Universal Sensing Platform Based on Responsive Hydrogel Interfometer

Sponsor: ASU Start-up Fund

Stimuli-responsive crosslinked polymers, hydrogels can change their volume significantly in response to small alterations of certain environmental parameters. As a network of soft polymers, hydrogel can be chemically adjusted to provide a large assortment of sensitivities as diverse as humidity, temperature, light, mechanical stress, magnetic or electric field, pH, glucose and other molecular species. It is also possible to finely tune the sensitivity and selectivity of each stimulus by tailoring polymer composition or geometry. Due to these properties, many hydrogel-based sensing designs have been developed with high performance demonstrated, including photonic crystals, hydrogel gratings and SPR sensors. Yet it is still challenging to fabricate a hydrogel sensing system that simultaneously satisfies the requirements of cost, robustness, sensitivity and versatility. To fulfill this goal, we’ve developed an interferometry-based hydrogel sensing platform with easy detectable apparent color change. Fast response and high sensitivity have been demonstrated upon 1 µM level of analyte injection in miliseconds. Theoretical mechanical and optical calculation has validated the experimental results and also provides insights for system design and optimization. Compared to other sensing techniques involving hydrogel or responsive polymers, our system doesn’t require complex or expensive fabrication procedure, can work under extreme conditions (e.g. fully dehydrated environment) and allows selectively detection of many analytes by proper gel modifications. We believe that our technique is an important development of externally actuated responsive nanomaterials with wide applications in environment and (bio)medicine.