Professor of Chemistry
Ph.D. University of Utah, 2006
(Analytical, Bioanalytical, and Electrochemistry)
The Zhang group develops a variety of ultrasensitive physical and analytical tools to explore interesting interfacial behaviors of single molecules, nanoparticles, and biological cells. Such tools include nanometer and micrometer-scale electrodes and their massive, uniform arrays, single-molecule and super-resolution fluorescence microscopies, dark-field microscopy, magnetic particles, nanopores and nanopipettes, and electron and ion microscopies. Current projects of special interest include understanding collision and electrochemical oxidation or reduction of single nanoparticles and molecules, probing neuronal activity with massive nanoelectrode arrays, and developing new methods to detect and manipulate single biomolecules and cells.
Redox Behavior of Single Nanoparticles/Molecules at the Electrode/Solution Interface
The electrochemical interface is an ultrathin interfacial region between the electrode and the electrolyte solution and is extraordinarily complex, involving highly dynamic processes, such as solvation and desolvation, electron transfer, molecular adsorption and assembly, and diffusion. Many of these processes are driven or modulated by the presence of a large interfacial potential gradient. The study and better understanding of the electrochemical interface is of key importance for designing better electrochemical systems where their applications may include batteries, fuel cells, electrocatalytic water splitting, corrosion protection, and electroplating. We aim to understand the electrode/solution interface by directly probing single molecules and nanoparticles using highly sensitive and ultrafast fluorescence techniques. A recent experiment has used a nanoscale electrochemical cell and single particle fluorescence to probe dynamic collision and oxidation behavior of single nanoparticles at the surface of a Pt nanoelectrode.
Imaging Neuronal Activity with Fluorescence and Massive Electrochemical Arrays
Neuronal communication is facilitated by the release of chemical messengers, often via a process called exocytosis. Some of these molecules, e.g., dopamine, epinephrine, 5-hydroxytryptamine, can be studied using microelectrodes at a single-cell level with millisecond or microsecond temporal resolution. We are interested in exploring the spatial heterogeneity in single-cell exocytosis and the ability to probe many neurons in a functional network. Toward these goals, we have developed massive electrochemical arrays containing >1,000,000 of nanoelectrodes to image neuronal activity with exceedingly high spatial/temporal resolution. A key aspect of this work is the use of fluorescence-enabled electrochemical microscopy (FEEM), a technique developed in our laboratory, to monitor electrochemical signal using fluorescence.
New Concepts and Tools for Ultrasensitive Bioanalysis
Many disease biomarkers present at very low concentrations, sometimes single copies, in complex matrices. We are interested in the development of simple and powerful bioanalytical methods to detect and manipulate individual biomolecules, particles, and cells. Of particular interest are circulating DNAs and tumor cells in blood.
Hao, R.;‡ Fan, Y. S.;‡ Zhang, B. “Imaging Dynamic Collision and Oxidation of Single Silver Nanoparticles at the Electrode/Solution Interface.” J. Am. Chem. Soc. 2017, 139, 12274–12282. (‡ equal contribution)
Lu, J.; Fan, Y. S.; Howard, M.; Vaughan, J. C.; Zhang, B. “Single-Molecule Electrochemistry on a Porous Silica-Coated Electrode.” J. Am. Chem. Soc. 2017, 139, 2964-2971.
Oja, S. M.; Vitti, N. J.; Edwards, M. A.; Robinson, D. A.; White, H. S.; Zhang, B. “Observing Multipeak Collision Behavior in Electro-Oxidation of Single Silver Nanoparticles.” J. Am. Chem. Soc. 2017, 139, 708-718.
Guo, Z. H.; Percival, S. J.; Zhang, B. “Chemically-Resolved Transient Collision Events of Single Electrocatalytic Nanoparticles.” J. Am. Chem. Soc. 2014, 136, 8879–8882. (JACS Spotlight article)
Guerrette, J. P.; Percival, S. J.; Zhang, B. "Fluorescence coupling for direct imaging of electrocatalytic heterogeneity" J. Am. Chem. Soc. 2013, 135, 855-861.
Guerrette, J. P.; Oja, S. M.; Zhang, B. “Coupled Electrochemical Reactions at Bipolar Microelectrodes and Nanoelectrodes.” Anal. Chem., 2012, 84, 1609-1616.
Adams, K. L.; Jena, B. K.; Percival, S. J.; Zhang, B. “Highly-Sensitive Detection of Exocytotic Dopamine Release using a Gold-Nanoparticle-Network Microelectrode.” Anal. Chem. 2011, 83, 920-927.
Guerrette, J. P.; Zhang, B. “Scan-Rate Dependent Current Rectification of Cone-Shape Silica Nanopores in Quartz Nanopipettes.” J. Am. Chem. Soc. 2010, 132, 17088-17091.