Physical Sciences and Mathematics Commons^™

Refractive Index Chemical Sensing With Noble Metal Nanoparticles, Phillip Blake

Graduate Theses and Dissertations

Chemical sensing is a key component in modern society, especially in engineering applications. Because of their widespread impact, improvements to chemical sensors are a significant area of research. One class of sensors, plasmonic sensors, is being heavily researched because of their ability to detect low levels of analyte in near real time without destroying the analyte. This work studies a new class of plasmonic sensor that utilizes diffractive coupling to improve sensor performance. Specifically, this work outlines the first study of diffractive coupling sensors with typical nanoparticle shapes. Sensitivity of this new class of sensor is directly compared to typical …

Rat Brain Pro-Oxidant Effects Of Peripherally Administered 5 Nm Ceria 30 Days After Exposure, Sarita S. Hardas, Rukhsana Sultana, Govind Warrier, Mo Dan, Rebecca L. Florence, Peng Wu, Eric A. Grulke, Michael T. Tseng, Jason M. Unrine, Uschi M. Graham, Robert A. Yokel, D. Allan Butterfield

Chemistry Faculty Publications

The objective of this study was to determine the residual pro-or anti-oxidant effects in rat brain 30 days after systemic administration of a 5 nm citrate-stabilized ceria dispersion. A ∼4% aqueous ceria dispersion was iv-infused (0 or 85 mg/kg) into rats which were terminated 30 days later. Ceria concentration, localization, and chemical speciation in the brain was assessed by inductively coupled plasma mass spectrometry (ICP-MS), light and electron microscopy (EM), and electron energy loss spectroscopy (EELS), respectively. Pro- or anti-oxidant effects were evaluated by measuring levels of protein carbonyls (PC), 3-nitrotyrosine (3NT), and protein-bound-4-hydroxy-2-trans-nonenal (HNE) in the hippocampus, cortex, and …

Nanoencapsulated Copper Pthalocyanine As Photodynamic Antimicrobial Chemotherapy, Prathima Arrabelly

All Capstone Projects

The growing resistance developed by microbes towards antimicrobial agents has driven our focus on developing alternative treatment modalities such as Photodynamic antimicrobial chemotherapy (PACT). It would be difficult for the microbes to develop resistance towards singlet oxygen generated during the PACT process. Photosensitizers are the vehicles of the transfer and translation of light energy into a type II chemical reaction (singlet oxygen generation) in photodynamic antimicrobial chemotherapy. PACT is proposed as a potential, low cost approach to treatment of locally occurring infection.

Photodynamic inactivation (PDI) of Escherichia coli and Staphylococcus aureus has been studied in cultures treated with photoactivated copper …

Multidentate Resorcinarene Surfactants For The Phase Transfer Of Metal Nanoparticles And Nanodiamonds: Applications In Catalysis And Diamond Film Growth, Vara Prasad Sheela

Chemistry & Biochemistry Theses & Dissertations

One main objective of the present work is to functionalize cuboctahedral platinum nanoparticles with various multidentate resorcinarene surfactants and study their influence in determining their catalytic activity. We hypothesized that catalytically active and recyclable catalysts can be achieved by incomplete yet strong passivation of the nanoparticle surfaces by using multidentate resorcinarene surfactants. We have developed phase transfer protocols for functionalizing cuboctahedral platinum nanoparticles with resorcinarene thiol or amine. Fluorescence assay confirmed that both these nanoparticles contained almost comparable unpassivated metal area. The activity of such phase transferred nanoparticles was tested in the catalytic hydrogenation of allyl alcohol. The conversion of …

Development Of Tailor-Designed Gold-Platinum Nanoparticles Binary Catalysts For Efficient Formic Acid Electrooxidation, Islam M. Al-Akraa Dr, Ahmad M. Mohammad Prof, Mohamed S. El-Deab Prof, Bahgat E. El-Anadouli Prof

Chemical Engineering

The modification of a glassy carbon (GC) electrode with platinum (PtNPs) and gold (AuNPs) nanoparticles is targeted to fabricate efficient anodes for the electrooxidation of formic acid (FA). A proper adjustment of the deposition sequence of PtNPs and AuNPs could eventually enhance the electrocatalytic activity of the electrode in such a way that suppresses the CO poisoning effect during FA oxidation. The highest catalytic activity is obtained at the Au/Pt/GC electrode (with PtNPs firstly deposited on the GC electrode followed by AuNPs). This superb enhancement is quantified by comparing the relative ratio of the direct vs. the indirect oxidation peaks …

