Gold nanoparticles as radiosensitizer for radiotherapy and diagnosis of COVID-19: A review

ABSTRACT Radiotherapy is an established therapy in cancer treatments that uses energy deposition directly into tumor tissue. With the introduction of radiosensitizers, invasive surgical and chemotherapy techniques can be avoided. Radiosensitizers with a high-Z base such as gold nanoparticles (AuNPs) are promising candidates for catalyzing tumor injury and simultaneously enabling tracking to be done inside the organ via a computed tomography scan or other diagnostic imaging. It has been documented that AuNP possess biocompatibility characteristics as well as nontoxic properties depending on the size of the application and the applied coating. Radiosensitizers can increase tumor targeting, thus providing more specific destruction than conventional techniques while minimizing damage to surrounding healthy tissues. This review focuses on the special properties of AuNP in assisting radiotherapy as a radiosensitizing agent. Important parameters for AuNP’s optimization are listed to offer general guidelines for which the specifications of AuNP should be directed. In addition, the mechanism of AuNP radiosensitization in physical, chemical, and biological phases is discussed. A list of in vitro and in vivo testing and current clinical trials of AuNP are presented in sequence. Finally, the utilization of AuNP for diagnosing and combating the COVID-19 pandemic is discussed for future outbreak surveillance and intervention.