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

Size and Shape Matter

Nitric oxide, NO, a reactive free radical, has proven effective in eradicating bacterial biofilms with reduced risk of fostering antibacterial resistance. Published in ACS Applied Materials & Interfaces, researchers in the Schoenfisch Group have evaluated the efficacy of NO-releasing silica nanoparticles against Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus biofilms as a function of particle size and shape.

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Three sizes of NO-releasing silica nanoparticles with identical total NO release were utilized to study antibiofilm eradication as a function of size. To observe the role of particle shape on biofilm killing, the group varied the aspect ratio of the NO-releasing silica particles from 1 to 8 while maintaining constant particle volume and NO-release totals. Nitric oxide-releasing particles with decreased size and increased aspect ratio were more effective against both P. aeruginosa and S. aureus biofilms, with the Gram-negative species exhibiting the greatest susceptibility to NO.

To further understand the influence of these nanoparticle properties on NO-mediated antibacterial activity, the group visualized intracellular NO concentrations and cell death with confocal microscopy. Smaller NO-releasing particles exhibited better NO delivery and enhanced bacteria killing compared to the larger particles. Likewise, the rod-like NO-releasing particles proved more effective than spherical particles in delivering NO and inducing greater antibacterial action throughout the biofilm.

 

Biocompatible Photoresist Plus

Researchers in the Allbritton Group have developed a novel photoresist composite incorporating poly(methyl methacrylate-co-methacrylic acid), the epoxy resin 1002F, and colloidal maghemite nanoparticles to produce a stable, transparent and biocompatible photoresist. As described in the Journal of Micromechanics and Microengineering, the composite photoresist was prepared in a scalable fashion in batches up to 1 kg with the particles remaining dispersed during room-temperature storage for at least six months.

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The ability to manipulate microstructures formed from the composite was demonstrated by magnetically collecting clonal colonies of HeLa cells from a micropallet array. The transparency, biocompatibility, scalable synthesis and superparamagnetic properties of the novel composite address key limitations of existing magnetic composites.

 

Representative Publications

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.

Ex Vivo Chemical Cytometric Analysis of Protein Tyrosine Phosphatase Activity in Single Human Airway Epithelial Cells. Ryan M. Phillips, Lisa A. Dailey, Eric Bair, James M. Samet, and Nancy L. Allbritton. Anal. Chem., 2014, 86 (2), pp 1291–1297.

Capture and 3D Culture of Colonic Crypts and Colonoids in a Microarray Platform. Yuli Wang, Asad A. Ahmad, Pavak K. Shah, Christopher E. Sims, Scott T. Magness and Nancy L. Allbritton. Lab Chip , 2013, 13, 4625-4634.

Flexible Software Platform for Fast-Scan Cyclic Voltammetry Data Acquisition and Analysis. Elizabeth S. Bucher, Kenneth Brooks, Matthew D. Verber, Richard B. Keithley, Catarina Owesson-White, Susan Carroll, Pavel Takmakov, Collin J. McKinney, and R. Mark Wightman. Anal. Chem., 2013, 85 (21), pp 10344–10353.

Nitric Oxide-Releasing Chitosan Oligosaccharides as Antibacterial Agents. Yuan Lu, Danielle L. Slomberg, and Mark H. Schoenfisch. Biomaterials; online, 20 November, 2013.

Role of Size and Shape on Biofilm Eradication for Nitric Oxide-Releasing Silica Nanoparticles. Danielle L. Slomberg, Yuan Lu, Angela D. Broadnax, Rebecca A. Hunter, Alexis W. Carpenter, and Mark H. Schoenfisch. ACS Appl. Mater. Interfaces, 2013, 5 (19), pp 9322–9329.

Scalable Synthesis of a Biocompatible, Transparent and Superparamagnetic Photoresist for Microdevice Fabrication. P K Shah, M R Hughes, Y Wang, C E Sims and N L Allbritton. J. Micromech. Microeng. 23 107002, P K Shah et al 2013.

Polaronic Transport and Current Blockades in Epitaxial Silicide Nanowires and Nanowire Arrays. Violeta Iancu, X.G. Zhang, Tae-Hwan Kim, Laurent D. Menard, P. R. C. Kent, Michael E. Woodson, J. Michael Ramsey, An-Ping Li, and Hanno H. Weitering. Nano Lett., Article ASAP, Online July 31, 2013, DOI: 10.1021/nl401574c.

β-Turn Sequences Promote Stability of Peptide Substrates for Kinases Within the Cytosolic Environment. Shan Yang, Angela Proctor, Lauren L. Cline, Kaiulani M. Houston, Marcey L. Waters and Nancy L. Allbritton. Analyst, 2013,138, 4305-4311.