Hydrogel microstructures combined with electrospun fibers and photopatterning for shape and modulus control

In order to improve the sensitivity of hair cell sensors for fluid flow detection, poly-ethylene oxide acrylic macromonomer is used as a crosslinkable photo-patterned material capable of being swollen into a hydrogel of different shapes and sizes. We demonstrated that simple arrays of various hydrogel structures can be synthesized by photopatterning with photomasks. The mechanical properties of the hydrogel materials were measured to be in the range of 5–100 Pa under varying crosslinking conditions. Additional support for these high-aspect ratio hydrogel structures was provided with electrospun polycaprolactone microfibers that were deposited onto the microfabricated hairs. These fibers served as scaffolding to support the swollen hydrogel. This approach looks to integrate several key design components in order to create a highly sensitive flow sensor.