Formation of thioglucoside single crystals by coherent molecular vibrational excitation using a 10-fs laser pulse

Izumi Iwakura,Shoji Akai,Keiko Komori-Orisaku,Atsushi Yabushita,Sena Hashimoto,Kenta Kimura

doi:10.1038/s42004-020-0281-6

Abstract

Compound crystallization is typically achieved from supersaturated solutions over time, through melting, or via sublimation. Here a new method to generate a single crystal of thioglucoside using a sub-10-fs pulse laser is presented. By focusing the laser pulse on a solution in a glass cell, a single crystal is deposited at the edge of the ceiling of the glass cell. This finding contrasts other non-photochemical laser-induced nucleation studies, which report that the nucleation sites are in the solution or at the air-solution interface, implying the present crystallization mechanism is different. Irradiation with the sub-10-fs laser pulse does not heat the solution but excites coherent molecular vibrations that evaporate the solution. Then, the evaporated solution is thought to be deposited on the glass wall. This method can form crystals even from unsaturated solutions, and the formed crystal does not include any solvent, allowing the formation of a pure crystal suitable for structural analysis, even from a minute amount of sample solution.

Highlights

Compound crystallization is typically achieved from supersaturated solutions over time, through melting, or via sublimation
In 2007, Sugiyama et al reported that focused irradiation with a continuous wave (CW) laser (1.06 μm) of a supersaturated solution of glycine led to continuous capture of molecular clusters due to the photon pressure, resulting in the formation of crystal nuclei because of the increase in the molecular density at the focal spot[9], which is thought to be another promising method for the formation of crystal nuclei of proteins[10]
Supplementary Movie 1 shows that the solid compounds and solvents evaporated by laser irradiation were cooled at the top of the quartz glass cell such that they transitioned from the gas phase to the solid phase or to the liquid phase

Summary

Introduction

Compound crystallization is typically achieved from supersaturated solutions over time, through melting, or via sublimation. In 2007, Sugiyama et al reported that focused irradiation with a continuous wave (CW) laser (1.06 μm) of a supersaturated solution of glycine led to continuous capture of molecular clusters due to the photon pressure, resulting in the formation of crystal nuclei because of the increase in the molecular density at the focal spot[9], which is thought to be another promising method for the formation of crystal nuclei of proteins[10]. It is necessary to develop methods to deposit a single crystal of compounds for which previous methods cannot be applied

Methods

Results

Conclusion