纳米可降解聚乳酸-羟基乙酸尿道支架的制备及性能

背景：聚乳酸-羟基乙酸可作为尿道替代物进行组织缺损的修复。目的：观察电纺丝法制备聚乳酸-羟基乙酸共聚物可降解尿道支架的可行性，并评价支架管的体外降解性能。方法：采用电纺丝技术制备纳米聚乳酸-羟基乙酸共聚物(摩尔比80∶20)尿道支架管，并以戊二醛对支架进行交联、改性，将交联后支架截成长约1 cm小段并浸于尿液中进行体外降解实验。结果与结论：支架管具有纳米结构，孔隙率约89%，孔径(32±19) µm；交联后可见纤维表面变粗糙，但纤维丝直径、孔径及孔隙率与交联前差异无显著性意义(P > 0.05)，但交联后支架管力学性能显著提高。支架降解初期速度相对较快，中后期降解速度减慢，至8周时材料质量损失约50%，第10周完全崩解。材料在体内降解过程中相对分子质量的变化趋势与质量损失大体相同，降解早期相对分子质量下降相对较快，后期下降速度减慢并趋于平稳。表明采用电纺丝技术制备的纳米聚乳酸-羟基乙酸共聚物尿道支架可满足尿道组织工程支架的要求。

Fabrication and properties of nano-biodegradable poly(lactic-co-glycolic acid) tubular urethral stents

BACKGROUND:Poly (lactic-co-glycolic acid) (PLGA) can be used as a substitute for urethral tissues. OBJECTIVE:To discuss the feasibility of the fabrication of co-polymer PLGA 80:20 tubular urethral stents by using electrospinning technique and to evaluate the degradable properties of the stents in vitro. METHODS:After synthesizing of PLGA (80:20), the electrospinning technique was used to fabricate the urethral graft. Crosslinking was carried out at a temperature of 4 ℃ using 1% glutaraldehyde for 24 hours. The morphology was investigated by scanning electron microscope. The tensile and anti-compression properties of the stents were tested. The stents were cut into pieces (1 cm in length) which were immersed in the urine to evaluate the degradability. The morphology, residual weight rate and molecular weight were investigated in each observation point. RESULTS AND CONCLUSION: The stents had the nanostructure and the morphology satisfied the demand of a degradable urethral scaffold. The porosity was about 89%, and the pore size was (32±19) µm. The tensile and anti-compression properties had improved after crosslinking by glutaraldehyde. The residual weight rate curve of the stents was close to a straight line, and degraded completely within 10 weeks. The decrease of molecular weight was apparently in the early stage, and the decreasing was slow down in the later stage. The properties of PLGA (80:20) urethral stents fabricated by electrospinning technique and crosslinked by glutaraldehyde can fully satisfy the demand of a degradable urethral graft.