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Chemistry

2019

University of Windsor

Articles 1 - 17 of 17

Full-Text Articles in Physical Sciences and Mathematics

Photophysical And Optical Properties Of Semiconducting Polymer Nanoparticles Prepared From Hyaluronic Acid And Polysorbate 80, Adam Langlois, Gage T. Mason, Michael H.L. Nguyen, Mehdi Rezapour, Paul Ludovic Karsenti, Drew Marquardt, Simon Rondeau-Gagné Dec 2019

Photophysical And Optical Properties Of Semiconducting Polymer Nanoparticles Prepared From Hyaluronic Acid And Polysorbate 80, Adam Langlois, Gage T. Mason, Michael H.L. Nguyen, Mehdi Rezapour, Paul Ludovic Karsenti, Drew Marquardt, Simon Rondeau-Gagné

Chemistry and Biochemistry Publications

Copyright © 2019 American Chemical Society. A nanoprecipitation procedure was utilized to prepare novel diketopyrrolopyrrole-based semiconducting polymer nanoparticles (SPNs) with hyaluronic acid (HA) and polysorbate 80. The nanoprecipitation led to the formation of spherical nanoparticles with average diameters ranging from 100 to 200 nm, and a careful control over the structure of the parent conjugated polymers was performed to probe the influence of π-conjugation on the final photophysical and thermal stability of the resulting SPNs. Upon generation of a series of novel SPNs, the optical and photophysical properties of the new nanomaterials were probed in solution using various techniques including …

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Covalently Functionalized Sawdust For The Remediation Of Phosphate From Agricultural Wastewater, Daniel Meister, David Ure, Angela Awada, Jean-Claude Barrette, Joel Gagnon, Bluent Mutus, John F. Trant Nov 2019

Covalently Functionalized Sawdust For The Remediation Of Phosphate From Agricultural Wastewater, Daniel Meister, David Ure, Angela Awada, Jean-Claude Barrette, Joel Gagnon, Bluent Mutus, John F. Trant

Chemistry and Biochemistry Publications

Phosphate remediation from wastewater is rapidly becoming an ever more attractive process due to a combination of both the economic pressure of increasing phosphate scarcity and the environmental damage caused by untreated agricultural runoff. Ideally, remediated phosphate will be recoverable and would be able to be reused as fertilizer. Many different resins have been investigated, but due to the scale of the challenge, any feasible solution will involve the use of very inexpensive waste products as the solid support. Sawdust, functionalized with iron-binding ligands, is such a potential resin. Sawdust alone binds 0.3 g/kg of phosphate which is insufficient. Iron …

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Generation And Reactions Of A Benzodehydrotropylium Ion-Co2(Co)6 Complex, Mariam A. Mehdi, Eric A.C. Bushnell, Sahar Nikoo, James W. Gauld, James R. Green Oct 2019

Generation And Reactions Of A Benzodehydrotropylium Ion-Co2(Co)6 Complex, Mariam A. Mehdi, Eric A.C. Bushnell, Sahar Nikoo, James W. Gauld, James R. Green

Chemistry and Biochemistry Publications

A series of 7-methylenedehydrobenzo[7]annulen-5-ol hexacarbonyldicobalt complexes were generated by Hosomi-Sakurai reactions of allylsilanes containing o-alkynylarylaldehyde-Co2(CO)6 complexes. One of cyclization products was converted into its corresponding dihydrobenzo[7]annulen-7-ol hexacarbonyldicobalt complex, an immediate precursor to a benzodehydrotropylium-Co2(CO)6. The cation was generated in situ and reacted with four nucleophiles, and its aromatic stabilization determined by computational methods.

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Peptide-Induced Lipid Flip-Flop In Asymmetric Liposomes Measured By Small Angle Neutron Scattering, Michael H.L. Nguyen, Mitchell Dipasquale, Brett W. Rickeard, Milka Doktorova, Frederick A. Heberle, Haden L. Scott, Francisco N. Barrera, Graham Taylor, Charles P. Collier, Christopher B. Stanley, John Katsaras, Drew Marquardt Sep 2019

Peptide-Induced Lipid Flip-Flop In Asymmetric Liposomes Measured By Small Angle Neutron Scattering, Michael H.L. Nguyen, Mitchell Dipasquale, Brett W. Rickeard, Milka Doktorova, Frederick A. Heberle, Haden L. Scott, Francisco N. Barrera, Graham Taylor, Charles P. Collier, Christopher B. Stanley, John Katsaras, Drew Marquardt

