Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regeneration
Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regeneration
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DOI：
10.1016/s0142-9612(98)00099-4
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发表时间：
1998-11-01
期刊：
影响因子：
14
通讯作者：
Mikos, AG
中科院分区：
文献类型：
--
作者：
Widmer, MS;Gupta, PK;Mikos, AG
我们已经制作了多孔的，可生物降解的管状导管引导组织再生使用相结合的溶剂铸造和挤出技术。本研究中使用的生物可降解聚合物是聚（DL-乳酸-共-乙醇酸）（PLGA）和聚（L-乳酸）（PLLA）。首先通过溶剂浇铸工艺制备聚合物/盐复合材料。干燥后，将复合材料挤出以形成管状构造。然后将构建体中的盐颗粒滤出，留下具有开孔结构的导管。PLGA作为模型聚合物进行了研究，以分析盐的重量分数，盐的粒度，和加工温度对挤出导管的孔隙率和孔径的影响。孔隙率和孔径被发现增加与盐的重量分数。增加盐粒度会增加孔径，但不影响孔隙率。高挤出温度降低了孔径而不改变孔隙率。对于在较高温度下制造的导管，观察到分子量的较大降低。在体外降解长达8周后，测试PLGA和PLLA导管的机械性能。PLLA导管的模量和破坏强度比PLGA导管高约10倍。两种导管的失效应变相似。降解8周后，PLGA和PLLA导管的分子量分别下降至初始值的38%和43%。然而，两个管道都保持了形状，没有倒塌。PLGA在整个时间过程中也保持无定形，而PLLA的结晶度从5.2%增加到11.5%。还用染色的微球测试了用用于移植的细胞或用用于药物递送的可生物降解的聚合物微粒接种导管的潜力。这些多孔管状结构对于需要管状支架的组织如外周神经、长骨、肠或血管的再生具有很大的希望。(C)1998爱思唯尔科技有限公司版权所有。
We have fabricated porous, biodegradable tubular conduits for guided tissue regeneration using a combined solvent casting and extrusion technique. The biodegradable polymers used in this study were poly(DL-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). A polymer/salt composite was first prepared by a solvent casting process. After drying, the composite was extruded to form a tubular construct. The salt particles in the construct were then leached out leaving a conduit with an open-pore structure. PLGA was studied as a model polymer to analyze the effects of salt weight fraction, salt particle size, and processing temperature on porosity and pore size of the extruded conduits. The porosity and pore size were found to increase with increasing salt weight fraction. Increasing the salt particle size increased the pore diameter but did not affect the porosity. High extrusion temperatures decreased the pore diameter without altering the porosity. Greater decrease in molecular weight was observed for conduits manufactured at higher temperatures. The mechanical properties of both PLGA and PLLA conduits were tested after degradation in vitro for up to 8 weeks. The modulus and failure strength of PLLA conduits were approximately 10 times higher than those of PLGA conduits. Failure strain was similar for both conduits. After degradation for 8 weeks, the molecular weights of the PLGA and PLLA conduits decreased to 38% and 43% of the initial values, respectively. However, both conduits maintained their shape and did not collapse. The PLGA also remained amorphous throughout the time course, while the crystallinity of PLLA increased from 5.2% to 11.5%. The potential of seeding the conduits with cells for transplantation or with biodegradable polymer microparticles for drug delivery was also tested with dyed microspheres. These porous tubular structures hold great promise for the regeneration of tissues which require tubular scaffolds such as peripheral nerve, long bone, intestine, or blood vessel. (C) 1998 Elsevier Science Ltd. All rights reserved.