The Application Of Electrospinning In Preparation For Blood Vessel Tissue Engineering Scaffolds

Novel vascular scaffolds were prepared and modified to resolve the degradability problem of vascular tissue engineering scaffold. Furthermore, the cytocompatibility and blood compatibility of the scaffold materials were improved. The optimization process of the scaffold materials was investigated. Moreover the biocompatibility of the scaffold was evaluated by implanting it in the subcutaneous. The study would give a preliminary experimental evidence so as to obtain the novel vascular tissue engineering scaffold material.The materials were manufactured in the biomaterial lab of Tsinghua University. The experimental materials were obtained by electrospinning poly(l-lactide) (PLLA) blending with polyvinyl pyrrolidone (PVP), and then modified with chitosan/heparin by electrostatic self-assembly.The properties of the PLLA films blending different ratios of PVP were investigated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and contact angle measurement (CA). The surface modified PLLA films were analysed by SEM, Fourier transform infrared spectroscopy test (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and CA.Vascular smooth muscle cells (VSMCs) were planted into the PLLA films with different ratios of PVP with the same density, respectively. The cell morphology and proliferation in the films were measured by SEM, laser scanning confocal microscopy (LSCM) and MTT assay after 2, 4, 6 days of culture. In addition, the blood compatibility of the films were tested by platelet adhesion and observed by SEM. The VSMCs and EVCs were seeded on the PLLA films modified by chitosan/heparin, respectively. The cell proliferation in the modified films were measured by MTT assay after 2, 4, 6 days of culture.The PLLA films with different ratios of PVP were put into PBS for degradation for 5 weeks. The films were tested by weight loss, the change of viscosity average molecular weight, SEM and pH change. The different materials were implanted in subcutaneouse of New Zealand white rabbits. After 4 and 15 days, the implantations were taken off and studied by histological analysis.We have succeeded in preparation of biodegradable vascular tissue engineering scaffolds. The PLLA films with PVP had a good structure and improved hydrophilicity. Moreover, the hydrophilicity of PLLA films got better with the increase of PVP content.Cell experiments showed that the films blended with PVP by electrospinning were beneficial to improve the VSMCs compatibility. The platelet adhesion test showed that the films had excellent blood compatibilities with the addition of PVP. The films modified with chitosan/heparin had inhibition of proliferation of VSMCs, however, it could improve the proliferation of EVCs. The degradation in vitro and animal experiments indicated that we had success to prepare the biodegradable scaffolds of vascular tissue engineering which had better tissue compatibility.In conclusion, we had successfully prepared novel biodegradable scaffolds for blood vessel tissue engineering. Moreover it had good biocompatibility and blood compatibility. The study provided the theoretical support for clinical application, especially in the small diameter vessels (<6 mm, ID).