Effects of cryoprotectant concentration and cooling rate on vitrification of aqueous solutions
| Autor: | Osama A. Alsaied, Robert E. Thorne, Viatcheslav Berejnov, Naji S. Husseini |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
Chemical Physics (physics.chem-ph)
0303 health sciences Aqueous solution Cryoprotectant Analytical chemistry FOS: Physical sciences Liquid nitrogen 010402 general chemistry 01 natural sciences General Biochemistry Genetics and Molecular Biology 0104 chemical sciences 3. Good health 03 medical and health sciences chemistry.chemical_compound chemistry Biological Physics (physics.bio-ph) Physics - Chemical Physics PEG ratio Cryoprotective Agent Glycerol Vitrification Physics - Biological Physics Ethylene glycol 030304 developmental biology |
| Popis: | Vitrification of aqueous cryoprotectant mixtures is essential in cryopreservation of proteins and other biological samples. We report systematic measurements of critical cryoprotective agent (CPA) concentrations required for vitrification during plunge cooling from T=295 K to T=77 K in liquid nitrogen. Measurements on fourteen common CPAs including alcohols (glycerol, methanol, isopropanol), sugars (sucrose, xylitol, dextrose, trehalose), PEGs (ethylene glycol, PEG 200, PEG 2 000, PEG 20 000), glycols (DMSO, MPD), and salt (NaCl) were performed for volumes ranging over four orders of magnitude from ~nL to 20 mkL, and covering the range of interest in protein crystallography. X-ray diffraction measurements on aqueous glycerol mixtures confirm that the polycrystalline-to-vitreous transition occurs within a span of less than 2% w/v in CPA concentration, and that the form of polycrystalline ice (hexagonal or cubic) depends on CPA concentration and cooling rate. For most of the studied cryoprotectants, the critical concentration decreases strongly with volume in the range from ~5 mkL to ~0.1 mkL, typically by a factor of two. By combining measurements of the critical concentration versus volume with cooling time versus volume, we obtain the function of greatest intrinsic physical interest: the critical CPA concentration versus cooling rate during flash cooling. These results provide a basis for more rational design of cryoprotective protocols, and should yield insight into the physics of glass formation in aqueous mixtures. 8 pages, 6 jpg figure, 2 tables |
| Databáze: | OpenAIRE |
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