Fig. 5.

Environmental influence on inter-bacterial forces. The graphs display the complete datasets for the average force lines displayed in Fig. 4. Force on approach and retreat for bacteria suspended in a deionized water, b NaCl solution, c autoclaved bacteria in TSB and d 1 μm polystyrene beads. Each bold line represents the force average of six bacterial pairs or six polystyrene bead pairs. Only the interaction of bacteria in deionized water result in a repulsive force for trap separations below 3 μm. All other experiments displayed no significant change in force for decreasing the separation distance of the traps. All measurements are corrected for drift