Chemistry and Biochemistry Publications

© 2019 American Chemical Society. Despite the prevalence of lipid transbilayer asymmetry in natural plasma membranes, most biomimetic model membranes studied are symmetric. Recent advances have helped to overcome the difficulties in preparing asymmetric liposomes in vitro, allowing for the examination of a larger set of relevant biophysical questions. Here, we investigate the stability of asymmetric bilayers by measuring lipid flip-flop with time-resolved small-angle neutron scattering (SANS). Asymmetric large unilamellar vesicles with inner bilayer leaflets containing predominantly 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and outer leaflets composed mainly of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) displayed slow spontaneous flip-flop at 37 -C (half-time, t1/2 = 140 h). However, …

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Neuro And Hepatic Toxicological Profile Of (S)-2,4-Diaminobutanoic Acid In Embryonic, Adolescent And Adult Zebrafish, Rosa-Maria Ferraiuolo, Daniel Meister, Dominique Leckie, Jonathan Franke, Lisa A. Porter, John F. Trant Aug 2019

Neuro And Hepatic Toxicological Profile Of (S)-2,4-Diaminobutanoic Acid In Embryonic, Adolescent And Adult Zebrafish, Rosa-Maria Ferraiuolo, Daniel Meister, Dominique Leckie, Jonathan Franke, Lisa A. Porter, John F. Trant

Chemistry and Biochemistry Publications

(S)-2,4-Diaminobutanoic acid (DABA) is a noncanonical amino acid often co-produced by cyanobacteria along with β-N-methylamino-l-alanine (BMAA) in algal blooms. Although BMAA is a well-established neurotoxin, the toxicity of DABA remains unclear. As part of our development of biocompatible materials, we wish to make use of DABA as both a building block and as the end-product of enzymatically-induced depolymerization; however, if it is toxic at very low concentrations, this would not be possible. We examined the toxicity of DABA using both in vivo embryonic and adult zebrafish models. At higher sub-lethal concentrations (700 µM), the fish demonstrated early …

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Calcium-Ion Batteries: Identifying Ideal Electrolytes For Next-Generation Energy Storage Using Computational Analysis, Mehdi Shakourian-Fard, Ganesh Kamath, S. Maryamdokht Taimoory, John F. Trant Jun 2019

Calcium-Ion Batteries: Identifying Ideal Electrolytes For Next-Generation Energy Storage Using Computational Analysis, Mehdi Shakourian-Fard, Ganesh Kamath, S. Maryamdokht Taimoory, John F. Trant

Chemistry and Biochemistry Publications

Calcium ion batteries show promise as a high-density, next generation replacement for current lithium ion batteries. The precise chemical structure of the carbonate electrolyte solvent has a large impact on calcium battery efficacy. In this computational study, we have investigated the solvation behavior of calcium tetrafluoroborate in both neat carbonates and carbonate mixtures using combined molecular dynamics simulations and quantum mechanical calculations. Our results indicate that both neat ethyl methyl carbonate and a mixture of ethylene carbonate and diethyl carbonate show the highest free-energy of solvation for the Ca2+ ion, making them likely candidates for further focus. The cation’s …

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Halogen Bonding And Host–Guest Chemistry Between N-Alkylammonium Resorcinarene Halides, Diiodoperfluorobutane And Neutral Guests, Fangfang Pan, Mohadeseh Dashti, Michael R. Reynolds, Kari Rissanen, John F. Trant, Ngong Kodiah Beyeh Apr 2019

Halogen Bonding And Host–Guest Chemistry Between N-Alkylammonium Resorcinarene Halides, Diiodoperfluorobutane And Neutral Guests, Fangfang Pan, Mohadeseh Dashti, Michael R. Reynolds, Kari Rissanen, John F. Trant, Ngong Kodiah Beyeh

Chemistry and Biochemistry Publications

Single crystal X-ray structures of halogen-bonded assemblies formed between host N-hexylammonium resorcinarene bromide (1) or N-cyclohexylammonium resorcinarene chloride (2), and 1,4-diiodooctafluorobutane and accompanying small solvent guests (meth- anol, acetonitrile and water) are presented. The guests’ inclusion affects the geometry of the cavity of the receptors 1 and 2, while the divalent halogen bond donor 1,4-diiodooctafluorobutane determines the overall nature of the halogen bond assembly. The crystal lattice of 1 contains two structurally different dimeric assemblies A and B, formally resulting in the mixture of a capsular dimer and a dimeric pseudo-capsule. 1H …

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Adsorption Of Bovine Serum Albumin (Bsa) By Bare Magnetite Nanoparticles With Surface Oxidative Impurities That Prevent Aggregation, Somayeh Rahdar, Abbas Rahdar, Shahin Ahmadi, John F. Trant Mar 2019

Adsorption Of Bovine Serum Albumin (Bsa) By Bare Magnetite Nanoparticles With Surface Oxidative Impurities That Prevent Aggregation, Somayeh Rahdar, Abbas Rahdar, Shahin Ahmadi, John F. Trant

Chemistry and Biochemistry Publications

Bare, uncoated magnetite nanoparticles, synthesized using an electrochemical surfactant-free synthesis, have highly oxidized surfaces that prevent aggregation. These particles have demonstrated highly intriguing biological activity showing extremely potent antibiotic activity against both gram-positive and gram-negative bacteria with little toxicity to rats. This difference in activity could be ascribed to the nature of the protein corona. In this study the kinetics and thermodynamics of the binding of bovine serum albumin, used as a model serum protein, to these magnetite nanoparticles was analyzed. There is no significant change in particle diameter by dynamic light scattering following adsorption indicating corona formation does not …

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Methanol Accelerates Dmpc Flip-Flop And Transfer: A Sans Study On Lipid Dynamics, Michael H.L. Nguyen, Mitchell Dipasquale, Brett W. Rickeard, Christopher B. Stanley, Elizabeth G. Kelley, Drew Marquardt Mar 2019

Methanol Accelerates Dmpc Flip-Flop And Transfer: A Sans Study On Lipid Dynamics, Michael H.L. Nguyen, Mitchell Dipasquale, Brett W. Rickeard, Christopher B. Stanley, Elizabeth G. Kelley, Drew Marquardt

Chemistry and Biochemistry Publications

© 2019 Biophysical Society Methanol is a common solubilizing agent used to study transmembrane proteins/peptides in biological and synthetic membranes. Using small angle neutron scattering and a strategic contrast-matching scheme, we show that methanol has a major impact on lipid dynamics. Under increasing methanol concentrations, isotopically distinct 1,2-dimyristoyl-sn-glycero-3-phosphocholine large unilamellar vesicle populations exhibit increased mixing. Specifically, 1,2-dimyristoyl-sn-glycero-3-phosphocholine transfer and flip-flop kinetics display linear and exponential rate enhancements, respectively. Ultimately, methanol is capable of influencing the structure-function relationship associated with bilayer composition (e.g., lipid asymmetry). The use of methanol as a carrier solvent, despite better simulating some biological conditions (e.g., antimicrobial …

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Gramicidin Increases Lipid Flip-Flop In Symmetric And Asymmetric Lipid Vesicles, Milka Doktorova, Frederick A. Heberle, Drew Marquardt, Radda Rusinova, R. Lea Sanford, Thasin A. Peyear, John Katsaras, Gerald W. Feigenson, Harel Weinstein, Olaf S. Andersen Mar 2019

Gramicidin Increases Lipid Flip-Flop In Symmetric And Asymmetric Lipid Vesicles, Milka Doktorova, Frederick A. Heberle, Drew Marquardt, Radda Rusinova, R. Lea Sanford, Thasin A. Peyear, John Katsaras, Gerald W. Feigenson, Harel Weinstein, Olaf S. Andersen

Chemistry and Biochemistry Publications

© 2019 Biophysical Society Unlike most transmembrane proteins, phospholipids can migrate from one leaflet of the membrane to the other. Because this spontaneous lipid translocation (flip-flop) tends to be very slow, cells facilitate the process with enzymes that catalyze the transmembrane movement and thereby regulate the transbilayer lipid distribution. Nonenzymatic membrane-spanning proteins with unrelated primary functions have also been found to accelerate lipid flip-flop in a nonspecific manner and by various hypothesized mechanisms. Using deuterated phospholipids, we examined the acceleration of flip-flop by gramicidin channels, which have well-defined structures and known functions, features that make them ideal candidates for probing …

