Sequential ROS-Responsive Micelles in Combination with a Multifunctional Hydrogel for Neoadjuvant Chemo-Photothermal Therapy Against Melanoma Recurrence

Malignant melanoma has a high recurrence rate after surgical resection, conventional neoadjuvant chemotherapy (NAC) suffers from off-target toxicity and limited efficacy. Leveraging elevated tumor-specific reactive oxygen species (ROS), we designed a sequential therapeutic strategy combining ROS-responsive micelles and a multifunctional hydrogel to combat local recurrence. By conjugating 3-indoleacetic acid to chondroitin sulfate via a ROS-responsive thioketal linker, an amphiphile (CS-TK-IAA, CTI) was synthesized, significantly enhancing tumor-specific uptake and ROS-scavenging capacity. CTI self-assembled into micelles (CLT@CTI) encapsulating celastrol (CLT), achieving high encapsulation efficiency (92.3%) and drug loading capacity (25.2%). Postoperatively, an injectable chitosan-based hybrid hydrogel (CPG) with self-healing, tissue adhesion, and hemostatic properties was applied to the resection site, triggering a photothermal effect via near-infrared light. In a mouse melanoma recurrence model, neoadjuvant CLT@CTI therapy effectively suppressed primary tumor growth, while postoperative CPG gel-mediated photothermal ablation of residual tumors dramatically delayed recurrence and improved 60-day survival rates. This sequential therapeutic regimen, neoadjuvant chemotherapy with postoperative photothermal therapy, provides a promising and viable solution for preventing melanoma recurrence.