The concept of reducing laboratory operations in scale such that they fit on a microfluidic chip has been met with great enthusiasm. Lab-on-a-chip devices promise to be cost effective to operate due to reduced reagent consumption, have the potential to offer shorter analysis times due to their short path lengths,...
The concept of reducing laboratory operations into microfluidic devices has been an attractive area of research for several decades. Due to several advantages of porous-media microfluidic devices including low mass, portability, power-free fluid transport, and the ability to store dried reagents in the porous structures, these devices show great promise...
For a number of reasons, miniaturization of chromatographic columns has been a general trend over the past three decades. Methods designed to enhance selectivity and efficiency can offer improved separation power and speed, expanding on the advantages of miniaturized columns. This dissertation describes novel approaches in this direction, focusing on...
A microfluidic nanofiltration module has been designed, fabricated and applied to the continuous-flow, pressure-driven, post-synthetic purification of macromolecules and nanoparticles via diafiltration using a commercially available organic solvent resistant nanofiltration membrane, STARMEM 122. This module will readily interface with other microscale components within a
"nanofactory" for the rapid synthesis, purification...
The overall concept of reducing laboratory operations to a scale that fits on a single microfluidic chip has been an attractive area of research over the last several decades. Despite a surge in research, few commercial success stories have been written. Lab-on-a-chip technologies have the capability to be cost effective...
Analytical chemistry is an area of chemistry primarily focused on the study and use of instruments for separation, identification, and quantification of an analyte of interest. Specifically, separation science within analytical chemistry often refers to the process of dividing mixtures into their small component parts based on differences in their...
Miniaturized and portable microfluidic analytical platforms have been widely explored in the broad field of chemical analysis. The concept of microfluidics offer a number of important advantages, including low reagent consumption, low-cost detection, high sample throughput, and shorter analysis time. Semiconductor nanocrystals or quantum dots have been extensively utilized in...
The development of micro total analysis systems (µTAS), also called “lab-on-a-chip”, or microfluidic analysis systems, is presented in this dissertation. Various research areas, covering subjects from magnetic particles synthesis to novel microchip fabrication techniques, are explored to develop a lab-on-a-chip system capable of performing magnetic bead-based bioassays. These devices are...
There has been a tremendous growth in interest in carbon nanodots (C-dots) in the past several years. As a nascent nanomaterial, C-dots have shown great promise in applications that benefit from their superior water dispersibility, low toxicity, non-blinking fluorescent output, chemical and biological compatibility, ease of functionalization and resistance to...
The emerging field of nanotechnology strictly requires the micro-scaling of the available separation technology and the design of novel devices for separations of molecules of interest. The separation of proteins and nanoparticles is challenging due to their relatively large size, non-specific adherence to surfaces and instability in many solvents.
This...
Due to a number of disadvantages associated with the use of antibodies as
affinity stationary phases, researchers have recently began to explore the use of RNA
and DNA aptamers for use as affinity stationary phases. These molecules have been
shown to be a viable choice for applications in many methods...
The challenges prompted by miniaturization of chromatographic systems have led scientists to explore new avenues in the synthesis of stationary phases. Packed capillary columns have found limited application in routine analysis due to a number of technical difficulties, most of which are attributable to the frits. New column designs insure...
Over the last decade, the miniaturization of analytical systems has become an increasingly important and interesting research area. Miniaturized systems offer many advantages, including reduced reagent and sample consumption, shorter analysis times, portability and disposability. This dissertation describes novel approaches in this direction, focusing on two areas: the miniaturization of...
The development of microfluidic devices for heavy metal extraction is presented in this dissertation. Various research areas, covering subjects from photochromic compound syntheses to microchip fabrication techniques are explored to develop microfluidic devices capable of extracting heavy metal ions from drinking water. Through integration of the beneficial characteristics of both...
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VincentT. Remcho
The development of microfluidic devices for heavy metal extraction is
Analytical techniques are utilized in a wide variety of applications. Traditionally, analytical measurements are achieved by trained personnel in a laboratory setting using expensive scientific instruments, which limits their applicability in resource-limited areas and point-of-care applications. Therefore, the concept of enabling these laboratory-based qualitative and quantitative assays in microfluidic device...
The intriguing size- and shape dependent properties of nanoparticles have garnered recent attention in many science and engineering areas. When the particle size is in the nanometer size range, the material exhibits very different properties such as surface plasmon resonance (of gold nanoparticles) and superparamagnetism (of iron oxide nanoparticles). The...
Continued interest in the development of miniaturized and portable analytical platforms necessitates the exploration of sensitive methods for the detection of trace analytes. Nanomaterials, on account of their unique physical and chemical properties, are not only able to overcome many limitations of traditional detection reagents but also enable the exploration...
Dielectrophoresis (DEP) is a separation method in which a non-uniform electric
field is used to induce a dipole moment in a suspended particle. If the polarization
of the particle is greater than that of the suspending medium, the particle will move
towards the region of higher field strength (positive DEP);...
