Researchers at the John Innes Centre (JIC) in Norwich, UK, are using black-eyed peas infected by a virus to build electronically active nanoparticles. Fortunately, this cowpea mosaic virus is harmless to humans and animals. The virus is used as a 'scaffold' for decoration with various chemicals to give different characteristics, depending on the application. And even if this project is still in the very early stages, the scientists hope that this research will lead to the development of the technology for use in medical as well as industrial applications. Some of these future applications may include biosensors or nanoelectronic devices.
Here is the introduction of the JIC news release.
What have Black-eyed peas got to do with nanotechnology? As well as sharing their name with a chart-topping U.S. band, Black-eyed peas (also known as Cowpeas) are being used by scientists at the John Innes Centre in Norwich to grow virus particles that can be decorated with a chemical turning the particles into a kind of molecular capacitor.
Below is a picture of this Cowpea mosaic virus which has all the characteristics of an ideal nanoscaffold/building block. "It has a sphere-like structure of 28 nm diameter and its properties are defined. The virus particles can be obtained in gram scale from 1 kg of infected plant leaves. Amino acids on the exterior surface of the virus particle provide sites of attachment for a range of chemicals." (Credit for caption: JIC; credit for picture: UCSF Computer Graphics Laboratory)
And here is a picture of "a leaf of the Cowpea plant infected with Cowpea mosaic virus showing characteristic yellow mosaic effect" (Credit: Andrew Davis, JIC).
Let's now switch to "Virus used to make nanoparticles" (BBC News, March 19, 2006) for more details.
The virus, which infects black-eyed peas, was employed as a "scaffold" on to which other chemicals were attached. By linking iron-containing compounds to the virus's surface, the John Innes Centre team was able to create electronically active nanoparticles.
The researchers tell the journal Small that their work could be used in the future to make tiny electrical devices. The work is yet another example of how scientists are now trying to engineer objects on the scale of atoms and molecules.
After these precisions written in plain English, here are more technical details given by Michael Gross for Chemistry World in "Plant virus fixed with antennae" (March 16, 2006).
[Dr David Evans and his colleagues] at the John Innes Centre (JIC) at Norwich used Cowpea mosaic virus, a plant pathogen that can be purified in gram quantities from a kilogram of infected leaf material. Its structure is known at near-atomic resolution and is characterised by an almost spherical protein shell with 60 identical subunits arranged in fullerene-like symmetry. With its well-defined geometry and a diameter of 28 nanometres, the virus represents a nanoscaffold, to which precisely targeted modifications can be applied.
The JIC group used free amine groups present at the surface of the shell, to attach ferrocenecarboxylic acid, a redox-active molecule, via peptide bonds. Using electrochemical measurements, they determined that the ‘decorated’ virus particles typically carry 240 ferrocene groups, or four on each subunit, and that each of the redox sites reacts independently of the others.
And for even more technical information, this research work has been published in Small, from Wiley InterScience, under the name "Decoration of Cowpea Mosaic Virus with Multiple, Redox-Active, Organometallic Complexes" (Volume 2, Issue 4 , Pages 530 - 533, March 1, 2006). Here is a link to the abstract.
Sources: John Innes Centre news release, March 6, 2006; and various web sites
You'll find related stories by following the links below.