Lee Soo-Hong, Kim Byung-Soo, Kim Soo Hyun, Kang Sun Woong, Kim Young Ha
Biomaterials Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650, Korea.
Macromol Biosci. 2004 Aug 9;4(8):802-10. doi: 10.1002/mabi.200400021.
A novel process was developed to fabricate biodegradable polymer scaffolds for tissue engineering applications, without using organic solvents. Solvent residues in scaffolds fabricated by processes involving organic solvents may damage cells transplanted onto the scaffolds or tissue near the transplantation site. Poly(L-lactic acid) (PLLA) powder and NaCl particles in a mold were compressed and subsequently heated at 180 degrees C (near the PLLA melting temperature) for 3 min. The heat treatment caused the polymer particles to fuse and form a continuous matrix containing entrapped NaCl particles. After dissolving the NaCl salts, which served as a porogen, porous biodegradable PLLA scaffolds were formed. The scaffold porosity and pore size were controlled by adjusting the NaCl/PLLA weight ratio and the NaCl particle size. The characteristics of the scaffolds were compared to those of scaffolds fabricated using a conventional solvent casting/particulate leaching (SC/PL) process, in terms of pore structure, pore-size distribution, and mechanical properties. A scanning electron microscopic examination showed highly interconnected and open pore structures in the scaffolds fabricated using the thermal process, whereas the SC/PL process yielded scaffolds with less interconnected and closed pore structures. Mercury intrusion porosimetry revealed that the thermally produced scaffolds had a much more uniform distribution of pore sizes than the SC/PL process. The utility of the thermally produced scaffolds was demonstrated by engineering cartilaginous tissues in vivo. In summary, the thermal process developed in this study yields tissue-engineering scaffolds with more favorable characteristics, with respect to, freedom from organic solvents, pore structure, and size distribution than the SC/PL process. Moreover, the thermal process could also be used to fabricate scaffolds from polymers that are insoluble in organic solvents, such as poly(glycolic acid). Cartilage tissue regenerated from thermally produced PLLA scaffold.
开发了一种用于制造组织工程应用中可生物降解聚合物支架的新方法，该方法不使用有机溶剂。通过涉及有机溶剂的方法制造的支架中的溶剂残留可能会损害移植到支架上的细胞或移植部位附近的组织。将聚（L-乳酸）（PLLA）粉末和NaCl颗粒在模具中压缩，随后在180℃（接近PLLA熔点）下加热3分钟。热处理使聚合物颗粒融合并形成包含截留的NaCl颗粒的连续基质。溶解用作致孔剂的NaCl盐后，形成了多孔可生物降解的PLLA支架。通过调节NaCl/PLLA重量比和NaCl粒径来控制支架的孔隙率和孔径。在孔结构、孔径分布和机械性能方面，将这些支架的特性与使用传统溶剂浇铸/颗粒沥滤（SC/PL）工艺制造的支架的特性进行了比较。扫描电子显微镜检查显示，使用热工艺制造的支架具有高度互连的开放孔结构，而SC/PL工艺产生的支架具有较少互连的封闭孔结构。压汞法显示，热制备的支架比SC/PL工艺具有更均匀的孔径分布。通过在体内构建软骨组织证明了热制备支架的实用性。总之，本研究开发的热工艺产生的组织工程支架在有机溶剂的使用、孔结构和尺寸分布方面具有比SC/PL工艺更有利的特性。此外，热工艺还可用于由不溶于有机溶剂的聚合物（如聚乙醇酸）制造支架。从热制备的PLLA支架再生的软骨组织。
