Multifunctional hydrogel patch for wearable colorimetric sensing and oral ulcer therapy

Traditional hydrogels function in a single modality, acting as either a biosensor or a therapeutic agent and thus can hardly meet the requirements of multifunctionality in health monitoring. The development of multifunctional hydrogels with diverse applications has aroused substantial interest in biomedical field. In this work, we developed a multifunctional hydrogel patch for both colorimetric detection and oral ulcer therapy by implementing Au nanostars into a polyacrylamide (PAAm) hydrogel. The hydrogel achieved multiple functionalities based on the excellent optical properties of Au nanostars. Due to the localized surface plasmon resonance (LSPR) property, the embedding of Au nanostars in the hydrogel network enabled a colorimetric patch for the detection of iodide. Furthermore, the addition of Au nanostars enhanced both the mechanical performance and conductivity of the PAAm hydrogel. Au nanostars also strongly absorbed near-infrared (NIR) light and efficiently converted it into heat. Due to the excellent photothermal effect of the PAAm/Au hydrogel, it achieved excellent antibacterial performance through the photothermal heating for oral ulcer therapy. The incorporation of functional nanomaterials into hydrogels provides a new strategy for the development of multifunctional platforms for healthcare applications.