Other Chemistry Commons^™

In-Situ-Investigation Of Enzyme Immobilization On Polymer Brushes, Meike Koenig, Ulla König, Klaus-Jochen Eichhorn, Martin Muller, Manfred Stamm, Petra Uhlmann

Department of Chemistry: Faculty Publications

Herein, we report on the use of a combined setup of quartz-crystal microbalance, with dissipation monitoring and spectroscopic ellipsometry, to comprehensively investigate the covalent immobilization of an enzyme to a polymer layer. All steps of the covalent reaction of the model enzyme glucose oxidase with the poly(acrylic acid) brush by carbodiimide chemistry, were monitored in-situ. Data were analyzed using optical and viscoelastic modeling. A nearly complete collapse of the polymer chains was found upon activation of the carboxylic acid groups with N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide and N-Hydroxysuccinimide. The reaction with the amine groups of the enzyme occurs simultaneously with re-hydration of the …

Development Of A Microcolumn One-Site Immunometric Assay For A Protein Biomarker: Analysis Of Alpha1-Acid Glycoprotein In Serum, Chenhua Zhang, Shae Lott, William Clarke, David S. Hage

Department of Chemistry: Faculty Publications

A one-site immunometric assay based on affinity microcolumns was developed for the analysis of alpha₁-acid glycoprotein (AGP) as a model protein biomarker. In this assay, a sample containing AGP was incubated with an excess amount of a labeled binding agent, such as fluorescein-labeled anti-AGP antibodies or F_ab fragments. The excess binding agent was removed by passing this mixture through a microcolumn that contained an immobilized form of AGP, while the signal was measured for the binding agent-AGP complex in the non-retained fraction. Theoretical and practical factors were both considered in selecting the concentration of labeled binding agent, …

Nmr Metabolomics Protocols For Drug Discovery, Fatema Bhinderwala, Robert Powers

Department of Chemistry: Faculty Publications

Drug discovery is an extremely difficult and challenging endeavor with a very high failure rate. The task of identifying a drug that is safe, selective and effective is a daunting proposition because disease biology is complex and highly variable across patients. Metabolomics enables the discovery of disease biomarkers, which provides insights into the molecular and metabolic basis of disease and may be used to assess treatment prognosis and outcome. In this regard, metabolomics has evolved to become an important component of the drug discovery process to resolve efficacy and toxicity issues, and as a tool for precision medicine. A detailed …

Reversible Mechanical Deformations Of Soft Microchannel Networks For Sensing In Soft Robotic Systems, Abhiteja Konda, Donghee Lee, Taesun You, Xiaoyan Wang, Sangjin Ryu, Stephen Morin

Department of Chemistry: Faculty Publications

Microfluidics has enabled numerous applications in, for example, analytical chemistry, medical diagnostics, microelectronics, and soft robotics. In most of these applications, the geometries of the microchannels are of fixed dimensions that (ideally) remain invariant during operation. In soft robotics, however, the geometries of the microchannels contained in soft actuation systems are inherently dynamic, and the specific dimensions are expected to change during operation, and, by extension, the fluid transport properties of the system are variable. If this characteristic is not properly considered, or if methods are not developed to control it, the progress of soft robotic devices with distributed fluid …

Design Of Single-Molecule Multiferroics For Efficient Ultrahigh-Density Nonvolatile Memories, Qing Yang, Tingting Zhong, Zhengyuan Tu, Lin Zhu, Menghao Wu, Xiao Cheng Zeng

Department of Chemistry: Faculty Publications

It is known that an isolated single-molecule magnet tends to become super- paramagnetic even at an ultralow temperature of a few Kelvin due to the low spin switching barrier. Herein, single-molecule ferroelectrics/multiferroics is proposed, as the ultimate size limit of memory, such that every molecule can store 1 bit data. The primary strategy is to identify polar molecules that possess bistable states, moderate switching barriers, and polarizations fixed along the vertical direction for high-density perpendicular recording. First- principles computation shows that several selected magnetic metal porphyrin molecules possess buckled structures with switchable vertical polarizations that are robust at ambient conditions. …

