Heat-Bath Cooling of Spins in Two Amino Acids

TL;DR

This paper demonstrates heat-bath cooling of amino acid carbons, achieving significant polarization increases, which could enhance in vivo 13C spectroscopy for metabolic studies.

Contribution

It introduces a novel application of heat-bath cooling to amino acids, showing effective entropy reduction and polarization enhancement in biological molecules.

Findings

Carbons in glutamate and glycine cooled by about 2.5-fold.

Polarization of C1 nearly doubled in some experiments.

Adding Magnevist affects heat-bath cooling efficiency.

Abstract

Heat-bath cooling is a component of practicable algorithmic cooling of spins, an approach which might be useful for in vivo 13C spectroscopy, in particular for prolonged metabolic processes where substrates that are hyperpolarized ex-vivo are not effective. We applied heat-bath cooling to 1,2-13C2-amino acids, using the alpha protons to shift entropy from selected carbons to the environment. For glutamate and glycine, both carbons were cooled by about 2.5-fold, and in other experiments the polarization of C1 nearly doubled while all other spins had equilibrium polarization, indicating reduction in total entropy. The effect of adding Magnevist, a gadolinium contrast agent, on heat-bath cooling of glutamate was investigated.