Electrospinning and electrospray are both nano-scale material fabrication techniques, based on related phenomena of electrically charged fluid spray from a droplet of liquid. Material is dissolved in liquid, then a spray is generated by applying a high voltage, creating an electric field, between the fluid dispensing capillary and a grounded...
A novel approach for the colorimetric detection of creatinine in a paper/polycaprolactone hybrid microfluidic device using alkaline3,5-dinitrobenzoate (DNB) is described. The reaction parameters of reagent concentration, alkalinity, and analysis time are optimized for fast reaction times and high color yield. Microfluidic devices incorporating this assay are designed and fabricated to...
The detection of biomolecules is critical for clinical diagnostics but requires specialty labor and high cost. The use of microfluidic paper-based analytical devices (µPADs) for bioassays is simpler and cheaper but has low sensitivity. Improved immobilization of antibodies onto cellulose is demonstrated through surface functionalization with APTES and glutaraldehyde. The...
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,...
Two improvements to the established procedures for synthesis and response detection of ion-selective optical sensors (optodes) were introduced.
The first improvement addresses the drawback of organic dye (optode-localized chromoionophore) photobleaching. This positively impacts fluorescence response and allows for (1) direct measurement of hydrogen ion activity upon binding with the dye,...
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...
A simple Janus-type membrane-based wicking microfluidic device fabricated on a polycaprolactone-filled glass microfiber membrane enables separation and collection of blood plasma or serum from whole blood. This device bridges the wicking and cut-capillary-based solution transport mechanisms in a single membrane. The initial portion of the device is fabricated using selective...
Gene synthesis is an important tool in molecular biology. However, the current
bench-top method of gene synthesis is a costly, time-intensive and reagent-consuming
process. Lab-on-chip technology has many benefits over current bench top methods.
Microchips consume smaller reagent volumes, are reusable and less expensive to make.
This thesis explores the...
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 simple, rapid, and sensitive methods for thiophenol detection is of great importance in various fields, including environmental monitoring and food quality. Here, we present a novel approach for the colorimetric detection of thiophenols using gold nanoparticles (AuNPs) as the sensing platform. AuNPs aggregate in the presence of...
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...
A system of Photoactuated Droplet Microfluidics (PDM), in which a droplet of
fluid is moved by way of the manipulation of the wettability of a spiropyran
functionalized surface via irradiation with ultraviolet and visible light, was proposed. The
photochromic behaviors of several species of spiropyran were studied and a procedure...
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...
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...
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...
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...
High Performance Liquid Chromatography-Mass Spectrometry coupled with filtration, centrifugation, and other common sample preparation techniques offers a rapid and robust method for separating and quantifying propofol, a commonly used anesthetic, from human blood and its synthetic analogs. Method development is important for not only optimizing separation and quantification for a...
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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Vincent T. 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...
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...
The cross over from batch nanoparticle synthesis to continuous synthesis processes is crucial to the commercialization of these materials. This project reports comparative studies of batch and continuous synthese of copper nanoparticles by the polyol method. Continuous synthesis of copper nanoparticles was done utilizing a stainless steel micro-mixer that yielded...
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Vincent T. Remcho
The cross over from batch nanoparticle synthesis to continuous
A system to reversibly extract Pb²⁺ ions from aqueous solutions using spiropyran functionalized nanofibers was proposed. Spiropyrans are photochromic compounds which undergo a conformational change that alters their physical properties and makes Pb²⁺ binding possible upon irradiation with UV light (365 nm). Irradiation with green light (525 nm) reverses this...
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...
Capillary electrophoresis as a technique has many applications in a broad range of fields including forensics, environmental analysis, and biological analysis and as a separation method for samples such as oligonucleotides, peptides, proteins, and pharmaceuticals. The research conducted herein is for the antibiotic pharmaceutical ciprofloxacin HCl and three impurities. Sample...
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...
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...
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...
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...
Over the last decade, the use of highly branched macromolecules, called dendrimers, is emerging. Polyamidoamine (PAMAM) dendrimers, in particular, have attracted high interest due to their unique properties, such as well-defined size, shape, and solubility in water. Our group, as part of an interdisciplinary team, is currently working on developing...
The “why” of any situation is one of the most important questions to ask. Inventors have ideas every day. Some ideas are the brilliant ideas that lead to a better tomorrow. To protect these ideas, inventors turn to patents, a governmental grant of the right to stop others, for a...
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...
Experiments were conducted with two strains of the coccolithophorid Emiliania huxleyi. Previous experiments with CCMP1742 and 372 at a light intensity of 60 µEin/m²-s showed that during five-day periods of continuous darkness, strain 1742 was taking up nitrate from the media while strain 372 was not. The nitrate uptake in...
