Polymerization-based signal amplification (PBA) is a colorimetric biodetection method for use in resource-limited settings. It uses phenolphthalein as a colorimetric reagent, but leaching of the dye from a resultant hydrogel can lead to variability in PBA results. In this work, we use polymerizable phenolphthalein in PBA to produce a phenolphthalein-conjugated hydrogel. Considering the photoinitiation mechanism of eosin Y and triethanolamine in air with an aqueous monomer solution, we determine reaction conditions for modified PBA that maintain a rapid polymerization response. Using the optimized conditions, we demonstrate that modified PBA can detect malaria antigen, PfHRP2, with reduced variability.
Keywords: colorimetric detection; dye leaching; dye-conjugated hydrogel; polymerizable phenolphthalein; visible light-induced polymerization.