Competitive adsorption of albumin against collagen at solution–air and solution–polythylene interfaces

The adsorption of human serum albumin (HSA) from the binary mixtures with collagen was monitored at solution–air and solution–polyethylene interfaces by the in situ measurements. The results clearly demonstrate that on both interfaces albumin is the only adsorbing protein within a large collagen solution concentration range. At the albumin concentration equal to 0.005 mg/mL, the presence of collagen in solution results in the enhancement of albumin adsorption at solution-air interface relative to its adsorption from the single protein system. The same phenomenon is manifested at the solution-polyethylene interface, although the increase in albumin adsorption at this interface occurs at the albumin concentration equal to 0.01 mg/mL. These results are attributed to the lowering in the solution–air and solution–polyethylene interfacial tensions, and thus to the increase in the spreading characteristics of albumin in the presence of collagen molecules. The desorption experiments carried out with a buffer solution on polyethylene surfaces reveal the irreversibility of adsorbed albumin from both the single and the binary mixtures with collagen. When after 20 h of adsorption from the solutions containing albumin only, collagen was added to these solutions or when the samples after that period of time were first rinsed with a buffer and then with a collagen solution, the amounts of albumin remaining at the surfaces were in both cases reduced by one-half. © 1993 John Wiley & Sons, Inc.