Use of Peldri II (a fluorocarbon solid at room temperature) as an alternative to critical point drying for biological tissues.

A new chemical, Peldri II, is evaluated as a compound for drying soft biological tissues for scanning electron microscopy. Peldri II, a fluorocarbon, is a solid at room temperature and is a liquid above 25 degrees C. Cells or tissues are embedded in Peldri II by immersing them in the liquid form and allowing it to solidify. Once solidified, Peldri II will sublime with or without vacuum to dry tissues, probably without introducing surface tension. Several types of cells and tissues have been examined to compare preservation with Peldri II and critical point drying techniques. No differences were detected between the two techniques when normal surface structures were examined. Peldri II appears to be a significant improvement over hexamethyldisilazane as a drying agent for scanning electron microscopy. It is also very convenient for drying large numbers of samples.