On-Command Disassembly of Microrobotic Superstructures for Transport and Delivery of Magnetic Micromachines

TL;DR

This paper introduces a novel microrobotic superstructure that can be disassembled on command using magnetic hyperthermia, enabling complex navigation and delivery tasks in microscale environments.

Contribution

It presents a new design of interconnected magnetic micromachines that can be remotely disassembled, enhancing maneuverability and functionality for biomedical applications.

Findings

Demonstrated controlled disassembly of superstructure via magnetic hyperthermia.

Showcased microrobots navigating complex channels with different magnetic fields.

Achieved targeted release and movement of micromachines within simulated biological environments.

Abstract

Magnetic microrobots have been developed for navigating microscale environments by means of remote magnetic fields. However, limited propulsion speeds at small scales remain an issue in the maneuverability of these devices as magnetic force and torque are proportional to their magnetic volume. Here, we propose a microrobotic superstructure, which, as analogous to a supramolecular system, consists of two or more microrobotic units that are interconnected and organized through a physical (transient) component (a polymeric frame or a thread). Our superstructures consist of microfabricated magnetic helical micromachines interlocked by a magnetic gelatin nanocomposite containing iron oxide nanoparticles (IONPs). While the microhelices enable the motion of the superstructure, the IONPs serve as heating transducers for dissolving the gelatin chassis via magnetic hyperthermia. In a practical demonstration, we showcase the superstructure's motion with a gradient magnetic field in a large channel, the disassembly of the superstructure and release of the helical micromachines by a high-frequency alternating magnetic field, and the corkscrew locomotion of the released helices through a small channel via a rotating magnetic field. This adaptable microrobotic superstructure reacts to different magnetic inputs, which could be used to perform complex delivery procedures within intricate regions of the human body.