Rapid Catalyst Capture Enables Metal-Free Parahydrogen-Based Hyperpolarized Contrast Agents

Abstract

<p>Hyperpolarization techniques based on the use of parahydrogen provide orders of magnitude signal enhancement for magnetic resonance spectroscopy and imaging. The main drawback limiting widespread applicability of parahydrogen-based techniques in biomedicine is the presence of organometallic compounds (the polarization transfer catalysts) in solution with hyperpolarized contrast agents. These catalysts are typically complexes of platinum-group metals and their administration in vivo should be avoided.</p> <p><br></p><p>Herein, we show how extraction of a hyperpolarized compound from an organic phase to an aqueous phase combined with a rapid (less than 10 seconds) Ir-based catalyst capture by metal scavenging agents can produce pure parahydrogen-based hyperpolarized contrast agents as demonstrated by high-resolution nuclear magnetic resonance (NMR) spectroscopy and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The presented methodology enables fast and efficient means of producing pure hyperpolarized aqueous solutions for biomedical and other uses.</p>

Direct Production of A Hyperpolarized Metabolite on a Microfluidic Chip

“…However, scavenger compounds that bind the catalyst could potentially be used for this purpose. 60,61…”

Real-Time Nuclear Magnetic Resonance Detection of Fumarase Activity Using Parahydrogen-Hyperpolarized [1-13C]Fumarate

“…Prior to application in vivo, it will be necessary to extract the catalyst from the solution. 45 Unfortunately, at this time there is no toxicological information available regarding the ruthenium catalyst, and this is something we hope to investigate in the near future. This work paves the way for accelerated preclinical studies with hyperpolarized fumarate for better understanding of the role it can play in diagnostics.…”