Cryogenic Cooling of Biological Samples for Electron and Optical Microscopy

Cryogenic liquid transfer systems have proven to be the method of choice for most cooling applications for spectrophotometric studies. The application of such methods to biological systems requires a few modifications. The cryogenic systems can operate in any position but most liquid samples must be placed in cuvettes in the vertical position from the top. Temperature control from 77K to room temperature can be accomplished using a liquid nitrogen supply, a 20 ohm strip heater, a silicon diode transducer and an automatic temperature controller.