制备赖氨酸改性聚乳酸纳米纤维支架的性能评价

Evaluation on the preparation and performance of lysine modified polylactic acid nanofiber stent

背景:聚乳酸作为可降解聚合物已被制成纳米纤维支架广泛应用于组织再生,但在某些组织工程应用中其作为支架材料存在降解速度慢、生物相容性差等局限。目的:制备赖氨酸/聚乳酸支架,通过控制不同赖氨酸浓度研究支架的结构及性能。方法:以1,4-二氧六环为溶剂体系、赖氨酸作为氨解剂,采用热致相分离技术制备赖氨酸改性聚乳酸纳米纤维支架,其中赖氨酸的浓度分别为5%,10%,15%,30%,以未改性的聚乳酸支架为对照,进行傅里叶变换红外光谱仪、扫描电镜、示差扫描仪热分析仪、接触角和机械性能分析等检测。结果与结论:(1)傅里叶变换红外光谱分析显示,聚乳酸支架被赖氨酸氨解改性成功;(2)扫描电镜显示,当非溶剂相为超轻水时,支架的纤维网格结构较差,未形成立体的三维结构;当赖氨酸浓度为5%时,支架呈片状、带状或大量团聚现象,没有形成良好的三维纤维的网络结构;随着赖氨酸浓度的增加,支架的纳米纤维结构逐渐形成,当赖氨酸浓度为10%时制备的支架仍存在片状及出现团聚现象;当赖氨酸浓度为15%时,支架有分布相对均匀的纳米纤维结构;但当赖氨酸浓度为30%时,支架纤维结构出现坍塌和大片团聚现象;(3)随着赖氨酸浓度的增加,支架的水接触角减少、抗压强度降低;(4)随着赖氨酸浓度的增加,支架的熔融温度稍有降低,但无明显变化,结晶度增加;(5)结果表明,赖氨酸的引入改善了聚乳酸支架的网格状纤维结构、亲水性和结晶度,降低了支架的机械性能。

BACKGROUND: Polylactic acid as a biodegradable polymer has been made into nanofiber stent, widely used in tissue regeneration. However, as a scaffold material, polylactic acid has some limitations, such as slow degradation rate and poor biocompatibility.OBJECTIVE: To prepare lysine-polylactic acid stents to study the structure and properties of stents by controlling different lysine concentrations. METHODS: With 1, 4-dioxane as solvent system and lysine as an ammonia solution, thermally induced phase separation technology was used to prepare the lysine-polylactic acid stents. Lysine concentrations were 5%, 10%, 15%, 30%, respectively. The detection of Fourier transform infrared spectrometer, scanning electron microscope, differential scanner thermal analyzer, contact angle and mechanical performance analysis were carried out with the unaltered polylactic acid bracket as the control. RESULTS AND CONCLUSION:(1) Fourier transform infrared spectral analysis showed that the polylactic acid stent was successfully modified by lysine ammonia.(2) The scanning electron microscope showed that when the non-solvent phase was deuterium depleted water, the fiber mesh structure of the bracket was poor and no three-dimensional structure was formed. When the concentration of lysine was 5%, the stent was flaky, ribbon or a large number of reunion phenomenon, and no good three-dimensional fiber network structure was formed. With the increase of lysine concentration, the nanofiber structure of the stent gradually formed. When the concentration of lysine was 10%, the prepared stent still had flaky and reunion phenomenon. When the concentration of lysine was 15%, the stent had a relatively uniform distribution of nanofiber structure. However, when the concentration of lysine was 30%, the structure of stent fiber collapsed and large areas reunited.(3) With the increase of lysine concentration, the water contact angle of the stent was reduced and the strength of pressure was reduced.(4) With the increase of lysine concentration, the melting temperature of the stent decreased slightly, but there was no obvious change, and the crystallization increased.(5) The results show that the introduction of lysine improves the mesh fiber structure, hydrophobicity and crystallization of polylactic acid stent and reduces the mechanical properties of the bracket.