In many biological systems, ligand-receptor
pairs bind to each other via noncovalent
interactions such as hydrogen-bonding and
Van der Waals forces. This project’s method
of studying these interactions uses electron
transfer theory. When a receptor binds to a
redox-modified ligand, there is a change in
the reorganization energy of the...
Germanium (Ge) nanowires were grown via
the vapor-liquid-solid growth mechanism
and surface-doped with manganese (Mn).
The nanowires were annealed at 350˚ C for
30 min to promote the Mn diffusion.
Pulsed-laser local electrode atom probe
tomography was used to determine the
concentration and distribution of Mn in the
Ge nanowires....
Silver nanoparticles exhibit distinctive
optical properties. When exposed to
electromagnetic radiation, a noble metal
nanoparticle demonstrates the unique
optical property of localized surface
plasmon resonance (LSPR). LSPR is
measured through an extinction spectrum,
the sum of absorption and Rayleigh
scattering, which results when the
collective oscillation of electrons is
resonant...
When the Aß peptides aggregate into
soluble oligomeric clusters, they form
central nervous system neurotoxins known
as amyloid-ß-derived diffusible ligands
(ADDLs). The assembly of ADDLs is
currently thought to be a pathogenic
process in Alzheimer's disease (AD).
Understanding the molecular structure and
properties of ADDLs could prove useful in
the...
Numerous studies have been structured to
investigate magnetoelectric multiferroic
materials, which possess simultaneous
ferroelectric and (anti)ferromagnetic
ordering. Bismuth ferrite (BiFeO3), referred
to as BFO, has drawn special attention
because of its unique ability to maintain both
electric and magnetic dipole moments at
room temperature. BFO shows great
potential to revolutionize...
A self-assembled monolayer of an alkene or
alkyne can be applied to a hydrogenpassivated
silicon surface using UV hydrosilylation.
This research shows that
field-induced oxides can be used as a
negative resist to selectively prevent
bromostyrene attachment, providing a
means of nanopatterning organic molecules
on silicon. The negative resist effects...
Pressure-assisted densification was used
by way of a hot press to optimize the
conditions of heat and pressure when
applied to anatase (TiO2). This study
optimized hot-pressing conditions, which
will be helpful when doping TiO2 because it
will allow optimization of bulk anatase for
transparent conductive oxide (TCO)
applications. Lessons...
Magnetic tweezers are a simple yet
powerful tool for the micromanipulation of
single molecules. In this study, a vertical
magnetic tweezer apparatus was
constructed for research on the micromechanics
of DNA, DNA supercoiling, and
DNA-protein interactions. By joining DNA
molecules to magnetic beads and attaching
these tethers to the wall...
This research explored the optical
properties of metal nanoparticles using the
discrete dipole approximation (DDA). A
method was developed to define nanoparticle
structures of arbitrary shapes, and this
method was interfaced with the preexisting
DDA code, DDSCAT 6.1. For each structure
and material, the scattering properties and
near electric-field enhancements...
This paper reports the synthesis of an
azide-functionalized deoxynucleoside as a
precursor for azide-terminated oligonucleotides.
Also reported is the synthesis of an
acetylene-terminated precursor, which can
be used to make a diverse array of
silyl-protected acetylene-terminated small
molecule cores. Both of these precursors
serve as basic building blocks en route...
Magnetic resonance imaging (MRI) is a
powerful technique used in clinical
medicine and biomedical research to
conduct noninvasive imaging of tissues and
organisms. Chelated gadolinium is often
used as an MRI contrast agent to improve
the spatial resolution of these images.
Recently developed “smart” MRI contrast
agents respond to specific...
The need for high-performance, solid-state
H2 gas sensors is one research effort aimed
at enabling the future hydrogen economy.
Improving the gas-sensing properties of
semiconducting oxide materials such as tin
oxide, zinc oxide, etc., necessitates the
control microstructure and composition.