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A H2ax–Carp-1 Interaction Regulates Apoptosis Signaling Following Dna Damage, Sreeja C. Sekhar, Jaganathan Venkatesh, Vino T. Cheriyan, Magesh Muthu, Edi Levi, Hadeel Assad, Paul Meister, Vishnu V. Undyala, James W. Gauld, Arun K. Rishi Feb 2019

A H2ax–Carp-1 Interaction Regulates Apoptosis Signaling Following Dna Damage, Sreeja C. Sekhar, Jaganathan Venkatesh, Vino T. Cheriyan, Magesh Muthu, Edi Levi, Hadeel Assad, Paul Meister, Vishnu V. Undyala, James W. Gauld, Arun K. Rishi

Chemistry and Biochemistry Publications

Cell Cycle and Apoptosis Regulatory Protein (CARP-1/CCAR1) is a peri-nuclear phosphoprotein that regulates apoptosis via chemotherapeutic Adriamycin (doxorubicin) and a novel class of CARP-1 functional mimetic (CFM) compounds. Although Adriamycin causes DNA damage, data from Comet assays revealed that CFM-4.16 also induced DNA damage. Phosphorylation of histone 2AX (γH2AX) protein is involved in regulating DNA damage repair and apoptosis signaling. Adriamycin or CFM-4.16 treatments inhibited cell growth and caused elevated CARP-1 and γH2AX in human breast (HBC) and cervical cancer (HeLa) cells. In fact, a robust nuclear or peri-nuclear co-localization of CARP-1 and γH2AX occurred in cells undergoing apoptosis. Knock-down …

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L-Tryptophan Adsorption Differentially Changes The Optical Behaviour Of Pseudo-Enantiomeric Cysteine-Functionalized Quantum Dots: Towards Chiral Fluorescent Biosensors, Faezeh Askari, Abbas Rahdar, John F. Trant Feb 2019

L-Tryptophan Adsorption Differentially Changes The Optical Behaviour Of Pseudo-Enantiomeric Cysteine-Functionalized Quantum Dots: Towards Chiral Fluorescent Biosensors, Faezeh Askari, Abbas Rahdar, John F. Trant

Chemistry and Biochemistry Publications

Water-soluble chiral graphene quantum dots (GQDs) with a strong blue emission were synthesized by covalently immobilizing l-cysteine or d-cysteine onto the GQDs. Either the amine or the thiol group of cysteine was used to make the bond through amide coupling or thiol-ene click chemistry respectively. The functionalized chiral GQDs were the characterized by FT-IR and UV–vis. The enantiomeric pairs exhibit equal but opposite bands in circular dichroism spectra suggesting that there is no difference in the efficacy of conjugation. The fluorescent response of these chiral GQDs when exposed to l-tryptophan was then studied. The fluorescence of the amide-conjugated GQDs was …

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Synthesis, Physical Characterization, Antifungal And Antibacterial Activity Of Oleic Acid-Capped Nanomagnetite And Cobalt-Doped Nanomagnetite, Abbas Rahdar, Hamid Beyzaei, Mohsen Saadat, Xiao Yu, John F. Trant Jan 2019

Synthesis, Physical Characterization, Antifungal And Antibacterial Activity Of Oleic Acid-Capped Nanomagnetite And Cobalt-Doped Nanomagnetite, Abbas Rahdar, Hamid Beyzaei, Mohsen Saadat, Xiao Yu, John F. Trant

Chemistry and Biochemistry Publications

Nanoparticles, 10-14 nm, consisting of either Fe3O4 or Co0.2Fe2.8O4 stabilized with oleic acid, were prepared using solution combustion. Their structural and magnetic properties were examined using X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry, and Fourier-transform infrared spectroscopy. The properties of both sets of materials are similar except the cobalt-doped particles are considerably less magnetic. The in vitro inhibitory activities of the nanoparticles were assessed against pathogenic bacteria Shigella dysenteriae, Klebsiella pneumoniae, Acinetobacter baumannii, Streptococcus pyogenes, and pathogenic fungi and molds Candida albicans, Fusarium oxysporum and Aspergillus …

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Unnatural Amino Acids Improve Affinity And Modulate Immunogenicity: Developing Peptides To Treat Mhc Type Ii Autoimmune Disorders, Daniel Meister, S. Maryamdokht Taimoory, John F. Trant Jan 2019

