Effects of denaturation and association of collagen on adsorption behavior: two-dimensional nanostructure and its property

Effects of denaturation and association of collagen on adsorption behavior were studied in various pH and temperature T by a quartz crystal microbalance QCM. The surface nanostructure, the adhesion force F _ad, and the local frictional coefficient μ of collagen were studied by an atomic force microscope AFM and a lateral force microscope LFM. Adsorptions of collagen were Langmuir type in the regions of pH 3.0–5.8 and T = 25–50 °C. With increasing pH and T, adsorption mass Γ increased, and adsorbed fibrils increased in width. At interface, the association of collagen molecules in solution enhanced the formation of fibrils. The results of F _ad in the solution of pH 3.0 increased with increasing Γ and T but decreased in pH 5.8. The results of μ increased with increasing Γ and T, and those in pH 3.0, were much greater than those in pH 5.8. From comparing them with the results of bovine serum albumin and sodium hyaluronate monolayer, we concluded that nonelectrostatic interactions and the softness of collagen layer contribute primarily to F _ad and μ.