kryoprotektantit

Kryoprotektantit, or cryoprotectants, are substances used to protect biological material from freezing injury during cryopreservation. They help reduce ice formation, limit osmotic and mechanical stress, and preserve cellular and tissue integrity at low temperatures.

Cryoprotectants are generally categorized as penetrating (cell-permeating) and non-penetrating. Penetrating agents such as dimethyl sulfoxide (DMSO), glycerol, ethylene glycol, and propylene glycol enter cells and lower the risk of intracellular ice formation. Non-penetrating agents such as sugars (sucrose, trehalose, glucose) and polymers (Ficoll, PVP) act primarily outside cells to stabilize membranes and modify solution properties. Some protocols use vitrification, a rapid cooling approach with high cryoprotectant concentrations that aims to form a glassy, ice-free state and minimize crystal formation.

Common cryoprotectants include DMSO, glycerol, ethylene glycol, propylene glycol, and sugars like trehalose. In practice, combinations are used to balance protective efficacy with toxicity, especially in clinical contexts such as reproductive medicine and stem cell banking, where optimized cocktails maximize post-thaw viability.

Applications span the cryopreservation of cells (blood, sperm, oocytes, embryos, stem cells), tissues (bone marrow, cartilage), and some small organs, as well as industrial uses in food preservation and biological sample storage. Cryoprotectants enable long-term storage and transport of biological material for research and therapeutic purposes.

Challenges and safety considerations include toxicity at high concentrations and during warming, which require careful optimization of concentration, cooling and thawing rates, and post-thaw handling. For clinical use, regulatory and quality-control measures govern the preparation and removal of cryoprotectants, and post-thaw viability is routinely assessed through viability assays and functional tests.