Biology Reference
In-Depth Information
Some reasons for the lowered incidence of enveloped VNPs in the nanotech
literature are as follows: (i) production of non-enveloped VNPs are more
feasible compared with generating enveloped VNPs; (ii) non-enveloped VNPs
are in general more stable; and (iii) use of non-enveloped non-mammalian
VNPs can be regarded as safe from a human health perspective compared to
working with potentially infectious enveloped mammalian VNPs.
Studies concerning the use of enveloped viruses for nanotechnology have
utilized
Rubella virus
(RV) and
Influenza virus
A/PR8 (H1N1) (Fischlechner
et al
., 2006). The envelope was exploited
in binding the particles onto solid supports for sensing applications. These
devices may prove useful in viral diagnostics (discussed in Chapter 7).
Another enveloped VNP that has been studied is
., 2005, 2006, 2007; Toellner
et al
Chilo irisdescent virus
(CIV)
(Radloff
., 2005). However, the envelope was removed prior to studying
the particle for potential applications in nanotechnology.
et al
2.1.2.1 Icosahedral paricles
Description of icosahedral symmetry.
derives from
the Greek language and means “twenty seat.” An icosahedron is a polyhedron
with 20 triangular faces. It has fivefold, threefold, and twofold rotational
symmetry axes, in short: 5:3:2 symmetry (Fig. 2.2).
The word
icosahedron
Figure 2.2
Schematic of an icosahedron with 20 triangular faces and 5:3:2 symmetry.
The fivefold axis is shown as red pentagrams, the threefold axis is depicted as a blue
triangle, and the twofold axis is highlighted by green rectangle.
The icosahedron as a structure is the largest closed shape that can be
formed by identical units (the coat proteins). Icosahedral symmetry requires
a defined number of coat protein units. To form an icosahedral virus
particle with 5:3:2 symmetry 60 coat protein subunits are required. Three
coat proteins are placed on each of the 20 triangular faces in an equivalent
manner (3 subunits
×
20 faces = 60 coat protein subunits) (Caspar & Klug,
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