GelMA复合凝胶的挤出式3D打印工艺及其性能研究

Extrusion 3D Printing Processes and Performance Evaluation of GelMA Composite Hydrogel

甲基丙烯酸酐明胶(Methacrylated gelatin,Gel MA)是具有光敏官能团的改性明胶,有良好的生物相容性,广泛用于构建皮肤、神经等软组织支架。然而,光照交联单一成分的GelMA,其力学性能和结构维持性较差,难以通过挤出3D打印成形生物支架。提出一种适用于挤出式打印且力学性能增强的GelMA复合凝胶,其主要成分为GelMA、明胶和海藻酸钠。黏度测试试验筛选出适合挤出3D打印的复合材料配比,3D打印工艺试验研究和分析了打印气压、喷头移动速度、喷头高度、光照条件对挤出连续性和微丝直径的影响。当喷头内径为200μm时,GelMA复合凝胶实现顺畅出丝(φ293~1211μm)的条件为气压在0.05~0.25 MPa,打印速度为1~15 mm/s,喷头高度为200~600μm,光照强度为70~272.56 mW/cm^2。拉伸试验表明光照交联后,复合凝胶较之同浓度Gel MA(5%,w/v)的弹性模量提高近1倍,伸长率保持一致。细胞培养试验显示GelMA复合凝胶具有良好的生物相容性,包埋在其内部的人真皮成纤维细胞培养至第7天时存活率达85%。

Methacrylated gelatin(GelMA)is a modified gelatin with photosensitive functional groups and has good biocompatibility which is used to construct soft tissue scaffolds such as skin and nerves.However,GelMA hydrogel only UV photocrosslinked has too poor mechanical properties and structural maintenance to construct three-dimensional scaffolds through extrusion-based bioprinting.This study proposes a kind of GelMA composite hydrogel consisting of GelMA,gelatin and sodium alginate which can be extruded and obtained the enhanced mechanical properties.The component ratio of GelMA composite was be determined suitable for extrusion printing through the viscosity test.The process parameters of printing pressure,nozzle moving speed,nozzle height and illumination conditions on extrusion continuity and microfilament diameter were further investigated by 3 D printing experiments.When the noozzle with the inner diameter of 200μm is used,the uniform and smooth filaments(φ293-1211μm)of GelMA composite hydrogel can be achieved with the process parameter ranges:the air pressure is 0.05 MPa to 0.25 MPa,the printing speed 1 mm/s to 15 mm/s,the nozzle height 200μm to 600μm,light intensity 76 mW/cm^2 to 272 mW/cm^2.The Young’s modulus of GelMA composite hydrogel has been found doubled of that of the GelMA hydrogel under the same UV crosslinking conditions(76 mW/cm2,5 min)with the same concentration(5%,w/v)in the tensile test.Good biocompatibility of GelMA composite hydrogel has been verified by the cell culture in which the survival rate of human dermal fibroblasts embedded reached 85%on day 7.