Department of Chemistry

Analytical Chemistry

Research ImageConsistently ranked as one of the top analytical divisions in the United States, ranked number 1 for the fifth year in a row by U.S. News and World Report magazine in its 2011 edition of "America's Best Graduate Schools," the analytical division is recognized as a world leader in this scientific area.

Following the tradition set by the late Professor Charles N. Reilley, the division extends the frontier of the field through a focus on fundamental studies related to chemical analysis and the development of innovative instrumentation. All traditional areas of research are represented, including electrochemistry, mass spectrometry, microscopy, sensors, separations and spectroscopy.

Research projects span a wide range of chemical analysis science and include, but are not limited to, biosensors, nanoscopic materials, neurochemistry, microvolume separations and analysis, protein adsorption, supercritical fluids and single-molecule analysis; for examples of currently active research projects please see the list below. The division has strong relationships with a large number of companies in the pharmaceutical, chemical and scientific instrumentation industries, which provide continued support of research fellowships and the Analytical Seminar series.

 

Recent Research Highlights

Fast-Scan Cyclic Voltammetry Software

Over the last several decades, fast-scan cyclic voltammetry, FSCV, has proved to be a valuable analytical tool for the real-time measurement of neurotransmitter dynamics in vitro and in vivo. Indeed, FSCV has found application in a wide variety of disciplines including electrochemistry, neurobiology, and behavioral psychology. The maturation of FSCV as an in vivo technique led users to pose increasingly complex questions that require a more sophisticated experimental design. To accommodate recent and future advances in FSCV application, the Wightman Group has developed High Definition Cyclic Voltammetry, HDCV. As described in Analytical Chemistry, HDCV is an electrochemical software suite that includes data acquisition and analysis programs.

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The data collection program delivers greater experimental flexibility and better user feedback through live displays. It supports experiments involving multiple electrodes with customized waveforms. It is compatible with transistor–transistor logic-based systems that are used for monitoring animal behavior, and it enables simultaneous recording of electrochemical and electrophysiological data. HDCV analysis streamlines data processing with superior filtering options, seamlessly manages behavioral events, and integrates chemometric processing. Furthermore, analysis is capable of handling single files collected over extended periods of time, allowing the user to consider biological events on both subsecond and multiminute time scales.

 

NO-Releasing Chitosan Oligosaccharides

As reported in Biomaterials, secondary amine-functionalized chitosan oligosaccharides of different molecular weights have been synthesized by the Schoenfisch Group. The process involved grafting 2-methyl aziridine from the primary amines on chitosan oligosaccharides, followed by reaction with nitric oxide, NO, gas under basic conditions to yield N-diazeniumdiolate NO donors. The total NO storage, maximum NO flux, and half-life of the resulting NO-releasing chitosan oligosaccharides were controlled by the molar ratio of 2-methyl aziridine to primary amines and the functional group surrounding the N-diazeniumdiolates respectively.

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The secondary amine-modified chitosan oligosaccharides greatly increased the NO payload over existing biodegradable macromolecular NO donors. In addition, the water-solubility of the chitosan oligosaccharides enabled their penetration across the extracellular polysaccharides matrix of Pseudomonas aeruginosa biofilms and association with embedded bacteria. The effectiveness of these chitosan oligosaccharides at biofilm eradication was shown to depend on both the molecular weight and ionic characteristics. Low molecular weight and cationic chitosan oligosaccharides exhibited rapid association with bacteria throughout the entire biofilm, leading to enhanced biofilm killing. At concentrations resulting in 5-log killing of bacteria in Pseudomonas aeruginosa (P. aeruginosa) biofilms, the NO-releasing and control chitosan oligosaccharides elicited no significant cytotoxicity to mouse fibroblast L929 cells in vitro.

 

Representative Publications

In Vivo Analytical Performance of Nitric Oxide-Releasing Glucose Biosensors. Robert J. Soto, Benjamin J. Privett, and Mark H. Schoenfisch. Anal. Chem., 2014, 86 (14), pp 7141–7149.

Medullary Norepinephrine Neurons Modulate Local Oxygen Concentrations in the Bed Nucleus of the Stria Terminalis. Elizabeth S Bucher, Megan E Fox, Laura Kim, Douglas C Kirkpatrick, Nathan T Rodeberg, Anna M Belle and Mark Wightman. Journal of Cerebral Blood Flow & Metabolism (2014) 34, 1128–1137.

Dynamics and Evolution of β-Catenin-Dependent Wnt Signaling Revealed through Massively Parallel Clonogenic Screening. Pavak K. Shah, Matthew P. Walker, Christopher E. Sims, Michael B. Major, and Nancy L. Allbritton. Integr. Biol., 2014,6, 673-684.

Small Sample Sorting of Primary Adherent Cells by Automated Micropallet Imaging and Release. Pavak K. Shah, Silvia Gabriela Herrera-Loeza, Christopher E. Sims, Jen Jen Yeh, and Nancy L. Allbritton. Cytometry Part A, Volume 85, Issue 7, pages 642–649, July 2014.

Optimization of 3-D Organotypic Primary Colonic Cultures for Organ-on-Chip Applications. Asad A Ahmad, Yuli Wang, Adam D Gracz, Christopher E Sims, Scott T Magness and Nancy L Allbritton. Journal of Biological Engineering 2014, 8:9.

Immobilization of Lambda Exonuclease onto Polymer Micropillar Arrays for the Solid-Phase Digestion of dsDNAs. Nyoté J. Oliver-Calixte, Franklin I. Uba, Katrina N. Battle, Kumuditha M. Weerakoon-Ratnayake, and Steven A. Soper. Anal. Chem., 2014, 86 (9), pp 4447–4454.

Chemical Vapor Deposition of Aminopropyl Silanes in Microfluidic Channels for Highly Efficient Microchip Capillary Electrophoresis-Electrospray Ionization-Mass Spectrometry. Nicholas G. Batz, J. Scott Mellors, Jean Pierre Alarie, and J. Michael Ramsey. Anal. Chem., 2014, 86 (7), pp 3493–3500.

Micropallet Arrays for the Capture, Isolation and Culture of Circulating Tumor Cells from Whole Blood of Mice Engrafted with Primary Human Pancreatic Adenocarcinoma. Guohua Xu, Yansheng Ye, Xiaoli Liu, Shufen Cao, Qiong Wu, Kai Cheng, Maili Liu, Gary J. Pielak, and Conggang Li. Biosensors and Bioelectronics, Volume 54, 15 April 2014, Pages 476–483.

Fluorous Enzymatic Synthesis of Phosphatidylinositides. Weigang Huang, Angela Proctor, Christopher E. Sims, Nancy L. Allbritton, and Qisheng Zhang. Chem. Commun., 2014,50, 2928-2931.

Response of Single Leukemic Cells to Peptidase Inhibitor Therapy Across Time and Dose Using a Microfluidic Device. Michelle L. Kovarik, Alexandra J. Dickinson, Pourab Roy, Ranjit A. Poonnen, Jason P. Fine and Nancy L. Allbritton. Integr. Biol., 2014, 6, 164-174.