Cation Exchange Protocols to Radiolabel Aqueous Stabilized ZnS, ZnSe, and CuFeS₂ Nanocrystals with ⁶⁴Cu for Dual Radio- and Photo-Thermal Therapy.

ABSTRACT: Here, cation exchange (CE) reactions are exploited to radiolabel ZnSe, ZnS, and CuFeS₂ metal chalcogenide nanocrystals (NCs) with ⁶⁴Cu. The CE protocol requires one simple step, to mix the water-soluble NCs with a ⁶⁴Cu solution, in the presence of vitamin C used to reduce Cu(II) to Cu(I). Given the quantitative cation replacement on the NCs, a high radiochemical yield, up to 99%, is reached. Also, provided that there is no free ⁶⁴Cu, no purification step is needed, making the protocol easily translatable to the clinic. A unique aspect of the approach is the achievement of an unprecedentedly high specific activity: by exploiting a volumetric CE, the strategy enables to concentrate a large dose of ⁶⁴Cu (18.5 MBq) in a small NC dose (0.18 µg), reaching a specific activity of 103 TBq g^-1. Finally, the characteristic dielectric resonance peak, still present for the radiolabeled ⁶⁴Cu:CuFeS₂ NCs after the partial-CE reaction, enables the generation of heat under clinical laser exposure (1 W cm^-2). The synergic toxicity of photo-ablation and ⁶⁴Cu ionization is here proven on glioblastoma and epidermoid carcinoma tumor cells, while no intrinsic cytotoxicity is seen from the NC dose employed for these dual experiments.

SUBMITTER: Avellini T 

PROVIDER: S-EPMC7357593 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature