Numerical and Analytical Modeling to Determine Performance Tradeoffs in Hydrogel-Based pH Sensors

摘要

Hydrogel-based pH sensors are promising candidates for implantable sensors due to their low cost and biocompatibility. Despite their commercial potential and numerous theoretical/experimental reports, the tradeoffs between different performance parameters are not well understood and explicitly stated. In this work, we develop a numerical and analytical framework to show that there is a fundamental tradeoff between the performance parameters, i.e., sensitivity/ dynamic range versus response-time/response-asymmetry in hydrogel sensors under constrained swelling conditions. Specifically, we consider the effect of the gel parameters, such as the ionizable group density () and its dissociation constant (), on the sensor performance. We show that improvement in sensitivity/dynamic range leads to degradation in response time/symmetry and, therefore, a compromise must be made to optimize device performance.