AFM study of bacterial swarming on nanostructured metal surfaces

C. DIAZ; P. L. SCHILARDI; R. C. SALVAREZZA; M. FERNANDEZ LORENZO

Mar del Plata

Simposio; 4th Latin American Symposium on Scanning Probe Microscopy, IV LASPM; 2007

<!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:1; mso-generic-font-family:roman; mso-font-format:other; mso-font-pitch:variable; mso-font-signature:0 0 0 0 0 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Arial","sans-serif"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:EN-US;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Bacteria use flagellar rotation to propel themselves (swim) through liquid environments and to crawl (swarm) across solid surfaces Bacterial swarming is influential in several pathogen-host interactions in plants and animals. This type of motility facilitates ascending colonisation of the urinary tract by bacteria yielding to biofilm formation in catheters 1,2 as well as migration in soil environments 3. The formation of rafts involved in bacterial swarming was studied on nano/micro engineered surfaces designed to tune bacterial size and sub-cellular motion organelles. Results showed that Pseudomonas fluorescens formed well defined raft structures on randomly oriented granular gold substrates (Fig. 1a and 1b). Changes in cell length and flagellation to improve cooperative motion were observed on the ordered nano/microstructures (Fig. 1c and 1d). However, swarming motion was impeded because bacterial alignment and cell-to-cell sticking were hindered on these surfaces. We also found that the nano/micro surface structures can alter the morphology of isolated bacteria and aggregates, the cell-to-cell sticking process, the interaction between aggregates, and also the orientation of cellular substructures involved in motion.