Cryogenic storage is often associated with maintaining extremely low temperatures.
However, not all stress in biobanking comes from temperature alone.
Repeated freeze–thaw cycles — even when minimized — can still occur in real laboratory workflows. When they do, they introduce a different type of challenge: mechanical stress that develops progressively over time.
What Happens During Freeze–thaw Cycles
A freeze–thaw cycle involves cooling a sample to low temperatures and then bringing it back to higher temperatures for use.
During this process, both the sample and the tube undergo physical changes.
This transition, taken individually, is not critical.
The key factor is repetition.
During each cycle, materials:
- Contract at low temperatures
- Expand during thawing
- Undergo mechanical stress at both material and interface level
At the same time, the sample itself may expand and contract, introducing internal pressure variations within the tube.
These changes are not always visible, but they can influence how the tube performs over time.
Why Closure Integrity Matters
In biobanking, sample integrity depends not only on storage conditions, but also on how reliably the container performs over repeated use.
Repeated freeze–thaw cycles can introduce small variations in the geometry of both the tube and its closure system. Over time, these variations may affect sealing consistency.
This can increase the risk of:
- Fluid loss
- Contamination
- Variability in sample conditions
The impact is not necessarily immediate, but cumulative, especially in workflows involving repeated handling or partial sample use.
The Role of Closure Design
Under repeated mechanical stress, closure performance becomes a critical factor.
Repeated freeze–thaw cycles can introduce small mechanical variations at the contact point between the cap and the tube. Over time, these variations may affect sealing consistency.
CryoGen® CLEARLine® tubes by Biosigma are designed with a bi-injected cap system in which the sealing component is directly integrated into the cap during manufacturing.
This design approach supports interface consistency between cap and tube, particularly during handling and temperature transitions.
In this context, closure design is not just a feature, but a contributing factor to long-term system reliability.
Beyond Temperature Stability
At ultra-low temperatures, tube performance is often judged by a single number: the minimum temperature it can withstand.
Freeze–thaw cycles highlight a different perspective: reliability is not only the ability to withstand low temperatures, but the ability to maintain consistency under repeated stress.
In cryogenic biobanking, this distinction is not always immediately visible. However, over time, it can influence how effectively samples are preserved.
About the Author
Biosigma S.p.A., founded in 1988, provides disposable plastic items for biotechnology, research, clinical chemistry and pharmaceutical laboratories. Our CLEARLine® products are ideal for the most sensitive applications. Products are manufactured under strict quality standards and certified by our internal laboratory.
