Hydrogel matrix effects on oxygen diffusion: Controlling properties for biosensor applications

Oxidoreductase enzymes coupled with oxygensensitive phosphors, when immobilized in injectable polymer hydrogels, provide a minimally-invasive way to transduce levels of biochemical substrates by transcutaneous interrogation. This work evaluates the performance of three hydrogel-based biosensor platforms, all containing glucose oxidase and a tetramethacrylated palladium benzoporphyrin dye as the model enzyme and phosphor, respectively. By characterizing the gel morphology, substrate diffusion kinetics, and overall optical response to glucose, we have elucidated the impact of dye and enzyme solubility as well as morphological homogeneity on overall device performance in vitro.