Thermoplastic Analysis of Cluster Crystallization of Cryoprotective Solutions

For the first time the possibility of using thermomechanical analysis to construct the fragments of state diagrams of cryoprotective solutions in the zone of glass transition temperatures has been considered. A method for studying cluster crystallization of cryoprotective solutions based on thermomechanical curves has been developed. The parameters of thermomechanical curves of frozen aqueous solutions of dimethyl sulfoxide (DMSO), polyethylene oxide 1500 (PEO-1500), glycerol were analyzed and the relationship between these parameters and the cluster crystallization kinetics for these solutions was established. On the basis of experimentally obtained thermomechanical curves for the frozen solutions of DMSO and PEO-1500 the possibility of formation of clusters of two types has been shown: on the basis of ice and cryoprotective substance microcrystals. Additional experimental data were obtained to construct a complete state diagrams of cryoprotective solutions, which include the existing cluster phase areas.

3D sub-nanometer analysis of glucose in an aqueous solution by cryo-atom probe tomography

Atom Probe Tomography (APT) is currently a well-established technique to analyse the composition of solid materials including metals, semiconductors and ceramics with up to near-atomic resolution. Using an aqueous glucose solution, we now extended the technique to frozen solutions. While the mass signals of the common glucose fragments CxHy and CxOyHz overlap with (H2O)nH from water, we achieved stoichiometrically correct values via signal deconvolution. Density functional theory (DFT) calculations were performed to investigate the stability of the detected pyranose fragments. This paper demonstrates APT’s capabilities to achieve sub-nanometre resolution in tracing whole glucose molecules in a frozen solution by using cryogenic workflows. We use a solution of defined concentration to investigate the chemical resolution capabilities as a step toward the measurement of biological molecules. Due to the evaporation of nearly intact glucose molecules, their position within the measured 3D volume of the solution can be determined with sub-nanometre resolution. Our analyses take analytical techniques to a new level, since chemical characterization methods for cryogenically-frozen solutions or biological materials are limited.

3D Sub-Nanometer Analysis of Glucose in an Aqueous Solution by Cryo-Atom Probe Tomography

Atom Probe Tomography (APT) is currently a well-established technique to analyse the composition of solid materials including metals, semiconductors and ceramics with up to near-atomic resolution. Using an aqueous glucose solution, we now extended the technique to frozen solutions. While the mass signals of the common glucose fragments CxHy and CxOyHz overlap with (H2O)nH from water, we achieved stoichiometrically correct values via signal deconvolution. Density functional theory (DFT) calculations were performed to investigate the stability of the detected pyranose fragments. This paper demonstrates APT’s capabilities to achieve sub-nanometre resolution in tracing whole glucose molecules in a frozen solution by using cryogenic workflows. We use a solution of defined concentration to investigate the chemical and spatial resolution capabilities as a step toward the measurement of biological molecules in solution in 3D with sub-nanometre resolution by using cryo-APT. Our analyses take analytical techniques to a new level, since chemical characterization methods for cryogenically-frozen solutions or biological materials are limited.

In-Situ X-ray Imaging Of Sublimating Spin-Frozen Solutions

Spin-freeze-drying is a promising technique to enable long-term storage of pharmaceutical unit doses of aqueous drug solutions. To investigate the sublimation of the ice during the primary phase of freeze-drying, X-ray imaging can yield crucial temporally resolved information on the local dynamics. In this paper, we describe a methodology to investigate the sublimation front during single unit-dose freeze-drying using 4D in-situ X-ray imaging. Three spin-frozen samples of different solutions were imaged using this methodology and the process characteristics were analysed and reduced to two-dimensional feature maps.

Long-term room temperature storage of DNA molecules

The simplest and most common method of long-term storage of DNA samples at present is the storage of their frozen solutions, which, however, has a number of disadvantages, including the destruction of DNA molecules during freezing and thawing, as well as energy consumption and the likelihood of losing valuable samples in the event of possible accidents. In this regard, long-term storage of DNA samples at room temperature in a dried state is preferable, especially since an even greater increase in the number of stored DNA samples is planned due to the planned preservation of non-biological data in this molecule, which is recognized at the International Economic Forum 2019 among the 10 most important innovative technologies as “DNA Data Storage” of the near future of mankind. Such storage requires the exclusion of hydrolysis and oxidation of DNA molecules under the action of water and reactive oxygen species, which can be achieved by placing DNA in an inert anhydrous atmosphere, including in the presence of additional ingredients in the form of, for example, trehalose, imitating wildlife, since it is known that this simple disaccharide, capable of vitrification, protects a wide range of anhydrobiont organisms from adverse environmental conditions. Currently, there are a number of technologies that provide long-term storage of DNA at room temperature, including those available from commercial sources, but not all problems have yet been solved, which is reflected in this review article.

Photodecay of guaiacol is faster in ice, and even more rapid on ice, than in aqueous solution

Guaiacol photodegradation rate constants in solution, liquid-like regions in ice (frozen solutions), and at the air–ice interface (vapor-deposited to snow).

Transformations of ferrates(iv,v,vi) in liquids: Mössbauer spectroscopy of frozen solutions

Two-step charge disproportionation mechanism of 3Fe(iv) to 2Fe(iii) and Fe(vi) via Fe(v) in ethanol.