Fabrication Of Biomimetic Tubular Vascular Scaffold And Inducing VSMCs Alignment

In vascular tissue engineering, if the vacular cells, e.g., smooth muscle cells (SMCs), could not regenerate their native 3D micro architectures or organization structures, their functions would disappear. Except for applying bioreactor introducing extra stress during vascular culture, fabricating biomimetic and tubular scaffold is another approach to induce the SMCs circumferencial alignment and elongation. Electrospinning and melt-spinning are two convenient ways that can produce nanoscale or microscale fibers continuously. Combining suitable receiving/wraping technology, tubular scaffold with circumferencial microchannel on outside and interconnected nano/micro pores within the wall would be prepared easily.In this study, the influence of the electrospinning parameters (solution concentration, voltage, the feed rate of syringe pump, the distance between syringe and collecting mandril, wraping speed) and the melt-spinning parameters (polymer melting temp., the right-and left removing and rotating speed of collecting mandril) on fibers'morphology and weave structure were investigated. Novel biodegradable tubular scaffolds with two layers and circumferential nano/micro channels on outside surface and interconnected nano/micro pores within the walls were fabricated by electrospinning, melting spinning, and solvent/nonsolvent bonding techniques.After modification with collagen, the scaffolds were seeded with the human bilical vein smooth muscle cells(VSMCs). SEM and fluorescence microscope imaging both showed that the SMCs all aligned along the microfibers and microchannels, demonstrating this novel type of scaffold had strong ability for inducing SMCs regenerating their microarchitecture in vivo. Biomimetic tubular vascular scaffold possessed good cell compatibility. This study will be beneficial for further developing biomimetic tubular scaffold to induce blood vessel regeneration in situ.On the base of in vitro culture, in vivo transplant trials of the biomimetic scaffolds were further performed in rabbit to evaluate the possibility of in situ regeneration of vessel. After 1 week and 1 month transplant, scaffords were taken out and observed by eyeballing and histological microcopy imaging. The results showed that the outer layer of scaffold had closely linked to the rabbit tissue while 0.4 mm thickness thrombus formed the inner cavity. VSMCs and fiberblasts attached to the circumferential channels of scaffold regularly.