Study On Biocompatibility Of Scaffolds For Tissue Engineering Based On Electrospinning

How to construct the scaffold for tissue engineering to mimic the structure and function of the native extracellular matrix(ECM) is of great interest in tissue engineering and regeneration all the time. Unlike conventional spinning, electrospinning makes use of charges to provide a stretching force to a collector where there is a potential gradient. When a sufficient high voltage is applied, a jet of polymer solution will erupt from a polymer solution droplet, then the evaporation of the solvent for polymer to solidify to form polymer fiber. Because of the morphology feature of small diameter, high surface area to volume ratio and high porosity, they can make better mimesis of the natural ECM compared with the conventional scaffolds. Nanofibers prepared by electrospinning can be act as excellent scaffold for tissue engineering. Biocompatibility can be defined as the ability of a material to perform with an appropriate host response in a specific application. Biocompatibility is the key subject in biomaterial research first midst and last. It is quick, convenient, good-repeating and cheap that examining the biocompatibility through cell-culturing method, and it plays more and more important role in evaluating the biomaterials in vitro.This thesis made a preliminary study on biocompatibility of scaffolds prepared by electrospinning for tissue engineering. Nanofibers were prepared by electrospinning to mimic the native ECM, such as slik fibroin scaffolds and chitosan/collagen composite scaffolds. Cell adhesion, proliferation and morphology were evaluated through MTT method and SEM. Then, RT-PCR was used to examine the gene expression.Silk fibroin nanofibers were prepared by electrospinning, HFIP as solvent. Endothelial cells were seeded on scaffolds, MTT results showed that the nanofibers could enhance cell adhesion and proliferation. After 7d co-culture, ECs on TCP proliferated three fold, and that on nanofibers also proliferated two point seven fold. PCNA was expressed in cells both on nanofibers and the control, in keeping with the results of cell proliferation. It showed that the electrospun silk fibroin had good biocompatibility.From the point of view of mimic, electrospinning of biocompatible chitosan and collagen was studied to biomimic the natural ECM from both structure and function in this paper. Chitosan/collagen composite nanofibers were successfully prepared by electrospinning, HFIP/TFA as solvent. It was found that the diameter of spun fibers became fine with the increase of the ratio of chitosan to collagen. GA, EDC, UV and heat cross-linking were chose to stabiliz the chitosan/collagen composite scaffold. SEM showed that the stabilized scaffolds could keep their dimensional and structural stability in wet stage after GA cross-linking.Biocompatibility is the key subject in biomaterial research first midst and last. Cell-culturing method was used to evaluate the biocompatibility of chitisan/collagen composite scaffolds. The MTT results showed that nanofibers can obviously enhance the proliferation of cells, and the cells have a good spreading and attachment on the composite nanofibers. SEM showed that the ECs could migrate into the fibrous-network structure and grew in the three-dimensional space. Simultaneously, gene expression was examined by RT-PCR. ICAM-1, PCNA and P53 were expressed in cells on electrospun chitosan/collagen composite scaffolds and the controls. The results showed that the gene expression was different among different gene. As far as the same gene was concerned, the expression was similar in cells on chitosan/collagen scaffolds in different mass ratios, and it had no significant difference when compared with the controls. It showed that the electrospun chitosan/collagen composite scaffolds had good biocompatibility.