Lars Liepold1, Joseph Frank2, Mark Young3, Trevor Douglas1
1Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA; 2Diagnostic Radiology Research, National Institutes of Health, Bethesda, MD, USA; 3Plant Sciences, Montana State University, Bozeman, MT, USA
Here we present a strategy to make highly efficient contrast agents by use of a branched polymer grown in the interior cavity of a protein cage. Gadolinium chelates are covalently linked to the monomers of the branched polymer resulting in 192 Gd3+ ions per cage. Here we report ionic relaxivity values of 20 sec-1 mM-1 and particle relaxivities of 3,821 sec-1 mM-1.