Facile synthesis of stable, water-soluble magnetic CoPt hollow nanostructures assisted by multi-thiol ligands

We report the synthesis of CoPt hollow nanostructures using a simple reduction method in aqueous solution in the presence of poly(methacrylic acid) pentaerythritol tetrakis (3-mercaptopropionate) (PMAA-PTMP) polymer or a mixture of O-[2-(3-mercaptopropionyl- amino) ethyl]-O'-methylpolyethylene glycol (PEG-SH) polymer and cysteine-cysteine-alanine-leucine-asparagine-asparagine (CCALNN) peptide ligands. The presence of the multi-thiol functional group of the ligands is essential for the formation of the hollow nanostructures and their perimeter size can be tuned within the range of 7-54 nm by changing peptide concentration or length of polymer. These hollow nanostructures are water-soluble and superparamagnetic at room temperature. They are stable in a wide range of pH from 1 to 10, high electrolyte concentration up to 2 M NaCl, and in cell culture medium which makes them have great potential to be utilised in biomedical applications.