Department of Biomedical Engineering, College of Design and Engineering, National University of Singapore, Singapore 117583, Singapore.
Institute of Sustainability for Chemicals, Energy and Environment, Agency for Science, Technology and Research (A*STAR), 1 Pesek Road, Jurong Island, Singapore 627833, Singapore.
ACS Appl Mater Interfaces. 2022 Sep 14;14(36):40590-40598. doi: 10.1021/acsami.2c09889. Epub 2022 Aug 29.
Soft robotics is a rapidly evolving research field that focuses on developing robots with bioinspired actuation/sensing mechanisms and highly flexible soft materials, some of which are similar to those found in living organisms. The hydrogel has the characteristics of excellent biocompatibility, softness, and elasticity, which makes it an ideal candidate material for the preparation of soft robots. Here we utilized a self-healing approach to develop a catalytically driven soft robot, which was constructed by dynamic imine bonds between modular hydrogels. One of the modules was a hydrogel formed by dynamic aldimine cross-linking of chitosan and glutaraldehyde, and the other module was a hydrogel embedded with catalase. The soft hydrogel robot moved because of catalytic reactions between the robot and environment [hydrogen peroxide (HO) fuel], giving rise to a fluidic release that supports propulsion, as inspired by the jet-propulsive mechanism in swimming dragonfly larvae. The speed of the soft robot can be mediated by adjusting the concentration of HO and enable/disable movement based on the folding and unfolding of enzymes. In addition, the hydrogel formed by replacing glutaraldehyde with dialdehyde-functionalized PEG had excellent elastic properties, and the soft robot based on PEG had a higher movement speed than that based on glutaraldehyde under the same HO concentration. Moreover, the addition of iron oxide nanoparticles can realize the magnetic guidance of the soft robot and the combination of different modules can realize different motion modes. The highly configurable self-healing catalytic soft robot holds great potential for a variety of interesting applications, including swimming robots, robot-assisted water treatment, and drug release.
软机器人是一个快速发展的研究领域，专注于开发具有仿生致动/传感机制和高度灵活的软材料的机器人，其中一些类似于生物体内发现的材料。水凝胶具有极好的生物相容性、柔软性和弹性，使其成为制备软机器人的理想候选材料。在这里，我们利用自修复方法开发了一种催化驱动的软机器人，它是由模块化水凝胶之间的动态亚胺键构建而成的。其中一个模块是由壳聚糖和戊二醛的动态亚胺交联形成的水凝胶，另一个模块是嵌入了过氧化氢酶的水凝胶。软水凝胶机器人由于机器人与环境之间的催化反应（过氧化氢（HO）燃料）而移动，从而产生类似于游泳蜻蜓幼虫中的射流推进机制的流体释放，从而实现推进。软机器人的速度可以通过调整 HO 的浓度来调节，并可以根据酶的折叠和展开来实现运动的开启和关闭。此外，用二醛官能化 PEG 代替戊二醛形成的水凝胶具有优异的弹性性能，在相同的 HO 浓度下，基于 PEG 的软机器人比基于戊二醛的软机器人具有更高的运动速度。此外，添加氧化铁纳米粒子可以实现软机器人的磁导向，并且不同模块的组合可以实现不同的运动模式。高度可配置的自修复催化软机器人具有广泛的有趣应用潜力，包括游泳机器人、机器人辅助水处理和药物释放。
