不同成分配比的聚酯/磷酸三钙复合材料体外降解行为观察

Observation on in vitro degradation of different ratio of polymer/tricalcium phosphate compound materials prefabricated by modified thermally induced phase separation

目的:探索用改良热致分相法实验室制备骨组织工程用聚酯/磷酸三钙(Tricalciumphosphate,TCP)复合材料,并模拟体内降解环境研究其体外降解行为,以便为进一步的体内植入材料筛选提供依据。方法:①将热致分相法与熔铸沥取法二者结合制备不同成分比例(7∶3,6∶4,5∶5)的聚消旋乳酸犤Poly(L-lacide-co-D,L-lactide),PDLLA犦/TCP及聚丙交酯-乙酯共聚物犤Poly(lactide-co-glycolide),PLGA犦/TCP复合材料。②扫描电镜观察材料孔隙结构及测量孔隙大小,体积法测定孔隙率,各组分别于1%胰酶PBS溶液中进行体外降解,定期其重量变化,连续6周。结果:①改良法制备出的材料平均孔隙率均>80%,电镜下测量孔径大小100～400μm。②体外降解实验中,随时间点变化,材料重量丧失以(5∶5)组为著,3周时即达到此组材料的82%以上(PDLLA组为82.6%,PL-GA组为83.1%),6周时(5∶5)组均完全溶解。③用SPSS10.0作统计学分析,P<0.01为差异有显著性意义;PDLLA/TCP(5∶5)比PDLLA/TCP(7∶3)(t=-22,P<0.01),PDLLA/TCP(5∶5)比PDLLA/TCP(6∶4)(t=-14,P<0.01),差异有显著性意义;PLGA/TCP(5∶5)比PLGA/TCP(7∶3)(t=-24,P<0.01),PLGA/TCP(5∶5)比PLGA/TCP(6∶4)(t=-16,P<0.01),差异有显著性意义;PDLLA/TCP(5∶5)比PLGA/TCP(5∶5)(t=2.5,P>0.01),差异无?

AIM:To prefabricate the bone tissue engineering oriented polymer[Poly(L lacide co D,L lactide) or Poly(lactide co glycolide)]/tricalcium phosphate(TCP)compound materials in laboratory by using a modified thermally induced phase separation(TIPS)method,and to study the in vitro degradation behaviors of the harvested materials by creating a mimicked degradation condition in vitro similar to that in vitro so as to provide a basis for selection of implant materials in vitro for further research. METHODS:①The compound materials of [Poly(L lacide co D,L lactide) or Poly(lactide co glycolide)]/TCP with different component ratios(7∶3,6∶4,5∶5) were prefabricated by combining the TIPS method with solvent casting particulate leaching approach(SCPL).②The microstructure was observed and the size of pores was measured under scanning electron microscope(SEM),and the porosity was assayed with stereometry.The harvested materials were placed into 1%pancreatin PBS, then degraded in vitro,and the weight loss of each sample was recorded once a week in a consecutive 6 week duration. RESULTS:①The average porosity of the materials harvested with modified TIPS method was over 80%and pore sizes ranged 100-400 μm under the SEM;②In the duration of in vitro degradation,at different time points,the average weight loss in material(5∶5) groups presented a noticeable change,i.e. just at 3 weeks,the average weight loss surpassed 82%( 82.6%and PLGA 83.1%in PDLLA group respectively);and at 6 weeks,the materials degraded completely in the material(5∶5) groups;③SPSS 10.0 software was used for statistical analysis,with P< 0.01 as statistical significance,a statistical significance existed in PDLLA/TCP(5∶5) vs PDLLA/TCP(7∶3)(t=-22,P< 0.01) and PDLLA/TCP(5∶5) vs PDLLA/TCP(6∶4)(t=-14,P< 0.01)respectively,also a statistical significance was observed in PLGA/TCP(5∶5)vs PLGA/TCP(7∶3)(t=-24,P< 0.01) and PLGA/TCP(5∶5)vs PLGA/TCP(6∶4)(t=-16,P< 0.01)respectively,but no statistical significance was shown in PDLLA/TCP(5∶5) vs PLGA/TCP(5∶5)(t=2.5,P >0.05). CONCLUSION:The porosity and pore sizes of the materials prefabricated by modified TIPS meet the demands of bone tissue engineering.Both of PDLLA/TCP(5∶5) and PLGA/TCP(5∶5) hold a faster degration rate than other material tested,and hence,they have potential prospect for bone implantation.