Plasma fibronectin (pFN) is secreted by hepatocytes as a major protein component of blood. pFN opsonizes bacteria and helps form clots. Plasma FN is widely used in cell culture to help cells attach to the substrate. It is particularly useful for culturing cells that are incapable of synthesizing their own biomatrix, including stem cells, and for culturing cells in serum-free medium. Akron’s pFN is a clear, sterile, buffered solution with a pH of about 7.3 to 7.7.
Cellular fibronectin (cFN) is produced by general fibroblasts and is a major component of the extracellular matrix. Within the matrix, cFN helps cells bind to each other and to the basement membrane, and helps direct the longer-term aspects of wound healing. The two strands of cFN contain a domain not present in pFN, so cFN has a slightly higher molecular weight. cFN is also used for cell attachment in cultures, but its efficacy relative to that of pFN has not been assessed. It seems possible, perhaps probable, that the relative efficacy of cFN may differ for various cell types.
Both fibronectins are high-molecular-weight glycoproteins formed as disulfide-linked dimers.