Gold nanoparticles as cancer theranostic agents

The application of nanotechnology in medicine involves using nanomaterials to develop novel therapeutic and diagnostic modalities. Given the unique physiochemical and optical properties of gold nanoparticle (GNP) such as good biocompatibility, nontoxic nature, surface properties and comparative stability, it has been widely studied in medicine, especially as a cancer theranostic agent. This review focuses on recent progresses in the field of gold nanostructures in cancer treatment and diagnosis. As far as cancer detection is concerned, several studies have indicated that GNPs can be used for X-ray, MR and optical imaging. With regard to cancer treatment, most studies have investigated the effect of GNPs in different treatment modalities like photothermal therapy, photodynamic therapy, sonodynamic therapy, drug delivery, and radiotherapy. In this paper, we have focused on reviewing the role of GNPs in improving radiotherapy efficiency as radiosensitizers. For optimization of parameters influencing the radiosensitization of GNPs, several studies have been undertaken in different scientific routes. We categorize these studies into three categories; Monte Carlo simulation, cellular studies and animal studies. Finally, according to findings reported by different researchers, the physical and biological mechanism of GNPs in generating radiosensitizing effect is discussed.