Inhibition of ice recrystallization and cryoprotective activity of wheat proteins in liver and pancreatic cells

Quality improvement of frozen cooked noodles by protein addition

This study investigated the impact of protein enrichment on the physicochemical, cooking, textural, and color properties of frozen cooked noodles (FCN) stored for 0-3 weeks at -18 °C. Incorporating casein, egg white protein, and soy protein into the noodles significantly increased moisture content, with casein-enriched noodles showing the highest initial moisture levels. The addition of proteins also led to increased ash content, indicating improved nutritional quality. Protein enrichment resulted in reduced cooking loss and enhanced water retention during cooking and frozen storage. Casein-enriched noodles exhibited the highest water absorption capacity and the most substantial enhancement in textural properties, maintaining cohesiveness, gumminess, and elasticity better than egg white protein and soy protein during storage. The results indicated that egg white protein promotes intermolecular interactions, leading to enhanced color stability over time. These findings suggest that enriching with the protein could be a viable approach to elevate the overall quality of FCN.

Cryopreservation of organoids: Strategies, innovation, and future prospects

Organoid technology has demonstrated unique advantages in multidisciplinary fields such as disease research, tumor drug sensitivity, clinical immunity, drug toxicology, and regenerative medicine. It will become the most promising research tool in translational research. However, the long preparation time of organoids and the lack of high-quality cryopreservation methods limit the further application of organoids. Although the high-quality cryopreservation of small-volume biological samples such as cells and embryos has been successfully achieved, the existing cryopreservation methods for organoids still face many bottlenecks. In recent years, with the development of materials science, cryobiology, and interdisciplinary research, many new materials and methods have been applied to cryopreservation. Several new cryopreservation methods have emerged, such as cryoprotectants (CPAs) of natural origin, ice-controlled biomaterials, and rapid rewarming methods. The introduction of these technologies has expanded the research scope of cryopreservation of organoids, provided new approaches and methods for cryopreservation of organoids, and is expected to break through the current technical bottleneck of cryopreservation of organoids. This paper reviews the progress of cryopreservation of organoids in recent years from three aspects: damage factors of cryopreservation of organoids, new protective agents and loading methods, and new technologies of cryopreservation and rewarming.

Self-Assembled Nanostructures of Homo-Oligopeptide as a Potent Ice Growth Inhibitor

This study reports the formation of self-assembled nanostructures with homo-oligopeptides consisting of amino acids (i.e., alanine, threonine, valine, and tyrosine), the resulting morphologies (i.e., spherical shape, layered structure, and wire structure) in aqueous solution, and their potential as ice growth inhibitors. Among the homo-oligopeptides investigated, an alanine homo-oligopeptide (n = 5) with a spherical nanostructure showed the highest ice recrystallization inhibition (IRI) activity without showing a burst ice growth property and with low ice nucleation activity. The presence of nanoscale self-assembled structures in the solution showed superior IRI activity compared to an amino acid monomer because of the higher binding affinity of structures on the growing ice crystal plane. Simulation results revealed that the presence of nanostructures induced a significant inhibition of ice growth and increased lifetime of hydrogen bonding compared with unassembled homo-oligopeptide. These results envision extraordinary performance for self-assembled nanostructures as a desirable and potent ice growth inhibitor.

Advanced biomaterials in cell preservation: Hypothermic preservation and cryopreservation

Cell-based medicine has made great advances in clinical diagnosis and therapy for various refractory diseases, inducing a growing demand for cell preservation as support technology. However, the bottleneck problems in cell preservation include low efficiency and poor biocompatibility of traditional protectants. In this review, cell preservation technologies are categorized according to storage conditions: hypothermic preservation at 1 °C~35 °C to maintain short-term cell viability that is useful in cell diagnosis and transport, while cryopreservation at -196 °C~-80 °C to maintain long-term cell viability that provides opportunities for therapeutic cell product storage. Firstly, the background and developmental history of the protectants used in the two preservation technologies are briefly introduced. Secondly, the progress in different cellular protection mechanisms for advanced biomaterials are discussed in two preservation technologies. In hypothermic preservation, the hypothermia-induced and extracellular matrix-loss injuries to cells are comprehensively summarized, as well as the recent biomaterials dependent on regulation of cellular ATP level, stabilization of cellular membrane, balance of antioxidant defense system, and supply of mimetic ECM to prolong cell longevity are provided. In cryopreservation, cellular injuries and advanced biomaterials that can protect cells from osmotic or ice injury, and alleviate oxidative stress to allow cell survival are concluded. Last, an insight into the perspectives and challenges of this technology is provided. We envision advanced biocompatible materials for highly efficient cell preservation as critical in future developments and trends to support cell-based medicine. STATEMENT OF SIGNIFICANCE: Cell preservation technologies present a critical role in cell-based applications, and more efficient biocompatible protectants are highly required. This review categorizes cell preservation technologies into hypothermic preservation and cryopreservation according to their storage conditions, and comprehensively reviews the recently advanced biomaterials related. The background, development, and cellular protective mechanisms of these two preservation technologies are respectively introduced and summarized. Moreover, the differences, connections, individual demands of these two technologies are also provided and discussed.

