Scheme 1

Design principle of the NIR light-activatable dissolving MN system (MN-pB/I) for multimodal theragnostic application in melanoma. a Schematic illustrations of the MN-pB/I. After directly injecting into the tumor sites, the matrix of the MN-pB/I quickly dissolved, releasing the Lipo/pB-DOX/ICG concentrated in the needle tips and distributing them evenly throughout the tumor tissue. The treatment regimens and efficacy could be guided and monitored by FI and PAI using the ICG photosensitizer. When exposed to NIR light, ROS produced by ICG performed PDT and activated pB-DOX for chemotherapy. The ICG can also exert PPT, as the high temperatures generated after irradiation promoted the dissolution of the MNs, as well as the permeation and cellular uptake of Lipo/pB-DOX/ICG, to effectively kill the melanoma cells. b Fabrication of the MN-pB/I patch: Lipo/pB-DOX/ICG loading, PVP casting, MNs drying, and patch peeling off