Antimicrobial activity of graphene nanoplatelets against Streptococcus mutans

Abstract

In recent years, several studies have demonstrated\ud the strong cytotoxicity toward bacteria of graphene-based\ud materials, suggesting their use as antimicrobial agents. The\ud objective of this study was to evaluate the antibacterial activity\ud against Streptococcus mutans, the principal microbiological agent\ud in the etiology of dental caries, of two types of graphene\ud nanoplatelets (GNPs), characterized by different thickness and\ud lateral dimensions of the flakes. The antimicrobial properties of\ud GNPs were valued on some plaque and saliva samples extracted\ud from children with dental caries. Our results show that the\ud killing effect of GNPs on S. mutans cells is both lateral size and\ud thickness dependent. In fact, lower thickness and smaller size\ud GNPs exhibit stronger antibacterial activity than larger and\ud thicker ones. Scanning electron microscopy analysis revealed that\ud GNPs interact strongly with cells. This study suggests that GNPs\ud may be highly effective against S.mutans and therefore caries

Zinc Oxide Nanorods-Decorated Graphene Nanoplatelets: A Promising Antimicrobial Agent against the Cariogenic Bacterium Streptococcus mutans

“…In addition, we demonstrated that GNPs, produced from thermal exfoliation of graphite intercalation compound, have bactericidal effects against P. aeruginosa and S. mutans cells. This is mainly due to a mechanical interaction originated by the GNP wrapping around the cells and a local damage of the cell wall produced by the GNP sharp edges acting as nano-knives [20,21]. However, the main problem in the use of GNPs in water-based colloidal suspension is the formation of aggregates, which inhibit the antimicrobial action of the nanostructures.…”

“…Therefore, the concentration of GNPs used in this study (50 µg/mL) was too low for killing S. mutans cells, probably due to the formation of large aggregates. Indeed, we previously reported a remarkable mortality rate for the planktonic form of this bacterium only at very high concentrations of GNPs [21]. …”

“…GNPs were produced by thermal expansion at 1050 °C for 30 s of commercially available Graphite Intercalation Compound (GIC), and successive liquid-phase exfoliation by probe sonication as described in Rago et al (2015) [21]. Pristine ZnO-NRs were produced through the thermal decomposition of zinc acetate di-hydrate and successive probe sonication as described in our earlier works [32,34].…”

“…In this context, graphene-related structures like graphene nanoplatelets (GNPs), can represent a valuable tool in the biological/medical field, also owing to the fact that their production process is very easy, inexpensive, and scalable [12]. The antimicrobial properties of GNPs against both gram-negative ( Pseudomonas aeruginosa ) and gram-positive ( S. mutans ) bacteria have been investigated in previous studies [20,21], and their very low cytotoxicity was also demonstrated through in vivo system ( Caenorhabditis elegans ) [20]. However, one of the main limitations for a wide exploitation of GNPs as antimicrobial agent in dental application, is represented by the grey color and by the aptitude in aggregating when dispersed in a colloidal suspension.…”

Antibacterial Activity against Staphylococcus Aureus of Titanium Surfaces Coated with Graphene Nanoplatelets to Prevent Peri-Implant Diseases. An In-Vitro Pilot Study

“…GNPs were produced as described in previous papers [36,37]. Briefly, graphite intercalated compound (GIC) was used as a precursor to form worm-like expanded graphite (WEG) through a thermal driven expansion in a muffle furnace.…”