Graphene-Based Photothermal Agent for Rapid and Effective Killing of Bacteria

Abstract

Conventional antibiotic therapies are becoming less efficient due to the emergence of antibiotic-resistant bacterial strains. Development of novel antibacterial material to effectively inhibit or kill bacteria is crucial. A graphene-based photothermal agent, magnetic reduced graphene oxide functionalized with glutaraldehyde (MRGOGA), was synthesized for efficient capture and effective killing of both gram-positive Staphylococcus aureus ( S. aureus ) and gram-negative Escherichia coli ( E. coli ) bacteria upon near-infrared (NIR) laser irradiation. In the present work, we took advantage of the excellent photothermal properties of reduced graphene oxide upon NIR laser irradiation and glutaraldehyde as an efficient capturing agent toward both bacteria. Its magnetic characteristic allows bacteria to be readily trapped in a small volume by the external magnet. The synergetic effects increase the heating extent by MRGOGA upon NIR laser irradiation and the killing of the captured bacteria. The survival rate and membrane integrity assay demonstrate that 80 ppm MRGOGA solution provided rapid and effective killing of up to 99% of both gram-positive and gram-negative bacteria in 10 min upon NIR laser irradiation under batch operation mode. Graphene demonstrated better photothermal antibacterial efficiency than carbon nanotubes. Furthermore, a microfluidic chip system under continuous operation mode demonstrates the reusability of MRGOGA and offers a biocompatible platform for online phothothermal sterilization.

Shell thickness-dependent antibacterial activity and biocompatibility of gold@silver core–shell nanoparticles

“…42 100 mL of cells solution was added into a 96-well plate at a density of 5000 cells per plate and incubated at 37 C, 5% CO 2 for 24 h. Then, cells were treated with various concentrations of each NPs solution and incubated for an additional 24 h. In parallel, cells with the addition of water served as negative controls. Then, 50 mL 0.5 mg mL À1 MTT bromide aqueous solution was added to each well of a 96-well plate.…”

Preparation, Characterization, and Antibacterial Activity of Silver Nanoparticle-Decorated Graphene Oxide Nanocomposite

“…In order to determine the effect of pH on the silver ion release profiles of the nanocomposite, HEPES (Sigma) buffers with different pH values at 5.5, 7, and 8.5 were used, respectively. The 5 mL tested samples were immersed in a beaker containing 95 mL of 10 mM HEPES at 37°C and sealed using PARAFILM M. The 1.5 mL solution was taken at regular time intervals (1,2,3,4,5,6,7,8,9, and 10 days) and analyzed for the amount of Ag ion released using inductively coupled plasma mass spectrometry NexION 300X (PerkinElmer).…”

Highly efficient ablation of metastatic breast cancer using ammonium-tungsten-bronze nanocube as a novel 1064 nm-laser-driven photothermal agent

“…To promote the photothermal conversion efficiency and gain access to efficient PTA therapy, a prerequisite is to develop biocompatible photothermal conversion agents, which should exhibit strong absorbance in the near-infrared (NIR) region. A variety of inorganic nanomaterials including plasmonic gold nanoparticles [13e17], AueAg alloy [18], carbon nanotube [6], graphene [19] and semiconductor copper sulfide nanoparticles [20,21] or organic nanoparticles such as porphysome and light-absorbing conductive polymers [22e25], have shown encouraging therapeutic effects in PTA therapy because these nanostructures exhibit high absorbance in the first tissuetransparent NIR optical window (650e950 nm). Recently, the second NIR window between 1000 and 1400 nm has been proven to possess deeper tissue penetration ability as compared with the first NIR window owing to the greatly reduced scattering (Mie and Rayleigh scattering are inversely proportional to the wavelength of NIR) and less optical absorption by tissues [26,27].…”