One-step preparation of hydrogel particles that show rapid detection of hydrogen peroxide: The dual role of new methylene blue

Abstract

We report a synthetic platform that offers a facile preparation route for stimuli-responsive hydrogels via redox radical initiation. The initiation mechanism has been efficiently used for the formation of many synthetic hydrogels since the redox reaction readily generates radical species and polymerizes monomers. In this conceptual study, we have created stimuli-responsive hydrogel particles using a new methylene blue dye that plays a significant dual role as a radical activator and a reactive site. Therefore, the dye not only facilitated redox radical initiation for the formation of hydrogel particles, but also imparted them with sensing capability. Furthermore, we could obtain the dye-labelled, micron-sized particles through inverse suspension polymerization, and use them for the rapid sensing of hydrogen peroxide as designed. The response of particles was found to be much faster (>1100%) than that of free dye molecules, and also the distinct colour change visualized the detection reaction. As a proof of concept, the hydrogel particles were able to detect the evolution of hydrogen peroxide from glucose that underwent enzymatic oxidation.