This study compares the effect of
dimensionality with the effect...
This research illustrates the modification of
an iodostyrene layer on a Si(111) surface
using a Sonogashira reaction. This was
accomplished by applying UV irradiation
(254 nm) to a hydrogen-passivated silicon
surface in a solution of iodostyrene in
benzene, followed by a Sonogashira
coupling between the iodine group from
iodostyrene and...
This research investigated the feasibility of
patterning with sol-gels using a nanofountain
probe in an atomic force microscope.
Two oxide sols — barium titanate and
cobalt ferrite — were used as inks in
patterning tests using fountain-pen
nanolithography (FPN). This was shown to
be a suitable method of depositing sol-gels...
In this study, particle sorting and transportation
in Brownian liquids were explored by
translating an optical standing wave. The
standing wave is produced by crossing two
coherent beams of light, and determining
the resulting period by the angle of the
intersection. Adjusting the period and
velocity of wave ridges allows...
Carbon nanotubes (CNTs) are highly
promising in the miniaturization of
electronic devices. However, there are
currently many limitations in mass
producing devices that involve the
application of CNTs, one of which is the
ability to physically pattern CNTs in specific
locations on a wafer, which is what this
study aims...
Weak, noncovalent interactions (dipoledipole
interactions, hydrogen bonding, and
Van der Waals forces) in ligand-receptor
pairs play a very important role in living
systems. A new way to study these
interactions is by using electron transfer
theory. The rate of electron transfer
between redox centers is dependent on
several factors, including...
Weak, noncovalent interactions (dipoledipole
interactions, hydrogen bonding, and
Van der Waals forces) in ligand-receptor
pairs play a very important role in living
systems. A new way to study these
interactions is by using electron transfer
theory. The rate of electron transfer
between redox centers is dependent on
several factors, including...
Antibiotin was labeled with colloidal Au
nanoparticles as a method of amplifying the
localized surface plasmon resonance
(LSPR) extinction maximum shift. This shift
allows for the monitoring of binding events
on the surface of nanosphere nithography
(NSL) fabricated silver nanoparticles. A
shift of +2.9 nm was observed for the
colloidal...
Magnetic nanostructures are of great
interest as platforms for medical applications,
including biomedical imaging and
targeted cancer therapy. However, current
magnetic nanostructures are limited by
magnetic strength and insufficient
biocompatibility. In this research project,
significant progress was made to address
these confines, including 1) increasing
magnetic responsiveness by replacing the...
Amyloid-β oligomers, also known as
amyloid-β derived diffusible ligands
(ADDLs), have been implicated in numerous
studies as being a possible cause for
Alzheimer’s disease (AD). The goal of this
study was to investigate the kinetics of the
oligomerization of the monomer amyloid-β
(Aβ) into ADDLs in various ratios of
dimethyl...
Surface patterns, formed by the coassembly
of cationic-anionic amphiphiles into
cylindrical micelles, were analyzed. The
competition between electrostatic forces
and the net incompatibility χ arising from
the different chemical natures of those
oppositely charged amphiphiles resulted in
the formation of segregated domains. These
surface domains are not macroscopically
segregated due...
The purpose of this study is to characterize
the nanometer-scale structure of an Al2O3-
W-Ge multilayer utilizing x-ray reflectivity.
Attributes such as layer thickness, density,
surface, and interface roughness are
determined and explained. The reasons for
using this particular multilayer are also
reviewed, as well as the benefits to science...
In this work, computational electrodynamics
is used to calculate extinction,
scattering, and local electric fields around
the transition metal nanoparticles. Rhodium
and ruthenium exhibit plasmon peak shifts
as a function of local refractive index
comparable to particles of silver and gold.1,2
In addition, the local fields calculated
indicate that Rh...
There is a continuing need for patterning
multifunctional materials to harness their
features and explore synergy among
diverse properties and phenomena. Soft
lithography, among various patterning
techniques, is a versatile method that can
generate inorganic patterns in a parallel
mode. Experimentation was performed
making use of flexible soft lithography to...
