Binding the tobacco mosaic virus to inorganic surfaces

We studied the adsorption behavior and surface chemistry of the tobacco mosaic virus (TMV) on well-defined metal and insulator surfaces. TMV serves as a tubular supramolecular model system with precisely known surface termination. We show that if the surface chemistry of the substrate and the pH-dependent chemistry of the molecular surface match, for example, by hydrogen bonding, a strong adsorption occurs, and lateral movement is impeded. Due to the immobilization, the virion can be imaged by atomic force microscopy (AFM) in contact mode. We also used self-assembled monolayers with an acyl chloride group to induce covalent bonding via ester formation. Noncontact AFM proved that TMV keeps its cylindrical cross section only under weak adsorption conditions, that is, on hydrophobic surfaces, while on hydrophilic substrates a deformation occurs to maximize the number of interacting chemical groups.