Biological systems emerge from evolved sophisticated processes developed by Nature.
Understanding of how the biological materials function can help
us to synthesize, control and manipulate materials at an atomic scale.
Biological nanotechnology aims at the design and synthesis of novel artificial materials
and devices for electronic, optical, biomedical, and spintronic applications. One of the examples
of a nanoscale biological system is a plant virus (see Figure 1).
Plant viruses have recently attracted attention as biological templates
for assembly of nanostructures and nanoelectronic circuits.
Vibrations in the rod-shaped TMV viruses immersed in air and water.
After A.A. Balandin and V.A. Fonoberov, J. of Biomedical Nanotechnology.
Plant viruses can be coated with metals, silica or semiconductor materials
and form end-to-end nano-rod assemblies (see Figure 2). Such virus as tobacco mosaic virus (TMV)
appropriate cylindrical shape and particularly suitable dimensions:
TMV is 300 nm long, 18 nm in diameter and with a 4 nm in diameter axial channel.
The knowledge of vibrational, i.e. phonon,
modes of these viruses is important for materials and structural characterization
of the virus-based nano-templates and
for in-situ monitoring of the virus-assisted
nanostructure self-assembly. NDL team has recently reported on the
application of Raman spectroscopy for
investigation of properties of
hybrid virus-inorganic nanotubes.
TEM micrograph of pure TMV and platinum coated TMV assembly. NDL, 2004.
Professor Balandin's Nano-Device
Laboratory (NDL) research group carries out theoretical and experimental research
on bio-inspired materials and development of novel characterization techniques for such hybrid materials.
focus on the characterization of properties and investigation of vibrational modes
in the plant viruses and plant virus-based assemblies (see Figure 3). Recent results on the subject
can be found in W.L. Liu, et al., Appl. Phys. Lett. (2005).
Some thrusts of this biological nanotechnology
research in NDL are performed under the framework of the DARPA-SRC funded
MARCO Center on Functional Engineered Nano
Artichectonics (FENA) .
The bio-nano-tech modeling and computer simulation work in NDL is closely corellated with
the group's experimental activities described HERE,
particularly micro-Raman spectroscopic investigation of phonons in
hybrid nanostructures. More information on Raman spectroscopy in NDL can be
Figure 3. Dispersion of the lowest vibrational frequencies for cylindrical viruses.
Solid (dashed) lines correspond to radial-axial vibrations of the virus in air (water).
In our recent paper we reported on calculation of the dispersion relations
for the lowest vibrational frequencies of TMV immersed in air and water (see Figure 3). In this work we
analysed the damping of
vibrations in water and discuss application of micros-Raman spectroscopy for monitoring
and control of the virus-based self-assembly
processes (see Figure 4).
For details see the rapid research note in
physica status solidi (2004) by V.A. Fonoberov and A.A. Balandin.
Figure 4. Raman spectra of TMV virus under visible laser excitation. NDL, 2004.
The signatures of the unique vibrational modes observed in Raman (Brillouin) spectra (see Figure 3) can be
used to monitor the process of virus functionalization, i.e. coating with different materials,
and self-assembly, i.e. attachment to other objects such as quantum dots, carbon nanotubes, etc., or
forming end-to-end superstructures (see Figure 5). Information, which can be obtained with the help of Raman
spectroscopy, is particularly valuable since other direct characterization techniques, such as
transmission electron microscopy (TEM), are difficult to carry out and
require special treatment of the samples. For details see A.A. Balandin and V.A. Fonoberov,
Vibrational Modes of Nano-Template Viruses published in the
Journal of Biomedical Nanotechnology.
Figure 5. Radial vibrational modes for TMV virus in air (a-c) and in water (d-f).
The length or arrows is proportional to the magnitude of the displacement.
Finally, talking about nanostructure growth, Figure 6
shows the growth of the tobacco mosaic viruses on (what else...)
tobacco plants. The growth is carried out at the facilities
of the UCR College of Natural and Agricultural Sciences.
As one can guess the method is not as expensive as
molecular beam epitaxy (MBE).
It is also a parallel process allowing mass production
of TMV nano-templates. At the same time, do not try it at
Figure 6. Growth of tobacco mosaic viruses on tobacco plants. UCR, 2004.
More information on the BIOLOGICAL NANOTECHNOLOGY
and other projects
currently under way in the Nano-Device Laboratory (NDL) can be
To join NDL as a graduate student or postdoctoral research visit
the web-page HERE.
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Devices and Circuits visit the web-page HERE.