Synthesis and characterization of PLLA-PLCA-PEG multiblock copolymers and their applications in modifying PLLA porous scaffolds

Poly(L-lactic acid)-poly(L-lactic acid-co-citric acid)-poly(ethylene glycol) multiblock copolymers (PLLA-PLCA-PEG) were synthesized through polycondensation reaction and characterized by H-1 NMR and DSC. The three-dimensional ultrafine fibre microporous PLLA/PLLA-PLCA-PEG scaffolds were then fabricated by modifying PLLA with PLLA-PLCA-PEG through blending and characterized as well. Properties of scaffolds such as swelling and degradation behaviors, morphology and mechanical moduli were fully investigated. Tetrandrine-loaded PLLA/PLLA-PLCA-PEG scaffolds were also fabricated and their drug releasing behaviors were taken into consideration. Compressive testing research shows that the mechanical flexibility improves as the content of PLLA-PLCA-PEG copolymers in the scaffolds increases. The TED encapsulation efficiency of the scaffold is enhanced when the amount of PLLA-PLCA-PEG increases because of the acid-base interaction between carboxylic acid groups of the copolymer with TED. The releasing velocity of TED speeds up while the PLLA-PLCA-PEG blocks ratios in scaffolds increase. So modification of PLLA scaffold with PLLA-PLCA-PEG shall broaden its applications in tissue engineering. (c) 2007 Elsevier Ltd. All rights reserved.