Detection, localization, and conformational analysis of single polysaccharide molecules on live bacteria

The nanoscale exploration of microbes using atomic force microscopy (AFM) is an exciting, rapidly evolving research field. Here, we show that single-molecule force spectroscopy is a valuable tool for the localization and conformational analysis of individual polysaccharides on live bacteria. We focus on the clinically important probiotic bacterium Lactobacillus rhamnosus GG, demonstrating the power of AFM to reveal the coexistence of polysaccharide chains of different nature on the cell surface. Applicable to a wide variety of cells, this single molecule method offers exciting prospects for analyzing the heterogeneity and diversity of macromolecules constituting cell membranes and cell walls.