Fabrication Process for Free-Standing Smart Hydrogel Pillars for Sensing Applications

Smart hydrogel structures can be used as chemical sensing components to measure the changes in the environmental concentration of analytes of biomedical relevance. Sensing schemes using smart hydrogels rely on the transduction of the stimulated change of the hydrogels’ physical properties into a usable signal. Recently, we reported on such a sensing technique employing resonance absorption of ultrasound in smart hydrogel microresonator structures as well as in a hydrogel sheet using medical ultrasound imaging as the transduction method. However, the mold-based fabrication process limited the possible geometries of the hydrogel structures, which resulted in a constrained response time. In this publication, we present an improved fast and cost-efficient fabrication process to create arrays of free-standing stimuli-responsive hydrogel pillars that can be used to address this challenge along with first preliminary experimental results using these smart hydrogel structures for ionic strength sensing.