Characterization Of The Microbial Phosphonate-Activating Pntc Enzymes, Kyle Rice

Theses and Dissertations (Comprehensive)

New strategies are urgently needed to combat infectious diseases in an era of rising antibiotic resistance. Furthermore, an emerging appreciation for the human microbiome’s role in maintaining health motivates discovery of species-specific antibiotics that minimally disrupt our native bacterial communities. Small molecule modifications to bacterial cell surfaces represent a potentially rich source of new targets for next generation antibiotics, as these molecules mediate virulence and evasion of the host immune response. Phosphocholine (PCho) is a rare cell surface modification that contributes to virulence, and modifications with phosphonates like 2-aminoethylphosphonate (AEP) are even more unusual and therefore provide opportunities for species- …

Molecular Memory With Downstream Logic Processing Exemplified By Switchable And Self-Indicating Guest Capture And Release, Brian Daly, Thomas S. Moody, Allen J.M. Huxely, Chaoyi Yao, Benjamin Schazmann, Andre Alves-Areias, John F. Malone, H.Q. Nimal Gunaratne, Peter Nockemann, A. Prasanna De Silva

Articles

Molecular-logic based computation (MLBC) has grown by accumulating many examples of combinational logic gates and a few sequential variants. In spite of many inspirations being available in biology, there are virtually no examples of MLBC in chemistry where sequential and combinational operations are integrated. Here we report a simple alcohol-ketone redox interconversion which switches a macrocycle between a large or small cavity, with erect aromatic walls which create a deep hydrophobic space or with collapsed walls respectively. Small aromatic guests can be captured or released in an all or none manner upon chemical command. During capture, the fluorescence of the …

Highly Selective Fluorimetric Turn-Off Detection Of Copper (Ii) By Two Different Mechanisms In Calix[4]Arene-Based Chemosensors And Chemodosimeters, Justine O'Sullivan, John Colleran, Brendan Twamley, Frances Heaney

Articles

Isoxazolo‐pyrene tethered calix[4]arenes selectively detect copper(II) ions without interference from related perchlorate ions. The fluorescence emission of the probes, synthesised by nitrile oxide alkyne cycloaddition, and characterised by spectroscopic and crystallographic data, is rapidly reduced by Cu(II) ions. Detection limits are in the micromolar or sub‐micromolar range (0.3–3.6 μM) based on a 1 : 1 sensor:analyte interaction. Voltammetric behaviour and 1H NMR data provide new insights into the sensing mechanism which is dependent on the calixarene substitution pattern. When the calixarene lower rim is fully substituted, Cu(II) detection occurs through a traditional chelation mechanism. In contrast, for calixarenes 1,3‐disubstituted on …

Synthesis Of N-Heterocyclic Molecules And Their Applicability Towards Ion Sensing: Polymeric Chemosensors, Aikohi M. Ugboya

College of Graduate Studies: Theses & Dissertations

Critical to biological and environmental processes are anions because often times their relative concentration in our body can be an indicator of one’s well-being. Therefore, highly sensitive and cost-efficient methods for ions recognition is necessary for human health. In recent times, polymeric chemosensors have become a vital tool for sensing ions because of its higher sensitivity and good mechanical properties compared to their monomeric counterparts. These sensors are designed to produce a measurable response in the presence of a targeted ion such as an electrochemical or optical signal. The unique structure and the photophysical properties of the 1,2,3-triazole core coupled …

Spheroid-3d And Monolayer-2d Intestinal Electrochemical Biosensor For Toxicity/Viability Testing: Applications In Drug Screening, Food Safety, And Environmental Pollutant Analysis, Evangelia Flampouri, Shahzad Imar, Kieran O'Connell, Baljit Singh

