Graphene Oxide and Methylglyoxal: a combined strategy against chronic wound pathogens

Chronic wound infections are difficult to treat due to the polymicrobial biofilms that delay wound healing increasing antimicrobial tolerance and limiting patient compliance. To address this challenge, we developed a non-antibiotic combination of Graphene Oxide (GO) and Methylglyoxal (MGO) (patent N. 102022000024408-Composizione per il trattamento delle infezioni a carico delle lesioni cutanee) against clinically relevant chronic wound pathogens. For the tests, clinical antimicrobial resistant Staphylococcus aureus and Pseudomonas aeruginosa were used. MGO MIC was determined and the best GO + MGO combination, evaluated by using checkboard test, was tested in terms of: i) fluid membrane changes; ii) S. aureus and P. aeruginosa CFUs/mg reduction in Lubbock Chronic Wound Biofilm-LCWB, a recognized polymicrobial in vitro chronic wound biofilm model; iii) P. aeruginosa motility. MGO MIC values ranged from 32 to 128 mg/l. Notably, synergistic interactions between GO and MGO were observed exclusively against S. aureus, whereas the combinations showed additive effects against P. aeruginosa. The best GO + MGO (6.25 + 64 mg/l) combination increased bacterial membrane fluidity, inhibited informing and mature LCWBs by 60-80% in terms of CFU/mg and P. aeruginosa twitching motility. GO + MGO combination exhibited an additive antimicrobial/antibiofilm activity with a multi-target action. Overall, the GO + MGO combination, at recognized non-toxic concentrations, is a valid and innovative non-antibiotic solution for wound management affecting the polymicrobial chronic wound biofilms and P. aeruginosa motility.