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• Modulation of crystal nucleation: Insights from molecular simulation

Web page

http://www.ipi.ac.uk/about/staff/individual/83

Categories

AMBER, Artificial Neural Networks, Bioinformatics, Biomathematics, Biomedical, Biomolecular Organisation, Biomolecular simulations, CASTEP, Complex Systems, Computer Science, Density functional Theory, Developmental Biology, e-Research, Evolutionary Algorithms, FFT, HECToR, HPC, Molecular Dynamics, Molecular Mechanics, Monte Carlo, MPI, Multi-physics, Multi-scale, Multigrid solvers, Scientific Computing, Software Engineering, Systems biology

Submitter

Chris-Kriton Skylaris

Complex Systems Simulation Seminar Series (CS^4)

from the Institute for Complex Systems Simulation, the Complexity in Real-World Contexts USRG, and the Computational Modelling Group.

Speaker

Professor Jamshed Anwar

http://www.ipi.ac.uk/about/staff/individual/83

Abstract

There is considerable interest, both fundamental and technological, in understanding how additives and impurities influence nucleation, and in being able to modulate nucleation in a predictable way using designer auxiliary molecules. Notable applications involving auxiliaries include the control of nucleation in proteins, inhibition of urinary stone formation, inhibition of ice formation in living tissues during cryoprotection, prevention of blockages in oil and gas pipelines due to wax precipitation, and gas hydrate formation. Despite the immense interest, our understanding of how these molecules exert their effect is still rudimentary, partially because the molecular level processes involved are inaccessible to experiment.

I shall review the challenges that nucleation presents to molecular simulation and outline current simulation approaches. I shall then present results of our investigations into the mechanisms of action of nucleation additives using simple models. The simulations yield explicit rules for designing additive molecules for modulating crystal nucleation. The studies reveal that an effective nucleation inhibitor should have a strong interaction with the solute and have a structure that is able to disrupt the periodicity characterizing the emerging nucleus. Disruption can be achieved by steric effects resulting from structural differences between the additive and solute molecules, the additive possessing extensive degrees of freedom, or via a strong energetic interaction with the solute. Additive molecules that have an amphi-philic character end up at the solute/solvent interface and can inhibit, retard, or promote nucleation depending on their specific structure and interactions with the solute and solvent. These findings should help to rationalize the mechanisms of action of known nucleation inhibitors and modulators. They will also serve as a framework for rationally identifying or designing additive molecules for either inhibiting or promoting nucleation in specific systems.

Recently, we have extended the above studies to the mechanism of action of anti-freeze proteins. I shall outline our progress focusing particularly on our approach to developing highly simplified models of both water and a particular AFP.

Refreshments

Available from 3:30pm, lecture starts at 4pm.

Complex Systems Simulation Seminar Series

For the complete CS^4 schedule please click here: http://www.multidisciplinary.soton.ac.uk/cs4.html