Nanoscale surface properties of microbial cells: from structure to function Yves F. Dufrêne Unité de Chimie des Interfaces – Université catholique de Louvain – Croix du Sud 2/18 – 1348 Louvain-la-Neuve – Belgium; Yves.Dufrene@uclouvain.be The nanoscale surface analysis of microbial cells represents a significant challenge of current microbiology and is critical for developing new biotech and biomed applications. Using atomic force microscopy (AFM) topographic imaging, researchers can visualize the ultrastructure of live cells under physiological conditions and their subtle modifications upon cell growth or treatment with drugs (1). Chemical force microscopy, in which AFM tips are modified with specific functional groups, allows investigators to measure molecular forces and chemical properties of cell surfaces on a scale of only 25 functional groups (2). Molecular recognition imaging using AFM offers a means to localize specific receptors on cells, such as cell adhesion proteins or antibiotic binding sites (3-5). Here, I will survey the different options offered by AFM for the nanoscale analysis of microbes, emphasizing the potential of the technique in biomedicine, e.g. for understanding pathogen-drug and pathogenhost interactions. (1) Dufrêne Y. F., Nature Rev. Microbiol. 2 (2004), 451. (2) Dague E., et al., Nanoletters, 7 (2007), 3026. (3) Dupres V., et al., Nature Methods 2 (2005), 515. (4) Hinterdorfer P., and Dufrêne, Y. F. Nature Methods, 3 (2006), 347. (5) Gilbert Y., et al., Nanoletters, 7 (2007), 796.