PGLA编织支架的制备与初步体内评价

目的:热拉伸会改变纤维的结构和性能,进而影响由纤维编织而成的支架的性能。本文考察了PGLA纤维的拉伸倍数对编织支架在SD大鼠皮下的体内降解行为的影响。方法:制备了基于生物可降解高分子材料聚乙交酯丙交酯(PGLA,GA/LA摩尔比=90/10)的完全生物可降解编织支架,通过测试支架在大鼠体内降解过程中的失重、表面形貌、热性能、径向压缩力等变化情况,考察了纤维的不同的拉伸倍数对支架体内降解过程的影响。结果:用拉伸倍数为5的PGLA纤维编织的支架在植入SD大鼠皮下后降解最慢,重量、吸水率、结晶度、化学成分和径向压缩力的变化最慢,植入体内10天后能够保持完整的支架形态。结论:纤维的拉伸倍数会影响由纤维编织成的支架的热性能和力学性能的变化,本研究结果表明这种新的手工编织的支架具有短暂支撑管腔狭窄的潜在应用,为支架的材料选择和制备方法提供了参考,为在体内起到短暂支撑作用的支架的深入研究提供了实验基础。

Preliminary in-vivo Evaluation of Hand-made Biodegradable Poly (glycolide-co-lactide) Braided Stents

Objective:Heat-stretching treatment will change structural morphologies and properties of the fibers, thereby affecting the properties of the stents made by these fibers. In this paper, the effect of draw ratio of PGLA filament on the degradation behaviors of PGLA stents was evaluated under dorsal subcutis of male SD rats.Methods:Poly (glicolide-co-lactide) (PGLA) stents were braided by a single strand of PGLA (glycolic acids/lactic acids (mole/mole) = 90/10) filament with a draw ratio of 3, 4 or 5. The stents were retrieved at different time and evaluated in terms of the morphology, weight loss, water uptake, and chemical composition, together with the mechanical and thermal properties after implantation in vivo for 20 days to investigate the effect of draw ratio of PGLA fiber on the degradation behaviors of PGLA stents.Results:Only the stents with a filament draw ratio of 5 could be separated and removed from the inner plastic tube and outer Ni-Ti alloy stent after 10 days of implantation. Results demonstrated that the stents with highest draw ratio (5) had slowest changes of stent weight loss, water uptake, crystallinity, chemical composition and radial compression strength after implantation. Moreover, the crystallinity of stent increased with implantation time during the investigated period and the glycolic acids (GA) segments of PGLA molecules hydrolyzed faster than the lactic acids (LA) ones.Conclusion:The results indicated that the filament draw ratio would certainly affect the degradation and mechanical properties of the stents, and this new hand-made braided stent has great potential for supporting intraluminal obstruction for a temporary period, which could offer experimental data for the selection of materials and preparation of biodegradable stents, thus attribute to development of braided biodegradable stents.