Articles

The rise of three-dimensional cell culture systems that provide in vivo-like environments for pharmaco-toxicological models has prompted the need for simple and robust viability assays suitable for complex cell architectural structures. This study addresses that challenge with the development of an in vitro enzyme based electrochemical sensor for viability/cytotoxicity assessment of two-dimensional (2D) monolayer and three-dimensional (3D) spheroid culture formats. The biosensor measures the cell viability/toxicity via electrochemical monitoring of the enzymatic activity of nonspecific esterases of viable cells, through the hydrolysis of 1-naphthyl acetate to 1-naphthol. The proposed sensor demonstrated strong correlation (r = 0.979) with viable …

Identification Of Burnt Smokeless Gunpowders Through Physical Characteristics, Cameron Taylor Hartwig

Graduate Theses, Dissertations, and Problem Reports (ETD)

Firearms are one of the most commonly used weapons by violent criminals throughout the United States. In crimes involving the discharge of a firearm, residues from the combustion products are deposited on the shooter and in the firing direction. Some of the residues left behind are unburnt and partially burnt particles of the propellant. The most common propellant used in modern firearms is smokeless powder. The identification of particles as smokeless powder and the determination of the brand of the powder are two ways a forensic examiner may be able to utilize smokeless powder evidence. The determination of the brand …

First Generation Amperometric Biosensing Of Galactose With Xerogel-Carbon Nanotube Layer-By-Layer Assemblies, Najwa Labban, Mulugeta B. Wayu, Ciara M. Steele, Tess S. Munoz, Julie A. Pollock, William S. Case, Michael C. Leopold

Chemistry Faculty Publications

A first-generation amperometric galactose biosensor has been systematically developed utilizing layer-by-layer (LbL) construction of xerogels, polymers, and carbon nanotubes toward a greater fundamental understanding of sensor design with these materials and the potential development of a more efficient galactosemia diagnostic tool for clinical application. The effect of several parameters (xerogel silane precursor, buffer pH, enzyme concentration, drying time and the inclusion of a polyurethane (PU) outer layer) on galactose sensitivity were investigated with the critical nature of xerogel selection being demonstrated. Xerogels formed from silanes with medium, aliphatic side chains were shown to exhibit significant enhancements in sensitivity with the …

Vibrational Analysis Of A Rate-Slowing Conformational Kinetic Isotope Effect, O. Maduka Ogba, Zichen Liu, Daniel J. O'Leary

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

An enthalpy-entropy approach to analyzing a rate-slowing conformational kinetic isotope effect (CKIE) in a deuterated doubly-bridged biaryl system is described. The computed isotope effect (kH/kD = 1.075, 368 K) agrees well with the measured value (kH/kD = 1.06, 368 K). The rateslowing (normal isotope effect) nature of the computed CKIE is shown to originate from a vibrational entropy contribution defined by the twenty lowest frequency normal modes in the ground state and transition state structures. This normal entropy contribution is offset by an inverse vibrational enthalpy contribution, which also arises from the twenty lowest frequency normal modes. Zero point vibrational …

Atom-Specific Activation In Co Oxidation, Simon Schreck, Elias Diesen, Jerry Larue, Hirohito Ogasawara, Kess Marks, Dennis Nordlund, Matthew Weston, Martin Beye, Filippo Cavalca, Fivos Perakis, Jonas Sellberg, André Eilert, Kyung Hwan Kim, Giacomo Coslovich, Ryan Coffee, Jacek Krzywinski, Alex Reid, Stefan Moeller, Alberto Lutman, Henrik Öström, Lars G. M. Pettersson, Anders Nilsson

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We report on atom-specific activation of CO oxidation on Ru(0001) via resonant X-ray excitation. We show that resonant 1s core-level excitation of atomically adsorbed oxygen in the co-adsorbed phase of CO and oxygen directly drives CO oxidation. We separate this direct resonant channel from indirectly driven oxidation via X-ray induced substrate heating. Based on density functional theory calculations, we identify the valence-excited state created by the Auger decay as the driving electronic state for direct CO oxidation. We utilized the fresh-slice multi-pulse mode at the Linac Coherent Light Source that provided time-overlapped and 30 fs delayed pairs of soft …

