Dopamine-enhanced polymeric electrodes for durable and efficient iontophoresis

ABSTRACT Iontophoresis electrodes are essential for biomedical applications such as sensing, electrical stimulation, and transdermal drug delivery. However, conventional Ag/AgCl electrodes exhibit poor stability under high currents and in humid environments, limiting their long-term usability and biocompatibility. Here, we present a dopamine-doped PEDOT:PSS (P-DA) electrode that demonstrates exceptional stability and performance under prolonged current operation in wet conditions. Dopamine enhances the PEDOT:PSS electrode through multifaceted mechanisms. At the molecular level, dopamine doping promotes tighter packing of polymer backbones. Electrochemically, dopamine acts as a sacrificial oxidant during iontophoresis, delaying PEDOT degradation. At the interface, dopamine’s adhesive functional groups strengthen bonding between the electrode and substrate, mitigating delamination caused by water swelling. Together, these effects yield significantly improved operational stability. In in-vitro transdermal drug delivery experiments, the P-DA electrode outperformed both PEDOT:PSS and Ag/AgCl electrodes, achieving superior stability and drug delivery efficiency, thereby demonstrating its promise for high-current biomedical applications.