Soft Hydrogel Microrobot Actuated Using NIR and EMA Integration System

Abstract

Recently, hydrogels with the characteristics of biocompatibility and biodegradability have been received a great interest. In addition, because the hydrogels can be swelled and deswelled by external stimuli such as pH or temperature changes, they have been considered as carriers for therapeutic drugs and cells delivery. Through these properties of hydrogels, this study proposes a spring type soft hydrogel microrobot which can be manipulated by magnetic field and responded to external stimuli such as temperature. To make a soft-spring type hydrogel microrobot, we adopt the simple method using the PFA micro tube and syringe. And, we use NIsopropylacrylamide (NIPAM) as temperature responsive hydrogels and add magnetic nano particles (MNPs) for the electromagnetic actuation. By using the near infra-red (NIR) and electromagnetic actuation (EMA) integration system, we verify the spring type soft hydrogel microrobot can be moved to the desired position by EMA system and swelled or deswelled by the external NIR stimulus. If the spring type hydrogel microrobot encapsulates therapeutic agents (drugs and cells), it can move to the target site using EMA and treat the lesion by controlled release of the encapsulated therapeutic agents.