The Application Of Novel Biofabrication Technique For The Tissue Engineered Urethral Graft

Objective:The tissue engineered urethral graft is a novel material for the treatment of urethral stricture.This study will compare the biocompatibility,mechanical property,cell infiltration and function expression in Wnt inhibitor loaded co-axial electrospinning scaffold,nanoyarn scaffold fabricated with dynamic liquid system and 3D bioprinted graft.Materials and methods: Various scaffolds were fabricated with co-axial electrospinning,dynamic liquid system and 3D bioprinter,then they were observed with scanning electron microscope(SEM)and transmission electron microscope to evaluate the micro-structure.The mechanical property was tested with Instron.To seed rabbit bladder epithelial cells,dermal fibroblast to drug loaded scaffold,to seed placental stem cell to nanoyarn,and to mix epithelial cells and smooth muscle cells to 3D bioprinting hydrogel.To use SEM and MTT assay to test the scaffoldcell interaction.To use immunofluorescence,PCR and western blot to test the extracellular matrix and fibrosis related genes.To test the viability and proliferation of cells with Live/dead assay.To track the cells with membrane dye.Results: The wnt inhibitor loaded nanofiber scaffolds were fabricated,which possessed the property of anti-fibrosis and had been confirmed by in vivo and in vitro study.The nanoyarn scaffold owned higher porosity,pore size and aligned fiber distribution.The SEM and MTS assay demonstrated the better proliferation and diffentiation of muscular tissue.The cells loaded hydrogel and material could be co-printed and got satisfied stability.The epithelial cells and smooth muscle cells showed good viablity in 7days,and the design of multiple pores could be improve the proliferation of cells.Conclusion: This study set the present problems as the beginning point and applied three advantagous methods to fabricate urethral graft,and evaluate their feasibility in invo and in vitro.The study is creative in the field of urethroplasty with the potential in clinical study.However,various questions should be solved before the application in the clinical use.