Joern Engelmann1, Deepti Jha1, Ritu Mishra1, Karl-Heinz Wiesmueller2, Kamil Ugurbil1,3
1High Field MR Center, Max-Planck-Institute for Biological Cybernetics, Tuebingen, Germany; 2EMC microcollections GmbH, Tuebingen, Germany; 3Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, USA
A novel cell penetrating peptide (CyLoP-1) was obtained by structure activity relationship studies. It exhibited efficient transport across the cell membrane and distribution in the entire cytosol as well. These distinctive properties were only slightly influenced by the coupling of Gd-DOTA. This conjugate was slightly less internalized into 3T3 fibroblasts, but the cellular distribution was retained. MR studies on labeled cells revealed an exceptional high contrast enhancement in T1-weighted images. These results demonstrate its potential to be used for efficient transmembrane delivery of imaging agents and as vector for probes specifically targeted to cytosolic constituent.