Problems of Cryobiology and Cryomedicine

On the 30th anniversary of the Ukrainian Antarctic station “Akademik Vernadsky”

Oleksandr Yu. Petrenko — Sun, 24 May 2026 00:00:00 +0200

Probl Cryobiol Cryomed. 2026; 36(1): 3-4

Microalgae cryopreservation techniques: choosing cryoprotectants and cooling regimens

Nadiia A. Chernobai, Anton P. Gerilovych, Nadiia O. Shevchenko — Sun, 24 May 2026 00:00:00 +0200

This review was aimed to summarize and array current methods to cryopreserve microalgae, particularly, the approaches to selecting cryoprotectants and optimal cooling parameters, aimed at preserving their viability and functional activity after thawing. The paper analyses the key aspects of cryopreservation of microalgae, including the efficiency comparison of different classes of cryoprotectants as well as their impact on cells; mechanisms of cryodamage and strategies for minimizing it; optimal cooling and warming regimens for various types of microalgae. Special attention has been paid to the dependency of cryopreservation efficiency on the concentration and composition of cryoprotective solutions, which vary depending on the specific species and cultures. Some microalgae has been noted to maintain high viability using elevated concentrations of non-penetrating cryoprotectants. The necessity for further research using new and combined cryoprotective solutions has been emphasized to expand the possibilities of long-term storage of microalgae.

Probl Cryobiol Cryomed. 2026; 36(1): 5—15

Temperature effect on the interaction of polyethylene glycol with membranes and orientation order of cytoskeleton proteins in human erythrocytes

Nina G. Zemlianskykh, Lyubov O. Babijchuk — Sun, 24 May 2026 00:00:00 +0200

The study identified discrepancies in the modification of erythrocyte membrane upon exposure to polyethylene glycol with a molecular weight of 1500 (PEG) at various temperatures (4 and 37 °C) using the fluorescent probe 4-(n-dimethylaminostyryl)-1-methylpyridinium-n-toluenesulfonate (DSM), as well as alterations in the orientation order of proteins in the membrane-cytoskeleton complex using polarization microscopy. Exposure of erythrocytes to PEG at 37 °C caused complete disappearance of the hydrophobic component from the DSM fluorescent spectrum due to competition between PEG and DSM molecules for binding sites. Lowering the exposure temperature of cells to a cryoprotective agent (CPA) to 4 °C reduced the possibility of its hydrophobic contacts with cell membranes attested by the presence of the hydrophobic component in the DSM spectrum, although at a lower level than in the control. The decrease in hydrophobic contacts of PEG to membranes upon a lowering temperature at the stage of erythrocyte exposure to CPA provided retaining to a large extent the orientation order of the membrane cytoskeleton molecules both under the incubation process with CPA and after freeze–thawing of cells.

Probl Cryobiol Cryomed. 2026; 36(1): 16—26.

Cryopreservation of L929 cell culture in protective solutions containing hyaluronic acid

Sun, 24 May 2026 00:00:00 +0200

Recently, cryobiological studies have focused on the prospects of using hyaluronic acid (HA) as a component of protective media during cryopreservation of various cell types. HA is a polysaccharide of natural origin and an integral component of the extracellular matrix, which determines its high biocompatibility and potential protective properties for cells under stressful conditions, in particular during freezing. The paper presents the results of cryopreservation of L929 cells using protective solutions containing 0.5% HA of various molecular weights as well as 5% of the classical endocellular cryoprotectant DMSO. Experimental protocols for the freezing of cells differed in the cryoprotective solution composition, the method of adding its components to cells, and the duration of cell exposure. The effectiveness of the cryopreservation protocols used was assessed by the viability of L929 cells and their adhesive properties. The results obtained showed that HA, regardless of its molecular weight, did not affect the penetration of DMSO through the membranes of L929 cells. The use of a cryoprotective solution containing only low-molecular-weight HA ensured cell survival at (72 ± 4.2) %, which did not differ from the values for the standard protocol. For high-molecular-weight HA, this index decreased to (42 ± 4.8) %. Regardless of the cryopreservation protocol, L929 cells retained the ability to attach to an adhesive surface. However, further growth and proliferation of cells largely depended on the composition of the cryoprotective solution and the conditions of administration of its components. Thus, it was shown that both low-molecular-weight HA and high-molecular-weight HA exhibited pronounced cryoprotective properties and can be used either as components of protective media in combination with DMSO, or as an independent impermeable cryoprotectant.

Probl Cryobiol Cryomed. 2026; 36(1): 27—31

Long-term storage of seeds from plant gene pool samples in the National Depository

Sun, 24 May 2026 00:00:00 +0200

Here, we have explored the viability of plant gene pool samples deposited for long-term storage at the National Depository for Plant Genetic Resources, where 50,743 seed samples from 741 species of 308 crops, originating from 123 countries, are stored at temperatures ranging from –18... –20 °C in sealed foil bags. The intake of samples for long-term storage over the past 24 years has been analyzed by crop group and origin. The dynamics of seed germination rates for various crops was assessed over a 20-year storage period. Among 13 crop groups, namely cereals (28.97%), corn (17.23%), grains (8.87%), legumes (15.53%), oilseeds (5.74%), industrial crops (7.37%), medicinal and essential oil crops (2.00%), forage crops (6.40%), vegetable and melon crops (7.36%), potatoes (0.01%), ornamental flower and herb crops (0.01%), fruit (0.01%), forest and woody ornamental (0.50%) crops, there have been identified the most cold-tolerant species capable of maintaining high germination rates (90–98%) for 15–20 years, as well as the samples with low seed longevity. The research findings are important for extending seed viability during long-term storage in gene banks and for further use in breeding programs.

