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 1H 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.