Effect of Heating on Fixation with Glutaraldehyde

A better alternative involves glutaraldehyde fixation by heating in a microwave oven. This approach completely prevents the artifactual parathyroid cell variants (Marti et al., 1987). The fixation in this case is uniformly accelerated throughout the specimen block. Some evidence indicates that microwave heating followed by osmication enhances postfixation with this metal. 

As explained in this chapter, glutaraldehyde introduces mostly irreversible protein crosslinks that may alter the conformation of the antigen (epitope) molecule. Such extensive crosslinkages become a barrier to the antibody penetration, and thus its accessibility to the epitope is hindered. This impediment becomes a serious problem when monoclonal antibodies specific for only one epitope type are used and/or when epitopes are not located at the surface of the antigen molecule. 

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