Precise temperature control of donor cornea tissue with reusable passive thermal container

To describe a new reusable passive thermal shipping container for domestic and international transport of human donor cornea, which maintains air temperature for 72 consecutive hours of harsh hypothermic and hyperthermic environmental challenges.

The passive thermal container (PTC) was prepared by storing the device at -30°C for 8 hours. On full activation of the biphasic wax-based compound, 2 human corneas for research and future histological studies were secured in either of 2 similarly prepared PTCs or 2 polystyrene containers with wet ice. Three thermal data loggers were enclosed in the bottom, side, and middle of each payload area. The container was then exposed to hyperthermic (range, 21.1 to 51.7°C) or hypothermic (range, 15.6 to -28.9°C) external temperatures for 72 hours after which all corneas were removed, and the air temperature readings from the loggers were reviewed.

Air temperature stability was measured at 5-minute intervals. The PTC maintained steady acceptable air temperatures for 71.13 consecutive hours in the hyperthermic challenge and 60.33 consecutive hours in the hypothermic challenge. The polystyrene containers with wet ice did not maintain a payload temperature between 2 and 8°C for more than 8 consecutive hours during the hypothermic challenge and never achieved industry regulation temperatures during the hyperthermic challenge.

We present a novel method for transporting human corneal tissue that ensures proper air temperature stability between 60 and 71 hours in harsh hypothermic and hyperthermic environments, which is also reusable. There may be applications for this technology in both domestic and international transportation of corneal tissue.