The use of antimicrobial materials, for example, silver nanoparticles, has been a cause for concern because they often exert an adverse effect on environmental and safety during their preparation and use. In this study, we report a class of green antimicrobial coating based on a supramolecular assembly of a protein extracted from daily food, without the addition of any other hazardous agents. It is found that a self-assembled nanofilm by mere hen egg white lysozyme has durable in vitro and in vivo broad-spectrum antimicrobial efficacy against Gram-positive/negative and fungi. Such enhanced antimicrobial capability over native lysozyme is attributed to a synergistic combination of positive charge and hydrophobic amino acid residues enriched on polymeric aggregates in the lysozyme nanofilm. Accompanied with high antimicrobial activity, this protein-based PTL material simultaneously exhibits the integration of multiple functions including antifouling, antibiofilm, blood compatibility, and low cytotoxicity due to the existence of surface hydration effect. Moreover, the bioinspired adhesion mediated by the amyloid structure contained in the nanofilm induces robust transfer and self-adhesion of the material onto virtually arbitrary substrates by a simple one-step aqueous coating or solvent-free printing in 1 min, thereby allowing an ultrafast route into practical implications for surface-functionalized commodity and biomedical devices. Our results demonstrate that the application of pure proteinaceous substance may afford a cost-effective green biomaterial that has high antimicrobial activity and low environmental impact.
In recent years, microbial colonization on the surface of biomedical implants/devices has become a severe threat to human health. Herein, surface-immobilized guanidine derivative block copolymers create an antimicrobial and antifouling dual-functional coating. We report the preparation of an antimicrobial and antifouling block copolymer by the conjugation of polyhexanide (PHMB) with either allyl glycidyl ether or allyloxy polyethylene glycol (APEG; MW 1200 and 2400). The allyl glycidyl ether modified PHMB (A-PHMB) and allyloxy polyethylene glycol modified PHMB (APEG-PHMB) copolymers were grafted onto a silicone rubber surface as a bottlebrush-like coating, respectively, using a plasma-UV-assisted surface-initiated polymerization. Both A-PHMB and APEG-PHMB coatings exhibited excellent broad-spectrum antimicrobial properties against Gram-negative/positive bacteria and fungi. The APEG-PHMB coating displayed an improved antibiofilm as well as antifouling properties and a long reusable cycle, compared with two other coatings, due to its abundant PEG blocks among those copolymers. Also, the APEG-PHMB-coated silicone coupons were biocompatible toward mammalian cells, as revealed by in vitro hemocompatibile and cytotoxic assays. An in vivo study showed a significant decline of Escherichia coli colonies with a 5-log reduction, indicating the APEG-PHMB coating surface worked effectively in the rodent subcutaneous infection model. This PHMB-based block copolymer coating is believed to be an effective strategy to prevent biomaterial-associated infections.
Biofilms in chronic wounds, including diabetic foot ulcers, pressure ulcers, and venous leg ulcers, pose a major challenge to wound management. Herein, we report a Janus-type antimicrobial dressing for eradication of biofilms in chronic wounds. The dressing consists of electrospun nanofiber membranes coupled with dissolvable microneedle arrays to enable effective delivery of a database designed antimicrobial peptide to both inside and outside biofilms. This antimicrobial dressing exhibited high efficacy against a broad spectrum of resistant pathogens in vitro. Importantly, such a dressing was able to eradicate methicillin-resistant Staphylococcus aureus (MRSA) biofilms in both an ex vivo human skin wound infection model and a type II diabetic mouse wound infection model after daily treatment without applying surgical debridement. Most *
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