Unnatural Amino Acids Improve Affinity And Modulate Immunogenicity: Developing Peptides To Treat Mhc Type Ii Autoimmune Disorders, Daniel Meister, S. Maryamdokht Taimoory, John F. Trant

Chemistry and Biochemistry Publications

Many autoimmune diseases, including multiple sclerosis (MS), rheumatoid arthritis (RA), and celiac disease (CD), arise from improper immune system recognition of self or benign peptides as threats. No autoimmune disease currently has a cure. Many treatments suppress the entire immune system to decrease symptom severity. The core molecular interaction underlying these diseases involves specific alleles of the human leukocyte antigen (HLA) receptor hosting the immunodominant peptides associated with the disease (i.e. myelin basic protein, Type II collagen, or α-gliadin) in their binding groove. Once bound, circulating T-cells can recognize the HLA-antigen complex and initiate the complex cascade that forms an …

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Chapter 3: The Behaviour Of Vitamin E In Membranes, J. Atkinson, D. Marquardt, T. Harroun Jan 2019

Chapter 3: The Behaviour Of Vitamin E In Membranes, J. Atkinson, D. Marquardt, T. Harroun

Chemistry and Biochemistry Publications

© 2019 The Royal Society of Chemistry. The neutral lipids of the vitamin E family (tocopherols and tocotrienols) are well known antioxidants with -tocopherol (-Toc) being the sole tocopherol retained in mammalian tissues after absorption from the diet. Because of their high hydrophobicity, tocopherols partition easily into biological membranes. The location and dynamic behavior of tocopherols and tocotrienols in phospholipid membranes is essential information for describing the mechanism(s) of action of these molecules. The bilayer orientation and dynamics are central to our comprehension of their action as antioxidants, protecting free radical-induced peroxidation of polyunsaturated phospholipids. Tocopherols and tocotrienols may also …

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Vitamin E-Inspired Multi-Scale Imaging Agent, Mikel Ghelfi, Lucas A. Maddalena, Jeffrey A. Stuart, Jeffrey Atkinson, Thad A. Harroun, Drew Marquardt Jan 2019

Vitamin E-Inspired Multi-Scale Imaging Agent, Mikel Ghelfi, Lucas A. Maddalena, Jeffrey A. Stuart, Jeffrey Atkinson, Thad A. Harroun, Drew Marquardt

Chemistry and Biochemistry Publications

© 2018 Elsevier Ltd The production and use of multi-modal imaging agents is on the rise. The vast majority of these imaging agents are limited to a single length scale for the agent (e.g. tissues only), which is typically at the organ or tissue scale. This work explores the synthesis of such an imaging agent and discusses the applications of our vitamin E-inspired multi-modal and multi-length scale imaging agents TB-Toc ((S,E)-5,5-difluoro-7-(2-(5-((6-hydroxy-2,5,7,8-tetramethylchroman-2-yl) methyl) thiophen-2-yl) vinyl)-9-methyl-5H-dipyrrolo-[1,2-c:2’,1’-f][1,3,2]diazaborinin-4-ium-5-uide). We investigate the toxicity of TB-Toc along with the starting materials and lipid based delivery vehicle in mouse myoblasts and fibroblasts. Further we investigate the uptake …

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Recent Advances In The Application Of Carbohydrates As Renewable Feedstocks For The Synthesis Of Nitrogen-Containing Compounds, S. Iraj Sadraei, Brent St Onge, John F. Trant Jan 2019

Recent Advances In The Application Of Carbohydrates As Renewable Feedstocks For The Synthesis Of Nitrogen-Containing Compounds, S. Iraj Sadraei, Brent St Onge, John F. Trant

Chemistry and Biochemistry Publications

Carbohydrates, in the form of chitin, chitosan and cellulose, are one of the most available, renewable, and sustainable chemical feedstocks. Their conversion to biofuels, fine chemicals, and industrially-relevant monomers is becoming increasingly viable and promising as innovation decreases the price of this technology, and climate change and the price of fossil fuels increases the social and economic costs of using traditional feedstocks. In recent years, carbohydrates have been increasingly used as sources for nitrogen-containing fine chemicals. This chapter, with 86 references, provides a brief overview of the conversion of carbohydrate biomass to the standard hydrocarbon and oxygen-containing derivatives, and then …

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