Formaldehyde is both a non-coagulant and an additive fixative. Formaldehyde is known to penetrate tissue quickly, but the fixation process may take a long time to form the various cross links with tissue proteins. Formalin fixation is thought to form cross links between the aldehydes and the proteins, creating a gel, thus retaining cellular constituents in their in vivo relationship. Once properly fixed, the tissue should be able to withstand the subsequent stages of tissue processing or staining. Although there is no true universal fixative, 10% neutral buffered formalin (NBF) is perhaps the most commonly used fixative throughout the world for light microscopy and is a somewhat forgiving fixative. Of the dozens and dozens of available fixatives, it is hard to imagine a fixative more commonly used than 10% NBF. 10% neutral buffered formalin is well suited for large throughput laboratories, and requires a relatively short period of fixation, but can also be used for the long-term storage of tissue.

10% neutral buffered formalin (NBF) is a popular general purpose histological fixative. It has been used to fix tissues, protein complexes and tumor samples.

Popular general purpose histological fixative.

Case containers are polypropylene with white leak-proof lids and are partially prefilled with 10% NBF.

Neutral buffered solution

Store tightly closed at room temperature. Do not freeze.