Playing “Nano -Lego ”: VNPs as Building Blocks for the Construction of Multi -Dimensional Arrays - Viral Nanoparticles: Tools for Materials Science and Biomedicine - page 183

aggregates on surfaces via the formation of disulfide linkages. In contrast,
symmetry-broken particles facilitated formation of a controlled monolayer
on the substrate (see Fig. 4.14) (Klem

., 2003).
Vertical patterning of Cys-added TMV particles on gold surfaces has
been shown (Fig. 7.11) (Royston

et al

., 2008, 2009). The favored vertical
ordering of the TMV particles was explained by the insertion side of the
Cys residue (Fig. 7.11). Although the Cys side chain is surface-exposed, it
is somewhat buried on the surface. The Cys is recessed within a groove
and partially covered by the carboxyl terminus of the coat protein. This
prevents interaction of the virus body with the gold surface. The Cys
residue is sufficiently exposed at the 3

et al

′

end of the virus, thus allowing
vertical attachment of the particles (recall the polar nature of TMV caused
by the encapsidated linear RNA molecule; the particles have defined 5

′

′

and 3 ends; see Section 3.5). The stably immobilized TMV particles could

subsequently be mineralized with silica, nickel, or cobalt. Because of the
vertical patterning, these metalized nanostructured surfaces offer extremely
high surface area and may find applications as electrodes, catalysts, or data
storage devices (Royston

., 2008, 2009).
Indeed, analysis of vertically patterned nickel-coated TMV surfaces
indicated the suitability for such a material to function as a battery electrode.
Electrode activity was confirmed; TMV-templated electrodes consistently
outperformed non-TMV-coated electrodes showing greater capacity. The
discharge capacity of nickel-coated TMV-templated battery electrodes was
calculated to be on the order of 10

et al

mAh/g; for a comparison, commercially
available lithium ion battery electrodes have a discharge capacity of
10

5

4

mAh/g (Royston et al ., 2008).

.. Single VnP Arrays

The fabrication of single VNP arrays has the great potential. VNPs
immobilized and arranged in a symmetric array offer multiple spatially
fixed attachment sites for modification and functionalization, thus allowing
precise construction of 2D arrays. VNP arrays offer an extremely large
surface area and are thus expected to find applications in manufacturing
miniaturized devices. The potential of TMV-based battery electrodes has
been demonstrated (see previous section). Nanolithographic and molding
techniques have been combined with viral nanotechnology leading to the
development of single CPMV, TMV, and M13 VNP arrays (Cheung et al .,

2003, 2006; Smith et al ., 2003; Suh et al ., 2006; Vega et al ., 2005).

refers to the fabrication of patterns on the nanometer
scale. A range of nanolithographic techniques have been developed; however,

Nanolithography