Carbon nanotubes have been shown to
behave as very effective conductors and
semiconductors, but their electronic uses
are limited by how well metallic and
semiconducting nanotubes can be sorted.
Recent investigations have shown an
effective method of separating laser
ablation–produced carbon nanotubes by
electronic type. However, laser ablation
nanotubes are...
Second harmonic generation (SHG),
a nonlinear optical tool, was used to
characterize DNA bound through a
chemical linker to the flat surface of a
hemispherical lens. Contact angle
measurements were used to guarantee
that the chemical linker did not hydrolyze
under experimental conditions. SHG
experiments followed the effects of salt...
Two-phase multiferroic nanostructures
have the potential to display magnetoelectricity
(ME) through interphase mechanical
coupling. Nanoscale ME-based technology
may lead to the next generation of computer
memory. In this research, soft electron
beam lithography (soft-eBL) was used to
fabricate submicron-sized structures of
cobalt ferrite (magnetostrictive) and barium
titanate (piezoelectric) as bottom...
Oligonucleotide-functionalized gold
nanoparticles (DNA-Au NPs) find
ubiquitous use in various biomolecular
detection schemes due to their unique
chemical and physical properties. This
study investigates the effects of nanoparticle
size and concentration of salt in
solution on the DNA loading of the Au NP
surface. The DNA loading studies are
performed...
The effects of volumetric size-control
techniques on the photoinduced conversion
of silver colloids to triangular nanoprisms
were examined. It was hoped that through
the application of size-control techniques
on photocatalyzed reactions, a new method
of controlling particle dimensions could
be established. Initial work focused on
optimizing the synthesis procedure in...
The use of a variable resistor-capacitor
(RC) bridge circuit was previously reported
to be a viable solution to the spurious
contribution of fringe capacitance during
nanoscale impedance microscopy (NIM).
In this paper, a refinement of this technique
combined with standard NIM is presented
as an impedance characterization tool for
organic...
The need to improve sensing technology for
widespread application in everyday life is
fueling the development of diffraction-based
sensing, an optical sensing technique.
Selectivity and sensitivity issues must first
be resolved. Both selectivity and sensitivity
can be increased by using resonance conditions
— that is, using a probe wavelength
where...
Many studies have focused on harnessing
the extraordinary optical properties of
noble metal nanoparticles for the development
of biological and chemical nanosensors.
Metallic nanoparticles emulate
surface roughness, facilitating the coupling
of light to surface plasmon polaritons. The
excitation of the plasmons enhances the
electromagnetic field near the surface so
that...
The aim of this research was to investigate
the use of atomic force microscopy (AFM)
for the high-resolution imaging of collagen
fibers in aqueous media. Collagen plays a
vital role in many processes in vivo, especially
in structural integrity, yet few studies
have used AFM to investigate the structure
of...
This project involved the study of Brownian
motion of polystyrene microspheres in the
presence of gravity and a one-dimensional
sinusoidal optical potential generated by
the interference of two laser beams. An
exponential relationship was observed
between applied laser power and particle
residence time of individual interference
fringes. Increasing laser power...
In this study, ligands modified to contain
a metal ion were synthesized and their
electrochemical properties were examined
alone and in the presence of a protein. We
chose to use avidin and biotin as a model
system. Probes have been developed in
which biotin is modified to coordinate to
a...
This work exploits the use of noble metal
nanoparticles to achieve sensitive and
selective detection of chemical and
biological analytes. The localized surface
plasmon resonance (LSPR) of these metal
nanoparticles is known to be sensitive to
shape, size, and the local environment.
Ag nanoparticles fabricated using the
nanosphere lithography (NSL)...
In this experiment, the optical properties
of several spherical nanoparticles were
observed. Particles were modeled using
Mie theory, a set of equations that calculate
the extinction coefficient of virtually any
spherical particle. Initially this theory was
used to model solid particles made of noble
metals. As time passed, its scope...
