Microneedle Patch with Dual Control of Temperature and Drug-Release for Synergistic Chemo-Photothermal Therapy of Melanoma

Microneedles (MNs) combining chemotherapy and photothermal therapy offer a smart strategy for melanoma treatment but are hindered by the inadequate control of hyperthermia temperature and drug release. In this study, a novel MN patch consisting of a backing layer and porous needle tips was developed. The backing layer is made of the poly(N-isopropylacrylamide-acrylamide) (PNA) hydrogel. The needle tips are made of ethoxylated trimethylolpropane triacrylate, and their pores are loaded with PNA hydrogel containing both chemotherapeutic drug doxorubicin and photothermal agent polydopamine. Leveraging the thermochromic properties of the backing layer, the MN patch can autonomously regulate the temperature of needle tips to lower critical solution temperature of PNA (around 43 °C) upon near-infrared laser irradiation, without the need for external temperature control devices. Combined with the thermosensitive volume change of PNA in needle tips, the MN patch enables on-demand drug release. In vivo anti-melanoma experiments demonstrated a potent tumor-killing efficacy, with a tumor suppression rate of 89.2%. This innovative MN patch integrating temperature self-regulation and on-demand drug release presents a promising alternative for melanoma therapy.