[Synthesis of a temperature-responsive multimodal motion microrobot capable of precise navigation for targeted controllable drug release].

Objectives: To synthesize a temperature-responsive multimodal motion microrobot (MMMR) using temperature and magnetic field-assisted microfluidic droplet technology to achieve targeted drug delivery and controlled drug release.

Methods: Microfluidic droplet technology was utilized to synthesize the MMMR by mixing gelatin with magnetic microparticles. The microrobot possessed a magnetic anisotropy structure to allow its navigation and targeted drug release by controlling the temperature field and magnetic field. In the experiment, the MMMR was controlled to move in a wide range along a preset path by rotating a uniform magnetic field, and the local circular motion was driven by a planar rotating gradient magnetic field of different frequencies. The MMMR was loaded with simulated drugs, which were released in response to laser heating.

Results: Driven by a rotating magnetic field, the MMMR achieved linear motion following a predefined path. The planar gradient rotating magnetic field controlled circular motion of the MMMR with an adjustable radius, utilizing the centrifugal force generated by rotation. The drug-loaded MMMR successfully reached the target location under magnetic guidance, where the gelatin matrix was melted using laser heating for accurate drug release, after which the remaining magnetic particles were removed using magnetic field.

Conclusions: The MMMR possesses multimodal motion capabilities to enable precise navigation along a predefined path and dynamic regulation of drug release within the target area, thus having great potential for a wide range of biomedical applications.