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Magnetic-core/Gold-shell Nanoparticles for the Detection of Trace Chemical Contaminants in Food Products

ORAL

Abstract

Magnetic-core/gold-shell nanoparticles (MAuNPs) are of interest for enabling portable detection of trace analytes in complex media, such as food. Gold coating provides biocompatibility and facile functionalization, and a magnetic core affords analyte concentration and controlled deposition onto substrates for surface-enhanced Raman spectroscopy. Iron oxide cores were synthesized and coated with gold by reduction of HAuCl$_{4}$ by NH$_{2}$OH. MAuNPs were grafted with polyethylene glycol (PEG) and/or functionalized with 4-mercaptobenzoic acid (4-MBA) and examined using a variety of microscopic, spectroscopic, magnetometric, and scattering techniques. The results showed 4-MBA displaced a significant amount of PEG. PEG displaced less 4-MBA, evidencing denser packing on the MAuNP surface. (4-MBA)-MAuNPs significantly enhanced the Raman signal, thus demonstrating functionality in direct detection of trace analytes. Magnetic deposition rate of MAuNPs and (4-MBA)-MAuNPs was explored. Deposition rate was slowed by 4-MBA. We postulate this originated from NP-substrate interactions. These findings emphasize the importance of ligand choice in reference to the medium, analyte, and substrate, as well as functionalization procedure in the design of similar sensing platforms.

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Authors

  • Anna Mills

    Florida State University

  • Robert Grzywacz

    Moscow Institute of Physics and Technology, University of Virginia, California Institute of Technology, National High Magnetic Field Laboratory, University and Student Affairs; Oak Ridge Laboratory, Brookhaven National Laboratory, Physicist, Brookhaven National Laboratory, Oak Ridge National Laboratory, USA, Center for Nuclear Study, University of Tokyo, Advanced Science Research Center, Japan Atomic Energy Agency, Florida State University, Presidency University, Kolkata, INDIA, VECC,Kolkata, INDIA, SINP,Kolkata, INDIA, UGC-DAE CSR (Kolkata), INDIA, IFIN-HH, ELI-NP, Romania, Variable Energy Cyclotron Centre,Kolkata, INDIA, IEM, Kolkata, India, Victoria Institution (College), Kolkata, INDIA, Variable Energy Cyclotron Centre, Kolkata, INDIA, NHMFL; Florida State University, FAMU-FSU College of Engineering, Florida State University, Physics Department, Florida State University, Mississippi State University, NHMFL-FSU, U. Colorado at Boulder, NHMFL, University of Alabama at Birmingham, Oak Ridge National Laboratory, Argonne National Laboratory, Alabama School of Math and Science, University of South Alabama, University of Florida, University of Notre Dame, University of Texas at Dallas, Bob Jones University, University of Tennessee at Chattanooga, The Autonomous University of San Luis Potosí, Northern Arizona University, Flagstaff, AZ, Harvard-Smithsonian Center for Astrophysics, Cambridge, National Institute of Standards and Technology, Clemson University, University of South Florida, Phenikaa University, University of Ulsan, Ohio University, University of Hawaii, University of California, Davis, University of California, Davis., Saleh Research Centre, Department of Physics, Florida State university, Tallahassee, FL32306, USA, WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK, Professor, facility manager, Student, Florida State University(Former), Hebrew University, Israel \& Ioffe Institute, St.\ Petersburg, Russia, University of Tennessee, Knoxville

  • Robert Grzywacz

    Moscow Institute of Physics and Technology, University of Virginia, California Institute of Technology, National High Magnetic Field Laboratory, University and Student Affairs; Oak Ridge Laboratory, Brookhaven National Laboratory, Physicist, Brookhaven National Laboratory, Oak Ridge National Laboratory, USA, Center for Nuclear Study, University of Tokyo, Advanced Science Research Center, Japan Atomic Energy Agency, Florida State University, Presidency University, Kolkata, INDIA, VECC,Kolkata, INDIA, SINP,Kolkata, INDIA, UGC-DAE CSR (Kolkata), INDIA, IFIN-HH, ELI-NP, Romania, Variable Energy Cyclotron Centre,Kolkata, INDIA, IEM, Kolkata, India, Victoria Institution (College), Kolkata, INDIA, Variable Energy Cyclotron Centre, Kolkata, INDIA, NHMFL; Florida State University, FAMU-FSU College of Engineering, Florida State University, Physics Department, Florida State University, Mississippi State University, NHMFL-FSU, U. Colorado at Boulder, NHMFL, University of Alabama at Birmingham, Oak Ridge National Laboratory, Argonne National Laboratory, Alabama School of Math and Science, University of South Alabama, University of Florida, University of Notre Dame, University of Texas at Dallas, Bob Jones University, University of Tennessee at Chattanooga, The Autonomous University of San Luis Potosí, Northern Arizona University, Flagstaff, AZ, Harvard-Smithsonian Center for Astrophysics, Cambridge, National Institute of Standards and Technology, Clemson University, University of South Florida, Phenikaa University, University of Ulsan, Ohio University, University of Hawaii, University of California, Davis, University of California, Davis., Saleh Research Centre, Department of Physics, Florida State university, Tallahassee, FL32306, USA, WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK, Professor, facility manager, Student, Florida State University(Former), Hebrew University, Israel \& Ioffe Institute, St.\ Petersburg, Russia, University of Tennessee, Knoxville

