One- and Two-Photon Crosslinked Polymer Hydrogel Microstructures for Optical Spectroscopy and Biosensing Applications

In this work, we report on a polymer toolkit for fabrication of hydrogel microstructures by means of one- and two-photon crosslinking process. Using home-built and commercial multi-photon lithography setups, we show the ability to prepare hydrogel structures attached to a solid substrate from developed copolymer or terpolymer layers. These polymers bear a photo-active benzophenone or anthraquinone moieties and additional groups enabling their chemical post-modification with biofunctional molecules. The crosslinked polymer networks can swell in water forming hydrogel structures with a geometry controlled by the UV or two-photon crosslinking imposed by a focused beam scanned over the substrate. In conjunction with post-modification, these micro-structured materials may serve in biosensing and other emerging applications such as responsive hydrogel-based miniature actuators supporting microfluidic devices and micromachines.