Effective long-term sample storage requires balancing a variety of competing factors, including safety, reliability, compliance, space considerations and cost. To maximize efficiency, biobanks must carefully consider how these parameters apply to everything from large components, like computer infrastructure and HVAC systems, all the way down to the smallest detail, like freezer racking and vial closures.
Although they may not seem significant compared to all the decisions involved in a large biological study, vial closures serve a critical role as the first line of defense between your sample and the environment, and the market reflects that importance with dozens of different options. How can you be certain you have chosen the closures that best meet your needs?Given the number of products commercially available today, selecting the right vial closure can be a difficult task. Here are five factors to keep in mind as you weigh your options.
- Safety and reliability. Since the primary goal of a biobank is to preserve samples with minimal environmental exposure and degradation, a vial closure needs to effectively isolate the sample from its surroundings and must remain sealed for the duration of storage. In addition to the safety of the sample – which may be the only specimen of its kind in existence – the safety of researchers and neighboring samples is paramount if your biobank stores pathogens, radioactive samples or other materials that could be harmful to researchers.
- Compatibility with storage type and temperature. Be sure to choose a vial closure that won’t become brittle or damaged if frozen. This is especially important for samples stored in liquid nitrogen, as ineffective closures can allow LN2 to leak into the vial, a hazard that can potentially cause an explosion when the sample is transferred back to room temperature! In addition to proper closures, tubes need to be outfitted with protective containers to protect against such issues when stored in the liquid phase of nitrogen. The rate at which a sample warms to room temperature can also be affected by these factors, as described in the Thermo Scientific cryopreservation manual ( see Figure 4).
- Ease of access. Flame-sealed glass ampoules are often used for long-term cryopreservation, but the difficulty of removing and replacing them means they wouldn’t be a smart choice if your study needs to access a sample frequently. Think about the future use of your samples and your process when selecting a closure: Will you remove caps using robotics, will the tubes be uncovered by hand or will you use a combination of the two? How often will you run tests on each sample? Will samples be transported to other biobanks? Each of these factors affects the pros and cons of any vial closure you consider.
- Cost. Although we don’t recommend prioritizing cost over safety or reliability, it is a significant factor in designing a storage solution. Whether you are a research facility operating its own repository or a third-party biobank, it’s important to compare different vendors and products before making a large scale purchase. Vial closures impact other costs in the organization as well. If instrumentation must be retrofitted or new instruments purchased outright to manage a certain style of cap, closures can start to have a much bigger cost footprint.
Don’t let their small size fool you – when you add up the number of samples needed for even a single study, vial closures can have a dramatic impact on the effectiveness, efficiency and economics of your biobank. What factors do you consider when you’re choosing closures for your samples?