形状记忆可吸收支架的制备及其在骨组织应用的体外研究

Preparation of shape memory polymers scaffold and in vitro study for bone tissue application

目的研究具有形状记忆功能的支架材料的制备方法,探讨其物理性能及生物相容性,为骨组织工程的应用作奠定基础。方法热压成形术合成孔隙大小及孔隙率适宜的形状记忆聚合物(SMP)支架,应用体式显微镜观察支架材料的形变过程,扫描电镜考察支架材料塑形前后的孔隙变化以及细胞在支架表面附着生长的情况,同时将兔骨髓间充质干细胞(BMSC)接种于支架材料,运用死活细胞染色方法检测该支架材料的生物相容性。数据分析采用方差分析,两两比较采用SNK检验。结果体式显微镜展现了材料自形变后的中间状态恢复到原始状态,形变恢复率约91%,合成的支架材料在人体温度(37℃)下具有形状记忆特性;扫描电镜下可见未形变的支架材料其具有良好的孔隙率(90.6±5.2)%,原始孔隙大小约165μm,压缩状态的孔隙大小约为33μm,同时BMSC与支架材料表面附着良好;死活细胞染色结果显示,BMSC在SMP支架表面培养1、7、14 d的活细胞率分别为(81.5±2.2)%、(86.3±1.9)%、(82.1±1.8)%,空白对照组1、7、14 d活细胞率分别为(82.3±1.7)%、(88.4±1.4)%、(83.7±2.1)%,两组间活细胞率差异无统计学意义(F=0.380,P=0.555)。而SMP支架组1、7、14 d的活细胞密度分别为(91±2.3)、(202±4.8)和(617±5.5)个/mm2,空白对照组1、7、14 d活细胞密度分别为(83±4.5)、(219±5.3)和(599±7.2)个/mm^2,均呈增长模式。结论制备所得支架材料孔隙均一,形变温度为37℃,具有良好形状记忆特性及生物相容性,能响应人体温度恢复到塑型前形状,在微创手术中有巨大的应用潜能。

Objective To fabricate a new smart shape memory polymers（SMP）scaffold and to evaluate its physical and biological properties in bone tissue engineering. Methods The thermo？compression method was used to build the SMP scaffold with proper pore size and porosity. The shape recovery process was detected by stereo？microscope. Electron microscope was used to check its pore size change and the cell attachment on the SMP？scaffold. Live/dead staining was used to test its biocompatibility of the scaffold. Experimental data were analyzed using ANOVA procedure. Differences between groups were compared with SNK？test. Results The pore size of SMP scaffold was 100~300μm and the porosity was（90.6±5.2）%. Under stereo？microscope,the SMP scaffold had an anticipated shape memory recovery in vitro from a small,compact structure to a voluminous structure;the recovery rate was 91%. SEM result demonstrated that the BMSCs attached and spread very well on the wall surface. The live/dead staining indicated that the living cell rates of SMP scaffold group after being incubated for 1,7 and 14 days was （81.5 ± 2.2）%,（86.3 ± 1.9）%,and（82.1 ± 1.8）%,while the control group was（82.3 ± 1.7）%,（88.4 ± 1.4）%,and（83.7±2.1）%,respectively. There was no significant difference（F=0.380,P=0.555）in cell＆amp;nbsp;survival between the control and SMP scaffold groups. The results of cell density were（91 ± 2.3）,（202 ± 4.8）,and（617 ± 5.5）cells/mm2 of SMP scaffold group,（83 ± 4.5）,（219 ± 5.3）,and（599 ± 7.2）cells/mm2 of the control group in 1,7 and 14 days,respectively,indicated that cell reproduction rate of both groups were on the rise. Conclusion SMP scaffold has excellent shape memory function and biocompatibility, which shows great application potential in the minimally invasive surgery.