Electrochemically synchronized, self-indicating iontophoretic patch with fully eco-degradable and self-powered system

Iontophoretic transdermal patches enable controllable and noninvasive drug delivery but face a persistent trade-off among user-adaptive interaction, architectural simplicity, and sustainability. Simpler systems favor uniform operation, whereas feedback-enabled designs require additional electronics, increasing complexity, bulk, and environmental burden. Here, we present a self-powered, fully eco-degradable iontophoretic patch integrated with an electrochromic module, which electrochemically unifies drug delivery and user-facing indication within a single synchronized loop. Galvanic iontophoresis electrodes simultaneously drive iontophoretic transport with ionic current and actuate an on-patch electrochromic gauge with electrical current, converting cumulative charge-correlated dose into an electrochromic reaction propagation-based indication. This material–architecture co-design, based on thin, soft, and eco-degradable materials, enables compact and flexible patch-level implementation with system-level eco-degradability after use. Ex vivo porcine skin studies show a linear correlation between electrochromic propagation distance and delivered dose, and a psoriasis mouse model confirms therapeutic delivery with skin-compatible operation.