Bistra Iordanova1, Clinton S. Robison1, Eric T. Ahrens1,2
1Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA; 2Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon Univeristy, Pittsburgh, PA, USA
Several recent molecular MRI techniques utilize the iron storage protein ferritin as a probeless reporter. One of the practical limitations of ferritin as a reporter for MRI is that it is a relatively weak contrast agent, especially at lower magnetic field strengths. To enhance MRI sensitivity, we fixed its heavy and light subunit stoichiometry by engineering a fusion single-chain ferritin. In this study we show that the new ferritin chimera loads significantly more iron and exhibits higher transverse relaxation rates than wild type ferritin both in human cells and in mouse brain.