Two-dimensional auto-organized nanostructure of sodium hyaluronate and its frictional Tproperties

The two-dimensional auto-organized nanostructure of sodium hyaluronate NaHA on bovine serum albumin BSA monolayer was studied by a layer-by-layer method. The surface properties were studied by a quartz crystal microbalance QCM method and by using an atomic force microscope AFM. NaHA showed a Langmuir-type adsorption and was found to form honeycomblike networks. With increasing adsorption amount of NaHA, their mesh size decreased and their strand size increased in width. The surface nanomechanical properties, such as adhesion force Fad and frictional forces Ff between the surfaces of the NaHA layers and the AFM tip, were studied in air and in NaHA solutions using a contact mode and a lateral force modulation LFM of AFM. The values of Fad and Ff obtained in air were found to be higher than those obtained in the solutions because of the effect of moisture film on the NaHA layers. The values of Fad and frictional coefficients in the solutions increased with increasing .