Fig. 1. Physico-chemical characteristics of staphylococcal cell surfaces.

a Initial bacterial removal rates from an aqueous phase (10 mM potassium phosphate buffer) by hexadecane as a function of pH. b Zeta potentials of staphylococci in 10 mM potassium phosphate buffer as a function of pH. c Contact angles on bacterial lawns with water (θ_w), formamide (θ_f), methylene iodide (θ_m), and staphylococcal surface free energy parameters and components. Total surface free energy γ^tot results from Lifshitz–Van der Waals γ^LW and acid-base γ^AB components, and electron-donating γ⁻ and electron-accepting γ⁺ parameters. Error bars in panels (a) and (b) represent standard deviations over measurements on three different bacterial cultures. ± signs in panel (c) represent standard deviations over measurements on six bacterial lawns, prepared from three separate bacterial cultures.