Nardid O. Intra- and intermolecular forces and their role in cryodamage and cryoprotection of biological structures

Objects were isolated and bound biomacromolecules, natural mixtures of proteins, natural and artificial membranes, cells and subcellular structures, solutions of low and highly molecular cryoprotective substances. The aim was to determine the regularities of the effect of low temperatures and cryoprotectants on intramolecular and intermolecular relationships of proteins, protein-lipid complexes, artificial and natural membranes and examine the role of these interactions in the resistance of biostructures under conditions of low temperature preservation. The methods were EPR, spectrophotometry, ultra high frequencies dielectrometry, IR spectroscopy, gel-chromatography, differential scanning calorimetry, standard statistical methods. It has been established that gradual (1-7 grad/min) freezing of proteins (GOD, COX, BSA) and natural protein mixtures (CBS, FL, HPE) led to the impairment of intramolecular interactions in biomacromolecules with loosening the surface polypeptide chains and further aggregation of biomacromolecules. There has been found the impairment of protein-lipid interactions in membranes in presence of non-penetrating cryoprotectants, which during following freezing of cells results in the disorders in membrane permeability. Its has been shown that a rapid freezing of mitochondria down to -196 C leads to the change in membrane originality, and the repeated one causes the alterations in structural organization of membranes. It has been proved that membrane of hepatocytes interferes the interaction of cryoprotectants' molecules with respiratory chain of mitochondria, but with rising the concentration the protective function of membrane reduces. There was created the technology of long-term preservation of electrochemical biosensors based on glucose oxidase.