Dynamics of the Mineral–Microbe Interface: Use of Biological Force Microscopy in Biogeochemistry and Geomicrobiology

At the most fundamental level, interand intramolecular forces delineate the interface between a microorganism and a mineral surface. A new technique, termed biological force microscopy (BFM), is described that can be used to directly probe the dynamics of the mineral–microbe interface. BFM quantiŽ es attractive and repulsive forces in the nano-Newton range between living microbial cells and mineral surfaces in aqueous solution. Native bacterial cells are linked to a force-sensor that is used in a force microscope to measure bacteria–mineral interactions as a function of the distance between the mineral surface and the cells on the sensor. The magnitudes and ranges of the measured forces re ect the chemical and structural intricacies of the mineral–microbe interface. BFM is presented with potential applications to studies assessing the role that microbes or biomolecules play in geochemical and mineralogical processes.