Cryopreservation and biobanking in medicine

What cryopreservation is

Cryopreservation is the process of cooling and storing living cells or tissues at extremely low temperatures — often around minus 196 degrees Celsius, the temperature of liquid nitrogen — so that they can survive being thawed and used later. At normal body temperature, cells quickly deteriorate outside the body. Cooling them to such extreme cold effectively pauses all the chemical activity of life, so the material can be kept for years without decaying. The challenge is that freezing can damage cells, mainly through ice crystals forming inside them. Cryopreservation techniques are designed to get cells safely through the freezing and thawing steps so that, once warmed, they can work as they did before.

How cells survive freezing

Left to freeze on their own, cells would be torn apart by ice crystals and by the concentration of salts as water turns to ice. To prevent this, scientists add special protective fluids called cryoprotectants, which act rather like antifreeze, reducing harmful ice formation. Two main approaches are used. Slow freezing cools the sample gradually in controlled steps. Vitrification cools it so rapidly that the liquid inside becomes a glass-like solid without forming damaging crystals at all. The best method depends on the type of cell or tissue. After storage, careful warming and washing steps remove the cryoprotectant so the recovered cells are ready for use in treatment or research.

Everyday uses in medicine

Cryopreservation is already part of routine care. In fertility treatment, eggs, sperm and embryos are frozen and stored, allowing people to preserve their fertility — for example before cancer treatment — or to use stored embryos in later cycles. Blood transfusion services freeze and store blood components and stem cells. Bone marrow and blood stem cells used in transplants for blood cancers are frozen until needed. Donor tissues such as heart valves, corneas and skin can be banked for surgery. Even some newer cell therapies rely on freezing cells so they can be shipped and given at the right moment. In each case, freezing turns a perishable, living material into something that can be stored and used when required.

What biobanks are

A biobank is an organised collection of biological samples — such as blood, tissue, DNA or cells — usually stored alongside health information about the donors. Some biobanks support patient treatment, keeping tissues or stem cells ready for use. Others are research biobanks, which gather large numbers of samples and linked health data so scientists can study why diseases develop and how they might be prevented or treated. Large national resources have collected samples and data from many thousands of volunteers, helping researchers make discoveries that would be impossible from small studies. Biobanks depend on careful cataloguing, secure storage and strict quality control so that every sample can be found, trusted and used properly.

Ethics, consent and the future

Because biobanks hold personal samples and sensitive health data, they operate under strict ethical and legal rules. In the UK, the use of human tissue is regulated, donors give informed consent explaining how their samples may be used, and data is protected and usually stored in a way that keeps donors anonymous to researchers. People can normally withdraw their consent. Looking ahead, better freezing methods, automated storage and links to genetic and digital health data are expanding what biobanks can do, supporting personalised medicine and the search for new treatments. As these technologies grow, maintaining public trust through transparency, consent and good governance remains just as important as the science itself.