber diameters and nanostructured morphologies of the electrospun membranes depended on the processing parameters, such as the solvent ratio and the polymer concentration. By adjusting both the solvent mixture ratio and the polymer concentration, we could fabricate uniform nanofiber non-woven membranes. Cell proliferation on the electrospun porous PLASB membranes was evaluated using mouse fibroblast cells; we compare these results with those of the cell responses on bulk PLASB films.
Journal of Applied Polymer Science, 2010
Significant progress has been made recently in the fabrication of polymeric nanofibers, their characterization and applications, new polymeric materials, theoretical analysis, and so forth. Hence, in this brief review, we report the progress made in these subjects during the last 5 years. Most of the work concerns nanofibers related to the field of medicine. On the other hand, negligibly few reports have been found on nanofibers related to membrane separation processes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Poly(lactic acid)-Based Electrospun Fibrous Structures for Biomedical Applications
Applied Sciences, 2022
Poly(lactic acid)(PLA) is an aliphatic polyester that can be derived from natural and renewable resources. Owing to favorable features, such as biocompatibility, biodegradability, good thermal and mechanical performance, and processability, PLA has been considered as one of the most promising biopolymers for biomedical applications. Particularly, electrospun PLA nanofibers with distinguishing characteristics, such as similarity to the extracellular matrix, large specific surface area and high porosity with small pore size and tunable mechanical properties for diverse applications, have recently given rise to advanced spillovers in the medical area. A variety of PLA-based nanofibrous structures have been explored for biomedical purposes, such as wound dressing, drug delivery systems, and tissue engineering scaffolds. This review highlights the recent advances in electrospinning of PLA-based structures for biomedical applications. It also gives a comprehensive discussion about the pro...
Keywords Highlights A Review of Electrospun Nanofiber Membranes Article info
Electrospun nanofiber membranes Water treatment Adsorptive membranes Membrane distillation Desalination • A new generation of membranes offering higher flux at lower applied pressure • Highly porous with interconnected pores • High specific surface area, suitable for adsorption applications • Have found applications in water treatment, air cleaning, membrane distillation, among many other uses Electrospun nanofiber membranes (ENMs) are new generation of membranes with many favorable properties such as high flux and low pressure drop. Although electrospinning has been known for more than a century, its applications in filtration and separation processes are relatively new. Electrospinning has provided the means to produce ultrathin fibers -as thin as a few nanometers -that can be used in preparing membranes with small and defined pore sizes. In addition, due to the small fiber diameter ENMs exhibit high surface area to volume ratio, making them suitable adsorption media with enhanced capacity compared with conventional adsorbents. This paper familiarizes the reader with the history and laboratory-scale preparation of ENMs, discusses parameters that influence properties of the fibers and the final membranes, and introduces a number of applications in which, ENMs have exhibited superior performances compared to competing conventional processes.