Iron oxide nanoparticles-loaded hydrogels for effective topical photothermal treatment of skin cancer

Purpose A hydrogel containing dextran-coated iron oxide nanoparticles (DEX-IONP) was developed, and its applicability in topical photothermal therapy (PTT) of skin cancer was explored in vitro and in vivo. Methods DEX-IONP carbopol hydrogel was prepared by adopting the pH-triggered in situ gel-forming method. After preparation, physical characteristics and the photothermal activities of the DEX-IONP gel were evaluated in vitro in varying DEX-IONP concentrations. The photothermal activity was further examined in B16F10 s.c. tumor-bearing mice. Lastly, the efficacy of DEX-IONP gel-based topical PTT was evaluated in vivo. Results The prepared DEX-IONP gel retained high viscosity favorable to maintain at the applied site. In addition, the DEX-IONP gel could induce effective heating by laser irradiation. The cellular and in vivo studies evidenced the applicability of DEX-IONP in topical PTT. Finally, the preliminary efficacy study results in the B16F10 s.c. mice model demonstrated that tumor volumes could be significantly reduced by the topical PTT with DEX-IONP gel. Notably, by a single PTT treatment with 100 mu gFe/mL DEX-IONP gel and applying 0.5 W laser power for 10 min, the tumor growth could be significantly inhibited by 85%. Conclusion Overall, our results demonstrate that DEX-IONP gels may serve as an effective topical PTT agent.