For Freezing Samples Should You Use a Cryovial® or a Micrewtube® ?

Simport owns the Cryovial® brand. Then naturally we would be tempted to direct you to these ranges of products to answer the initial question. But some of our competitors clearly suggest that the two are interchangeable (probably because their cryogenic vial range is not great, but anyway, let’s move on…).

Cryovials® were designed for freezing. Their thick walls and the different types of closures used were designed specifically for this purpose. Thus, all our models of lip seal or O-ring cap cryovials perform extremely well stored in the short or long term in the vapor phase of liquid nitrogen. They are also available with a round bottom or free-standing, self-locking base in most cryogenic vial racks, allowing them to be opened with one hand.

Micrewtubes® are microtubes for centrifugation. That’s why they were designed. They are microtubes with a screw cap that provides better protection against aerosols, as centrifugation is an aerosol-creating technique. But they look like mini cryovials as much in shape as in design and it is tempting to mistake them for the other.

Let’s be clear. Micrews seal tightly and can be frozen. But some caps are not made of the same material as the tube which can cause imperfect adjustments because the expansion coefficients of the two types of resins are different when exposed to different temperatures. Not surprisingly as they were not originally designed for this purpose. In addition, the Cryovial® storage boxes are made of polycarbonate, an incredibly resistant material, while the Micrew storage box, which looks like its twin brother, is made of polystyrene, a resin more advantageous in terms of price but less robust. So, what do we do? 

Without being an official recommendation, here is my common-sense conclusion. If storing in liquid nitrogen, use Cryovials®, which are more robust and designed for this purpose because this type of storage is infinitely more demanding for the containers used. But if you store enzymes at -20° C or samples in a typical -86° C ultralow temperature freezer, Micrews will likely offer comparable performance at a lower price

Are you looking for the right answer? Ask us and we will tell you what it really is.