Optimization of Smart Microactuators Utilizing 2D and 3D Lithography

Smart soft microstructures hold significant promise for in vivo applications such as tissue manipulation, cellular cargo-release, and diagnostics. This interest is particularly strong for microstructures made of stimuli-responsive hydrogels, due to their suitability for developing micro-scale actuation upon an applied stimulus (e.g. light, temperature, pH). Their compliance, like the one of biological tissues, is also appealing when interacting with surrounding biological tissue, avoiding adverse effects. This study investigates the actuation response of microstructures made of a thermoreponsive hydrogel, poly(N-isopropylacrylamide)– PNIPAM, fabricated with 2D and 3D lithography methods, using. These microstructures are fabricated using two different hydrogel preparation protocols, and two patterning strategies. Mask lithography is used as a cost-effective, high-throughput method for 2D patterning of PNIPAM microstructures, while two-photon polymerization (2PP) is used for the fabrication of more complex 3D geometries. This research presents a thorough investigation of how chemical composition, physical dimensions, and exposure parameters affect the actuation efficiency of the resulting microstructures.