An economical insulated shipping container providing a $> 4$-day lifetime for frozen biosamples without dry ice

Abstract

Many research projects in the life sciences require the shipment of biosamples which *must* remain frozen. We describe the design, construction, testing, and use of an economical and reusable insulated "super-box" which, in conjunction with reusable phase-change--material "cold packs", reliably maintains a volume of about 38~liters (sufficient to hold 34 standard $13.4 \times 13.4 \times 5.2$~cm cryoboxes) below $-15^\degree$C for about 3.5~days, and below $-5^\degree$C for about 4.5~days. The entire system is readily constructed from commercially-available materials at a cost of under US\$500. In contrast to systems using dry ice (frozen CO$_2$) during shipment, the super-box and cold packs do not require special handling during shipment and are not considered "dangerous cargo" by commercial shippers.