Antimicrobial and Antibiofilm Efficacy of Graphene Oxide against Chronic Wound Microorganisms

Chronic wounds represent an increasing problem worldwide. Graphene oxide (GO) has been reported to exhibit strong antibacterial activity toward both Gram-positive and Gram-negative bacteria. The aim of this work was to investigate thein vitro antimicrobial and antibiofilm efficacy of GO against wound pathogens.Staphylococcus aureus PECHA 10,Pseudomonas aeruginosa PECHA 4, andCandida albicans X3 clinical isolates were incubated with 50 mg/liter of GO for 2 and 24 h to evaluate the antimicrobial effect. Optical and atomic force microscopy images were performed to visualize the effect of GO on microbial cells. Moreover, the antibiofilm effect of GO was tested on biofilms, both in formation and mature. Compared to the respective time controls, GO significantly reduced theS. aureus growth both at 2 and 24 h in a time-dependent way, and it displayed a bacteriostatic effect in respect to the GOt = 0; an immediate (after 2 h) slowdown of bacterial growth was detected forP. aeruginosa , whereas a tardive effect (after 24 h) was recorded forC. albicans . Atomic force microscopy images showed the complete wrapping ofS. aureus andC. albicans with GO sheets, which explains its antimicrobial activity. Moreover, significant inhibition of biofilm formation and a reduction of mature biofilm were recorded for each detected microorganism. The antibacterial and antibiofilm properties of GO against chronic wound microorganisms make it an interesting candidate to incorporate into wound bandages to treat and/or prevent microbial infections.