Henry S. White

photo of Distinguished Professor Henry White

ANALYTICAL CHEMISTRY

Distinguished Professor
Dean, College of Science

B.S., University of North Carolina, 1978
Ph.D., University of Texas, 1983
Postdoctoral Associate, Massachusetts Institute of Technology, 1983-84

 

Phone: (801) 585-6256

Office: B423 TBBC

Email: white@chem.utah.edu

White Research Group

Interfacial and Bioanalytical Chemistry (IBAC)

Activities & Awards

  • Allen J. Bard Award, The Electrochemical Society, 2015
  • Utah Governor's Medal for Science and Technology, 2014
  • Fellow of the American Chemical Society, 2012
  • Fellow of the American Association for the Advancement of Science, 2011
  • Fellow of the American Academy of Arts & Sciences, 2011
  • Carl Wagner Award, The Electrochemical Society, 2010
  • American Chemical Society Utah Award, 2008
  • W.W. Epstein Outstanding Educator Award, U of Utah, 2007
  • David Grahame Award, The Electrochemical Society, 2005
  • President, Society of Electroanalytical Chemistry, 2003-2005
  • Associate Editor, Journal of the American Chemical Society
  • ACS Analytical Division Award in Electrochemistry, 2004
  • University of Utah Distinguished Research Award, 2004
  • Students Choice Teaching Award, Associated Students of the U of Utah, 2003
  • Faraday Medal, Royal Society of Chemistry, Electrochemical Section, London, 2002
  • Chair, Gordon Research Conference on Electrochemistry, 2002
  • Charles N. Reilley Award, The Society of Electroanalytical Chemistry, 2000

Research Interests

My colleagues and I are engaged in both experimental and theoretical aspects of electrochemistry, with diverse connections to analytical, biological, physical, and materials chemistry. Please see our group website for fuller project descriptions and links to recent publications.

Transport in Thin Layer Batteries. We are studying ion transport in batteries in which the anode and cathode is separated by a ultra-thin electrolyte layer (10s of nanometers wide). At this length scale, the electrical double layers that form at both the anode and cathode begin to overlap which results in changes in the molecular transport (diffusion and migration) of ions. We investigate this phenomenon both theoretical, using finite element simulations, and experimental, using nanometer-scale electrochemical cells.

Nanopore Analysis of DNA. The protein pore αHL has emerged as a powerful tool with which DNA can be analysed. While ssDNA can pass through the smallest constriction in αHL (1.4 nm), dsDNA, which has a nominal diameter of 2.0 nm, cannot. However, it is possible to capture dsDNA inside the α-HL vestibule and unzip it into its constituent single-stranded components. We have recently discovered that structural modifications in DNA in a duplex can also be detected from the magnitude to which ion flow is attenuated during dsDNA residence inside the protein pore. We are currently exploring uses of this sensing zone for identifying and discriminating damage sites in dsDNA.

Nanopore Physics. Ion transport in confined geometries is significantly different from bulk solutions. For example, ion current rectification (ICR) in nanopores is a phenomenon that arises due to the asymmetric charge distribution of the nanopores. Our group has discovered a number of interesting ion transport and fluid phenomena in nanopore systems, including negative differential electrolyte resistance in which a fluid bistability results in a decrease in current with increasing applied voltage.

Nanoparticle Analysis. We have developed an understanding of the dynamics of particles travelling through pores, the forces involved, and the various ionic contributions to the shape of the resistive pulse. This understanding has enabled us to develop a multipass resistive pulse method, where we switch the pressure/voltage to repeatedly pass individual nanoparticles back and forth through the orifice of a conical nanopore/nanopipette. This leads to a precisely determined mean blocking current equating to sub-nanometer particle size resolution. We are currently exploring controlled delivery of single particles & molecules to electrochemical interfaces.

Nanobubbles. Gas nanobubbles formed at solid/liquid interfaces have received significant attention during the past decade due to their remarkable properties. We have developed an electrochemical approach for investigating the formation and properties of single nanobubbles of H2, N2, CO2, or O2 using Pt disk electrodes radii between 5 and 50 nm. The nanobubble experiments reveal the nucleation mechanism of single nanobubble at the interface, as well as provide insight into the structure and chemical dynamics of electrochemical three-phase solid/liquid/gas boundaries.

Modeling Experimental Systems. For the systems investigated in the our group, the experimentally measured quantity is most typically the current, or a statistical measure derived from it, whereas our interest usually lies in the underlying physical and chemical phenomena. Interpretation of our data is typically underpinned by a theoretical model of the system, which may be an analytical expression or a numerical calculation, relating the measured quantity to one or more physical quantities. Typical problems include, for instance, relating electron-transfer rates with the local electrostatic potential distribution, computing the forces of a nanoparticle and its resulting velocity, or studying the effect of ion transport in confined spaces on the discharge rate of a 3D battery.

