Observing real time ligand-induced structural changes at the single nanocluster limit.

ORAL

Abstract

Water-soluble metallic clusters are an important class of nanomaterial with applications in biosensing, diagnostic imaging and catalysis. These clusters require ligand molecules to stabilize their structure and prevent aggregation. It is not entirely clear what affect these ligands have on the cluster's structural kinetics and this has implications regarding cluster stability and reactivity. Direct observation of these fluctuations at the single cluster limit has been difficult to achieve because of the length scales involved ($D_{\mathrm{c}} \quad =$ 2nm). To overcome this limitation, our group has utilized resistive-pulse nanopore sensing to simultaneously trap and monitor structural fluctuations of thiolate-capped gold nanoclusters at the single particle limit. The technique is based on the Coulter-counting principle applied at the nanoscale. The nanocluster enters the pore and blocks the flow of ions through the pore giving rise to a current blockade. Fluctuations within each blockade correspond to ligand induced structural changes. Here we report our observations that show the structure fluctuations scale with the size of the ligand molecules and that by trapping the cluster in the pore, we can probe and monitor surface reactions (i.e. ligand exchange) at the single cluster limit.

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Authors

  • Joseph Reiner

    Virginia Commonwealth University

  • Emmanuel Sarpong

    Georgia State University, University of Alabama at Birmingham, American Association of Physics Teachers, Bradley University, Michigan State University, University of St. Thomas, Kansas State University, Physical and Computational Sciences Directorate and Institute for Integrated Catalysis, Pacific Northwest National Laboratory, University of Delhi, University of Mississippi, Vanderbilt University, Universidad de los Andes (Colombia), President of UNCW SPS Chapter, Duke University, NC Central University, Davidson College, Beijing Normal University, University of California, Los Angeles, University of Tennessee, Chattanooga, University of Kentucky, Syracuse University, Clemson University, Department of Physics & Astronomy, Florida International University, Oak Ridge National Lab, Indiana University, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), Bowie State University, MD, Oak Ridge National Laboratory, University of Tennessee, Knoxville, Arizona State University, University of California, Davis, North Carolina State University, Virginia Commonwealth University, North Carolina A&T State University, UNC Charlotte

  • Emmanuel Sarpong

    Georgia State University, University of Alabama at Birmingham, American Association of Physics Teachers, Bradley University, Michigan State University, University of St. Thomas, Kansas State University, Physical and Computational Sciences Directorate and Institute for Integrated Catalysis, Pacific Northwest National Laboratory, University of Delhi, University of Mississippi, Vanderbilt University, Universidad de los Andes (Colombia), President of UNCW SPS Chapter, Duke University, NC Central University, Davidson College, Beijing Normal University, University of California, Los Angeles, University of Tennessee, Chattanooga, University of Kentucky, Syracuse University, Clemson University, Department of Physics & Astronomy, Florida International University, Oak Ridge National Lab, Indiana University, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), Bowie State University, MD, Oak Ridge National Laboratory, University of Tennessee, Knoxville, Arizona State University, University of California, Davis, North Carolina State University, Virginia Commonwealth University, North Carolina A&T State University, UNC Charlotte

  • Emmanuel Sarpong

    Georgia State University, University of Alabama at Birmingham, American Association of Physics Teachers, Bradley University, Michigan State University, University of St. Thomas, Kansas State University, Physical and Computational Sciences Directorate and Institute for Integrated Catalysis, Pacific Northwest National Laboratory, University of Delhi, University of Mississippi, Vanderbilt University, Universidad de los Andes (Colombia), President of UNCW SPS Chapter, Duke University, NC Central University, Davidson College, Beijing Normal University, University of California, Los Angeles, University of Tennessee, Chattanooga, University of Kentucky, Syracuse University, Clemson University, Department of Physics & Astronomy, Florida International University, Oak Ridge National Lab, Indiana University, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), Bowie State University, MD, Oak Ridge National Laboratory, University of Tennessee, Knoxville, Arizona State University, University of California, Davis, North Carolina State University, Virginia Commonwealth University, North Carolina A&T State University, UNC Charlotte