Theoretical study in comparison of astatine adsorptions on metal carrier materials for targeted alpha therapy applications

Targeted Alpha Therapy treatments using astatine-211 ( 211 At) is being studied as a promising method for cancer treatment, and gold nanoparticles have been studied as one of the promising carriers to deliver astatine to the target area. Since there are other promising metals that can be used for biomedical purposes, we started by looking at the feasibility of improving the flexibility of such methodology by performing a theoretical study on the adsorption of astatine on different noble metals. We thus considered platinum, silver, and copper as potential materials for carriers, and compare their adsorption characteristics of astatine to gold. We found the adsorption strength of astatine on platinum to be superior to the other metals studied. The analysis based on charge densities and electronic states lead us to conclude that adsorption strength depends the level of electronic filling of the metals’ valence orbitals. Considering that the platinum 5d orbital is partially filled, it allows for a stronger adsorption of astatine on its surface, compared to the other three fully-filled metals. We hope this study can galvanize interest in other metallic materials being considered in the future, to allow for a more robust methodology.