聚(D，L-乳酸)基仿生聚合物材料的合成与表征

Synthesis and characterization of biomimetic polymeric material based on poly(D,L-lactic acid) modifications

探索一种新型聚乳酸基仿生聚合物材料的制备新方法。具体实验步骤是：利用聚乳酸上叔碳原子的自由基反应活性,在过氧化二苯甲酰的催化作用下,将马来酸酐引入聚乳酸侧链上,以此提供高反应活性的酸酐键；然后利用酸酐基团与—NH_2发生N-酰化反应这一特点。将脂肪族二胺引入聚乳酸侧链上,从而克服聚乳酸降解产物的体液环境呈酸性的缺陷；再用碳二亚胺作缩合剂,在二胺改性聚乳酸材料中共价引入一种细胞粘附肽段Arg-Gly-Asp-Ser(RGDS),赋予材料生物活性和生物特异性,这样就制备了一种新型聚乳酸基仿生材料。采用MALLS、FTIR和XPS对仿生材料进行结构表征；采用罗丹明比色法、茚三酮显色法和氨基酸分析仪检测法对仿生材料中的马来酸酐、二胺和粘附肽RGDS进行定量测定。结果表明,按文中所述之制备技术,在不改变聚乳酸材料主链结构的前提下,该仿生材料中粘附肽RGDS的含量是5．12μmol/g。这就形成了一种具有类似细胞外基质的新型仿生材料。

A novel poly（lactic acid）（PLA） based biomimetic polymeric material was prepared by bulk modification as follows. Firstly, maleic anhydride groups were introduced to the side chain of PLA by way of melt free radical copolymerization using benzoyl peroxide as an initiator. Then, to neutralize the acidic degrading products of PLA, aliphatic diamine was introduced to the side chain of PLA by the N-acylation of anhydrides with -NH2. On this basis,in order to endow PLA with bioactivity and biospecificity,adhesive peptide arg-gly-asp-ser （-RGDS） were grafted onto the backbone of PLA by using carbodiimide as condensating agent. In this paper, MALLS,FTIR and XPS were used to characterize the synthetic biomimetic material and rhodamine-carboxyl interaction method,ninhydrin reaction and amino acid analyzer were used to determine the content of maleic anhydride,diamine and RGDS, respectively. The results demonstrated that, in the context of remaining main chain structure of PLA,the content of RGDS is 5.12μmol/g by the developed synthetic method,which provides theoretical and technical supports for further detecting biocompatibility of this material and finally applications in biomedical field.