Cryoprotection of Biological Materials



Cryoprotection of Biological Materials



For long term storage of cells, DNA and proteins you are generally advised not to freeze and thaw your samples. Multiple rounds of freezing and thawing can damage protein structures, leading to rapid loss or viability due to a number of biochemical processes such as proteolysis, aggregation, fragmentation precipitation. Freeze thaw cycles can even lead to minor DNA damage resulting in uninterpretable data from PCR. Ice crystals that are formed during the freeze-thaw process can cause cell membranes to rupture and an imbalance in osmotic pressure. They can cause the salts and proteins in the buffer to become concentrated. This problem is known as freeze concentration and can cause significant stress on the stability of proteins. Multiple freeze-thaw cycles can also cause an increase in oxidative stress and production of reactive oxygen species, free radicals produced as by-products of redox, reactions. This results in molecular damage to DNA, proteins, and cell membranes. Biological material subjected to multiple freeze thaw cycles will in effect undergo irreversible structural changes unless they are returned to their optimal working environment or protected using certain storage additives.   At Polygenyn Ltd. we have a formulation which has shown to protect proteins, DNA and cells during the freezing process and extending further protection to precious samples after multiple freeze thawing cycles.   PG04 Freeze/thaw protectant: Protects the integrity of biological materials during freezing and freeze thawing cycles. Applications: Protection against protein, enzyme antibody and DNA damage during freezing and freeze thaw cycles. Helps with long term storage at -20oC. Protection of DNA integrity in sperm, tissue, blood and other body fluids. This may help in the storage of precious samples such as forensic samples, animal and plant cell lines where there is a need to preserve the structure of the DNA and prevent fragmentation. The production of unpredictable fragment sizes due to freeze thaw damage may lead to inefficient PCR resulting in loss of sensitivity which is highly undesirable when dealing with small amounts of DNA.