Avoiding sample degradation is essential to ensure the integrity of the research efforts that biobanks support. A constant freezer temperature is a crucial factor in ensuring sample quality since a warm storage environment, even for a short period, can lead to degradation. Unfortunately though, despite best efforts, there are a few ways that traditional processes and manual freezers inadvertently contribute to sample degradation by creating damaging variations in temperature. In this blog, we'll reveal some of the key ways you could be unwittingly degrading the samples within your biobank.
Within a traditional biobank set-up, there are often inherent issues within the sample collection and management process, that lead to unequal treatment of samples – exposing some to more degradation than others. For instance, when collecting and managing samples, researchers typically work in batches, gathering several racks of samples together before transporting them to the freezer. The samples processed earlier are exposed to the environment and experience more degradation than those handled later. Even before samples reach the freezer unit, they may already be of variable quality. Rapid pneumatic transportation, sample by sample, direct from processing to storage is a good solution this problem.
The next phase of a traditional biobanking process poses further problems. Typically, having batched samples as above, researchers will transport samples to the refrigeration unit using dry ice. Dry ice isn't as efficient as people may assume, despite the belief that it holds a temperature of -80° C. Due to the transfer of heat through transportation trays, the actual temperature that samples are exposed to may, in fact, be at -50° c or worse. At this level, the safety of samples, unfortunately, isn't guaranteed. We urge researchers to avoid being lulled into a false sense of security when transporting samples to the final destination using dry ice.
Once samples are in the freezer, a range of other challenges emerge. One of those issues is failing to pay proper attention to the organization within the storage. If the inside of the freezer isn't well managed, we can unwittingly stop air from circulating correctly and create hotspots and coldspots. Happily, this is a more straightforward issue to address. By carefully organizing your freezer using racking; it is possible to mitigate these specific issues to some extent.
A trickier issue to resolve within a traditional biobank set up is the temperature variation caused by the circulation of warm air when we open and close the door. When we conducted some research monitoring samples in a manual freezer, we got some troubling results. All samples- no matter their location- reached temperatures warmer than –70°C. Even more worrying, were the results we obtained from particular areas of the freezer like the middle section towards the front of the door. This area is highly exposed to warm air, and samples that are stored in this location might have quality issues.
A typical manual freezer uses a racking system. This type of system means that to retrieve one sample; we need to pull an entire plate of 500- 1000 tubes out of the protected storage conditions. Again, this is sub-optimal. For the sake of the few samples you need at a given time, you are risking the quality of the other specimens on the rack. Unfortunately, this issue stands to be replicated many times over a year, with samples subjected to multiple such ‘thermal shocks’ before they are eventually picked. The result is severe degradation over time.
As we can see, there are multiple risks to sample quality within a traditional biobank process using a manual freezer. Yet what is most worrying is that, in many instances, the quality issues in the samples might not ever come to light. Some sample types like DNA and RNA are covered by a well-defined QC assessment that would prevent them from being used in the event of degradation. On the other hand, for protein-based samples like serum and plasma, such measures don't exist. Degraded samples could make their way into research without the quality issue ever being detected. This would risk undermining the integrity of essential efforts like biomarker research. In the absence of a straightforward, simple test to determine the quality of some types of sample we have to do everything in our power to optimize equipment and processes and keep specimens in the best possible conditions for meaningful research.
To learn more about automated storage check out or webinar 'Automated sample storage – Is it worth it?' which considers if automated sample storage is a worthwhile investment, including any benefits to sample quality and the impact this could have on your research. We will also review and compare the associated investment of an automated sample storage solution versus manual approaches.