Quantification of bacterial adhesion forces using atomic force microscopy (AFM)

This study demonstrated that atomic force microscopy (AFM) can be used to o btain high-resolution topographical images of bacteria, and to quantify the tip-cell interaction force and the surface elasticity. Results show that t he adhesion force between the Si3N4 tip and the bacteria surface was in the range from - 3.9 to - 4.3 nN. On the other hand, the adhesion forces at th e periphery of the cell-substratum contact surface ranged from - 5.1 to - 5 .9 nN and those at the cell-cell interface ranged from - 6.5 to - 6.8 nN. T he two latter forces were considerably greater than the former one, most Li kely due to the accumulation of extracellular polymer substance (EPS). Resu lts also show that the elasticity varied on the cell surface. (C) 2000 Else vier Science B.V. All rights reserved.