Lithographic structuring of thermoresponsive hydrogel on a micron scale

Hydrogel microstructures and microchannels are important tools in biophysical bottom-up approaches for studying the interactions between extracellular obstacles or boundaries and cells. In prior studies, several microstructuring techniques, cell sources, and gel types have been employed to mimic static cellular environments. However, the dynamic nature of the extracellular environment, which exerts forces on cells, plays an important role in tissue-level contexts. To date, only few approaches have been implemenmted to mimic these forces of the extracellular environment. Here, we present an approach for generating arrays of hydrogel microstructures, that expand and contract dynamically in response to temperature modulations. To do this, we use a thermoresponsive hydrogel and a custom-built lithographic setup. Through direct lithographic photopatterning of a liquid phase, we fabricate smart hydrogel microstructures at the micrometer scale (10-100 m) with well-defined geometries. These hydrogel microstructures display reversible size changes of over 70% triggered by temperature modulations. Our study represents a step towards mimicking the dynamic properties of biological boundaries and obstacles. The dynamic nature of smart hydrogel microstructures holds the potential to mimic the micron-scale dynamics of extracellular environments. Our results may thus be relevant for the fields of bioengineering and systems level biophysics offering opportunities for manipulating and exploring cellular interactions with dynamic obstacles.