Melanin-like nanoparticles for nanomedicine and drug delivery

Melanin plays important roles in coloration and photoprotection in living organisms. Because of its intrinsic biocompatibility, melanin and its biomimetic replicates find important applications in nanomedicine. Thanks to their unique optical and electronic properties, melanin-based materials could be used for both diagnostics and therapeutics. Modes of detection include photoacoustic imaging (PAI) and magnetic resonance imaging (MRI). Therapeutic activities include photothermal therapy (PTT), antioxidant (AOX) therapy, and drug delivery. In this review paper, we summarize and discuss the most recent applications of melanin-like nanoparticles (NPs) as multifunctional agents in nanomedicine and drug delivery. Although most of these applications involve the most popular biomimetic form of melanin, polydopamine (PDA, resulting from the oxidative polymerization of dopamine), in the last part of the review, we show that alternative forms of melanin are becoming more and more important for nanomedicine.