Emmanuel, Alaina E. O. (2015) Molecular simulation of ice growth inhibition by biomimetic antifreeze macromolecules. PhD thesis, University of Warwick.

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Abstract

Many polar fishes, insects and plants have evolved to produce biological antifreezes known as antifreeze proteins and glycoproteins (AF(G)Ps). These proteins reduce the size of ice crystals, thereby mitigating the structural damage that ice crystals cause to their cells.

Recent experimental work has shown that synthetic polymers, namely poly(vinyl alcohol) (PVA) and poly(hydroxyproline) (PHYP) can also reproduce some of the properties of native AF(G)Ps. This has enormous potential for use in cryobiological storage, such as the cryopreservation of organs in medicine and food preservation, because synthetic polymers are highly tunable and scalable. As a results, they can be tailored to create ideal antifreeze polymer, with high availability. Unfortunately the mechanism by which AFGPs and their synthetic mimics function remains a mystery. The ability to understand how these proteins and their synthetics mimic work will aid the rational design of an ideal synthetic antifreeze polymer. In this thesis, we use a computational technique known as molecular dynamics simulation to investigate the molecular mechanism of action for antifreeze active (PVA and HYP) and inactive polymers (poly(ethylene glycol)) at the ice/water interface.

The main results from this study are that the all the polymers decrease the growth velocity of ice. They achieve this by disrupting the rate of water addition to the ice crystals and can arrest ice growth through temporary immobilization onto the ice lattice. The emerging di↵erence between IRI active and inactive polymers lies in the polymers’ abilities to pause the crystallization process during their immobilization. Overall, the results from this study lead us to conclude that PVA and PHYP function in very di↵erent ways and that neither of the antifreeze active polymers function via a pre-ordering mechanism because none of the polymers increase the orientational order of water vicinal molecules.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Antifreeze proteins, Ice crystals -- Growth
Official Date:	December 2015
Dates:	Date Event December 2015 Submitted
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Notman, Rebecca ; Gibson, Matthew I.
Extent:	xxiv, 236 pages : illustrations (colour), charts
Language:	eng

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