Figure 3.

The force vs. distance profile was measured between a streptavidin and a monolayer of 4.5 mol % DSPE-EO₄₅ under conditions described in the text. The best fits of the data to Derjaguin–Landau–Verwey–Overbeek theory gave −54 ± 2 mV and −41 ± 5 mV for the electrostatic potentials of the streptavidin and PEG-displaying bilayers, respectively. Similar fits were obtained using constant potential (solid line) or constant charge (dashed line) boundary conditions.