Selected Publications:

  • Rukshan T. Perera, Robert P. Johnson, Martin A. Edwards, and Henry S. White, “The Effect of the Electric Double Layer on the Activation Energy of Ion Transport in Conical Nanopores,” Phys. Chem., ASAP web publication. DOI: 10.1021/acs.jpcc.5b08194 (2015).
  • Qianjin Chen, Hilke S. Wiedenroth, Sean R. German, and Henry S. White, “Electrochemical Nucleation of Stable N2 Nanobubbles at Pt Nanoelectrodes,” JACS, Am. Chem. Soc., 137 (37), 12064–12069 (2015).
  • Jiewen Xiong, Qianjin Chen, Martin A. Edwards, and Henry S. White, “Ion Transport within High Electric Fields in Nanogap Electrochemical Cells,” ACS Nano, 9, 8520–8529 (2015).
  • Rukshan T. Perera, Aaron M. Fleming, Robert P. Johnson, Cynthia J. Burrows, and Henry S. White, “Detection of Benzo[a]pyrene-Guanine Adducts in Single-Stranded DNA using the α-Hemolysin Nanopore,” Nanotechnology, 26, (2015).
  • Qianjin Chen, Long Luo, and Henry S. White, “Electrochemical Generation of a Hydrogen Bubble at a Recessed Platinum Nanopore Electrode,” Langmuir, 31, 4573–4581 (2015).
  • Alexander von Weber, Eric T. Baxter, Sebastian Proch, Matthew D. Kane, Michael Rosenfelder, Henry S. White, and Scott L. Anderson, “Size-Dependent Electronic Structure Controls Activity for Ethanol Electro-Oxidation at Ptn/Indium Tin Oxide (n = 1 to 14),” Physical Chemistry Chemical Physics. 17, 17601-17610 (2015).
  • Alexander von Weber, Eric T. Baxter, Henry S. White, and Scott L. Anderson, “Cluster Size Controls Branching between Water and Hydrogen Peroxide Production in Electrochemical Oxygen Reduction at Ptn/ITO,” Phys. Chem. C, 119, 11160–11170 (2015).
  • Na An, Aaron M. Fleming, Henry S. White, and Cynthia J. Burrows, “Nanopore Detection of 8-Oxoguanine in the Human Telomere Repeat Sequence, “ACS Nano, 9, 4296–4307 (2015).
  • Yun Ding, Aaron M. Fleming, Henry S. White, and Cynthia J. Burrows, “Internal vs Fishhook Hairpin DNA: Unzipping Locations and Mechanisms in the α-Hemolysin Nanopore,” Phys. Chem. B, 118, 12873–12882 (2014).
  • Robert P. Johnson, Aaron M. Fleming, Cynthia J. Burrows, and Henry S. White “Effect of an Electrolyte Cation on Detecting DNA Damage with the Latch Constriction of α-Hemolysin,” Phys. Chem. Lett., 5, 3781–3786 (2014).
  • Sean R. German, Timothy S. Hurd, Henry S. White, and Tony L. Mega, “Sizing Individual Au Nanoparticles in Solution with Sub-Nanometer Resolution,” ACS Nano, 9, 7186–7194 (2015).
  • Wen-Jie Lan, Clemens Kubeil, Jie-Wen Xiong, Andreas Bund, and Henry S. White. “ Effect of Surface Charge on the Resistive Pulse Waveshape during Particle Translocation through Glass Nanopores”, Phys. Chem. C, 118, 2726–2734 (2014).
  • Long Luo, Deric A. Holden, Henry S. White,Negative Differential Electrolyte Resistance in a Solid-State Nanopore Resulting from Electroosmotic Flow Bistability”, ACS Nano, 8, 3023–3030 (2014)
  • Lixin Fan, Yuwen Liu, Jiewen Xiong, Henry S. White, and Shengli Chen, “Electron-Transfer Kinetics and Electric Double Layer Effects in Nanometer-Wide Thin-Layer Cells”, ACS Nano, 8, 10426–10436 (2014).
  • Robert P. Johnson, Aaron M. Fleming, Qian Jin, Cynthia J. Burrows, and Henry S. White, “Temperature and Electrolyte Optimization of the α-Hemolysin Latch Sensing Zone for Detection of Base Modification in Double-Stranded DNA,” Biophysical Journal, 107, 924–931 (2014).
  • Qianjin Chen, Long Luo, Hamaseh Faraji, Stephen W. Feldberg, and Henry S. White, “Electrochemical Measurements of Single H2 Nanobubble Nucleation and Stability at Pt Nanoelectrodes,” Phys. Chem. Lett., 5, 3539−3544 (2014).