Antimicrobial peptides (AMPs) with dual intrinsic antibacterial and antioxidative functions have emerged as promising choice to cure infected wound. However, the most widely applied approach to endow AMPs with antioxidative function is to combine with antioxidative moieties, which may affect the spatial structure and physiological stability of AMPs. Herein, a new type of AMPs with inherent desired stability, antibacterial activity, and reactive oxygen species (ROS) scavenging is developed to effectively heal the infected wound. This formulation is in situ formed at wound site by tyrosinase‐triggered oxidation and self‐assembly of lyophilized antimicrobial peptide Trp‐Arg‐Trp‐Arg‐Trp‐Tyr, providing enhanced stability and a fourfold and sevenfold increasement in antibacterial efficiency against E. coli and S. aureus compared to peptide monomers. The antimicrobial peptide is first oxidized and then assembled into nanoparticles. The melanin‐like structure has been demonstrated with efficient antioxidant properties, and the experimental data show that peptide nanoparticles to scavenge superoxide radicals, hydroxyl radicals, and H2O2. In vivo experiments confirmed that peptide nanoparticles effectively heal infected wounds and obviously reduce ROS. Overall, the research provides a new approach to formulating antimicrobial peptides to treat wound with high healing efficiency.
Delayed implant-associated infection is an important challenge, as the treatment involves a high risk of implant replacement. Mussel-inspired antimicrobial coatings can be applied to coat a variety of implants in a facile way, but the adhesive 3,4-dihydroxyphenylalanine (DOPA) group is prone to oxidation. Therefore, an antibacterial polypeptide copolymer poly(Phe7-stat-Lys10)-b-polyTyr3 was designed to prepare the implant coating upon tyrosinase-induced enzymatic polymerization for preventing implant-associated infections. Both poly(Phe7-stat-Lys10) and polyTyr3 blocks have specific functions: the former provides intrinsic antibacterial activity with a low risk to induce antimicrobial resistance, and the latter is attachable to the surface of implants to rapidly generate an antibacterial coating by in situ injection of polypeptide copolymer since tyrosine could be oxidized to DOPA under catalyzation of skin tyrosinase. This polypeptide coating with excellent antibacterial effect and desirable biofilm inhibition activity is promising for broad applications in a multitude of biomedical materials to combat delayed infections.
Uniform gold nanoclusters (AuNCs) are hardly available unless through abundant strong ligands (at the cost of low catalytic activity and narrow catalytic spectrum) or through well-defined (but expensive) templates, and it appears a tougher challenge for direct preparing supported and uniform AuNCs. Here, we show that with an amphiphilic and dendritic molecular template in hand, highly catalytically active, uniform, and supported AuNCs are one-pot achievable. Branched polyethylenimine (PEI) is modified with a few thioether groups and alkylated with hydrophobic acetyls and polystyrene chains to afford reverse micelle-like dendritic polymers. The structurally optimized dendritic polymer can act as a surfactant to mediate very stable water-in-oil high internal phase emulsion (HIPE) within a wide pH spectrum. Moreover, the dendritic polymer switches into the unimolecular state along the interface of the HIPE when pH is below 6, which is critical to the formation of uniform AuNCs. Experimentally, upon the transformation of HIPE into an open-cellular polyHIPE, the gold ions are simultaneously transformed into AuNCs. Direct preparation of the supported and uniform AuNCs (1.8 ± 0.2 nm) are feasible because the dendritic polymer can simultaneously act as a surfactant, a polymer ligand, and a unimolecular template. Meanwhile, the trace thioether groups in the PEI core reduce the size of AuNCs by enhancing nucleation of AuNCs since in the absence of thioether groups, larger particles are obtained. The supported AuNCs are catalytically active because they are stabilized by weak coligands. For the model reaction of the catalyzed reduction of 4-nitrophenol, the catalyst shows a turnover frequency of 112.5 h–1, which is very high. The catalyst is durable and well recyclable.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.