An official journal of the Society for Biology of Reproduction and the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn

March 2008 (No. 1)

Maximum rates of cooling by three programmable freezers, and the potential relevance to sperm cryopreservation

Phillip Matson 1,2,3, Wendy Kappelle 2, Sandra Webb 2

2 Reproductive Biology Unit, Perth Zoo, Western Australia 6151, Australia 3School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch, Western Australia 6150, Australia.

Maximum rates of cooling for the Asymptote EF 100 and the Cryologic CL8800 temperature controller with either a standard or fast chamber were determined and viewed in the context of sperm cryopreservation. All three systems use liquid nitrogen to cool the plate or chamber which would hold the sample, opposed by a variable amount of heat from an internal heater. Maximum rates of cooling for all systems were a function of the temperature gradient between the liquid nitrogen and the plate/chamber and at a plate/chamber temperature of 15°C were 16.5°C/min, 13.3°C/min and 8.0°C/min for the Asymptote EF100, Cryologic fast and slow chambers respectively. These machines are not suited to the freezing of sperm from species requiring rapid rates of cooling, an important consideration when planning to purchase a piece of equipment for this application, and scientists are advised to discuss specifically their requirements with prospective suppliers.
Reproductive Biology 2008 8 (1): 69-73

1 Corresponding author: Phillip Matson, Perth Zoo, 20 Labouchere Road, South Perth, Western Australia 6151, Australia; e-mail: