Photothermal Effect-based Cytotoxic Ability of Melanin from Mytilus edulis Shells to Heal Wounds Infected with Drug-resistant Bacteria in vivo

Objective Owing to antibiotic abuse and the subsequent development of antibiotic resistance,bacterial infection has become one of the most persistent unresolved problems.New antibacterial agents,especially those that are environmental-friendly,are urgently needed.Methods Melanin extracted by filtration centrifugation and acid and proteolytic hydrolysis was characterized using UV,FTIR,TEM,and XPS.Photothermal conversion was calculated,and the bacteriostatic effects,in vitro and in vivo,were assessed by plate counting and ratios(%)of wound areas.Results Natural melanin hydrolyzed by trypsin had good photothermal conversion effects,which resulted in superior bacteriostatic activities.The extracted melanin along with laser NIR irradiation at808 nm promoted the healing of wounds infected by drug-resistant bacteria in vivo and was biocompatible according to toxicity tests in vivo and in vitro.Conclusion The present findings indicated a safe and efficient method of developing natural antibacterial agents.

Direct Synthesis of Bienzyme-like Carbide-derived Carbons via Mild Electrochemical Oxidation of Ti_(3)AlC_(2)MAX

Objective To develop effective alternatives to natural enzymes,it is crucial to develop nanozymes that are economical,resource efficient,and environmentally conscious.Carbon nanomaterials that have enzyme-like activities have been extensively developed as substitutes for traditional enzymes.Methods Carbide-derived carbons(CDCs)were directly synthesized via a one-step electrochemical method from a MAX precursor using an ammonium bifluoride electrolyte at ambient conditions.The CDCs were characterized by systematic techniques.Results CDCs showed bienzyme-like activities similar to that of peroxidase and superoxide dismutase.We systematically studied the dependence of CDC enzyme-like activity on different electrolytes and electrolysis times to confirm activity dependence on CDC content.Additionally,the synthesis mechanism and CDC applicability were elaborated and demonstrated,respectively.Conclusion The demonstrated synthesis strategy eliminates tedious intercalation and delamination centrifugation steps and avoids using high concentrations of HF,high temperatures,and halogen gases.This study paves the way for designing two-dimensional material-based nanocatalysts for nanoenzyme and other applications.