聚酯/磷酸三钙人工骨载体的表面修饰及不同骨移植材料的比较研究

采用热致分相法(TIPS)与熔铸颗粒沥取法(SCPL),实验室条件下制备适宜组分配比(7:3)的聚乳酸-聚羟乙酸/磷酸三钙[PLGA/TCP]复合人工骨载体[PLGA/TCP(L)];另外采用先进快速成形技术(RP)制备相同组分配比(7:3)的PLGA/TCP(RP)复合材料.扫描电镜(SEM)观察人工骨载体的超微结构,并用I型胶原(Col I)对载体材料进行表面修饰.进而复合诱骨生长因子-牛骨形态发生蛋白(bBMP)以制备出仿生活性人工骨.将PLGA/TCP(L)、PLGA/TCP(RP)、牛松质骨脱钙骨基质(DBM)、仿生活性人工骨及OsteoSet(R)人工骨进行多种比较.结果发现,先进RP技术制备的PLGA/TCP(RP)大段人工骨载体结构明显优于实验室常规方法所制备的PLGA/TCP(L)载体.PLGA/TCP(L)载体、DBM、PLGA/TCP(RP)载体及OsteoSet(R)人工骨的孔隙率分别为21.5%、70.4%、58.6%和0%,其中DBM和PLGA/TCP(RP)载体的孔隙率最高(P＜0.01).此外,RP制备的PLGA/TCP(RP)人工骨载体孔径大(350 μm),并与天然DBM的孔径最为接近.PLGA/TCP(L)、PLGA/TCP(RP)人工骨载体经I型胶原表面修饰后[PLGA/TCP(L)-Col I、PLGA/TCP(RP)-Col I],明显改善其对bBMP的亲和力,人工骨载体表面及孔隙内对bBMP的复合能力明显增强,仿生活性人工骨[PLGA/TCP(L)-Col I-bBMP、PLGA/TCP(RP)-Col I-bBMP]的制备效率亦显著提高.其中采用先进RP技术结合载体材料表面修饰新工艺研制的PLGA/TCP(RP)-Col I-bBMP仿生活性人工骨具有与天然骨最接近的空间三维结构,并含有关键的成骨活性因子,因此具有更为广阔的研究与应用前景.

Surface Modification of Biodegradable Polymer/TCP Scaffolds And Related Research

Under laboratory condition, the compound materials of Poly (DL-lactic-co-glycolic acid)/Tricalcium phosphate [PLGA/TCP(L), with component ratio of 7:3] were fabricated by combining the thermally induced phase separation (TIPS) with solvent-casting particulate-leaching (SCPL) approach. On the other hand, rapid prototyping (RP) technique manufactured PLGA/TCP scaffolds [PLGA/TCP(RP)] were obtained. These two kinds of carriers were coated with collagen type I (Col I). The extracted bovine bone morphogenetic protein (bBMP) was loaded into carriers to establish biomimetic synthetic bones. PLGA/TCP(L) scaffolds, demineralized bone matrices (DBM) of bovine cancellous bone, PLGA/TCP(L) scaffolds, biomimetic synthetic bones and OsteoSet bone graft substitutes were investigated. Scanning electron microscopy revealed that the microarchitecture of PLGA/TCP(RP) scaffolds was much better than that of PLGA/TCP(L) scaffolds. The diameter of macropore of PLGA/TCP(RP) scaffold was 350 microm. The porosities of PLGA/ TCP(L) scaffolds, DBM, PLGA/TCP(RP) scaffolds and OsteoSet bone graft substitutes were 21.5%, 70.4%, 58.6% and 0%, respectively (P<0.01). Modification of PLGA/TCP scaffolds with collagen type I [PLGA/TCP(L)-Col I and PLGA/TCP(RP)-Col I] essentially increased the affinity of the carriers to bBMP. Among these synthetic materials, PLGA/TCP(RP)-Col I-bBMP composite is promising as a novel bone graft substitute due to its advanced fabrication technique, good tri-dimensional microarchitecture and ideal components.