ADSORPTION OF ADHESIVE PROTEINS FROM THE MARINE MUSSEL, MYTILUS-EDULIS, ON POLYMER-FILMS IN THE HYDRATED STATE USING ANGLE-DEPENDENT X-RAY PHOTOELECTRON-SPECTROSCOPY AND ATOMIC-FORCE MICROSCOPY

The adsorption of mussel adhesive protein (MAP) from the marine mussel Mytilus edulis has been investigated on polystyrene (PS) and poly(oct adecyl methacrylate) (POMA) surfaces using angle dependent X-ray photo electron spectroscopy (XPS) and atomic force microscopy(AFM). AFM imag es previously published in the dehydrated state using contact mode are compared with images acquired in the hydrated state using fluid Tappi ng Mode to assess the contribution that hydration has on the architect ure of the adsorbed proteins. To further characterize the adsorbed pro tein layer XPS analysis was performed at liquid nitrogen (LN2) tempera ture without dehydrating the samples and at room temperature after the surfaces were dehydrated. The differences observed upon dehydration c an be attributed to the strength of the interactions between MAP and t he two surfaces. The AFM and XPS data indicate that adsorbed MAP is st abilized on the surface of the PS through interactions that prevent th e protein layer from being disrupted upon dehydration. The adsorbed MA P on the POMA surface is representative of a loosely bound protein lay er that becomes highly perturbed upon dehydration.