Formalin is one of the most common fixatives used in histology due to its effective preservation of tissue morphology and cellular detail. It is a solution of formaldehyde gas in water, typically at a concentration of about 10%, known as 10% neutral buffered formalin (NBF). This buffer helps to maintain a neutral pH, which is crucial for preserving the cellular structures during tissue fixation.
The effectiveness of formalin as a fixative is attributed to its ability to cross-link proteins, thus stabilizing the tissue structure and preventing autolysis and putrefaction. It is widely utilized in both clinical and research laboratories for a variety of tissue types, making it a standard choice for histological preparations.
While alcohol and acetic acid are also used in certain histological applications, they are not as widely applied for routine fixation compared to formalin. Alcohol serves primarily for dehydration and may not preserve tissue morphology as effectively, while acetic acid is often used in specific contexts, such as fixing nucleic acids or when a rapid fixation is needed. Isopropanol, similar to ethanol, is typically used more for dehydration processes rather than as a primary fixative. Thus, formalin remains the most recognized and utilized fixative in hist