Protein crystallisation with air bubble templates: case of gas–liquid–solid interfaces

Abstract

Crystal formation on air bubble–liquid interface, as soft template to efficiently prompt nucleation of proteins.

Protein Nucleation and Crystallization Process with Process Analytical Technologies in a Batch Crystallizer

“…It was reported that the formation of needle-shaped crystals was due to the secondary nucleation and low supersaturation, which was consistent with the phenomena in this work; the needle-shaped crystals only appeared in stage 2 with existing crystals in the solution. However, in the hanging drop experiments with very low supersaturation, there were no needle-shaped crystals observed under similar crystallization conditions. The shear was reported to influence the crystallization process and crystal morphology, , and it was assumed that the shear also played an important role in the nucleation of the metastable needle-shaped crystal due to enhancement of mass transfer.…”

“…The area, A (unit in μm 2 ), was measured by automatically calculating using the software to enclose the crystal edges in the images, which was then converted into crystal size. The crystal size was estimated by using the circular equivalent diameter, D (unit in μm), …”

“…The induction time decreased with the increase in lysozyme or NaCl concentrations, shown in Figure 2a, whose trend was consistent with the results of microscale experiments. 27 The induction time in the crystallization process is defined as the time between the establishment of the supersaturation and the occurrence of the nucleation, 29 which was often approximated as the observation of the first crystal in the solution. 30 In this work, FBRM was used to detect the onset of crystal count increase as the starting point of the nucleation.…”

Protein crystallisation with gas microbubbles as soft template in a microfluidic device

“…After mixing, the crystallisation solution had 0.55 M NaCl and 25–60 mg mL −1 lysozyme. The period between mixing and injecting into the microfluidic device was under 2 min, which was very short compared to the nucleation time at the equal crystallisation condition, 30 to ensure there was no nucleation before the mixed solution was pumped into the capillary. The liquid flowrate to the microfluidic chip was set at 60 ml h −1 .…”

“…The globular protein like lysozyme was found to hold strong conformational stability and resisted the unfolding at the gas–liquid interface, 29 which can crystallise on the gas–liquid interface. 30 However, the mechanism of crystallisation on the interface between gas–liquid–solid are still not fully understood, the influences of the surface properties of the gas bubbles on protein molecules or the protein crystals require further investigations.…”