Cryoguard^TM Thermal Exposure Indicators signal thermal exposure or temperature abuse in cryopreserved materials. The indicators are used to monitor frozen tissues, blood products, biologicals, pharmaceuticals and frozen adhesives during shipping and storage. The indicators can also be used to detect failures or fluctuations in refrigeration or freezers.

Cryoguard Thermal Exposure Indicators are available with four (4) different pre-set "signal" temperatures:-40°C(M-40),-70°C(M-70),-100°C(M-100) and-120°C(M-120). When an indicator is exposed to temperatures above its signal temperature, it irreversibly changes color from green to red (see - signal temperature graph below). This irreversible color change is what signals temperature abuse of cryopreserved materials, which might otherwise go undetected.

Each Cryoguard Thermal Exposure Sensor is a chemical formulation sealed in a polycarbonate vial (approximately 1/2" x 1"). Indicators are activated by freezing to at least 30°C below its signal temperature, and then depressing an activator pin in the bottom of the unit. (see cryoguard activation diagram)

Cryoguard Thermal Exposure Indicators are designed to attach to Nunc brand cryovials and standard cryovial freezer canes. Eyelets on indicators facilitate wiring of indicators to perishables. The M-40 indicator is used to monitor materials cooled in dry ice. The M-70, M-100 and M-120 indicators are frequently used to monitor materials in dry shippers that are cooled by liquid nitrogen or liquid nitrogen dry ice mixtures. Indicators should be chosen with signal temperatures at least 30^oC higher than that of the environment to be monitored. Thus, the M-40, M-70, M-100 and M-120 indicators are recommended for monitoring environments at or below -70^oC, -100^oC, -130^oC and -150^oC, respectively. Each thermal exposure indicator contains a label stipulating the trigger temperature, interpretation of green or red color, expiration date and our website address.

Cryoguard Signal-Temperature Graph: