Mim Mim Lim

Fabrication and evaluation of polycaprolactone/gelatin-based electrospun nanofibers with antibacterial properties

Nanofibrous scaffolds were fabricated through blending of a synthetic polymer, polycaprolactone (PCL), and a natural polymer, gelatin (GE), using an electrospinning technique. Processing and solution parameters were optimized to determine the suitable properties of PCL/GE-based nanofibers. Several characterizations were conducted to determine surface morphology by scanning electron microscopy (SEM), wettability using water contact angle measurement, and chemical bonding analysis using attenuated total reflectance (ATR) of PCL/GE-based nanofibers. Experimental results showed that 14% (w/v) PCL/GE with a flow rate of 0.5 mL/h and 18 kV demonstrated suitable properties. This nanofiber was then further investigated for its in vitro degradation, drug loading (using a model drug, tetracycline hydrochloride), and antibacterial testing (using zone inhibition method).

Conductive PEDOT:PSS coated polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) electrospun membranes: Fabrication and characterization.

UNLABELLED In the current study, electrospinning technique was used to fabricate composite membranes by blending of a synthetic polymer, polylactic acid (PLA) and a natural polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV. Conductive membranes were prepared by dipping PLA/PHBV electrospun membranes into poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) ( PEDOT PSS) solution, which is a biocompatible polymer. The coated and uncoated membranes were evaluated using several techniques. The electrical conductivity of the coated membranes was measured using a digital multimeter. In vitro cell cytotoxicity and cell viability were measured by culturing human skin fibroblast (HSF) cells onto the membranes using MTT assays. It was observed that electrospinning of 20% (w/v) PLA/PHBV with a weight ratio of 50:50 produced the most uniform fibers with no beads. It was observed that the wettability and surface roughness of the PEDOT PSS coated PLA/PHBV membranes were greatly increased than uncoated membrane. The results of cell viability using MTT assay, cell attachment and cell proliferation showed that the conductive PEDOT PSS coated PLA/PHBV membrane were more favorable for tissue engineering application than their uncoated counterparts.

Polycaprolactone(PCL)/Gelati(Ge)-Based Electrospun Nanofibers for Tissue Engineering and Drug Delivery Application

Recent development of tissue engineering has been emphasized on tissue regeneration and repairing in order to solve the limitation of organ and tissue transplantation issues. Biomaterial scaffold, which plays an important role in this development, not only provides a promising alternative in order to improve the efficiency of cell transplantation in tissue engineering but also to deliver cells with growth factors and drugs into injured tissue to increase the survival of cell via drug delivery system. In this study, nanofibers were fabricated through blending of a synthetic polymer polycaprolactone (PCL) and a natural polymer Gelatin (Ge) using electrospinning technique. Processing parameters were optimized to determine the most suitable properties of PCL/Ge nanofibers. The surface morphology of PCL/Ge nanofibers were then characterized using Scanning Electron Microscopy (SEM). Six samples of nanofibers from different amount of gelatin mixed with 10% PCL (w/v) were successfully fabricated. Experimental results showed that 18kV of high voltage provided more homogenous and less beaded nanofibers. Meanwhile, the 0.8g of Ge in 10% PCL (w/v) was set as the maximum concentration while 0.2g of Ge in 10% PCL (w/v) was set as the minimum concentration to reduce the bead formation.

Composite Synthetic Scaffolds for Tissue Engineering and Regenerative Medicine

The aim of tissue engineering is to develop cell, construct, and living system technologies to restore the structures and functions of damaged or degenerated tissues. Scaffolds are supporting materials used in tissue engineering applications to repair or restore damaged tissues. Biomaterials are used to fabricate scaffolds. There are different types of biomaterials including biopolymers, bioceramics and biodegradable metals. Biomaterials have to be biocompatible and nontoxic. To fabricate scaffold, appropriate biomaterial has to be chosen according to the desired characteristics and application of the scaffold. This chapter reviews different types of biomaterials for different tissue engineering applications.

In vitro biological evaluation of electrospun Polycaprolactone/gelatine nanofibrous scaffold for tissue engineering

The fabrication of biocompatible and biodegradable scaffolds which mimic the native extracellular matrix of tissues to promote cell adhesion and growth is emphasized recently. Many polymers have been utilized in scaffold fabrication, but there is still a need to fabricate hydrophilic nanosized fibrous scaffolds with an appropriate degradation rate for skin tissue engineering applications. In this study, nanofibrous scaffolds of a biodegradable synthetic polymer, polycaprolactone (PCL), and blends of PCL with a natural polymer, gelatine (Ge), in three different compositions: 85:15, 70:30, and 50:50 were fabricated via an electrospinning technique. The nanofibrous scaffold prepared from 14% w/v PCL/Ge (70:30) exhibited more balanced properties of homogeneous nanofibres with an average fibre diameter of 155.60 ± 41.13 nm, 83% porosity, and surface roughness of 176.27 ± 2.53 nm. In vitro cell culture study using human skin fibroblasts (HSF) demonstrated improved cell attachment with a flattened morphology on the PCL/Ge (70 : 30) nanofibrous scaffold and accelerated proliferation on day 3 compared to the PCL nanofibrous scaffold. These results show that the PCL/Ge (70:30) nanofibrous scaffold was more favourable and has the potential to be a promising scaffold for skin tissue engineering applications.

