Elucidating the mechanisms of cryoprotection using Scattering and Diffraction

by Prof. Gary Bryant (RMIT University)

Monday 14 Dec 2020, 10:00 → 11:00 Europe/Berlin

Zoom Webinar

The interaction between membranes and small molecules is a key factor in determining survival of organisms or cells during dehydration and/or freezing. Cryoprotective molecules fall into two categories: those important in desiccation and freezing tolerance in nature (such as sugars), which cannot pass through membranes; and penetrating molecules, such as DMSO, which are used in laboratory cryopreservation. Both types of molecules can affect membrane structure, but the interactions, and therefore cryoprotective mechanisms, are different.

To understand these mechanisms we have previously studied the structure of synthetic membranes in the presence of small sugars using SAXS and SANS [eg 1-2]. More recently we have used membrane diffraction, which yields higher order diffraction peaks, allowing Fourier reconstruction of the bilayer structure [3-4]. These experiments are conducted on stacked multilamellar membranes (with and without the relevant molecules) under partially dehydrated conditions (relevant to desiccation and freezing). By deuterating one or more components, and adjusting the neutron contrast of the water by changing the D2O/H2O ratio, it is possible to isolate the locations of the molecules in the bilayer region with high precision.

In this talk I will provide an overview of the scientific problem, and look at how scattering techniques have been used to shed light on the mechanisms of action of molecules involved in cryoprotection.

 

[1] C.J. Garvey, T. Lenné, K.L. Koster, B. Kent, G. Bryant Int. J. Molecular Sciences 14, 8148 (2013).

[2] B. Kent, C.J. Garvey, T. Lenné, L. Porcar, V.M. Garamus, G. Bryant Soft Matter 6, 1197 (2010).

[3] B. Kent, T. Hunt, T.A. Darwish, T. Hauß, C.J. Garvey, G. Bryant J. Royal Soc. Interf. 11, 20140069 (2014).

[4] B. Kent, T. Hauß, B. Demé, V. Cristiglio, T. Darwish, T. Hunt, G. Bryant, C.J. Garvey Langmuir 31, 9134 (2015).