NANOSCALE IMPEDANCE MICROSCOPY ON SINGLE BACTERIA. A THEORETICAL STUDY.

In recent years it has been recognized that single cell studies with microbial cells, as compared to the more common population based studies, may provide answers to some unresolved scientific questions [1]. Most of the advances reported until now have been produced with microorganisms with relatively large sizes (yeast cells, algae, amebae, etc.) of at least 5 μm in diameter and hence accessible by optical techniques and conventional micromanipulation technologies at the single cell level [2]. Much less has been done with small bacteria with typical sizes around 1 μm which lye at the frontier of conventional techniques and hence require more advanced (nano)techniques, essentially Atomic Force Microscopy (AFM). [3,4,5] This technique has allowed obtaining three dimensional images of the live bacterial cell surfaces with high spatial resolution as well as quantification of adhesion to molecules and surfaces, the study of the antibacterial effect of different compounds, evidence for horizontal genetic transfer through conjugative pili, DNA-protein interactions, etc. In spite of these results, still a lot remains to be explored in order to better understand the properties of these small single bacterial cells. In our groups we are exploring novel applications of atomic force microscopy to th