ABSTRACT
The techniques used to ensure that both morphology and nucleic acids are preserved for in situ hybridization are similar to those used for classical electron microscopy. This includes the sampling and fixation of tissue under near sterile conditions. Fixation of biological material, including tissue (organs, biopsies, etc.) or cells in a culture (monolayers, suspensions), must be carried out using the appropriate technique such as post-embedding technique, pre-embedding technique, and frozen sections. All types of biological material such as tissues and cells may be fixed. The chapter discusses principles, conditions and parameters of fixation of tissue. Different types of fixatives such a crosslinker fixatives and chemical fixatives are described along with its advantages and disadvantages. The chapter discusses cell suspensions/cell monolayers. The summary of different steps in fixation by perfusion and fixation by immersion are also discussed.
