Comparison of microwave and convective heating in rapid specimen preparation techniques for electron microscopy

Chemical fixatives preserve tissue for electron microscopy. Microwave heating (MWH) reduces fixation time from hours to seconds. Comparison of microwave heating (915 MHz and 2.45 GHz) with convective heating suggests that acceleration of fixation is not unique to microwave exposure. Other heating modes appear suitable and may have advantages in cost and convenience. It is demonstrated that equally good fixation can be obtained by raising the temperature of specimens in glutaraldehyde to 40-45 degrees C in a short time interval (10-60 s) via MWH or convective heating (CH). The results suggest that heat is the primary cause of the reduced fixation times associated with MWH and that the heating mode is secondary.<>