Hyperpolarised 2-13C-pyruvate by 13C SABRE in an acetone/water mixture

Signal Amplification By Reversible Exchange (SABRE) can provide strong signal enhancement (SE) to an array of molecules through reversible exchange of parahydrogen (pH2) derived hydrides and a suitable substrate coordinated to a transition metal. Among the substrates that can be used as a probe for hyperpolarised NMR and MRI, pyruvate has gained much attention. SABRE can hyperpolarise pyruvate in a low cost, fast, and reversible fashion that does not involve technologically demanding equipment. Most SABRE polarization studies have been done using methanol-d4 as a solvent, which is not suitable for in vivo application. The main goal of this work was to obtain hyperpolarized pyruvate in a solvent other than methanol which may open the door to further purification steps and enable a method to polarize pyruvate in water in future. This work demonstrates hyperpolarization of the [2-13C]pyruvate as well as [1-13C]pyruvate by SABRE in an acetone/water solvent system at room temperature as an alternative to methanol, which is commonly used. NMR signals are detected using a 1.1 T benchtop NMR spectrometer. In this work we have primarily focused on the study of [2-13C]pyruvate and investigated the effect of catalyst concentration, DMSO presence and water vs. acetone solvent concentration on the signal enhancement. The relaxation times for [2-13C]-pyruvate solutions are reported in the hope of informing the development of future purification methods.Signal Amplification By Reversible Exchange (SABRE) can provide strong signal enhancement (SE) to an array of molecules through reversible exchange of parahydrogen (pH2) derived hydrides and a suitable substrate coordinated to a transition metal. Among the substrates that can be used as a probe for hyperpolarised NMR and MRI, pyruvate has gained much attention. SABRE can hyperpolarise pyruvate in a low cost, fast, and reversible fashion that does not involve technologically demanding equipment. Most SABRE polarization studies have been done using methanol-d4 as a solvent, which is not suitable for in vivo application. The main goal of this work was to obtain hyperpolarized pyruvate in a solvent other than methanol which may open the door to further purification steps and enable a method to polarize pyruvate in water in future. This work demonstrates hyperpolarization of the [2-13C]pyruvate as well as [1-13C]pyruvate by SABRE in an acetone/water solvent system at room temperature as an alternative to methanol, which is com