UVA-responsive Fe₃O₄@ZnO nanocarrier grafted with anti-EGFR antibody for precision delivery of Nrf2-siRNA and brusatol: A novel platform for integrated photodynamic, gene, and chemotherapy

Photodynamic therapy (PDT) remains underutilized as a primary cancer treatment due to the limited lethality of reactive oxygen species (ROS) and poor targeting efficiency of traditional photosensitizers. This the aim of the study is to develop a Fe₃O₄@ZnO nanoparticle photosensitizer co-loaded with anti-EGFR antibody, brusatol, and Nrf2-siRNA to improve the therapeutic effect of PDT. This system can be guided to tumors by a magnetic field and further targets cancer cells through EGFR-specific binding. Under UVA light, brusatol and Nrf2-siRNA are released, enabling combined chemo-, gene, and photodynamic therapy. With the photosensitizer treatment, ROS levels in cutaneous squamous cell carcinoma cells were elevated by 191.09 ± 10.02 % through suppression of Nrf2 and its associated antioxidant defenses, significantly enhancing cell lethality and reducing cell viability by 80.43 ± 9.37 %. In vivo studies further demonstrated a tumor suppression rate of 76.30 ± 5.12 % in nude mice, highlighting the robust anti-tumor efficacy of the photosensitizer and its potential for clinical application in targeted cancer therapy. The biocompatibility and high therapeutic efficacy of this photosensitizer highlight its promise as a safer and more effective option for treating cutaneous squamous cell carcinoma.