In vitro degradation of porous poly(L-lactic acid) foams
In vitro degradation of porous poly(L-lactic acid) foams
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DOI：
10.1016/s0142-9612(00)00048-x
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发表时间：
2000-08-01
期刊：
影响因子：
14
通讯作者：
Mikos, AG
中科院分区：
文献类型：
--
作者：
Lu, LC;Peter, SJ;Mikos, AG
本研究研究了多孔聚左旋乳酸 (PLLA) 泡沫在 37 摄氏度、pH 7.4 磷酸盐缓冲盐水中 46 周的体外降解情况。使用溶剂浇铸、颗粒浸出技术制造了四种类型的 PLLA 泡沫。三种类型的初始盐重量分数分别为70%、80%和90%，盐颗粒尺寸为106-150μm，而第四种类型的初始盐重量分数为90%，尺寸范围为0-53μm。所得泡沫的孔隙率分别为0.67、0.79、0.91和0.84。相应的中值孔径为33、52、91和34μm。 PLLA 泡沫的宏观降解与孔形态无关，降解过程中泡沫重量、厚度、孔分布、压缩蠕变行为和形态变化不显着。然而，在降解结束时观察到熔融温度降低和结晶度略有增加。基于重均分子量的泡沫半衰期为11.6+/-0.7(70％；106-150μm)、15.8+/-1.2(80％，106-150μm)、21.5+/-1.5(90％，106-150μm)和43.0+/-2.7(90％，106-150μm)。 0-53μm）周。与盐重量分数为 90% 的泡沫相比，盐重量分数为 70% 或 80% 的泡沫的孔壁更厚，有助于自催化效应，导致泡沫降解更快。此外，与盐浓度为106-150μm的泡沫相比，使用0-53μm范围内的盐制备的泡沫的孔表面/体积比的增加增强了降解产物的释放，从而减弱了自催化作用并导致泡沫降解更慢。盐重量分数为 90% 的泡沫在降解早期会形成和释放结晶 PLLA 颗粒。这些结果表明，多孔泡沫的降解速率可以通过改变孔壁厚度和孔表面/体积比来设计。 (C) 2000 Elsevier Science Ltd. 保留所有权利。
This study investigated the in vitro degradation of porous poly(L-lactic acid) (PLLA) foams during a 46-week period in pH 7.4 phosphate-buffered saline at 37 degrees C. Four types of PLLA foams were fabricated using a solvent-casting, particulate-leaching technique. The three types had initial salt weight fraction of 70, 80, and 90%, and a salt particle size of 106-150 mu m, while the fourth type had 90% initial weight fraction of salt in the size range 0-53 mu m. The porosities of the resulting foams were 0.67, 0.79, 0.91, and 0.84, respectively. The corresponding median pore diameters were 33, 52, 91, and 34 mu m. The macroscopic degradation of PLLA foams was independent of pore morphology with insignificant variation in foam weight, thickness, pore distribution, compressive creep behavior, and morphology during degradation. However, decrease in melting temperature and slight increase in crystallinity were observed at the end of degradation. The foam half-lives based on the weight average molecular weight were 11.6 +/- 0.7 (70%; 106-150 mu m), 15.8 +/- 1.2 (80%, 106-150 mu m), 21.5 +/- 1.5 (90%, 106-150 mu m), and 43.0 +/- 2.7 (90%, 0-53 mu m) weeks. The thicker pore walls of foams prepared with 70 or 80% salt weight fraction as compared to those with 90% salt weight fraction contributed to an autocatalytic effect resulting in faster foam degradation. Also, the increased pore surface/volume ratio of foams prepared with salt in the range 0-53 mu m enhanced the release of degradation products thus diminishing the autocatalytic effect and resulting in slower foam degradation compared to those with salt in the range 106-150 mu m. Formation and release of crystalline PLLA particulates occurred for foams fabricated with 90% salt weight fraction at early stages of degradation. These results suggest that the degradation rate of porous foams can be engineered by varying the pore wall thickness and pore surface/volume ratio. (C) 2000 Elsevier Science Ltd. All rights reserved.