The binding kinetics of fluorescently labeled microtubules to kinesin-coated surfaces permits the determination of the density of kinesin motor proteins adhered to the surface in the range of 0.1-30 mu m(-2). This extreme sensitivity, corresponding to protein coverages of 0.004 -1 ng cm(-2), enables the characterization of advanced non-fouling coatings, such as (EG)(3)OH-terminated SAMs and PEGMA with applications in biomedical engineering and bionanotechnology.