Several phosphonate-functionalized molecular
squares have been successfully synthesized,
and the fabrication of multilayer films
on both conductive and semiconducting
platforms has been demonstrated. These
films were grown using the well-documented
zirconium phosphonate multilayer method.
The layer-by-layer growth rate is uniform.
Experiments suggest, however, that the
molecular squares adopt a semi-collapsed...
The development and applications of
organic/DNA molecules for the use of DNA
detection systems are reported here. In particular,
two different hybrids are synthesized:
DNA/polymer hybrids and small-molecule
DNA hybrids. DNA/polymer hybrids are especially
useful considering that their functionality
may be varied according to the polymer
selected. The hybrids are...
Recent research suggests that ultraviolet
illumination is essential for the creation of
monolayers of Undecylenic Acid Methyl
Ester (UDAME), as it is believed that the
UV illumination initiates the radical-chain
polymerization. Samples created without
UV illumination, however, also show signs
of a monolayer. In this study, samples were
analyzed using...
This research project explores two different
processes that can be used to pattern
organic molecules on silicon. In the first
process, hydrogen-terminated silicon surfaces
were anodized in nanometer scale with
a contact-mode atomic force microscope
(AFM). Anodization was done by applying a
positive bias voltage to the surface with
respect...
Feedback-controlled lithography (FCL)
enables atomically precise patterning of
individual molecules on the technologically
significant Si(100)-2 x 1:H surface. However,
because it is performed in an ultrahigh vacuum
(UHV) environment, FCL has thus far
been restricted to surface chemistries that
can be delivered in the gas phase. The present
research attempts...
Transmission and reflection diffraction
gratings were fabricated by micropatterning
polymers on transparent substrates and
drop-coating polymers onto etched silicon
wafers. Exposure of these gratings to three
nerve toxin mimics at very low concentrations
resulted in mimic sorption by the polymers,
changing the polymer’s refractive
index. As a result, the grating’s...
The effects of 13 nm Au colloid and 10 nm Ag
colloid on the growth of the yeast species
Saccharomyces cerevisiae were compared
to control samples cultured in a growth
media of yeast extract, bacto peptone, and
dextrose (YPD) to determine the toxicity of
nanoparticles. Growth curves were generated
for...
In modern medicine, physicians destroy
otherwise healthy tissues in patients’ bodies
because of the lack of site-target specificity
and sensitivity in detecting and attacking
cancerous cells. Many cancer patients are
left with the difficult task of weighing the
benefits against the harm of undergoing
current cancer treatments. Members of the...
Chemists and physicists have been interested
in the optical properties of metal nanoparticles
since the time of Michael Faraday.1
New approximation techniques for different
sizes and geometries have created renewed
interest in and investigation of these particles.
Many different arrays of particle extinctions
of various shapes and sizes have been...
While nanoscale device prototypes using
carbon nanotubes abound, no mass
production-scale technique exists for examining
properties of a batch of nanotubes.
Dielectrophoresis, on the other hand, has
received much attention in the press as a
method of separating and trapping particles.
In this research, a method of developing
mass production-scale...
Fullerene and inorganic fullerene-like nanotubes
are molecules with the unique geometry
of a single layer or multiple layers of a bulk
material oriented in a tube. These molecules
have novel mechanical properties and great
potential in experimental systems for nanotechnology
and nanodevices. The threedimensional
atom-probe (3DAP) microscope
is an atomic...
The effects of Ru, W, and Re on the temporal
evolution of the gamma prime precipitates in
a Ni-Cr-Al alloy were investigated by threedimensional
atom probe (3DAP) microscopy.
The spatial distribution of the gamma prime
precipitates in a model Ni-8.5Cr-10Al alloy
was investigated using atomic force
microscopy (AFM). We reported...
This study investigated the precipitation
strengthening of the binary Al-0.14wt% Sc,
0.16% Ti alloy system. Ingots of Al-2.1wt% Sc
and Al-4.68wt% Ti were melted together, and
the nucleation, growth, and coarsening of
precipitates were analyzed. The microstructural
evolution of the nanoscale L12 precipitates
phase was examined with Vickers
microhardness testing,...
Electron transfer theory predicts reorganization energy to be one factor that determines the electrochemical potential of a metal ion. This paper describes part of a study that aims to increase understanding of solvent reorganization energy in noncovalent systems by systematically varying the environment around a metal ion, specifically ruthenium. The...
Alzheimer’s disease (AD) is a progressive
mental disorder that affects 23 million people
worldwide. It is pathologically characterized
by amyloid plaques and tau tangles that
form in the brain. The hard, insoluble amyloid
plaques develop from the naturally
secreted amyloid beta peptide, which can
also assemble into toxic oligomeric forms...
Every year millions of Americans go to the
emergency room with symptoms of a heart
attack. More than half a million Americans
die each year of myocardial infarctions (MI)
caused by coronary heart disease (CHD).
CHD detection is currently limited to EKG
analyses of electrical signals generated by
the heart...
The optical properties of spherical gold
nanoparticles are calculated using classical
electrodynamics. The wavelength corresponding
to maximum extinction shifts to
longer wavelengths as the size of the
nanoparticle is increased. The influence of
higher-order multipoles is evident for large
nanoparticles, making the spectra more
complex. When the shell thickness of...
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...
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...
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....
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....
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...
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 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...
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...
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...
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 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....
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...
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...
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 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 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...
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...
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 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...
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 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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...