posted on 2016-05-09, 00:00authored bySumedha Sharma, Yuly Andrea Jaimes-Lizcano, Ryan B. McLay, Patrick C. Cirino, Jacinta C. Conrad
We
investigate the deposition and transient adhesion of Escherichia
coli on alkyl and fluoroalkyl silanized glass
surfaces of different carbon chain lengths. The rate at which bacteria
deposit onto these surfaces decreases as the shear stress is increased
from 3 to 67 mPa, but trends in the deposition rate across all surfaces
cannot be predicted from extended DLVO calculations of the interaction
potential. As the surface root-mean-square (rms) roughness increases,
the deposition rate increases and the percentage of motile tethered
cells decreases. Furthermore, on surfaces of root-mean-square roughness
of less than 0.2 nm, bacteria exhibit mobile adhesion, for which surface-associated
cells linearly translate distances greater than approximately 1.5
times their average body length along the flow direction. E. coli bacteria with and without flagella exhibit mobile
adhesion, indicating that this behavior is not driven by these appendages.
Cells that express fimbriae do not exhibit mobile adhesion. These
results suggest that even subnanoscale roughness can influence the
deposition and transient adhesion of bacteria and imply that strategies
to reduce frictional interactions by making cells or surfaces smoother
may help to control the initial fouling of surfaces by E.
coli bacteria.