Hyperpolarized 15N-labeled, deuterated tris(2-pyridylmethyl)amine as an MRI sensor of freely available Zn2+
Eul Hyun Suh, Jae Mo Park, Lloyd Lumata, A. Dean Sherry, Zoltán Kovács
Abstract
Abstract Dynamic nuclear polarization (DNP) coupled with 15 N magnetic resonance imaging (MRI) provides an opportunity to image quantitative levels of biologically important metal ions such as Zn 2+ , Mg 2+ or Ca 2+ using appropriately designed 15 N enriched probes. For example, a Zn-specific probe could prove particularly valuable for imaging the tissue distribution of freely available Zn 2+ ions, an important known metal ion biomarker in the pancreas, in prostate cancer, and in several neurodegenerative diseases. In the present study, we prepare the cell-permeable, 15 N-enriched, d 6 -deuterated version of the well-known Zn 2+ chelator, tris(2-pyridylmethyl)amine (TPA) and demonstrate that the polarized ligand had favorable T 1 and linewidth characteristics for 15 N MRI. Examples of how polarized TPA can be used to quantify freely available Zn 2+ in homogenized human prostate tissue and intact cells are presented.