Adsorption of fibrinogen to droplets of liquid hydrophobic phases. Functionality of the bound protein and biological implications.

Fibrinogen adsorbs spontaneously from aqueous media containing that protein to droplets of liquid hydrophobic phases dispersed in those same media. Examples of such phases include mineral oils, straight-chain hydrocarbons, and various plant- and animal-derived oils. Lecithin preexisting on the surface of oil droplets reduces significantly the amount of fibrinogen that can otherwise bind to them. When bound, fibrinogen remains active in the classic sense of fibrin gelation. As a consequence, oil droplets coated with fibrinogen can participate in a host of biologically important adhesive processes in which the protein would be expected to participate. Certain polyanions, eg, heparin, pentosan polysulfate, dextran sulfate, and suramin, bind to adsorbed fibrin(ogen) and prevent thrombin-dependent adhesion of fibrinogen-coated surfaces. Thus, these polyanions can be used to prevent adhesion between fibrin(ogen)-coated oil droplets and other fibrin(ogen)-coated surfaces. Potential practical applications and biological implications of these phenomena are presented and discussed.