Silicon dots in Radiotherapy

Abstract

introduction: Radiation therapy is an important treatment modality for many types of human cancer. Although this therapeutic approach is effective in many cases, normal tissue toxicity limits the total radiation dose a patient can receive. Advances in instrumentation and technology lead to more precise X-rays,targeting eliminating of some of the normal tissue damage. In particular, nanomaterials used as radiosensitizers are known to increase the efficiency of X-rays causing more localized damage to DNA and targeted organelles of tumor cells. The targeted localized damage due to the small size of the particlesand their versatile surface modification with specific recognition molecules, and the capability of nanoparticles (NPs) to produce reactive radicals upon irradiation are key properties to take advantage of in the enhancement strategies of cytostatic and cytolytic activities in tumor cells by high-energy(MeV) ionizing radiation.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 (1O2) and to photoreduce O2, methyl viologen and metal ions such as Au3+ and Ag+. Remarkable properties of SiDs when compared to other materials are their biocompatibility, biodegradability, and tunable surface derivatization for drug delivery. In vivo assays indicate that SiDs are metabolized andeliminated from the body in relatively short times. In this regard, there is an increased interest in new applications of SiDs. In this chapter we discuss the progress in SiDs studies as therapeutic agents enhancing the effects of radiation therapy.