Antimicrobial and Antibiofilm Efficacy of Graphene Oxide against Chronic Wound Microorganisms

Abstract

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 the antimicrobial and antibiofilm efficacy of GO against wound pathogens. PECHA 10, PECHA 4, and 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 the growth both at 2 and 24 h in a time-dependent way, and it displayed a bacteriostatic effect in respect to the GO = 0; an immediate (after 2 h) slowdown of bacterial growth was detected for, whereas a tardive effect (after 24 h) was recorded for Atomic force microscopy images showed the complete wrapping of and 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.

Graphene Oxide affects Staphylococcus aureus and Pseudomonas aeruginosa dual species biofilm in Lubbock Chronic Wound Biofilm model

“…In a previous study, we demonstrated the antimicrobial and antibiofilm effect of GO against S. aureus PECHA 10, P. aeruginosa PECHA 4 and Candida albicans X3 single clinical isolates with a major effect against Staphylococci 12 . This major antimicrobial action against the Gram positive bacterium was demonstrated by AFM analysis that evidenced S. aureus cells wrapped by GO 12 , 23 . In addition, as reported by Song et al .…”

“…In LCWB model, GO is capable to interfere on the S. aureus and P. aeruginosa clustering in the dual species biofilm formation and it is also capable to disaggregate and disperse microbial sessile cells in the mature biofilm. Therefore, in the first phase of microbial colonization, GO can act delaying the infection process whereas, in the mature biofilm, GO can favour the disruption of the clustered bacteria embedded in the extracellular polymeric substances promoting the release of planktonic cells for which has been demonstrated the GO effect in terms of CFU reduction 12 .…”

“…Differently from graphene, consisting essentially of sp 2 carbon atoms and strong covalent Csp 2 –Csp 2 bonds, GO presents oxygenated carbon moieties that confer it a low tendency to form aggregates and a strong capability to disperse homogeneously in water 10 and other polar environments. Thanks to van der Waals, electrostatic, π–π and hydrogen bond interactions, GO can easily adsorb polymers and proteins 11 , negatively interfering with the growth of the microorganisms and their aggregation and adhesion to surfaces 12 . These interesting recognized GO properties represent a promising approach for antimicrobial and antibiofilm applications.…”

“…Recently, GO has been reported to exhibit good antibacterial activity toward both Gram positive and Gram negative bacteria 13 together with antibiofilm properties against human pathogens 14 – 18 and, in particular, chronic wound microbial isolates 12 .…”

Antimicrobial activity of multifaceted lactoferrin or graphene oxide functionalized silver nanocomposites biosynthesized using mushroom waste and chitosan

“…This has been attributed to different mechanisms, in which GO hinders the adhesion and penetration the biolm matrix, 65 and the Ag + ion is able to inhibit protein which then disrupts the synthesis of EPS that build up the biolm. In this study, the antimicrobial effect of chitosan could be overwhelmed by the AgGO, resulting in the greater anti-bacterial effect on Gram- negative bacteria.…”