Erica Tennenhouse, PhD
Keeping Cool Outside of the Lab
Refrigerators and freezers are integral pieces of equipment in many research and clinical labs. Low temperatures are required to preserve samples and specimens, ensure vaccines and drugs do not degrade, and keep certain reagents from spoiling. Often, though, temperature-sensitive materials must be collected or transported beyond the confines of the lab. Maintaining the cold chain is a considerable challenge, but one that can be readily addressed with the right portable cold storage system.
Rise of the cold chain
According to Cameron Haring, a senior global product manager at Thermo Fisher Scientific (Waltham, MA), demand for portable cold storage is on the rise. “This is being driven in one sense by the explosion of research targeting new cell therapies with the promise of personalized and preventive medicine,” he says. The clinical trials associated with this work, along with growing demand for exported plasma, necessitate the movement of samples between laboratories and health care facilities worldwide.
The trend is apparent to Gary Bissig, vice president at LABRepCo (Horsham, PA), who has noticed a recent spike in requests for small cold and ultracold storage units in remote clinical locations. “They’re looking at enough space for a handful of vials,” he says, “not the huge freezers that you would see in research.” Demand in the past has been mostly domestic, but Bissig is also beginning to see greater international need for these systems.
Agents of cool
Dry ice is a common means of preservation, as it is readily available and relatively cheap. However, using containers filled with dry ice presents a temperature maintenance challenge. As Maria Thompson, PhD, vice president of scientific affairs at MedCision (San Rafael, CA), points out, when vials are placed in dry ice, only a small zone above the ice stays below –50°C. “This means fragile, temperature-sensitive samples are exposed to partial thawing and freeze-thaw cycles that encourage ice recrystallization damage,” she explains.
To address this problem, MedCision offers dry ice–based ultralow-temperature (ULT) transporters and mobile workstations specifically designed to maintain stable low-temperature work zones to depths of ten inches. This kind of working depth can keep multiple cryostorage boxes safe while critical patient samples are being collected, processed, and transferred to storage, Thompson says. She notes an added benefit: “All of this can be maintained with a minimal amount of dry ice, which helps save lab resources.”
Liquid nitrogen (LN2), as Haring points out, is another primary source of chilling capacity, with products aimed at keeping samples below their “glass transition” temperature of approximately –130°C. LN2 dewars “feature durable, vacuum-sealed, double-walled aluminum that insulates the container and limits LN2 burn-off while providing structural rigidity for longer transport durations,” he says. According to Haring, there has been product innovation in novel container construction that “bridges the gap between corrugated and vacuum-insulated aluminum.”
As for portable freezers, technology has come a long way. “Being able to have something small and portable at –80°C is probably the latest and greatest,” says Bissig. For its part, LABRepCo supplies portable ULT freezers that can be run off a 12-volt battery. “You could actually run a small –80°C [freezer] off a car battery,” he remarks, “so if you had a power failure or a Superstorm Sandy...you could simply pick up the 40-pound freezer, move it to your vehicle, and run it for a period of time until power would be restored.” This feature is particularly useful in remote locations, where emergency power might not be available.
Better products, better service
“At some point, development scientists stopped thinking in terms of what’s ‘good enough’ to keep things cold,” says Thompson, who sees companies starting to use materials that allow better temperature efficiency and incorporating electronic design that allows temperature tracking and connectivity.
While the products are certainly advancing, some of the most significant advances in portable cold storage have been on the service side, Haring notes. “There are a number of companies offering services, which has led to very robust turnkey offerings, making it much easier for end users to deal with their cold-chain needs—it can be very complicated to independently manage and verify the critical handoffs and storage.”