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Gold nanoparticles as dose-enhancement agent for kilovoltage X-ray therapy of melanoma

Abstract Purpose: Melanoma is mainly treated by surgery and rarely with radiation because of the high radioresistance of this tumor. Nevertheless, radiotherapy is the preferred treatment modality for unresectable lesions and avoiding cosmetic disfigurement caused by surgical excision. This study investigated the therapeutic advantage of gold nanoparticles (AuNPs) for kilovoltage X-ray treatment of melanoma. Materials and methods: Commercial AuNPs were evaluated for cytotoxicity and cellular internalization. The sensitivity of human skin melanoma cells to 150 and 450 kVp X-ray exposure was assessed in terms of clonogenicity with or without spherical AuNP treatment. Results: AuNP treatment elicited dose enhancement effect on melanoma cells exposed to kilovoltage X-rays. Treatment with 320 μM 50 nm AuNPs before exposure to 150 kVp X-rays at 2 Gy resulted in clonogenic cell death equivalent to that caused by 4.3 Gy X-rays without AuNP treatment. Conclusion: AuNPs of 50 nm in size can regulate melanoma cells in kilovoltage X-ray treatment by functioning as dose-enhancement agent and thus improving radioresponse of the cells. Melanomas of stages T1–T3 gain therapeutic benefits from 150 kVp X-ray treatment.