Environmental synergies and microbial growth phase enable formation of bionanohybrid lifeforms
Dr. Robert Barnes
Chemical and Petroleum Engineering
March 18, 2021
From the dawn of life itself, microbes have had intimate associations with minerals, with a few organisms in natural environments producing nano-particulate oxide or sulfide mineral phases, internally or externally on their cells. Recently a wider range of bacteria have demonstrated an ability to synthesize surface-associated nanoparticles (SANs) through exogenous metal ions reacting with sulfide via cysteine metabolism, resulting in the emergence of a new lifeform – a biological nanoparticle hybrid (bionanohybrid). The attached nanoparticles may couple to extracellular electron transfer, facilitating de novo photoelectrochemical processes. While SAN-cell coupling in hybrid organisms is opening a range of biotechnological possibilities, observation of bionanohybrids is not commonly reported in natural environments and their lab-based engineered remains difficult to control. We describe, for the first time, the critical role that microbial growth stage, cell densities and exogenous metal concentrations, play in defining and controlling the form and occurrence of diverse bionanohybrids. A minimum cell density of cells is needed, at a given metal ion dosing, to uniformly coat cells with SANs. This can be altered by adjusting the amount of cysteine bearing peptide present. Critically, bionanohybrids exhibit a remarkable ability for binary fission and cysteine metabolism, creating subsequent generations of this novel lifeform. We show that bacterial cells can biosynthesize composite metal sulfide SANs from diverse mixtures of copper, silver and bismuth metal ions, and that by fine-tuning cysteine levels, microbial growth and metal dosing, different bacterial species can be coaxed into a bionanohybrid lifestyle. This opens an avenue to controlled production of SANs tailored to specific technological functions.
Chemistry of Nanoporous Metal Organic Frameworks from Fundamental to Commercial
Dr. George Shumizu
November 27th 2019
Metal-organic frameworks (MOFs) are a newer class of porous solids. They offer essentially limitless opportunities for modular structural variation. This leads to tunable properties, but an Achilles Heel for MOFs has been high stability to harsh chemical environments and high temperatures. We have focused our efforts on using MOFs for gas separations and as new proton conductors. Through both themes, we have spanned more basic to more applicable materials. This talk will cover our efforts in both areas including a MOF that is being commercialized for industrial carbon capture.
From Electrochemistry to Emulsions; A Tale of Interface-Governed Materials Science
Dr. Brandy (Kinkead) Pilapil
Chemical Petroleum Engineering
November 29th 2018
Materials science is a highly interdisciplinary field with a common focus – understanding and applying matter to perform a task with maximum efficiency. In my research, an extensive understanding of interfacial interactions (or lack thereof) has been key in the development of materials for applications ranging from liquid crystal displays, to fuel cells and petroleum technology. In this presentation, I will discuss my research in the development of bi-continuous hierarchical fuel cell electrocatalysts from self-assembled templates and studies of particle-stabilized oil-in-water emulsions.
Cathodic catalyst layers are a common limiting material in the development of H2/O2 fuel cells due to their high precious-metal content required for effective catalysis and limited durability. In this work, interfacial self-assembly is used as a tool to develop catalyst layers for ORR with exceptional mass transport properties and well-dispersed nanocatalysts, to enable efficient catalysis with minimal precious metal loading. Moreover, favourable interactions between the precious metal catalysts and the incorporated support materials improve long-term durability due to the intimate interactions afforded by the material preparation method.
Emulsion stabilization and de-stabilization is of utmost importance to a range of applications including food sciences and enhanced oil recovery. Particle-stabilized emulsions were discovered over 100 years ago by Pickering and Ramsden, and have since been studied extensively for their abilities to provide extensive stability and additional functionality to emulsions and emulsion-derived materials. In the work presented here, emulsions were determined to be “particle-stabilized” without interfacial interactions between the oil-water interface and the particle surfaces. Characterization of these fascinating new materials is presented and the stabilization mechanism discussed
Nature inspired multifunctional nanomaterials for energy, environment and health
Dr. Vinayaraj Ozhukil Kollath
Chemical and Petroleum Engineering
October 25th 2018
Nature inspired chemistry provides us several interesting materials with tunable properties and cost-effectiveness. Shape and size controlled stable organic nanoparticles (NPs) will have versatile applications in both fundamental and applied research. Bio-inspired catechol-amine, dopamine is known to produce spherical NPs in a one-pot method. During this talk, the parameters affecting the size and shape of such organic NPs and their fluorescent properties will be discussed. Other catechol-amine molecules in the safe family as dopamine is used to produce contrasting size and shaped organic fluorescent NPs. Applications of the developed NPs vary from studies of colloidal systems to carbon support in energy storage-conversion devices to potential carrier for drug/vaccines.
Surface Engineering Nanoparticles for Their Use in Nanocomposite Latexes and Film
Dr. Stephanie Kedzior
Chemical and Petroleum Engineering
February 6th 2018
Surface engineering nanoparticles allows us to fully take advantage of their properties for their use in applications such as nanocomposite latexes and films. This talk will focus on my PhD work, using cellulose nanocrystals as property modifiers in adhesive latexes, and will also describe my current postdoctoral work using nanocomposite films for oil sensors. Cellulose nanocrystals (CNCs) are rod-shaped, anionic, colloidally stable nanoparticles that are extracted by sulfuric acid hydrolysis from renewable sources. CNCs have recently been shown to stabilize oil-in-water emulsions and foams. In my PhD work, CNCs were non-covalenty modified with either surfactant or polymer in order to provide improved surface activity. Miniemulsion polymerization was performed with CNC-surfactant combinations, and micro suspension polymerization was performed with CNC-polymer combinations. The resulting latex particle size, size distribution, surface charge and morphology as well as polymer molecular weight and conversion were studied. Furthermore, CNCs were also covalently modified to yield hydrophobic particles that were incorporated inside the polymer latexes. The work aimed to extend the use of CNCs in emulsion polymerization and in particular impart new approaches to incorporate CNCs into adhesives latexes. My current postdoctoral work involves the preparation and characterization of nanocomposite films to be used as sensors for oil leaks, strain sensing, and temperature.
Theories of Quantum Resources
Dr. Gilad Gour
October 26th 2017
A common theme in Chemistry, Thermodynamics, and Information Theory is how one type of resource -- be it chemicals, heat baths, or communication channels -- can be used to produce another. These processes of conversion and their applications are studied under the general heading of "resource theories". While resource theories use a wide range of sophisticated and apparently unrelated mathematical techniques there is also an emerging general mathematical framework which seems to underpin all of them. In this talk, I will give an overview on the field of quantum resource theories, starting with examples in quantum information science, focusing particularly on the theory of quantum entanglement. I will then discuss the general structure of quantum resource theories, introduce different mathematical models, and discuss the mathematical techniques used in this field. I will end with some applications in different areas of physics.