Multifunctional Peptide-Melanin Hybrid Nanodots with Robust Anti-Cutaneous Photoaging Activity

Skin aging is a systematic and complex process, mainly including intrinsic aging caused by time change and extrinsic aging caused by environmental factors. Photoaging caused by ultraviolet (UV) irradiation is the principle extrinsic factor of skin aging, which can directly or indirectly cause damage to DNA and other biomolecules, generate reactive oxygen species (ROS), and induce a decrease in collagen synthesis and other adverse effect. Herein, to address the causative factors and multiple side effects of skin photoaging, we constructed multifunctional peptide-melanin hybrid nanodots (PMHDs) to achieve multifaceted synergistic anti-skin aging by using melanin-like nanodots (MDs) and functional peptides as active motifs. Among them, the peptide has the activity of promoting collagen synthesis, while the MDs have the function of absorbing UV light and scavenging free radicals. Additionally, the MDs also act as a carrier to increase the cellular uptake of the peptide. The anti-photoaging effects of the PMHDs were systematically verified in a multidimensional manner at the biochemical, cellular and small animal levels, respectively.