可3D打印生物高分子水凝胶材料设计及电控平滑肌驱动单元构建

Bio-bots, defined as robots powered by living tissues and bio-energy, has been an interdisciplinary frontier in science and technology. Because of its high efficiency, adaptivity, miniaturization, and possibility of inosculating with human body, applications of bio-bots in both health care and military matters are extensive and expectable. Boosting the power of electronic controlled skeletal muscle actuators is a main issue of Bio-bots, which straightforwardly limited by the actuator’s own mechanical strength. Herein, this project will improve the actuator’s mechanical strength by molecular designs, macro interpenetrating hydrogel networks, and bio 3D printing. With proper materials selection, cross-linking design, and backbone modification, as-proposed biopolymer hydrogel can be processed by 3D printer. Meanwhile, by judicious selecting pI value of as-proposed biopolymer hydrogel, growth factors will be able to self-assemble onto the hydrogel’s backbone without covalent bonding and induce myogenesis in as-proposed hydrogel. Moreover, a macro interpenetrating hydrogel network, which consists as-proposed biopolymer hydrogel and additional structural polymer hydrogel with higher mechanical strength, will be designed through 3D modeling, optimized by finite element analysis, and printed through bio 3D printer. Finally, bioelectrodes will be assembled to complete electronic controlled skeletal muscle actuators and these bio-actuators will be examined in aspects like moving abilities, reliability, life time, and failure models. As-proposed skeletal muscle actuator will be an essential foundation of bio-bots and suitable for future developments of miniaturized machines, medical devices for patients with muscular atrophy and/or paraplegia, exoskeletal suits, bio-robots, etc.

利用生物能来驱动机械结构的生物机械（Bio-Bot）因其高效、自适应、小型化及与生命体高度融合的可能性，已成为国际前沿的设计理念，将在医疗卫生和军事领域产生深远的影响。提高平滑肌电控驱动单元的负载能力成为生物机械发展的关键技术之一，其中提高驱动单元自身机械强度是必要基础条件。本项目将从水凝胶分子设计、宏观结构设计和3D打印成型等角度开展研究。通过生物水凝胶材料的分子设计，使其适应生物3D打印的成型过程；通过等电点调控，实现生长因子与水凝胶骨架的非共价自组装固载，诱导平滑肌纤维体外再生；通过构建宏观互穿水凝胶网络加入较高强度的结构水凝胶，提高平滑肌驱动单元整体机械强度；通过生物3D打印成型并加入电信号控制，构建平滑肌电控驱动单元并研究其驱动能力、可靠性、使用寿命和失效机理。本项目的研究成果将在微型机械、肌肉萎缩、截肢、截瘫、人体外骨骼、仿生机器人等方面有广阔的应用前景。

基于Gtn-HPA二元酶聚合水凝胶体系，初步完成了生物3D打印机的改造工作，能够进行交联-挤出协同打印。探明了表面能和蔗糖浓度对细胞粘附的影响规律，为细胞-无机系统结合提供了可行的调控手段。验证了静电引力、张力梯度等自组装机理作为水凝胶骨架改性机理和细胞作为自组装单元的可行性，为细胞自组装和生物3D打印结合的新型生物应用和大尺寸生物组织结构制备方法提供了理论基础，初步完成了基于C2C12团块的水凝胶三维培养成大尺寸肌肉组织的技术路线，为后续研究提供机理和技术路线基础。