Consistently 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.
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.
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.
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.
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.
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.
Lipid Pools As Photolabile "Protecting Groups": Design of Light-Activatable Bioagents. Luong T. Nguyen, Nathan P. Oien, Nancy L. Allbritton, David S. Lawrence. Angew. Chem., online 31 JUL 2013, DOI: 10.1002/anie.201305510.
Microfluidic Chemical Cytometry of Peptide Degradation in Single Drug-Treated Acute Myeloid Leukemia Cells. Michelle L. Kovarik, Pavak K. Shah, Paul M. Armistead, and Nancy L. Allbritton. Anal. Chem., 2013, 85 (10), pp 4991–4997.
Array of Biodegradable Microrafts for Isolation and Implantation of Living, Adherent Cells. Yuli Wang, Colleen N. Phillips, Gabriela S. Herrera, Christopher E. Sims, Jen Jen Yeh and Nancy L. Allbritton. RSC Adv., 2013,3, 9264-9272; DOI: 10.1039/C3RA41764F.
Controlled Iontophoresis Coupled with Fast-Scan Cyclic Voltammetry/Electrophysiology in Awake, Freely Moving Animals. Anna M. Belle, Catarina Owesson-White, Natalie R. Herr, Regina M. Carelli, and R. Mark Wightman. ACS CHEMICAL NEUROSCIENCE, 4 (5):761-771, MAY 2013; DOI:10.1021/cn400031v.
Automated Capillary Electrophoresis System for Fast Single-Cell Analysis. Alexandra J. Dickinson, Paul M. Armistead, and Nancy L. Allbritton. Anal. Chem., 2013, 85 (9), pp 4797–4804.