Conductometric and optical sensing of stimuli senssitive hydrogels inside microfluidic channels

In this paper, a MEMS on-chip microfluidic platform was designed, fabricated and characterized. This MEMS device can provide characterization for various stimuli sensitive hydrogels at microscale level, which makes it a useful tool for developing and comparing different hydrogels. The hydrogel swelling behavior can be visually monitored by optical methods, as well as by an embedded conductometric sensing. One sample hydrogel was tested utilizing the proposed MEMS device, showing 200% surface area increase and 35% resistance decrease due to swelling.