3D打印PCL/β-TCP可降解椎间融合器的体外降解及生物力学研究

目的:研究以质量配比为5:5的聚己内酯(PCL)与磷酸三钙(β-TCP)为原材料,应用3D打印技术制备的的可降解的颈椎椎间融合器在体外的降解特性,为临床应用提供理论依据。方法:将制备好的融合器浸泡于模拟体液中,置于37℃温箱,每2周更换浸泡液,按浸泡时间的不同分为六组:分别为空白对照组、2周、4周、12周、26周、52周组。每组浸泡前后经室温真空干燥后用同一天平测量质量,计算失重质量及失重率,应用凝胶渗透色谱仪分析各组融合器中PCL的分子量变化,并应用INSTRON万能试验机进行抗压强度力学测试。空白对照组为样本室温密闭容器放置,在初始称重并检测分子量及抗压强度测试,52周后计算失重率、检测分子量及抗压强度。结果:该种可降解椎间融合器初始抗压强度达到(23.21±2.28)MPa,在体外降解52周后其抗压强度下降不明显,为(18.99±0.49)MPa(P>0.05);其在体外可缓慢降解,52周后失重率约9.23%(P<0.05),其中PCL分子量从初始的10万左右降至7万左右(P<0.05)。结论:该种可降解椎间融合器抗压力学强度适中且能长时间维持,符合临床应用要求,其在体外可缓慢降解,评估其在生物体内的降解吸收特性较好,在人体椎间融合手术中应用的可行性及有效性较高。

In vitro Degradation and Biomechanical Study of 3D Printed PCL/β-TCP Degradable Intervertebral Fusion Cage

Objective:The aim of this study was to assess the degradation characteristics of the biodegradable cervical intervertebral fusion cagemade of polycaprolactone(PCL)andβ-tricalcium phosphate(β-TCP)with a mass ratio of 5:5]prepared by 3D printing technology,which provides theoretical basis for clinical application.Methods:The prepared fusion cage was immersed in simulated body fluid,placed in a 37℃incubator,and the immersion solution was changed every two weeks.According to the different immersion time,it was divided into six groups:blank control group,2 weeks,4 weeks,12 weeks,26 weeks,52 weeks group.Every cage of each group was dried by vacuum drying at room temperature before and after soaking,then its weight was measured by the same balance,and the weight loss and weight loss rate were calculated.The molecular weight of PCL in each cage was analyzed by gel permeation chromatograph,and the compressive strength was tested by INSTRON universal testing machine.In the blank control group,the samples were placed in sealed containers at room temperature,weighed initially and tested for molecular weight and compressive strength.After 52 weeks,the weight loss rate,molecular weight and compressive strength were calculated.Results:The initial compressive strength of this kind of degradable intervertebral fusion cage was(23.21±2.28 MPa),and the strength did not decrease significantly(18.99±0.49 MPa)after 52 weeks of degradation in vitro(P>0.05);the weight loss rate was about 9.23%after 52 weeks(P<0.05),and the molecular weight of PCL decreased from around 100,000 dropped to around 70,000(P<0.05).Conclusion:The biodegradable intervertebral fusion cage has moderate compressive strength and can be maintained for a long time,which meets the requirements of clinical application.It can be degraded slowly in vitro,and its biodegradation and absorption characteristics in vivo are evaluated to be good.Therefore,its application in human intervertebral fusion surgery is feasible and effective.