A Novel Route To Copper(Ii) Detection Using 'Click' Chemistry-Induced Aggregation Of Gold Nanoparticles, Carol Hua, William H. Zhang, Swahnnya De Almeida, Simone Ciampi, Danmar Gloria, Guozhen Liu, Jason Brian Harper, J Justin Gooding

Australian Institute for Innovative Materials - Papers

A simple colorimetric method for the detection of copper ions in water is described. This method is based on the 'click' copper(i)-catalyzed azide-alkyne cycloaddition reaction and its use in promoting the aggregation of azide-tagged gold nanoparticles by a dialkyne cross-linker is described. Nanoparticle cross-linking, evidenced as a colour change, is used for the detection of copper ions. The lowest detected concentration by the naked eye was 1.8 μM, with the response linear with log(concentration) between 1.8-200 μM. The selectivity relative to other potentially interfering ions was evaluated.

Design Of Colloidal Composite Catalysts For Co2 Photoreduction And For Co Oxidation, Bijith D. Mankidy

USF Tampa Graduate Theses and Dissertations

In this doctoral dissertation, novel colloidal routes were used to synthesize nanomaterials with unique features. We have studied the impact of nanoparticle size of catalyst, role of high surface area of a photocatalyst, and the effect of varying elemental composition of co-catalytic nanoparticles in combination with core-shell plasmonic nanoparticles. We have demonstrated how physical and chemical characteristics of nanomaterials with these unique features play a role in catalytic reactions, specifically the oxidation of CO and the photoreduction of CO2. The first objective of this doctoral dissertation involved the preparation of CoO nanoparticles with discrete nanoparticles sizes (1-14 nm) using a …

Investigations Of Oxidative Stress Effects And Their Mechanisms In Rat Brain After Systemic Administration Of Ceria Engineered Nanomaterials, Sarita S. Hardas

Theses and Dissertations--Chemistry

Advancing applications of engineered nanomaterials (ENM) in various fields create the opportunity for intended (e.g. drug and gene delivery) or unintended (e.g. occupational and environmental) exposure to ENM. However, the knowledge of ENM-toxicity is lagging behind their application development. Understanding the ENM hazard can help us to avoid potential human health problems associated with ENM applications as well as to increase their public acceptance. Ceria (cerium [Ce] oxide) ENM have many current and potential commercial applications. Beyond the traditional use of ceria as an abrasive, the scope of ceria ENM applications now extends into fuel cell manufacturing, diesel fuel additives …

Identification Of The Biogenic Compounds Responsible For Size-Dependent Nanoparticle Growth, Paul M. Winkler, John Ortega, Thomas Karl, Luca Cappellin, Hans R. Friedli, Kelley Barsanti, Peter H. Mcmurry, James N. Smith

Civil and Environmental Engineering Faculty Publications and Presentations

The probability that freshly nucleated nanoparticles can survive to become cloud condensation nuclei is highly sensitive to particle growth rates. Much of the growth of newly formed ambient nanoparticles can be attributed to oxidized organic vapors originating from biogenic precursor gases. In this study we investigated the chemical composition of size-selected biogenic nanoparticles in the size range from 10 to 40 nm. Particles were formed in a flow tube reactor by ozonolysis ofα-pinene and analyzed with a Thermal Desorption Chemical Ionization Mass Spectrometer. While we found similar composition in 10 and 20 nm particles, the relative amounts of …

Optical Detection Of Melting Point Depression For Silver Nanoparticles Via In Situ Real Time Spectroscopic Ellipsometry, S. A. Little, T. Begou, R. W. Collins, S. Marsillac

Electrical & Computer Engineering Faculty Publications

Silver nanoparticle films were deposited by sputtering at room temperature and were annealed while monitoring by real time spectroscopic ellipsometry (SE). The nanoparticle dielectric functions (0.75 eV-6.5 eV) obtained by SE were modeled using Lorentz and generalized oscillators for the nanoparticle plasmon polariton (NPP) and interband transitions, respectively. The nanoparticle melting point could be identified from variations in the oscillator parameters during annealing, and this identification was further confirmed after cooling through significant, irreversible changes in these parameters relative to the as-deposited film. The variation in melting point with physical thickness, and thus average nanoparticle diameter, as measured by SE …