Cell Co-Culture On Patterned Fibrous Scaffolds For Vascular Tissue Engineering

The mature vessels are formed by the inner layers of endothelial cells (ECs) and outer layers of smooth muscle cells (SMCs), which provide mechanical strength and arrangement and modulate the thickness of vascular walls. In order to mimic the vascular structures, the purpose of this paper is to use electrospining and lithography technologies to preparate patterned fibrous mats with ridge and groove features. Co-culture of ECs and SMCs are proposed by seeding SMCs on patterned fibrous mats and ECs on random fibrous mats to construct a similar vascular structure in vitro.The results of cell culture study showed that SMCs were mainly distributed on the ridge of patterned fibrous mats, and the extracellular matrices (ECM) secretion by SMCs also had a certain orientation. SMCs showed a high penetration into the pattern of fibrous mats. Compared the culture of ECs and SMCs on the fibrous mats separately, the coculture system promoted the proliferation of both ECs and SMCs, and the secretion of laminin (LN) and collagen Ⅳ (Col Ⅳ) by ECs and the secretion of a-smooth muscle actine (a-SMA) and collagen Ⅰ (Col Ⅰ) by SMCs. The promotion effects were more significant for SMCs compared with ECs.Sufficient growth factors are essential to form a functional vascular vessel, and vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are the important factors to promote the adhesion and growth of ECs and SMCs. Accordingly, patterned fibrous mats and random fibrous mats with the encapsulation of CaP nanoparticles containing plasmids ecoding VEGF (pVEGF) and bFGF (pbFGF) were prepared to evaluate the behavior of ECs and SMCs. The coculture of ECs and SMC on these fibrous mats showed that the introduction of pDNA promoted the cell proliferation, the secretion of LN and Col IV by ECs and the secretion of a-SMA and Col I by SMCs. SMCs indicated a good orientation on the patterned fibrous mats, and penetration of SMCs into the fibrous mats was significant enhanced by the introduction of pDNA.Coculture primary ECs and SMCs on fibrous mats were established on a tube fibrous scaffold to construct a blood vessel substute in vitro. After culture for2months ECs formed a lumen in the inner layer, and SMCs penetrated into the fiber scaffolds and were andarranged into a layer closely attached around the EC layer. Mechanical property tests showed that the radial compliance and bursting strength of the obtained vessels were around0.56%/100mm Hg and650mm Hg, respecetively, which were lower than those of normal blood vessels.