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The first and best characterized virus is a plant virus, Tobacco mosaic virus (TMV). This 300 nm long protein/RNA nanotube, of 18 nm diameter, offers a well-defined array of chemical functionalities on its outer surface, and in its tubular 4 nm wide channel. TMV is usually employed in aqueous suspension, and imaged by electron microscopy in vacuum.
Latest data from the Self-Assembly group at nanogune help to understand the binding of metal and oxide nanoparticles to TMV: Attachment to RNA bases is only possible at the two orifices of the tube, while binding on the outer surface can be controlled in a purely electrostatic fashion. The protonation of TMV is the key factor to control type and size of the produced virus/nanoparticle superstructure. An exciting alternative to binding the particles is their synthesis directly on or in TMV. Recent experiments allow to clarify how solutions of metal complexes interact with the virus, with a special focus on effusion from the 4 nm channel. This leads to the more basic question how nanostructures interact with water (and with other liquids). Environmental electron microscopy techniques allow to observe wetting below 50 nm, but the big challenge is the molecular scale below 5 nm, where liquids loose their bulk properties, and where interfaces dominate. |
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