The effect of nanoparticle coating on biological, chemical and biophysical parameters influencing radiosensitization in nanoparticle-aided radiation therapy.

Abstract

Nanoparticle-based composites have the potential to meet requirements for radiosensitization in both therapeutic and diagnostic applications. The radiosensitizing properties of nanoparticles could be reliant on the nature of their coating layer. Any gains in reduced toxicity and aggregation or improved delivery to tumor cells for coated nanoparticles must be weighed against the loss of dose enhancement. The radiosensitization potential of coated NPs is confirmed by numerous studies but in most of them, the coating layer is mostly applied to reduce toxicity of the NPs and for stability and biocompatibility aims. While the direct effects of the coating layer in radiosensitization-were ignored and not considered. This review provides an overview of double-edged impact of nanoparticle coating on the radiosensitization potential of nanostructures and discusses the challenges in choosing appropriate coating material in the aim of achieving improved radioenhancement. Coating layer could affect the radiosensitization processes and thereby the biological outcomes of nanoparticle-based radiation therapy. The physicochemical properties of the coating layer can be altered by the type of the coating material and its thickness. Under low-energy photon irradiation, the coating layer could act as a shield for nanoparticles capable of absorb produced low-energy electrons which are important levers for local and nanoscopic dose enhancement. Also, it seems that the coating layer could mostly affect the chemical process of ROS production rather than the physicochemical process. Based on the reviewed literature, for the irradiated coated nanoparticles, the cell survival and viability of cancer cells are decreased more than normal cells. Also, cell cycle arrest, inhibition of cell proliferation, DNA damage, cell death and apoptosis were shown to be affected by coated metallic nanoparticles under irradiation.