[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.