The objective of this study was to identify aroma volatiles in sweet whey powder. Volatiles were isolated by solvent extraction and solvent assisted flavor evaporation. Fractionation was followed to separate acidic volatiles from nonacidic volatiles. Gas chromatography/olfactometry and gas chromatography-mass spectrometry were used for the identification ofaroma compounds. Osme methodology...
This report details preliminary studies towards the development of a microfluidic
sensor that exploits ferromagnetic resonance, excited in magnetic bead labels, for signal
transduction. The device consists of a microwave circuit in which a slotline and a coplanar
waveguide are integrated with a biochemically activated sensor area. The magnetic beads...
Full Text:
.
Vincent T. Remcho received his BS in biochemistry in 1989 and his Ph.D. in chemistry
(with Prof. Harold
This report details preliminary studies towards the development of a microfluidic
sensor that exploits ferromagnetic resonance, excited in magnetic bead labels, for signal
transduction. The device consists of a microwave circuit in which a slotline and a coplanar
waveguide are integrated with a biochemically activated sensor area. The magnetic beads...
Full Text:
@eecs.oregonstate.edu,
Oregon State University
Remcho*, Vincent
Department of Chemistry, Vincent.Remcho
This report details preliminary studies towards the development of a microfluidic
sensor that exploits ferromagnetic resonance, excited in magnetic bead labels, for signal
transduction. The device consists of a microwave circuit in which a slotline and a coplanar
waveguide are integrated with a biochemically activated sensor area. The magnetic beads...
This report details preliminary studies towards the development of a microfluidic sensor that exploits ferromagnetic resonance, excited in magnetic bead labels, for signal transduction. The device consists of a microwave circuit in which a slotline and a coplanar waveguide are integrated with a biochemically activated sensor area. The magnetic beads...
In this paper we present a novel fabrication technique that utilizes polycaprolactone (PCL) as bonding media due to its low melting temperature property. PCL is biodegradable polyester with a melting point of 60°C, and a glass transition temperature of -60°C [1-10]. It is employed as a rapid bonding technique in...
New graphite intercalation compounds (GICs) containing N,N-n-alkyl substituted pyrrolidinium cation intercalates (Py[subscript n.m], n, m = alkyl chain lengths) are obtained via cationic exchange from stage-1 donor-type GIC [Na(ethylenediamine)₁.₀]C₁₅. Powder X-ray diffraction and thermogravimetric analyses are used to determine the GIC structures and compositions. [Py₄.₈]C₄₇·0.71DMSO and [Py₈.₈]C₄₈ with intercalate monolayers...
Chemical synthesis of oligonucleotides is a widely used tool in the field of biochemistry.
Several methods for gene synthesis have been introduced in the growing area of genomics.
In this paper, a novel method of constructing dsDNA is proposed. Short (28-mer) oligo fragments
from a library were assembled through successive...
Full Text:
and an
Oligo Library
Sumate Pengpumkiat1, Myra Koesdjojo1, Erik R. Rowley2, Todd C. Mockler3, Vincent
Chemical synthesis of oligonucleotides is a widely used tool in the field of biochemistry.
Several methods for gene synthesis have been introduced in the growing area of genomics.
In this paper, a novel method of constructing dsDNA is proposed. Short (28-mer) oligo fragments
from a library were assembled through successive...
Chemical synthesis of oligonucleotides is a widely used tool in the field of biochemistry. Several methods for gene synthesis have been introduced in the growing area of genomics. In this paper, a novel method of constructing dsDNA is proposed. Short (28-mer) oligo fragments from a library were assembled through successive...
The Micralyne microfluidic toolkit (μTK) was an instrument built by Micralyne in the early 2000’s. It was built for electrophoresis and has a sensitive laser-induced fluorescence detection system. The updates to the system were upgrading the control GUI from running in LabVIEW 5 (Windows XP, 2000) to LabVIEW 2012 (Windows...
Halogenated Polycyclic Aromatic Hydrocarbons (X-PAHs) are ubiquitous contaminants that are thought to be generated by processes such as chemical industries and incomplete combustion, including waste incineration and electronic waste (e-waste) burning. X-PAHs are a concern for environmental and human health because they are toxic, mutagenic, and are expected to be...
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...
Radiation exposure to the brain can occur from a variety of events, including space missions, nuclear accidents, and clinical treatments. The effects of high dose radiation are well studied, but those of lower dosage are more elusive. Decline of memory and cognition is observed in patients exposed to low dose...