Determination of antibacterial and photothermal properties of novel composites based on graphene oxide/reduced graphene oxide, gold nanoparticles, and graphene quantum dots

Abstract

Pathogenic bacteria have emerged as a worldwide health problem nowadays as a result of excessive use or misuse of antibiotics. Thus the prevention of bacteria-mediated infections through the development of novel antibacterial materials has received significant importance. Here, we combined graphene-based materials, namely graphene oxide (GO) and reduced graphene oxide (rGO), with gold nanoparticles and modified graphene quantum dots to obtain improved composite materials. Also, we measured their light-to-heat conversion under an 808 nm laser illumination and their ability to generate singlet oxygen under photoexcitation. We determined their antibacterial properties against 8 bacterial strains. The composite of rGO showed slightly improved photothermal conversion compared to the GO counterpart due to its larger sp² domains, while the GO composite showed the highest capacity to generate ¹O<inf>2</inf> under blue-light photoexcitation. All prepared composites had the minimum inhibitory concentrations in the range of 125 μg mL⁻¹ to 500 μg mL⁻¹ and did not show any cytotoxicity against MRC-5 cells.