What to freeze in: bags, vials, straws?
Question: We are freezing very small tissue fragments. What container should we use for this specimen?
Answer: Good question. Selection of a freezing container is very important. Storage at low temperatures is adverse for most materials (materials get brittle at low temperatures). Biospecimens stored at low temperatures should use containers designed to be used at low temperatures.
There are three different general categories of containers for low temperature storage: straw, vial and bag. Straws are used typically to store small volumes (<1ml). Vials contain volumes ranging from ~1 to 5 ml. Bags can have the widest range of volumes but most commonly from 30150 ml (volume of liquid to be placed in the bag). Tissues may also be frozen in bags (albeit a very different construction from bags to contain cell suspensions or biofluids).
When storing a specimen from a single patient, you may actually need all three containers (straw, vial, bag) depending upon the assay for a specific biomarker. It is important to think about the volumes that you may need before you freeze and select the appropriate container. Each container has unique problems and limitations. We discuss in the short course advantages and disadvantages of the containers commonly used to store biospecimens.
It may also be helpful for you to know that some manufacturers hve flexible manufacturing capabilities and can custom manufacture a cryogenic biospecimen container to meet your individual needs (size, type of port, geometry, etc).
