One-step preparation of gold nanoparticles - exfoliated graphene composite by gamma irradiation at low doses for photothermal therapy applications

Graphene is an excellent material to anchor metal nanoparticles due to its large surface area. In this paper, we report the use of electrochemically exfoliated graphene as support to anchor gold nanoparticles (Au NPs). Au NPs are synthesized via the reduction of chloroauric acid under gamma irradiation at low doses of 1, 5, and 10 kGy and directly deposited onto the graphene surface, making this procedure simple and fast. Good water dispersibility of exfoliated graphene, due to the presence of oxygen-containing functional groups in the structure of graphene, provides long-term stability of Au NPs - graphene composite dispersions. The majority of the Au NPs obtained by this method have sizes of up to 40 nm, while the increase in the applied dose leads to an increase in the amount of smaller nanoparticles. The increase of temperature of the prepared composite material upon irradiation with an 808 nm continuous wave laser was monitored. All samples show a temperature increase between 21.5 and 25.6 °C for 10 min of the laser exposure, which indicates that Au NPs - graphene composite can effectively be used in photothermal treatment for cancer therapy