Credit: RSC

Numerous methods have been developed for the synthesis of one-dimensional nanostructures, with advances often being sought in terms of structural control and ease of processing. An increasingly popular approach exploits the predictable self-assembly of biological systems to form structures that can act as scaffolds.

Tobacco mosaic virus (TMV) is a rod-shaped particle comprised of over 2000 identical proteins arranged in a helical fashion around a single RNA strand. Native TMV particles have a diameter of 18 nm and are 300 nm long, and they can self-assemble head-to-tail to form even longer nanorods. The stability of these larger aggregates depends strongly on their environment, and they may fall apart under certain conditions. However, Qian Wang of the University of South Carolina in the US and co-workers1 have now shown that it is possible to reinforce these structures by using them as templates for the formation of composite nanofibres.

Self-assembled virus nanorods were coated with a small organic molecule called aniline. Upon addition of an oxidant, the aniline molecules zip themselves together to form a polyaniline coating around the TMV nanorod, essentially gluing the structure together. Nanofibres up to 10 microns long were observed under a transmission electron microscope and small angle X-ray scattering measurements show that the diameter of the nanofibres increases relative to native TMV particles.

The authors speculate that their composite nanofibres may find application in optics, electronics and biomedical engineering.