直接心辅装置CRG/PVA复合水凝胶隔离层的制备与性能研究

基于气动肌肉的直接心辅装置近年来成为研究热点,针对该装置,提出一种水凝胶生物材料隔离层,用于避免气动肌肉与心脏直接接触,减小摩擦力与排异反应。首先选取聚乙烯醇(PVA)作为水凝胶隔离层3D打印的前驱体材料,并进行PVA水凝胶的制备;然后针对水凝胶固化时间长无法应用于3D打印的问题,加入卡拉胶(CRG)进行优化,并进行力学以及溶胀性能探究;最后将3D成型技术运用到隔离层的成型过程,并对水凝胶隔离层的摩擦磨损性能进行研究。结果表明,CRG/PVA复合水凝胶材料拉伸断裂应变及应力分别为280%、0.84 MPa,力学性能良好;CRG不仅能缩短水凝胶固化时间,且其含量从1%增加至5%,水凝胶溶胀度提高到3.70;水凝胶隔离层在120个工作周期后表面仅轻微损伤,进一步验证该结构能改善心脏摩擦环境。

Preparation and properties of CRG/PVA composite hydrogel isolation layer for direct cardiacassist device

In recent years,the direct cardiac assist device based on pneumatic muscle has become a research focus.For the device,a hydrogel biomaterial isolation layer is proposed to avoid the direct contact between pneumatic muscle and the heart,thereby reducing friction force and rejection reaction.Firstly,polyvinyl alcohol(PVA)is selected as the precursor material for the 3D printing of the hydrogel isolation layer,and the preparation of PVA hydrogel is carried out.Then,carrageenan(CRG)is added to optimize PVA hydrogel for solving the problem that hydrogel can not be applied to 3D printing for it has a long curing time,and the mechanical and swelling properties of the proposed material are explored.Finally,3D printing technology is applied to the forming of the isolation layer,and the friction and wear properties of the hydrogel isolation layer are studied.The results show that the tensile fracture strain and stress of CRG/PVA composite hydrogel are 280%and 0.84 Mpa,respectively,which reveals its good mechanical properties.The use of CRG can not only shorten the curing time of hydrogel,but also increase its swelling degree to 3.70 with the content increasing from 1%to 5%.The hydrogel isolation layer shows no obvious surface damage after 120 working cycles,which further verifies that the proposed structure can reduce the friction of direct cardiac assist device against the heart.