Enzyme mimicking based on the natural melanin particles from human hair

SUMMARY Natural enzymes are mainly composed by the protein part and metallic cofactor part, both of which work cooperatively to achieve high catalytic activity. Here, natural melanin particles (NMPs) were extracted from human hair and further bound with metal ions to mimic natural enzymes. The different metal-bound NMPs (M-NMPs) exhibited different enzyme-like activities with great promise in diverse biomedical applications. It was found that Fe-bound NMPs (Fe-NMPs) showed outstanding peroxidase (POD)-like activity which possessed potential in antibacterial applications. And Mn-bound NMPs (Mn-NMPs) displayed catalase (CAT)-like activity with a remarkable radiotherapy sensitization effect in cancer therapy. Besides, Cu-bound NMPs (Cu-NMPs) could serve as combined POD, superoxide dismutase (SOD) and CAT alternatives, which exhibited prominent reactive oxygen species (ROS) scavenging ability, revealing great potential in anti-inflammation. The versatile enzyme-like activities of M-NMPs derived from hair might give extensive perspective for designing biomedical materials and provide a promising tool in solving biomedical problems.