Fabrication and characterization of polycaprolactone (PCL)/gelatin electrospun fibers

Over the past few decades, there has been considerable interest in developing electrospun fibers by using electrospinning technique for various applications. Polymer blending is one of the most effective methods in providing desired properties. In this study, synthetic polymer polycaprolactone (PCL) was blended together with natural polymer gelatin where both of them have different properties. It is done by using electrospinning technique. 10 %w/v and 14 %w/v PCL/gelatin electrospun fibers were successfully electrospun with different weight ratio. Processing parameters were set constant in this study and only solution parameters were altered. The optimized electrospun fiber formed was 14 %w/v PCL/gelatin 70:30 with average fiber diameter of 246.30 nm. No beaded fiber was formed in this scanning electron microscope (SEM) image. The result obtained also showed that by increasing the overall polymeric concentration of PCL/gelatin, average fiber diameter decreases. Fiber diameter was also found decreasing with the increase of the concentration of gelatin in the same concentratoin of PCL/gelatin blended electrospun fiber. Blending of PCL and gelatin in different weight ratio had provided different properties of electrospun fibers. It is believed that blended electrospun fibers can be used for biomedical applications.

Scaffold Fabrication Protocols

Development of scaffolds in tissue engineering applications is growing in a fast pace. Scaffolds play a pivotal role in scaffold-based tissue engineering. The scaffolds must possess some important characteristics. Scaffolds should be biocompatible, should have appropriate porosity and porous microstructure and proper surface chemistry to allow cell attachment, proliferation and differentiation. Scaffolds should possess adequate mechanical properties and controlled biodegradability. There are many techniques available to fabricate scaffolds including freeze drying, electrospinning and rapid prototyping. Some of these techniques have gained much attention due to their versatility. This chapter points up the protocols for the fabrication and characterization of appropriate scaffolds for tissue engineering using biopolymers and composite biomaterials.

Fabrication and Characterization of Polymer and Composite Scaffolds Using Freeze-Drying Technique

This chapter reports the emulsion freezing/freeze-drying technique for the formation of three dimensional scaffolds. Composite scaffolds based on biodegradable natural polymer and osteoconductive hydroxyapatite (HA) nanoparticles can be promising for a variety of tissue engineering (TE) applications. This study addressed the fabrication of three dimensional (3D) porous composite scaffolds composed of HA and chitosan fabricated via thermally induced phase separation and freeze-drying technique. The scaffolds produced were subsequently characterized in terms of microstructure, porosity, mechanical property. In vitro degradation and in vitro biological evaluation were also investigated. The scaffolds were highly porous and had interconnected pore structures. The pore sizes ranged from several microns to a few hundred microns. The incorporated HA nanoparticles were well mixed and physically co-existed with chitosan in composite scaffold structures. The addition of 10 % (w/w) HA nanoparticles into chitosan enhanced the compressive mechanical properties of composite scaffold compared to pure chitosan scaffold. In vitro degradation results in phosphate buffered saline (PBS) showed slower uptake properties of composite scaffolds. Moreover, the scaffolds showed positive response to mouse fibroblast L929 cells attachment. Overall, the findings suggest that HA/chitosan composite scaffolds could be suitable for TE applications.

Fabrication of Polymer and Composite Scaffolds Using Electrospinning Techniques

This chapter reports the electrospinning technique for the formation of nano and microfibers. Due to the ability to fabricate fibrous scaffolds with micro and nano-scale properties, electrospinning technique has received much interest. Poly(caprolactone) (PCL) fibrous scaffolds with micro and nano-scale fibers and surface-porous fibers have not been explicitly investigated. In this study, the results of modulating the factors on processing route on nanofibrous scaffold morphology were investigated. 10 and 13 % w/v of PCL/dichloromethane (DCM) or chloroform was used at different flow rate and applied voltage. The result shows that 13 % w/v of PCL/chloroform produced better fibers. The fibrous scaffolds had two different ranges of fiber diameters. Average fiber diameter in the higher range was 4.52 μm while average fiber diameter in the lower range was 440 nm. In vitro degradation study suggested slow degradability of PCL electrospun fibers. This chapter also reports the fabrication of hydroxyapatite/PCL microfibers and their characteristics.

Drug loading, drug release and in vitro degradation of poly(caprolactone) electrospun fibers

In this study, model drug of Fluorescein Isothiocyanate-Dextran (FD70S) was incorporated into poly(caprolactone) (PCL) electrospun fibers. Drug loading was successful and drug release was measured by using microplate reader. The result showed FD70S was successfully released from PCL electrospun fibers. In order to investigate the biodegradable ability of PCL electrospun fibers, in vitro degradation was investigated for 107 days by immersing PCL electrospun fibers in phosphate buffer saline (PBS) which mimics extracellular fluid. Electrospun fibers degraded slowly and were not fully degraded. Fibers became more random and the average fiber diameters decreased from 350 nm to 240 nm after degradation of 107 days.