Hyperpolarized 15N-labeled, deuterated tris(2-pyridylmethyl)amine as an MRI sensor of freely available Zn2+

Abstract

AbstractDynamic nuclear polarization (DNP) coupled with 15N magnetic resonance imaging (MRI) provides an opportunity to image quantitative levels of biologically important metal ions such as Zn2+, Mg2+ or Ca2+ using appropriately designed 15N enriched probes. For example, a Zn-specific probe could prove particularly valuable for imaging the tissue distribution of freely available Zn2+ 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, 15N-enriched, d6-deuterated version of the well-known Zn2+ chelator, tris(2-pyridylmethyl)amine (TPA) and demonstrate that the polarized ligand had favorable T1 and linewidth characteristics for 15N MRI. Examples of how polarized TPA can be used to quantify freely available Zn2+ in homogenized human prostate tissue and intact cells are presented.