Since their discovery in the 1990s, the great potential of carbon nanotubes (CNTs) has made them a focus of many research endeavors, including their application as components of biosensors. The inherent chemical "inertness" of CNTs makes their application to biosensing a challenge. It is necessary to "decorate" their surfaces to...
Electrodeposition is a versatile polymer deposition technique to create nano-microscale materials using an electrical field generated from a charged droplet of solution and a grounded collector. Electrospinning or electrospraying can occur during electrodeposition, leading to the creation of nanofibers or bead-like materials depending on the process parameters. Photopolymerization of the...
We have developed a compact micro total analysis system (μTAS) to serve as a platform for in-situ spectrophotometric water quality monitoring. Individual fluidic, optical, and electrical components were designed, developed, and characterized. These components were combined in both an integrated (single lithographic “chip-based” platform) and a modular manner. The microfluidic...
Advances in energy technologies and electronics have typically occurred through either heightened performance or cost reduction. This dissertation explores both routes through a series of fundamental material studies that may contribute to the enabling of next generation devices. Solution based syntheses and deposition of chemical products offer a low cost...
The development of nanomaterials and the potential enhancement of their chemical, mechanical, electrical, and optical properties have led to the investigation of methods for their synthesis at lower cost with enhanced performance for next generation devices. Along with the pursuit of new materials that exhibit properties of interest, industry requires...
Dental plaque is one of the well-characterized biofilms in the human body. Oral bacterial species play vital roles in maintaining healthy bacterial homeostasis as well as causing oral infections. Many of the oral diseases are caused by opportunistic pathogens, and therefore, the bacterial metabolic activities become important in dictating their...
The general theme of this dissertation is the development of new analytical sensors to quantitatively study biological and environmental samples in aqueous and non-aqueous environments. A platinum ultramicroelectrode (UME) and a unique carbon-based pH microprobe were used to design a new SECM-based electrochemical bioassay. The Pt UME was used to...
Microalgae has been under careful consideration as a sustainable feedstock for renewable fuel recently due to its year round production with high energy yields per unit area, reduced need for arable land, water treatment benefits with nutrient cycling, and minimal competition with the food industry. Despite of all these advantages,...
Ethanol production from lignocellulosic feedstock has been under intense scrutiny as a transportation fuel due to its potential to address concerns of increasing energy consumption, limited fossil energy resources, climate changes due to greenhouse gas emissions from fossil fuels, and especially use of non-food biomaterials, which address the biggest limitation...
Background: The Oregon Wrestling Weight Monitoring Program establishes the athlete’s minimum wrestling weight (MW) for the season. This program specifies the
wrestler’s maximum weight loss rate and was implemented in order to reduce
unhealthy weight-cutting behaviors commonly practiced by wrestlers. Aims: (1) To
compare differences in percent body fat (%BF)...
While fluorochemicals have been detected all over the world and in wastewater
treatment plants, the effect of wastewater effluent on the receiving waters has not been
evaluated. In the first study, the mass flow of fluorochemicals emanating from
wastewater treatment plants along the Glatt River in Switzerland was evaluated. The...
This dissertation describes the racemic and enantioselective synthesis cavicularin. Cavicularin is a macrocyclic bisbibenzyls family member natural product. It has been an attractive synthetic target due to its intriguing structure: the macrocyclic core imparts sufficient strain on the system to force one benzene rings to adopt a boat-shaped conformation, out...
Fluorinated alkyl substances, which can be persistent, toxic, and
bioaccumulative, have been quantitated in many densely populated and
remote regions, including in air, surface waters, groundwater, and biota;
however, little is known about their transport or behavior in the environment.
Wastewater effluent is one of the principal routes for introducing...
It is often perceived that late maturity of grape gives a more complex aroma
profile to Pinot noir wine, however, there is little understanding of the basic flavor
chemistry of grape maturity on wine aroma. The aroma contributing compounds in
Pinot noir were first identified by aroma extract dilution analysis...
Novel synthetic strategies are developed to prepare new intercalation compounds and nanocomposites with several layered hosts (NiPS₃, Na-montmorillonite, MoS₂ and MoO₃). In these products, alkali metals are ionic intercalates and linear polymers, dendrimers or amines act as co-intercalates. In addition to new synthetic approaches, new structures are identified and characterized....
Ion-selective polymeric optical sensors – ion optodes – are a promising alternative to ion-selective electrodes and fluorescent dyes for analytical and biological applications, e.g. extra- and intracellular measurements. They are non-toxic, highly selective robust probes for ionic fluxes monitoring.
A large-scale fabrication of ion optodes using a solvent displacement method...
