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

Abstract

Nanomaterials are revolutionizing the field of medicine to improve the quality of life due to the myriad of applications stemming from their unique properties, including the antimicrobial activity against pathogens. In this study, the antimicrobial and antibiofilm properties of a novel nanomaterial composed by zinc oxide nanorods-decorated graphene nanoplatelets (ZNGs) are investigated. ZNGs were produced by hydrothermal method and characterized through field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) techniques. The antimicrobial activity of ZNGs was evaluated against Streptococcus mutans, the main bacteriological agent in the etiology of dental caries. Cell viability assay demonstrated that ZNGs exerted a strikingly high killing effect on S. mutans cells in a dose-dependent manner. Moreover, FE-SEM analysis revealed relevant mechanical damages exerted by ZNGs at the cell surface of this dental pathogen rather than reactive oxygen species (ROS) generation. In addition, inductively coupled plasma mass spectrometry (ICP-MS) measurements showed negligible zinc dissolution, demonstrating that zinc ion release in the suspension is not associated with the high cell mortality rate. Finally, our data indicated that also S. mutans biofilm formation was affected by the presence of graphene-zinc oxide (ZnO) based material, as witnessed by the safranin staining and growth curve analysis. Therefore, ZNGs can be a remarkable nanobactericide against one of the main dental pathogens. The potential applications in dental care and therapy are very promising.

Exploring Needle-Like Zinc Oxide Nanostructures for Improving Dental Resin Sealers: Design and Evaluation of Antibacterial, Physical and Chemical Properties

“…Some microorganisms escape oxidative stress by living in anaerobic microhabitats; all others must deal with the consequences of intracellular O 2 [51]. However, almost all of these microorganisms suffer poor growth, elevated mutagenesis, or even death when they are exposed to O 2 levels that exceed those of their native habitats [52]. E. faecalis represents an important clinical problem due to virulence factors such as the regulation of the oxidative stress response by transcriptional regulation by estrogen receptors [53].…”

Antibacterial Effect of Zinc Oxide-Based Nanomaterials on Environmental Biodeteriogens Affecting Historical Buildings

“…Their morphology was observed through high-resolution field emission scanning electron microscopy (FE-SEM). 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 [25]. About the synthesis of ZnO-NR-decorated graphene nanoplatelets (ZNGs), rod shaped ZnO-NRs, with a diameter of~36 nm and length in the range of 300-400 nm, were directly grown over the planar shaped pristine graphene nanoplatelets (GNPs), forming ZNGs [27].…”

Recent Progress in Two‐Dimensional Antimicrobial Nanomaterials

“…Due to the favorable photocatalytic activities, 2D metallic compounds, such as ZnO nanorods, MgO, and TiO 2 , have shown outstanding antibacterial performances and attracted intense attention. The reasons for this activity can be attributed to large specific surface areas, rich surface‐active sites, and short migration distances for photogenerated charges from the bulk to material surface .…”

“…It is speculated that the high concentration of Ag NPs around the bacteria and the polyvalent effect result in strong interactions between nanocomposites and bacteria, which is responsible for effectiveinactivation of bacteria. Due to the favorable photocatalytic activities, [70] 2D metallic compounds, such as ZnO nanorods, [71] MgO, [72] andT iO 2 , [73] have shown outstanding antibacterial performances and attracted intense attention.T he reasons for this activity can be attributedt ol arge specific surfacea reas, rich surface-active sites, and short migration distances for photogenerated charges from the bulk to material surface. [74] Among 2D metallic nanocompounds, ultrathin TiO 2 nanosheets (TNS) are the most accessible antibacterial materials because of their low cost, promisings tability,h igh disinfection efficiency, nontoxicity,a nd robust oxidizing capability.…”

“…Schematic illustration of Pd@Ag NSs for the synergetic treatment of bacteria (left). The time-dependent temperature increase (middle)and Ag + release (right) profileu pon irradiationo fP da nd Pd@Ag NSssuspensions by a0.5 Wcm À2 808 nm laser.R eproduced with permission from ref [71]…”