Two-Photon Polymerized Heterogeneous Materials Microactuators for Local Responsiveness and Remote Locomotion

Soft microactuators leveraging biomimetic designs and microfabrication advances show substantial promise for soft robotics, precision sensing, and targeted drug delivery. However, simultaneously achieving rapid deformability with mechanical robustness in such systems remains a significant challenge. Herein, a hybrid microactuator with heterogeneous materials is fabricated via femtosecond laser two-photon polymerization. Incorporating acrylic acid as a functional monomer imparts pH-responsive behavior to the hydrogel, whereas the rigid photoresist ensures structural integrity. Moreover, embedded magnetic nanoparticles enable contactless and precise locomotion under an external magnetic field. As a proof-of-concept, a scorpion-inspired microactuator with dual pH/magnetic responsiveness demonstrates programmable functions including capture, transport, and release. This strategy provides a versatile platform for adaptive microrobots with localized responsiveness and remote motion, paving the way for precision therapeutics and cellular micromanipulation.