Stabilized, Hybrid Solid-State Photocatalysts For Water Purification: Preparation, Properties And Performance Under Visible Light Irradiation, Karpagavalli Ramji

Seton Hall University Dissertations and Theses (ETDs)

Stabilized heterogeneous photocatalysts that use only solar light and air have been prepared and successfully employed to decontaminate water from organic pollutants. Organic dye pollutants present, for example in textile effluents, are one of the major sources of water pollution owing to their limited biodegradability, toxicity and potential carcinogenic risks. Before certifying water for public consumption, reuse in industries or for discharge in surface water the organic pollutants must be degraded, an effort that is energy intensive and currently requires complex methodologies. We report solid-state photocatalysts that use only visible light and air to treat wastewater. Perfluoroalkyl perfluoro-substituted zinc phthalocyanine …

Kcnq1/Kcne1 Interaction In The Cardiac Iks Channel And Its Physiological Consequences, Jiajing Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Dynamic conformational changes of ion channel proteins during activation gating determine their function as carriers of current. The relationship between these molecular movements and channel function over the physiological timescale of the action potential (AP) has not been fully established due to limitations of existing techniques. We constructed a library of possible cardiac IKs protein conformations and applied a combination of protein segmentation and energy linearization to study this relationship computationally. Simulations reproduced the effects of the beta-subunit (KCNE1) on the alpha-subunit (KCNQ1) dynamics and function, observed in experiments. Mechanistically, KCNE1 increased the probability of “visiting” conducting pore conformations on …

Syntheses Of A Tin (Iv) Meso-Tetra(4-Pyridyl) Porphyrin Dichloride-Tetrachlorobis (Bipy)2 Ruthenium (Ii) Complex And Studies Of Photophysical Properties Of 1-Nitropyrene, Phillip Sharp

Electronic Theses and Dissertations

Development of a photosensitizer that can work in both aerobic and anaerobic environments would increase the robustness of the cancer treatment known as photodynamic therapy. The development of a photosensitizer was first attempted by synthesizing a tin (IV) meso-tetra (4-pyridyl) porphyrin dichloride-tetrachlorobis (Bipy)₂ ruthenium (II) complex. The synthesize of the tin porphyrin was done by a method from literature and had a percent error of 31.58 and 37.31 when comparing the theoretical percentages of carbon (55.39) and nitrogen (12.92) meaning that photosensitizer was not synthesized.

The second type of chromophore that was studied was 1-nitropyrene do determine if it …

My Experience Teaching General Chemistry To A Student Who Is Visually Impaired, Katherine M E Stewart

Journal of Science Education for Students with Disabilities

This paper summarizes my experience with teaching a first-year, General Chemistry course to a visually impaired student. This includes accommodations and modifications for both the lecture material and the laboratory. Included are also examples of formats and syntax for txt-based quizzes, tests, and laboratory reports, as well as other general accommodations for both the student and the service dog.

‘Cassette’-Ises (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds For Hydrolytic Kinetic Resolution Across A Range Of Epoxides, Sangeeta Dey, Douglas R. Powell, Chunhua Hu, David B. Berkowitz

Department of Chemistry: Faculty Publications

‘Cassette’-ISES (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds for Hydrolytic Kinetic Resolution Across a Range of Epoxides

A new ‘Cassette’-In Situ Enzymatic Screen (ISES) for combinatorial catalysis is introduced. This allows the experimentalist to obtain an information-rich readout, in real time, providing an estimate of the sense and magnitude of enantioselectivity across more than one substrate. In its first iteration, the screen identified Co^III-salen catalysts with β-pinene- and α-naphthylalanine-derived chiral scaffolds with broad, yet complementary, substrate specificities.

Guanidinium Compounds, Stephen Dimagno, Bao Hu

Department of Chemistry: Faculty Publications

The present application provides , inter alia , chemical com pounds useful as synthesis intermediates , said compounds comprising one or more guanidinium moieties and a hyper valent iodine atom . Methods for making these compounds are also provided.