Stimuli-Responsive Polypyrrole Hydrogel Integrated into a Mg Battery for Controlled Drug Release

Although stimulus-responsive drug delivery systems allow for precise drug release, electro-assisted delivery methods are seldom incorporated into transdermal platforms, highlighting a major research gap. In this work, we developed a self-powered, controllable drug delivery platform using a conductive gelatin methacryloyl-polyacrylamide-polypyrrole hydrogel (GPP) as the cathode in a magnesium battery. The GPP hydrogel was synthesized via UV cross-linking and in situ polymerization, exhibiting a compact porous structure, enhanced mechanical strength (fracture strain: 234%), stable electrochemical performance, and excellent cytocompatibility. It also functioned as a sensitive strain sensor (gauge factor: 1.14). Drug release was precisely tuned by electrical stimulation, increasing from 0.2 mg/g at 0 V to nearly 1.6 mg/g at -0.8 V within 180 min. The integrated Mg-GPP battery powered drug delivery effectively, achieving a 5-fold enhancement over passive diffusion. This system provides a promising strategy for advanced personalized transdermal therapy with combined electrically controlled release and motion sensing capability.