The materials Fe₂(Si,Ge)(S,Se)₄, Cu₃PS[subscript 4-x]Se[subscript x] (0 ≤ x ≤ 4), and Cu₃PxAs[subscript 1-x]S₄ (0 ≤ x ≤ 1) have been synthesized and studied as new earth-abundant absorbers for single and multijunction photovoltaic cells as well as solar fuel generation. The synthesis, single-crystal growth, and optical and electrical properties of...
It is the responsibility of humans, as environmental stewards, to monitor our impact on the environment so that efforts can be made to remediate the effects of our actions and change behaviors. To better understand our environmental footprint, sensitive and simple analytical methods are needed to quantify the contaminants that...
One post-transcriptional mechanism that regulates the progression of cancer and other diseases involves small 22-23 nucleotide sequences called microRNA (miR). Early detection of small changes in concentration of these biomarkers holds potential to diagnose diseases at their earliest stages. Use of current nucleic-acid based biosensors, like molecular beacons, for in...
The influence of cultivar and maturity on polyphenolic composition and
antioxidant activity was investigated by UV-Visible spectrophotometry and
analytical high performance liquid chromatography (HPLC) in commercially
important blackberry cultivars and selections. The anthocyanin pigments changed
tremendously with ripening. Total anthocyanins increased from 74.7-317 mg/100g
fw from underripe to over ripe...
Dendrimers are nanoscale macromolecules that have highly branched, core-shell structures. Higher generation dendrimers have close-packed peripheral functional groups and a hollow interior. The chemistry of the core and the terminal functionalities can be tailored according to the specific application. These structural characteristics provide room for the design of dendrimers to...
The distribution of anthocyanin pigments and polyphenolics of sweet (Prunus avium) and sour cherries (Prunus cerasus) were determined by Ultraviolet- Visible (UV-Visible) spectrophotometry and High Performance Liquid Chromatography with photodiode array detector (HPLC-DAD). Their antioxidant properties were determined by Oxygen Radical Absorbance Capacity (ORAC) and Ferric Reducing Antioxidant Power (FRAP)....
Historically, brewers have used dry-hopping (a cold extraction of nonvolatile and volatile chemicals from hops into fermenting or finished beer) to increase the microbial stability and shelf life of their beer. As hoppy beer styles have gained in popularity over the last decade (2007-2017), the objective of dry-hopping has turned...
New analytical methods and instrumentation were developed for the determination of dissolved oxygen (DO) at low concentrations in water. The methods were based on monitoring the absorbance increase due to the oxidation of reduced indigo carmine (IC) by oxygen in the sample in different types of spectrometer cells. Spectrophotometer cells...
Proteins are essential to all biological systems. Proteins participate in numerous cellular processes by interacting with other proteins, other metabolites and membranes in a dynamic environment. Studying the structural and conformational properties of proteins in the solution phase is necessary to understand their protein folding and interaction dynamics. This research...
Public attention and concern about per- and polyfluoroalkyl substances (PFASs) are increasing due to detection of PFASs in drinking water supplies, the environment, including remote locations, and wildlife and to the lowering of the federal health advisory levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in drinking water. Aqueous film-forming...
Used Nuclear Fuel (UNF) contains transuranic (TRU) elements and numerous fission products as a result of the uranium fission process and neutron activation that occur in commercial light water power reactors. Recent environmental and nuclear proliferation concerns have spawned the development of advanced reprocessing techniques to close the nuclear fuel...
Transition metal oxides are an important class of materials for the wide variety optical, electrical, dielectric, magnetic, and thermal properties observed. Their unique structure-property relationships allow for property tuning and often provide insight into the fundamentals of chemistry. The work in this thesis was focused on the design, synthesis and...
The focus of this study is to develop a general and low-cost solution-based
process to fabricate micro- and nano-structured semiconductors that are suitable
for electronics. This process uses simple metal halide precursors dissolved in a
solvent (organic or aqueous) and is capable of forming uniform and continuous
thin films via...
Carboxylic acids have played an important role in the field of actinide (An) and lanthanide (Ln) separations and the reprocessing of irradiated nuclear fuel. Recent bench-scale experiments have demonstrated that 3-carboxy-3-hydroxypentanedioic acid (citric acid) is a promising aqueous complexant that can effectively aid in the separation of transition metals from...
State-of-the-art, high-resolution mass spectrometry techniques for acquisition of metabolomic and lipidomic data coupled with advanced computational methods provide new opportunities for interpreting large and complex datasets and comprehending the underlying biological processes of diseases. Both metabolomics and lipidomics strive to obtain comprehensive analyses of small molecules, i.e., metabolites and lipids,...
There is significant interest in harnessing the biosynthetic capacities of photosynthetic diatom microalgae for the production of unique bioinspired nanomaterials. Specifically, this research focuses on understanding the photoluminescent properties of diatom biosilica and β-chitin nanofiber production in diatoms. Diatoms are single-celled microalgae that possess intricately patterned biosilica shells called, frustules....