Direct Laser Writing of Magnetic Micro Actuators With a Stimulus‐Responsive Compliant Hinge

ABSTRACT We present a modular design strategy for the one‐step fabrication of arrays of magnetically responsive microactuators connected to the substrate via compliant hinges. We use direct laser writing in the form of two‐photon crosslinking within bilayer films to generate three‐dimensional microstructures in which magnetic nanoparticles are embedded in the upper layer. This part of the generated structure drives the actuation, while the hydrogel bottom layer is used to form a mechanically compliant hinge structure. The chemical composition and geometrical features of the hinge control the actuation amplitude, the mechanical properties, and the environmental adaptability. Hydrogel hinges provide stability and strong actuation in an aqueous environment, while stimulus‐responsive hinges allow for the dynamic reconfiguration of the actuation and bistable behavior without altering the magnetically driving component. This hinge‐based approach establishes a new class of adaptive microactuators and provides a generalizable platform for programmable soft micromachines.