ABSTRACT
Silicon semiconductor nanoparticles or silicon dots (SiDs) have received great attention as they combine a size-dependent photoluminescence, a rich surface chemistry, and the capacity to photosensitize singlet oxygen and to photoreduce O2, methyl viologen and metal ions such as Au and Ag. A complete analysis of the action of ionizing radiation and nanoparticles (NPs) is not based only on the primary energy transfer mechanisms, but in secondary physical effects and also chemical and biological properties. High-energy photon beam is the most common form of radiation used for cancer treatment. In radiotherapy, clinically relevant doses of radiation to generate DNA damage could lead to early cell death but rather result in cell death after one or more cell divisions. Aqueous suspensions of semiconductor NPs showed a proportional increase in reactive oxygen species (ROS) generation with increasing doses of low-energy X-rays. Probable mechanisms involved in radiosensitizing effects of gold NPs are cell cycle changes and elevated ROS generation.
