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Conventional wound dressings fail to provide features that can assist the healing process of chronic wounds. Multifunctional wound dressings address this issue by incorporating attributes including antibacterial and antioxidant activity, and the ability to enhance wound healing. Herein, polyethylene glycol (PEG)-based antibacterial hydrogel sponge dressings are prepared by a rapid and facile gas foaming method based on an acid chloride/alcohol reaction where tannic acid (TA) is included as a reactant to impart antibacterial efficacy as well as to enhance the mechanical properties of the samples. The results reveal that the TA-integrated sponges possess excellent antibacterial properties against both Escherichia coli and Staphylococcus aureus with approximately 6-8 log reduction in the microbial colony count after 6 h, indicating their high potential for management of infection-prone wounds. Compared to the control sample, TA incorporation increases the elastic modulus by twofold. As the samples also exhibit biocompatibility, antioxidant activity, and wound healing capacity, the novel TA-incorporated hydrogels can be an alternative to traditional wound dressings for wounds with low-to-moderate exudate., (© 2024 The Author(s). Macromolecular Bioscience published by Wiley‐VCH GmbH.)

In this study, antibacterial, antifungal, antihyaluronidase, anticollagenase and antielastase activity of Hypericum bithynicum, Malva neglecta, Morus alba, Rubus discolor, Sambucus ebulus and Smilax excelsa were investigated. Methanol extracts of M. neglecta and R. discolor and all extracts of H. bithynicum were more active against Staphylococcus epidermidis. Similarly, water extracts of M. alba and S. ebulus were more active against Streptococcus pneumonia. Additionally, S. ebulus and S. excelsa had prominent antifungal activity on Candida albicans. Besides, methanol extract of M. neglecta and n-hexane extract of H. bithynicum were determined to have significant antihyaluronidase activity. Only R. discolor showed significant antielastase effect.

Significance: This study investigated the development of an antimicrobial coating on silicone hydrogel contact lenses that may have the capacity to reduce contact lens-related infection and inflammatory events., Purpose: The purpose of this study was to develop an effective antimicrobial coating for silicone hydrogel contact lenses by attachment of Mel4 peptide., Methods: Lotrafilcon A, comfilcon A, somofilcon A, senofilcon A, and lotrafilcon B silicone hydrogel contact lenses were plasma coated with acrylic acid followed by Mel4 antimicrobial peptide immobilization by covalent coupling. Peptide immobilization was quantified by x-ray electron spectroscopy. Contact lens diameter, base curve, center thickness, and lens surface wettability were measured by captive-bubble contact-angle technique. Antimicrobial activity of the lenses was determined against Pseudomonas aeruginosa and Staphylococcus aureus by viable plate count and also after soaking with artificial tears solution for 1 day. In vivo safety and biocompatibility were determined in an animal model for 1 week., Results: Mel4 peptide-coated silicone hydrogel contact lenses were associated with high antimicrobial inhibition (>2 log), except for lotrafilcon B and senofilcon A. Lotrafilcon B did not exhibit any activity, whereas senofilcon A showed 1.4- and 0.7-log inhibition against P. aeruginosa and S. aureus, respectively. X-ray electron spectroscopy revealed significant increases in the lens surface-bound amide nitrogen in all contact lenses except for lotrafilcon B. All contact lens parameters remained unchanged except for the base curve and center thickness for senofilcon A. Mel4 immobilization was associated with a decrease in contact angle. Mel4-coated contact lens wear was not associated with any signs or symptoms of ocular irritation in a rabbit model study. Reduced antimicrobial activity was observed with all the lenses after soaking with artificial tears solution or rabbit wear., Conclusions: Mel4 antimicrobial coating may be an effective option for development of antimicrobial silicone hydrogel contact lenses.

The fight against infection in an era of emerging antibiotic resistant bacteria is one of the grandest scientific challenges facing society today. Nano-carriers show great promise in improving the antibacterial activity of antibiotics as they are able to enhance their solubility, provide sustained release and reduce toxic side effects via specifically targeting infection sites. Here, we investigate the antibacterial effect of two lipidic nano-carriers that contain the poorly soluble antibiotic rifampicin in their bilayers. One nanoparticle is assembled solely from the lipid monoolein, thus is neutral at physiological pH and the other contains a mixture of monoolein and the cationic lipid N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate (DOTAP), thus is positively charged. Our results show that rifampicin-loaded nanoparticles reduce the minimum inhibitory concentration against Staphylococcus aureus compared to rifampicin alone, however this reduction was most pronounced for the positively charged nanoparticles. Fluorescent microscopy revealed binding of all nanoparticles to the bacteria and enhanced binding was observed for the charged nanoparticles. This suggests that the cationic lipids promote electrostatic interactions with the negatively charged bacterial membrane. Förster resonance energy transfer demonstrated that the cationic charged nanoparticles were able to fuse with bacterial membranes whilst atomic force microscopy and transmission electron microscopy revealed structural damage to the bacterial membranes caused by the nanoparticles. Significantly, we identified a concentration window in which the nanoparticles exhibited antibacterial activity while not affecting HeLa and CHO cell viability. This ability to improve the efficacy of antibiotics without affecting their eukaryotic cytotoxicity is of significant importance for future development of nanomedicine based strategies to combat infections., (Copyright © 2018 Elsevier Inc. All rights reserved.)