Probl Cryobiol Cryomed. 2026;36(1):32—39

Clinical and morphological aspects of low-temperature storage of malignant tumors (pilot study)

Igor Y. Galaychuk, Volodymyr D. Nikoliuk, Volodymyr V. Bigunyak, Yurii M. Orel — Sun, 24 May 2026 00:00:00 +0200

The article discusses the possibility of long-term low-temperature postoperative storage of malignant tumors for the purpose of manufacturing an individual anticancer vaccine. Morphological analysis of 23 fragments of malignant tumors (skin melanoma, colon cancer, breast cancer, soft tissue fibrosarcoma) was carried out at different temperature regimens (–20, –196 °C) and storage periods: 2-4 months, 10–12, 22–24 and 36 months. The percentage of preserved cells in the malignant tumors was determined in ten randomly selected fields of view on histological slides according to the method of G. Avtandilov. In skin melanoma samples stored at –20 °C, histologically intact tissues were (78.5 ± 4.1)%, and after storage in liquid nitrogen — (72.0 ± 5.1)%. The histological structure of colon cancer fragments under storage conditions at –20 °C was intact at (71.8 ± 5.3)%, and when stored in liquid nitrogen, regardless of the duration of cryopreservation, total necrosis was observed in two fragments, and in two more fragments the preserved tumor parenchyma was 63.3 and 90.8%, respectively. In breast cancer fragments stored at –20 °C, morphologically intact tissues constituted (73.1 ± 5.1)%. Soft tissue fibrosarcoma fragments during long-term storage at –20 °C consisted of (82.0 ± 3.6)% morphologically unchanged structures. Based on the results of this study and relevant scientific publications, the theoretical aspects of the production of personalized anticancer DC vaccines or mRNA vaccines, the antigenic substrate for which can be samples of malignant tumors stored at low (–20 °C) and ultra-low (–196 °C) temperatures, have been substantiated.

Probl Cryobiol Cryomed. 2026;36(1):40—49

Lyophilised human cord blood leukoconcentrate triggers formation of dendritic cells with a tolerogenic phenotype

Sun, 24 May 2026 00:00:00 +0200

In this research we investigated the lyophilized human cord blood leukoconcentrate (lHCBL) as an inducer of the in vitro formation of dendritic cells (DCs) with a tolerogenic phenotype, obtained from native mononuclear cells (MNCs) of the animals’ bone marrow. The phenotypic affiliation of DCs to tolerogenic was assessed by the expression of markers characteristic of them: CD11b, CD80, CD86, CD14, and CD83. To form the tolerogenic phenotype of DCs, lHCBL was additionally added to the RPMI-1640 culture medium containing mouse recombinant GM-CSF, IL-4 and dexamethasone in different doses (1x 10³, 1x 10⁴ and 1x 10⁵ cells/ml). A dose-dependent effect of lHCBL on the in vitro formation of DCs with phenotypic features of tolerogenic cells from bone marrow MNCs was established. The conditions for obtaining DCs in vitro under the influence of LHCBL with the maximum tolerogenic effect were determined, that was manifested by a significant decrease in the expression level of co-stimulatory molecules CD80 and CD86 (by 1.6 times), an increase in CD11b (by 1.2 times) and the content of CD11b⁺-DCs (by 25%) compared to the control values, that confirms the tolerogenic phenotype of the obtained cells. This fact indicates a limitation of the ability of DCs formed in culture to implement cooperative interactions and activation of T-effector cells.

Probl Cryobiol Cryomed. 2026; 36(1): 51—57

Preservation of protein fractions and hormones of placental blood serum after freeze-drying

Sun, 24 May 2026 00:00:00 +0200

The preservation of placental blood serum (PBS) following freeze-drying was studied, factoring in the course of pregnancy in parturient women. Placental blood was obtained from women with a physiological pregnancy, premature births, and concomitant autoimmune thyroiditis or hypertension. Serum was obtained by separating the supernatant after centrifugation of placental blood. After freeze-drying, the concentration of total protein and the ratio of protein fractions in the PBS were determined by the biuret method, and the levels of prolactin, human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP), cortisol and somatotropin (STH) were measured by the enzyme-linked immunosorbent assay. It was found that the composition of the PBS depended on the course of pregnancy. Extragenital pathology is accompanied by a redistribution of protein fractions and changes in prolactin, AFP, STH and hCG levels. After freeze-drying the PBS from healthy parturients, the studied parameters did not differ from those in native serum, whereas in cases of complicated pregnancy, changes in the ratio of protein fractions were observed.

Probl Cryobiol Cryomed. 2026;36(1):58—65

Activity of hypothalamus-pituitary-thyroid axis in rats of different ages after long-term cold exposure

Viktoria V. Lomako, Oleksandr V. Shylo, Dmytro G. Lutsenko, Svitlana V. Lomako — Sun, 24 May 2026 00:00:00 +0200

Probl Cryobiol Cryomed. 2026;36(1):66—68

Activity and release of enzymes embedded in polyvinyl alcohol-based cryohydrogels under –20 °C storage conditions

Sun, 24 May 2026 00:00:00 +0200

Probl Cryobiol Cryomed. 2026; 36(1): 69—72

In memoriam of Tetyana M. Yurchenko

Editorial Board Problems of Cryobiology and Cryomedicine — Sun, 24 May 2026 00:00:00 +0200

Probl Cryobiol Cryomed. 2026; 36(1): 73-74

Instruction for Authors

Editorial Board Problems of Cryobiology and Cryomedicine — Sun, 24 May 2026 00:00:00 +0200

Probl Cryobiol Cryomed. 2026; 36(1): 75-76