Translational cooling and storage of protonated proteins in an ion trap at subkelvin temperatures

TL;DR

This paper demonstrates the cooling and storage of protonated proteins in an ion trap at subkelvin temperatures using Coulomb interactions with laser-cooled ions, enabling long storage times and broad applicability.

Contribution

It introduces a method for translational cooling and storage of complex proteins at subkelvin temperatures in an ion trap, extending the potential for molecular studies.

Findings

Proteins cooled below 0.75 K in an ion trap.

Storage times exceeding 20 minutes, extendable beyond an hour.

Technique applicable to various complex molecules.

Abstract

Gas-phase multiply charged proteins have been sympathetically cooled to translational temperatures below 1 K by Coulomb interaction with laser-cooled barium ions in a linear ion trap. In one case, an ensemble of 53 cytochrome c molecules (mass ~ 12390 amu, charge +17 e) was cooled by ~ 160 laser-cooled barium ions to less than 0.75 K. Storage times of more than 20 minutes have been observed and could easily be extended to more than an hour. The technique is applicable to a wide variety of complex molecules.