Design of bioinspired polymeric materials based on poly(D,L-lactic acid) modifications towards improving its cytocompatibility

To design novel bioinspired polymeric material, poly(D,L-lactic acid) (DL-PLA) was on the base and modified in the bulk. Firstly, maleic anhydride (MA) groups were introduced to the side chain of DL-PLA by the way of melting free radical copolymerization using benzoyl peroxide as an initiator. Then, to neutralize the acid generated during DL-PLA degradation, aliphatic diamine was immobilized by the N-acylation of anhydrides with butanediamine. As the following stage, adhesive peptides Arg-Gly-Asp-Ser (RGDS) were grafted into the backbone of DL-PLA by using carbodiimide as a coupling agent, in order to endow DL-PLA with bioactivity and biospecificity. The characterizations of the obtained polymers were by the means of GPC-MALLS, FTIR, ¹³C NMR and XPS to explore the structures and rhodamine-carboxyl interaction method, ninhydrin reaction and amino acid analyzer to determine the content of MA, butanediamine, and RGDS, respectively, followed the test of pH changes during degradation in distilled water (pH = 6.45). Finally, the osteoblast behavior on different DL-PLA based films was investigated and the results indicated that the introduction of diamine could promote cell attachment and viability, and the incorporation of RGDS further improved its cytocompatibility. The synthetic DL-PLA based bioinspired material may have potentials for tissue engineering and other biomedical applications.