Mild-Sunlight-Activated Safe Photodynamic Therapy Using On-Off Polymer Photosensitizers in Wearable Microneedle Patch

Nature Communications, Published online: 02 May 2026; doi:10.1038/s41467-026-72550-1 Photodynamic therapy (PDT) is often limited by its reliance on specialized photosources, the need for clinic-based treatment, and risks of phototoxicity. Here, the authors report mild-sunlight-activated PDT microneedle patches incorporating polymeric photosensitizers with an intrinsic “on-off” reactive oxygen species-generating mechanism, enabling bio-safe, deep-tissue, and self-administered PDT.