Unleashing Electrochemistry’s Potential: Resistance Is Futile

Organizers: Karole Blythe, Stephen Fosdick, Elizabeth Nettleton, Amy Stafford, Maggie Weber, and David Yancey, Department of Chemistry, University of Texas at Austin, Austin, TX, tel: (512) 475-7461, Email: klblythe3@gmail.com, sefosdick@gmail.com, enettleton@gmail.com, amyjstafford@gmail.com, mlweber@mail.utexas.edu, and dfyancey@mail.utexas.edu.

This was the symposium hosted by the 2011 Spring Graduate Student Symposium Planning Committee, GSSPC, from The University of Texas at Austin. The speakers were recruited by the student committee, and the goal of the event was to connect a broad audience with distinguished researchers who have been pushing the limits of electrochemistry throughout their careers.

Julie Macpherson of the University of Warwick in England opened the symposium by describing her work involving carbon nanotube electrochemistry. Her group grows single-walled nanotubes (SWNT) using catalytic chemical vapor deposition on insulating silicon oxide substrates. This growth method results in interconnected, high purity SWNT networks of low surface coverage (<1%). Ultramicroelectrodes (UMEs) made from SWNT networks display superior characteristics compared to conventional electrodes due to their fast response times, low background currents and access to high mass transfer rates.

Next, William Heineman from the University of Cincinnati discussed the benefits of spectroelectrochemisty techniques to increase the selectivity of sensors. His experiments involve the partitioning of metal ion analytes into Nafion films that cover an indium tin oxide slide allowing for potential control over the sample. He then uses Attenuated Total Internal Reflection Spectroscopy to optically interrogate electrochemically produced species in the film. He demonstrated how electrochemistry can be used to differentiate between overlapping spectra from two molecules being detected optically. He can also pinpoint when a molecule gets reduced based on the spectral information collected. In the future, Heineman hopes to transform this technique so that it can be used in portable sensor devices.

Henry White from the University of Utah concluded the morning session and discussed nanopore-based chemical analysis. Nanopores can be used as nanoparticle counting devices that also have the ability to determine nanoparticle structure in the sub-100 nm range. These nanopores can also be functionalized for other applications such as DNA sensing, where damaged DNA bases cause clear amperometric signals as the DNA strand moves into and out of the nanopore membrane. The ultimate goal in nanopore electrochemistry for DNA is to be able to sequence a DNA strand that is traversing through the nanopore.

When the afternoon session reconvened, Andrew Ewing from the University of Gothenburg in Sweden talked about chemical sensing at the single cell level. By creating a nanoelectrode array that can be placed within hundreds of nanometers of a cell, they could spatially resolve exocytosis events from a single cell. He extended this to sensing in a microfluidic channel where an entire cell is electrochemically lysed and interrogated. He also discussed electrochemical sensing of single vesicle lysing events. His overall goals are to understand the chemistry of single nerve cells and vesicles.

Similarly to Henry White, Charles Martin of the University of Florida, discussed work in nanopore electrochemistry. His group creates conical nanopores and uses them for single-molecule counting studies. These nanopores are etched from polymeric membranes containing ballistic damage tracks by placing the membrane between two electrolyte solutions with an applied potential difference. By using antibodies for selective analysis, fluctuations of the ionic current within the nanopore can be used to monitor the migration of specific protein molecules.

The keynote speaker of the symposium was Allen J. Bard of The University of Texas at Austin. Professor Bard spoke about his group’s work in single-molecule and nanoparticle electrochemistry. Specifically, they use ultramicroelectrodes to detect the collisions of single catalytic nanoparticles with the electrode. These studies are groundbreaking because they allow for stochastic measurements, and information can be gained at the single-particle level. To date, the group has used this method to study the collision frequency and size of the particles. Information may also be gained about the nature of individual charge transfer events at the electrode surface.

This symposium successfully exposed its attendees to the breadth and power of electrochemical research. Our speakers spoke about biochemical applications, sensing techniques, and fundamental studies. The audience engaged in lively discussion after each talk, and everyone seemed to enjoy the event. We are extremely happy with the results of our planning and appreciate the opportunity from CHED to have served as the 2011 Spring GSSPC. The spring 2012 committee is based out of the California Institute of Technology. Their topic for the San Diego meeting is, “Chemical Biology: When two heads are better than one.” They look forward to seeing you at their symposium and will appreciate your help and support over the coming year. If you have questions or would