Biology Reference
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The assembly of nanopatterned arrays of single TMV particles was
achieved using a combination of dip-pen nanolithography and coordination
chemistry. Precise immobilization and positioning of single VNPs was
demonstrated (Fig. 7.15) (Vega
., 2005). The chemical immobilization
approach relies on the ability of metal ions (such as Zn
et al
) to bridge
carboxylates from an MHA-patterned surface with TMV surface carboxylates.
In brief, MHA patterns were generated using dip-pen nanolithography and
the surrounding surface was passivated with PEG. Coordination with Zn
2+
2+
was achieved by exposing the surface to a solution of Zn(NO
3
. In the
subsequent step, TMV was introduced. Different feature sizes were tested.
The ideal template consisted of 350 × 110 nm-sized features (TMV has
dimensions of 300 × 18 nm). Using this template, single 2D arrays of TMV
were fabricated (Fig. 7.15). Smaller feature sizes resulted in a less uniform
assembly, where not all sites were occupied with VNPs. Larger feature sizes
could result in several VNPs binding to one site. Dot templates with features
of 350 nm in diameter also facilitated the fabrication of 2D arrays. TMV
particles bound to the dot features adopted a curved structure (Fig. 7.15)
(Vega
)
2
et al
., 2005).
Figure 7.15
AFM tapping-mode images and height profiles of TMV nanoarrays: (a) 3D
topographical images of pairs of virus particles within larger arrays: a parallel array
(left), a perpendicular array (middle), and dot arrays (right); (b) topographic images
and height profiles of a perpendicular array of single virus particles (40 × 40 mm
2
);
(c) topographic image and height profiles of a TMV nanoarray (20 × 20 mm
) formed
on an array of MHA dot features (diameter = 350 nm) pre-treated with Zn(NO
3
2
O.
Reproduced with permission from Vega, R. A., Maspoch, D., Salaita, K., and Mirkin,
C. A. (2005) Nanoarrays of single virus particles,
)
·6H
2
2
Angew. Chem. Int. Ed.
,
44
(37),
6013-6015.
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