[Membrane roughness: A relevant concept in haemodialysis]

The molecular process that occurs at the interface between blood and a haemodialysis membrane determines the host response. The resulting reactions define the degree of membrane biocompatibility. These reactions are triggered by plasma protein adsorption onto the membrane and blood cell stress. Over the past decade, atomic force microscopy (AFM) has provided mechanistic insights into the molecular level of interactions that occur at the biomaterial surface. AFM provides tridimentional images produced by both changes in applied shear nanoforces and dynamic imaging through the molecular analysis of attraction and repulsion forces. The aim of the present brief review is to shortly present the technique of AFM and its emerging applications in haemodialysis, comparing hydrophilic and hydrophobic structures. Dialysis membrane roughness and protein adsorption mapping can be quantitatively estimated, since AFM resolution power is in the range of a nanometer. It is suggested that estimation of roughness and force mapping determining structure/function relationship should be proposed for the best understanding of membrane biocompatibility.