Wireless Hybrid-Actuated Soft Miniature Robot for Biomedical Applications

Wireless soft miniature robots have been studied for biomedical applications. However, the wireless soft miniature robots developed so far are mainly composed of synthetic polymers that do not guarantee biocompatibility and biodegradability. Additionally, current soft robots have limitations in demonstrating mobility in narrow spaces, such as blood vessels within the body, by using their flexible body. This study proposes a wireless hybrid-actuated soft miniature robot for biomedical applications. The proposed soft miniature robot consists of biodegradable chitosan and magnetic nanoparticles (MNPs) and is fabricated into an eight-arm shape by laser micromachining. The soft miniature robot can implement hydrogel swelling and magnetic-actuated shape morphing by using the difference in MNP density and magnetic field responsiveness within the robot body, respectively. Furthermore, the soft miniature robot can be guided by external magnetic fields. As feasibility tests, the soft miniature robot demonstrated on-demand pick-and-place motion, grasping a bead, moving it to a desired location, and releasing it. Furthermore, in an in-channel mobility test, the flexible body of the soft miniature robot passed through a tube smaller in size than the robot itself through magnetically actuated shape morphing. These results indicate that the soft miniature robot with controllable shape change and precise magnetic-driven mobility can be a minimally invasive surgical robot for disease diagnosis and treatment.