Formaldehyde immunocytochemical fixative

Evers P, Uylings HB. Effects of microwave pretreatment on immunocytochemical staining of vibratome sections and tissue blocks of human cerebral cortex stored in formaldehyde fixative for long periods. /. Neurosci. Methods 1994 55 163-172. 

Amino acids are small and highly mobile molecules, thus them efficient fixation in tissues is an essential prerequisite for their subsequent immunocytochemical detection. The main fixatives that can be used for immobilizing amino acids in tissues are glutaraldehyde, carbodiimide, and formaldehyde (formaldehyde is referred to here as paraformaldehyde, to distinguish it from formalin). Glutaraldehyde has traditionally been the fixative of choice for retaining amino acids in tissues prior to their immunocytochemical detection. Unfortunately, glutaraldehyde is incompatible with immunofluorescence-... 

After collection and smear-section preparation, samples should be washed with PBS, fixed in 4% formaldehyde in phosphate-buffered saline (PBS), and p>ermeabilized for 10 min in PBS containing 0.25% Triton X-100. Immunocytochemical staining can be perform performed by incubating the samples with pritnaiy antibodies in PBS/Tween (PBS containing 0.1% Tween 20 and 3% BSA) for 1-2 hr, followed by incubation with appropriate secondary antibodies diluted according to the manufacturer s recommendation in PBS/Tween solution for 1-2 hr. Stained samples can then be visualized with confocal microscope. 

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