Small Angle X-ray Scattering Study of Palladium Nanoparticle Growth on Genetically Engineered Tobacco Mosaic Virus Nanotemplates.
metal nanoparticles possess valuable specific size dependent properties that arise at
the nanoscale, and differ significantly from their bulk properties. However, the
fabrication of these nanoparticles is often difficult to predict and control due to
harsh reaction conditions and effects of capping agents or surfactants. Therefore, there
is a critical need for facile rout... read morees toward controllable nanoparticle fabrication.
Biological supramolecules, such as viruses, offer attractive templates for nanoparticle
synthesis, due to their precise size and shape. In addition, simple genetic
modifications can be employed to confer additional functionality with a high number of
precisely spaced functional groups. In this work we exploit the specificity of
genetically modified Tobacco Mosaic Virus (TMV1cys) for readily controllable palladium
(Pd) nanoparticle synthesis via simple electroless deposition. TMV1cys, engineered to
display one cysteine residue on the surface of each of over 2000 identical coat
proteins, provides high density precisely spaced thiol groups for the preferential
nucleation and growth of Pd nanoparticles. Small-Angle X-ray Scattering (SAXS) was
employed to provide a statistically meaningful route to the investigation of Pd
nanoparticle size ranges formed on the viral-nanotemplates. Specifically, we examine the
size range and thermal stability of Pd nanoparticles formed on surface assembled
TMV1cys. Further, we investigate the growth of Pd nanoparticles on TMV1cys in solution
using in situ SAXS to better understand and predict nanoparticle growth on these
nanotemplates. Lastly, we compare TMV1cys templated particle growth to Pd nanoparticle
growth in the absence of TMV1cys to elucidate the role of TMV in particle formation. We
show that Pd nanoparticles form preferentially on surface assembled TMV1cys in high
density in a broad particle size range (4-18nm). Further, we show that Pd nanoparticles
are significantly smaller and more uniform when formed on TMV1cys in solution as
compared to Pd particle growth in the absence of TMV1cys. Finally, we provide insight
into the fundamental Pd growth mechanism through in depth in situ SAXS analysis. We
anticipate that this work will have a broad and significant impact on the use of
biological supramolecules for the well-controlled fabrication of nanoparticles for a
wide range of applications by providing fundamental information on particle
Thesis (Ph.D.)--Tufts University, 2011.
Submitted to the Dept. of Chemical and Biological Engineering.
Advisor: Hyunmin Yi.
Committee: Byeongdu Lee, Nak Ho Sung, and Terry Haas.
Keywords: Nanotechnology, and Chemical engineering.read less