NANOPARTICLE-MEDIATED DELIVERY OF CRYOPROTECTANTS FOR CRYOPRESERVATION

Nanotechnology research has continued to garner interest and is investigated across a number of fields and industries, ranging from water treatment to clinical and biomedical applications. In biomedical research, for example, polymeric nanoparticles can be leveraged for controlled delivery of drugs and chemical compounds into cells. In cryobiological applications, polymeric nanoparticles can be utilized to deliver cryoprotectants (CPAs) and other protective agents, particularly those impermeable to the cell membrane, into cells to study their effects on cells during cooling down and warming back and at low temperatures. This perspective will discuss how polymeric nanoparticles have been used in cryobiology, with particular focus on how delivery systems have been specifically developed for low temperature applications and the potential for these systems going forward.

The properties, biotechnologies, and applications of antifreeze proteins

By natural selection, organisms evolve different solutions to cope with extremely cold weather. The emergence of an antifreeze protein gene is one of the most momentous solutions. Antifreeze proteins possess an importantly functional ability for organisms to survive in cold environments and are widely found in various cold-tolerant species. In this review, we summarize the origin of antifreeze proteins, describe the diversity of their species-specific properties and functions, and highlight the related biotechnology on the basis of both laboratory tests and bioinformatics analysis. The most recent advances in the applications of antifreeze proteins are also discussed. We expect that this systematic review will contribute to the comprehensive knowledge of antifreeze proteins to readers.

Presence of a basic secretory protein in xylem sap and shoots of poplar in winter and its physicochemical activities against winter environmental conditions

XSP25, previously shown to be the most abundant hydrophilic protein in xylem sap of Populus nigra in winter, belongs to a secretory protein family in which the arrangement of basic and acidic amino acids is conserved between dicotyledonous and monocotyledonous species. Its gene expression was observed at the same level in roots and shoots under long-day conditions, but highly induced under short-day conditions and at low temperatures in roots, especially in endodermis and xylem parenchyma in the root hair region of Populus trichocarpa, and its protein level was high in dormant buds, but not in roots or branches. Addition of recombinant PtXSP25 protein mitigated the denaturation of lactate dehydrogenase by drying, but showed only a slight effect on that caused by freeze-thaw cycling. Recombinant PtXSP25 protein also showed ice recrystallization inhibition activity to reduce the size of ice crystals, but had no antifreezing activity. We suggest that PtXSP25 protein produced in shoots and/or in roots under short-day conditions and at non-freezing low temperatures followed by translocation via xylem sap to shoot apoplast may protect the integrity of the plasma membrane and cell wall functions from freezing and drying damage in winter environmental conditions.

Y2SK2 and SK3 type dehydrins from Agapanthus praecox can improve plant stress tolerance and act as multifunctional protectants

Two dehydrins from Agapanthus praecox (ApY₂SK₂ and ApSK₃) show important protective effects under complex stresses. Both ApY₂SK₂ and ApSK₃ contain one intron and consist of a full-length cDNA of 981 bp and 1057 bp encoding 186 and 215 amino acids, respectively. ApY₂SK₂ and ApSK₃ transgenic Arabidopsis thaliana show reduced plasma membrane damage and ROS levels and higher antioxidant activity and photosynthesis capability under salt, osmotic, cold and drought stresses compared with the wild-type. ApY₂SK₂ and ApSK₃ are mainly located in the cytoplasm and cell membrane, and ApY₂SK₂ can even localize in the nucleus. In vitro tests indicate that ApY₂SK₂ and ApSK₃ can effectively protect enzyme activity during the freeze-thaw process, and ApY₂SK₂ also exhibits this function during desiccation treatment. Furthermore, ApY₂SK₂ and ApSK₃ can significantly inhibit hydroxyl radical generation. These two dehydrins can bind metal ions with a binding affinity of Co²⁺> Ni²⁺> Cu²⁺> Fe³⁺; the binding affinity of ApSK₃ is higher than that of ApY₂SK₂. Thus, ApY₂SK₂ has a better protective effect on enzyme activity, and ApSK₃ has stronger metal ion binding function and effect on ROS metabolism. Moreover, plant cryopreservation evaluation tests indicate that ApY₂SK₂ and ApSK₃ transformation can enhance the seedling survival ratio from 23% to 47% and 55%, respectively; the addition of recombinant ApY₂SK₂ and ApSK₃ to plant vitrification solution may increase the survival ratio of wild-type A. thaliana seedlings from 24% to 50% and 46%, respectively. These findings suggest that ApY₂SK₂ and ApSK₃ can effectively improve cell stress tolerance and have great potential for in vivo or in vitro applications.