A rationale for system-dependent advantages and disadvantages of solution crystal growth at low gravity

Rosenberger, Franz; Vekilov, Peter G.; Lin, Hong; Alexander, J. Iwan D.

doi:10.2514/6.1997-679

Cited by 5 publications

(6 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More rapid convective transport to the interface leads to a reduction of the kinetics fluctuations (step bunching). This observation corroborates our previous conclusion that the fluctuations and step bunching represent an intrinsic response of the system of coupled transport and interfacial processes to perturbations in step density. , Since kinetic unsteadiness causes inhomogeneities in the crystal, these studies also support the rationale for system-dependent effects of the changes in transport conditions on the quality of solution-grown crystals. , …”

Section: Discussionsupporting

confidence: 89%

See 1 more Smart Citation

Effects of Convective Solute and Impurity Transport in Protein Crystal Growth

1998

Self Cite

View full text Add to dashboard Cite

High-resolution optical interferometry was used to investigate the effects of forced solution convection on the crystal growth kinetics of the model protein lysozyme. Most experiments were conducted with 99.99% pure protein solutions. To study impurity effects, ∼1% of lysozyme dimer (covalently bound) was added in some cases. We show that the unsteady kinetics, corresponding to bunching of growth steps, can be characterized by the Fourier components of time traces of the growth rate. Specific Fourier spectra are uniquely determined by the solution conditions (composition, temperature, and flow rate) and the growth layer source activity. We found that the average step velocity and growth rate increase by ∼10% with increasing flow rate, as a result of the enhanced solute supply to the interface. More importantly, faster convective transport results in lower fluctuation amplitudes. This observation supports our rationale for system-dependent effects of transport on the structural perfection of protein crystals. We also found that solution flow rates >500 μm/s result in stronger fluctuations while the average growth rate is decreased. This can lead to growth cessation at low supersaturations. With the intentionally contaminated solutions, these undesirable phenomena occurred at about half the flow rates required in pure solutions. Thus, we conclude that they are due to enhanced convective supply of impurities that are incorporated into the crystal during growth. Furthermore, we found that the impurity effects are reduced at higher crystal growth rates. Since the exposure time of terraces is inversely proportional to the growth rate, this observation suggests that the increased kinetics instability results from impurity adsorption on the interface. Finally, we provide evidence relating earlier observations of “slow protein crystal growth kinetics” to step bunch formation in response to nonsteady step generation.

show abstract

Section: Discussionsupporting

confidence: 89%

“…17,20 Since kinetic unsteadiness causes inhomogeneities in the crystal, these studies also support the rationale for system-dependent effects of the changes in transport conditions on the quality of solution-grown crystals. 17,48 3. Solution flow also enhances the interfacial supply of impurities that are incorporated into the crystal.…”

Section: Discussionmentioning

confidence: 99%

Effects of Convective Solute and Impurity Transport in Protein Crystal Growth

1998

Self Cite

View full text Add to dashboard Cite

show abstract

“…By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in space experiments, we have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. Past protein crystallization experiments conducted in a reduced gravity environment have provided inconclusive results [11][12][13]. While 20% of the grown crystals have shown higher quality (fewer defects), others have yielded inconclusive or even negative results.…”

Section: Protein Crystal Growth In High Magnetic Fieldsmentioning

confidence: 99%

Using magnetic fields to control convection during protein crystallization—analysis and validation studies

Ramachandran

Leslie

2005

Journal of Crystal Growth

View full text Add to dashboard Cite

“…In an effort to realize ideal, undisturbed (diffusion limited) growth conditions, investigators have sought to conduct crystal growth experiments in the weightless environment of space [1][2][3]. However, to date, only about 20% of the protein crystal growth experiments conducted in space have shown improved quality (fewer defects) [4]. Terrestrial techniques used to damp convective motion in melts and solutions include steady and dynamic magnetic fields [5][6][7], crystal growth in capillary tubes, and in gels [8].…”

Section: Introductionmentioning

confidence: 99%