Weak interactions in ligand-receptor
pairs are important in biological systems.
However, the energetics of these interactions
are often difficult to quantify for ligandreceptor
pairs. Weak interactions are a part
of reorganization energy, which plays a role
in electron transfer reactions. Under certain
conditions the rate of electron transfer
can be...
The bio-barcode assay is a nanotechnology-based
method for capturing and
detecting proteins. It shows extraordinary
sensitivity in detecting certain antigens at
extremely low concentrations, now without
the use of the polymerase chain reaction
(PCR). This assay uses disease identification
biomarkers that cannot be used in the
conventional assays of today....
This report describes the development of
bioorganic small-molecule complexes for the
directed assembly of functional nanomaterials.
In particular, it examines the synthesis of
small acetylene-based organic precursors for
attaching DNA to form DNA/organic hybrids.
This work continues previous studies
demonstrating how DNA/polymer hybrid
composites have sharper melting points than
DNA...
The intention of this research was to investigate
the ink diffusion that takes place in
dip-pen nanolithography in order to better
understand how to enhance the possibilities
of nano fountain probes. Varying concentrations
of 16-mercaptohexadecanoic acid in
ethanol were used as ink in dip-pen nanolithography,
and the relationships between
contact...
Monolayers on H-Si(111) were formed thermally
using decene and 10-bromodecene.
Samples were subjected to 100 percent
humidity in order to induce oxidation for
upwards of three weeks. The ability of
bromine to bind to the Si(111) and inhibit
oxidation through steric hindrance was
intended to be analyzed. Atomic force
microscopy...
In this study liquid-phase nanolithography
(LPN) techniques using conductive atomic
force microscopy are investigated in order
to study properties of nano-patterned
organic molecules covalently bound to a
silicon substrate. Previous work has shown
that LPN in the inert organic solvent hexadecane
forms patterned features on
hydrogen-passivated Si(111). Due to hexadecane’s...
The purpose of this study was to select an
alloy with a low driving force for nucleation
for a more in-depth study of the nucleation
of γ’-precipitates. To do this, three Ni-Cr-Al
alloys were chosen close to the solvus line
of a Ni-Cr-Al phase diagram, ensuring low
supersaturation and therefore...
In this study attention was focused on a
templated fabrication of Au nanotubular
structures that could carry a highly magnetic
entity such as cobalt. In brief, experimentation
was performed to create Co@Au
core-shell nanorods of different lengths. The
preliminary core-shell structures were first
characterized using x-ray diffraction (XRD),
scanning electron...
This project focused on the growth of Cu2O
nanocubes in microwells from nanoparticle
“seeds.” The seeds were first formed by the
reduction of copper sulfate with ascorbic
acid in the presence of the surfactant
poly(ethylene glycol) (PEG). Upon reaction
within the microwell, the seed solution
formed a larger single crystal....
The performance of mixed-phase TiO2 was observed in an effort to test its practical use as
a semiconductor photocatalyst. Synthesis of mixed-phase TiO2, characterization using xray
diffraction analysis, monitoring testing using the gas chromatography-FID, and
testing gas phase reactor were four techniques used in this research to evaluate mixedphase
TiO2....
Chemical vapor deposition was used to
synthesize CdS nanowires via the vaporliquid-solid
growth mechanism. After Ti/Au
contacts were patterned to the nanowires
using electron beam lithography, photoresponse
studies were conducted. A significant
response was observed when the
wires were exposed to visible light; this
occurred as electrons in the nanowires...
This paper explores the various approaches
to time-resolved single nanoparticle spectroscopy.
Due to the novelty of these types
of experiments, several difficulties arise in
creating a feasible physical setup capable
of imaging single nanoparticles less than
100 nm in size. The various difficulties in
setup and their attempted resolutions will...