High Speed, High Resolution Atomic Force Microscopy

CIC nanoGUNE Seminars

Speaker

Stephen C. Minne, Vecco - Bruker, Santa Barbara, CA, USA

When

2012/05/24
13:00

Place

nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian

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The challenge of scanning probe technology for biological applications has historically been to obtain high spatial resolution (sub-nanometer), high force sensitivity (<pN) and high speed all in a well-controlled in-vitro environment. This presentation will examine recent results in high speed AFM for capturing dynamics of biological processes. High resolution and mechanical maps showing atomic resolution images, with correlated force curves on Mica and Calcite, along with videos of self-assembly, of Bacteriorhodopsin will be presented as demonstrations of SPM performance. This capability will be applied to visualizing mechanisms and dynamics of E. coli being attacked by Antimicrobial Peptides (AmP). The problem of antibiotic-resistant bacteria, coupled with the selectivity of AmPs for microbial cells, has made the study of this interaction as a potential therapeutic increasingly important. In this study, high-resolution imaging revealed the appearance of features on the surface of individual E. coli cells resembling the S-layer lattice structure. Within 30 seconds, cells exposed to 20 μg/mL of the AmP CM15 showed the onset of the disruption of the cell membrane surface through membrane rippling and protrusions, and the formation of defects <15nm width. AFM videos at the cellular and mole ecular level will be shown.