2 research outputs found
Protein crystallisation with air bubble templates: Case of gas-liquid-solid interfaces
Heterogeneous surfaces, such as solid particles, are known to efficiently increase
nucleation rates during crystallisations from solution. In this work, air bubbles have
been used to act as heterogeneous surfaces, to facilitate the critical nuclei formation
of large protein molecules. Protein crystallisation experiments were performed using
the hanging-drop method, to investigate the effects of concentrations of lysozyme and
sodium chloride, and air bubbles on the nucleation of crystals. The introduction of an
air bubble template resulted in an overall reduction in the nucleation induction time,
over the majority of test conditions. With air bubbles in the hanging droplets, the
population density of the lysozyme crystals was up to 1.5 times higher than that in the
droplets that contained no bubbles. For the studied experimental conditions, the mass
yield was also found to increase by adding air bubbles into the droplet
Positive and negative effects of graphite flake and monolayer graphene oxide templates on protein crystallization
Heterogeneous template-induced nucleation is a promising way to regulate protein crystallization events and could be employed for purification processes and crystallographic studies. Protein crystallization process with graphite and graphene oxide, as heterogeneous templates, were investigated. More than 640 hanging drops with different concentrations of Lysozyme (30, 50, 70, 100 mg/mL) and NaCl (0.7, 0.9, 1.1, 1.3, 1.5 M) were crystallised at 4 °C with or without graphite/graphene oxide templates. The induction times and crystallization process were observed under the microscope. The lysozyme in the solutions with graphite flakes nucleated faster under all the conditions than the lysozyme with equal experimental conditions without templates. The crystals preferred to grow around the edge of graphite flakes than on the flat surfaces. In the droplets with monolayer graphene oxide, more crystals appeared around graphene oxide particles, and the faster or slower nucleation processes with templates were dependent on the lysozyme and NaCl concentrations. Graphene oxide templates strongly inhibited nucleation at high lysozyme concentrations but promoted nucleation at low lysozyme concentrations. Both heterogeneous templates changed the crystal morphology and the crystallization kinetics. More crystals were observed in the solution with graphite templatesthan with graphene oxide templates and without any template