Biosensors comprising microscale/nanoscale components embedded within biocompatible hydrogels present opportunities to create materials that respond to multiple analytes. Encapsulated domains are proposed to house reagents that generate optical signatures that change in response to target analytes. Here we report on composite materials that provide specific responses to small metabolites through use of enzymes that drive oxygen depletion or pH decrease, and optical reporters based on phosphorescence and surface-enhanced Raman scattering (SERS). Benzoporphyrin phosphors provide long-wavelength emission with a lifetime that depends on oxygen, while gold nanoparticles provide enhancement of Raman scattering for surface-attached pH reporters. Prototype materials representing single analyte sensors have been tested for feasibility in static conditions, followed by combinations of analytes and multimode responses—combined phosphorescence and SERS. Multiple pH-sensitive ligands allow coverage from pH 4 to 10. Oxygen and pH-responsive materials were shown to generate changes in phosphorescence and SERS that signals track enzymatic reactions involving oxidase enzymes and urease, respectively. This presentation will describe studies of the influence of different hydrogel matrix materials as well as microdomain type and concentration on the measured responses in static and dynamic conditions.

Mixed microdomains in hydrogels – strategies for multiplexed and multimode chemically-responsive materials

256th National Meeting (2018)

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