Behaviour of proteins at interfaces.

The adsorption and conformational changes of three plasma proteins, (bovine) serum albumin, .y-globulin and fibrinogen, on several (bio)polymer surfaces are reported. A theory is developed which invokes reversible adsorption of the proteins in the initial stages and a time dependent conformational change of adsorbed protein leading to essentially irreversible long-term adsorption. In each case experimental evidence indicates that there .is a time-dependent decrease in structural order. It is postulated that the protein unfolds to optimize surface bonding, thus inducing the c;hemistry of the protein/water interface by bonding at the protein/ /polymer interface. Cell binding studies support the concept that the plasma proteins unfold to optimize the polymer/protein interaction.