  • Robert Grzywacz

    Moscow Institute of Physics and Technology, University of Virginia, California Institute of Technology, National High Magnetic Field Laboratory, University and Student Affairs; Oak Ridge Laboratory, Brookhaven National Laboratory, Physicist, Brookhaven National Laboratory, Oak Ridge National Laboratory, USA, Center for Nuclear Study, University of Tokyo, Advanced Science Research Center, Japan Atomic Energy Agency, Florida State University, Presidency University, Kolkata, INDIA, VECC,Kolkata, INDIA, SINP,Kolkata, INDIA, UGC-DAE CSR (Kolkata), INDIA, IFIN-HH, ELI-NP, Romania, Variable Energy Cyclotron Centre,Kolkata, INDIA, IEM, Kolkata, India, Victoria Institution (College), Kolkata, INDIA, Variable Energy Cyclotron Centre, Kolkata, INDIA, NHMFL; Florida State University, FAMU-FSU College of Engineering, Florida State University, Physics Department, Florida State University, Mississippi State University, NHMFL-FSU, U. Colorado at Boulder, NHMFL, University of Alabama at Birmingham, Oak Ridge National Laboratory, Argonne National Laboratory, Alabama School of Math and Science, University of South Alabama, University of Florida, University of Notre Dame, University of Texas at Dallas, Bob Jones University, University of Tennessee at Chattanooga, The Autonomous University of San Luis Potosí, Northern Arizona University, Flagstaff, AZ, Harvard-Smithsonian Center for Astrophysics, Cambridge, National Institute of Standards and Technology, Clemson University, University of South Florida, Phenikaa University, University of Ulsan, Ohio University, University of Hawaii, University of California, Davis, University of California, Davis., Saleh Research Centre, Department of Physics, Florida State university, Tallahassee, FL32306, USA, WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK, Professor, facility manager, Student, Florida State University(Former), Hebrew University, Israel \& Ioffe Institute, St.\ Petersburg, Russia, University of Tennessee, Knoxville

  • Robert Grzywacz

    Moscow Institute of Physics and Technology, University of Virginia, California Institute of Technology, National High Magnetic Field Laboratory, University and Student Affairs; Oak Ridge Laboratory, Brookhaven National Laboratory, Physicist, Brookhaven National Laboratory, Oak Ridge National Laboratory, USA, Center for Nuclear Study, University of Tokyo, Advanced Science Research Center, Japan Atomic Energy Agency, Florida State University, Presidency University, Kolkata, INDIA, VECC,Kolkata, INDIA, SINP,Kolkata, INDIA, UGC-DAE CSR (Kolkata), INDIA, IFIN-HH, ELI-NP, Romania, Variable Energy Cyclotron Centre,Kolkata, INDIA, IEM, Kolkata, India, Victoria Institution (College), Kolkata, INDIA, Variable Energy Cyclotron Centre, Kolkata, INDIA, NHMFL; Florida State University, FAMU-FSU College of Engineering, Florida State University, Physics Department, Florida State University, Mississippi State University, NHMFL-FSU, U. Colorado at Boulder, NHMFL, University of Alabama at Birmingham, Oak Ridge National Laboratory, Argonne National Laboratory, Alabama School of Math and Science, University of South Alabama, University of Florida, University of Notre Dame, University of Texas at Dallas, Bob Jones University, University of Tennessee at Chattanooga, The Autonomous University of San Luis Potosí, Northern Arizona University, Flagstaff, AZ, Harvard-Smithsonian Center for Astrophysics, Cambridge, National Institute of Standards and Technology, Clemson University, University of South Florida, Phenikaa University, University of Ulsan, Ohio University, University of Hawaii, University of California, Davis, University of California, Davis., Saleh Research Centre, Department of Physics, Florida State university, Tallahassee, FL32306, USA, WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK, Professor, facility manager, Student, Florida State University(Former), Hebrew University, Israel \& Ioffe Institute, St.\ Petersburg, Russia, University of Tennessee, Knoxville