Melanin/melanin-like nanoparticles in tumor photothermal and targeted therapies

Melanin is a pigment found in nature that has good photothermal conversion qualities as well as stability, adaptability, and ease of manufacture. In addition to displaying the inherent properties of melanin, melanin/melanin-like nanoparticles (NPs) also have strong dispersion stability, excellent biocompatibility and biodegradability. Melanin/melanin-like NPs have been extensively studied for tumor therapy due to their unique photothermal properties and ability to target tumor cells. They have demonstrated particular promise in photothermal therapy of cancers. Using photothermal conversion materials to create a thermal effect by light irradiation, photothermal therapy (PTT) is a therapeutic approach that kills tumor cells locally. In this paper, we firstly review the preparation methods and physicochemical properties of melanin/melanin-like NPs, and then systematically and in-depth describe the recent advances of melanin/melanin-like NPs, especially synthetic polydopamine (PDA) melanin, in oncology applications, mainly focusing on tumor photothermal and targeted therapies. In addition, we summarize the advantages of melanin/melanin-like NPs in improving the efficacy of photothermal therapy, reducing toxic side effects, and enhancing tumor targeting, and discuss the current challenges and future directions.