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of ordering are controlled by virus concentration and deposition speed.
At low concentration and high deposition speed, 1D fibers are assembled.
At higher concentration and slower deposition rate, strong head-to-tail and
parallel assembly is induced and thus 2D films are deposited (Wargacki
et
al
., 2008). Metallization of the virus fibers within the film with silver led to
conductive arrays of wires with lengths up to many centimeters (Fig. 7.7)
(Kuncicky
., 2006).
Electrospinning and wetspinning techniques can also be applied to
generate long-range ordered films of VNPs; this has been demonstrated
for M13. In wetspinning, a VNP-containing solution is extruded through
a capillary tube to produce fibers. A M13 suspension was extruded
through a 20-
et al
µ
m capillary tube into an aqueous glutaraldehyde solution.
The glutaraldehyde fixes and cross-links the fibers. Wet-spun fibers
were 10-20
µ
m in diameter and showed nematic ordering of the phages.
Electrospinning uses high voltage to draw fibers from a liquid. Electrospun
fibers were 100-200 nm thick. To preserve the processing ability and
integrity of the VNP during electrospinning, the suspension was blended
with the polymer polyvinyl pyrrolidone (PVP). The resulting M13/PVP
fibers were continuous and could be transformed into non-woven fabrics
(Fig. 7.8) (Lee & Belcher, 2004).
Figure 7.8
Electronspun fiber of M13 virus-blended with polyvinyl pyrolidone. (a)
Photograph of non-woven fiber spun through the mask inscribed with the word
“NANO”, (b) SEM image (scale bar: 1
m). Reproduced with permission from Lee, S.
W., and Belcher, A. M. (2004) Virus-based fabrication of micro- and nanofibers using
electrospinning,
µ
Nano Lett
.,
4
(3), 387-390.
.  d ArrAyS oF ICoSAhdrAl VnPs
Icosahedral particles have the intrinsic property to self-assemble into highly
ordered 2D or 3D crystals. Self-organized hexagonal 2D monolayers of
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