Melanin-based nanoparticles in biomedical applications:From molecular imaging to treatment of diseases

Melanin nanoparticles(MNPs) is a kind of natural nanomaterial, not only retain the inherent characteristics of melanin(metal ion chelation, photothermal conversion property, etc.) but also can exhibit more excellent properties, such as high dispersion stability, good biocompatibility and biodegradability. Furthermore, these performances can be enhanced to target the specific sites and treat diseases by the surface modification or combination with functional substance. All these advantages of MNPs made it an ideal platform for developing biomedical applications. In this paper, the MNPs preparation methods were summarized first. Biomedical applications of MNPs were also reviewed,including molecular imaging(magnetic resonance, positron emission tomography, and photoacoustic imaging) and treatment of diseases(drug delivery, photothermal therapy, antioxidant therapy, and iron overload therapy). Further development and prospects of MNPs for practice in biology or medicine were also discussed.