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.
A new strategy for magnetically manipulating and isolating adherent cells with extremely high post-collection purity and viability is reported in Biomicrofluidics by the Allbritton Group. Micromolded magnetic elements, termed microrafts, were fabricated in an array format and used as culture surfaces and carriers for living, adherent cells. A poly(styrene-co-acrylic acid) polymer containing well dispersed magnetic nanoparticles was developed for creating the microstructures by molding. Nanoparticles of γFe2O3 at concentrations up to 1% wt./wt. could be used to fabricate microrafts that were optically transparent, highly magnetic, biocompatible, and minimally fluorescent. To prevent cellular uptake of nanoparticles from the magnetic polymer, a poly(styrene-co-acrylic acid) layer lacking γFe2O3 nanoparticles was placed over the initial magnetic microraft layer to prevent cellular uptake of the γFe2O3 during culture.
The microraft surface geometry and physical properties were altered by varying the polymer concentration or layering different polymers during fabrication. Cells plated on the magnetic microrafts were visualized using standard imaging techniques including brightfield, epifluorescence, and confocal microscopy. Magnetic microrafts possessing cells of interest were dislodged from the array and efficiently collected with an external magnet. To demonstrate the feasibility of cell isolation using the magnetic microrafts, a mixed population of wild-type cells and cells stably transfected with a fluorescent protein was plated onto an array. Microrafts possessing single, fluorescent cells were released from the array and magnetically collected. A post-sorting single-cell cloning rate of 92% and a purity of 100% were attained.
Researchers in the Allbritton Group used Polystyrene (PS), a standard material for cell culture consumable labware, to mold microstructures with high fidelity of replication by an elastomeric polydimethylsiloxane (PDMS) mold. The process was a simple, benchtop method based on soft lithography using readily available materials. The key to successful replica molding by this simple procedure relies on the use of a solvent, for example, gamma-butyrolactone, which dissolves PS without swelling the PDMS mold. PS solution was added to the PDMS mold, and evaporation of the solvent was accomplished by baking the mold on a hotplate. Microstructures with feature sizes as small as 3 μm and aspect ratios as large as 7 were readily molded.
Prototypes of microfluidic chips made from PS were prepared by thermal bonding of a microchannel molded in PS with a flat PS substrate. The PS microfluidic chip displayed much lower adsorption and absorption of hydrophobic molecules (e.g. rhodamine B) compared to a comparable chip created from PDMS. The molded PS surface exhibited stable surface properties after plasma oxidation as assessed by contact angle measurement. The molded, oxidized PS surface remained an excellent surface for cell culture based on cell adhesion and proliferation. To demonstrate the application of this process for cell biology research, PS was micromolded into two different microarray formats, microwells and microposts, for segregation and tracking of non-adherent and adherent cells, respectively. The micromolded PS possessed properties that were ideal for biological and bioanalytical needs, thus making it an alternative material to PDMS and suitable for building lab-on-a-chip devices by soft lithography methods.
Distinguishing Single DNA Nucleotides Based on Their Times of Flight Through Nanoslits: A Molecular Dynamics Simulation Study. Brian R. Novak, Dorel Moldovan, Dimitris E. Nikitopoulos, and Steven A. Soper. J. Phys. Chem. B, 2013, 117 (12), pp 3271–3279.
A Microfluidic Chip Integrating DNA Extraction and Real-Time PCR for the Detection of Bacteria in Saliva. Emily A. Oblath, W. Hampton Henley, Jean Pierre Alarie and J. Michael Ramsey. Lab Chip, 2013,13, 1325-1332.
Identification of Methicillin-Resistant Staphylococcus aureus using an Integrated and Modular Microfluidic System. Yi-Wen Chen, Hong Wang, Mateusz Hupert and Steven A. Soper. Analyst, 2013,138, 1075-1083.
Characterization of Freestanding Photoresist Films for Biological and MEMS Applications. D M Ornoff, Y Wang, and N L Allbritton. J. Micromech. Microeng. 23 025009, 2013, Vol 23, Nbr 2.
A Device for Performing Lateral Conductance Measurements on Individual Double-Stranded DNA Molecules. Laurent D. Menard, Chad E. Mair, Michael E. Woodson, Jean Pierre Alarie, and J. Michael Ramsey. ACS Nano, 2012, 6 (10), pp 9087–9094, DOI: 10.1021/nn303322r.
Electrokinetically-Driven Transport of DNA through Focused Ion Beam Milled Nanofluidic Channels. Laurent D. Menard and J. Michael Ramsey. Anal. Chem., 2013, 85 (2), pp 1146–1153.
A Microfluidic Chip Integrating DNA Extraction and Real-Time PCR for the Detection of Bacteria in Saliva. Emily A. Oblath, W. Hampton Henley, Jean Pierre Alarie and J. Michael Ramsey. Lab Chip, 2013, Advance Article, DOI: 10.1039/C3LC40961A.
Synthesis and Electrochemistry of 6 nm Ferrocenated Indium–Tin Oxide Nanoparticles. Joseph J. P. Roberts , Kim T. Vuong , and Royce W. Murray. Langmuir, 2013, 29 (1), pp 474–479.
Laser-Based Directed Release of Array Elements for Efficient Collection into Targeted Microwells. Nicholas C. Dobes, Rahul Dhopeshwarkar, W. Hampton Henley, J. Michael Ramsey, Christopher E. Sims and Nancy L. Allbritton. Analyst, 2013,138, 831-838.
Microfabricated Arrays for Splitting and Assay of Clonal Colonies. Philip C. Gach, Wei Xu, Samantha J. King, Christopher E. Sims, James Bear, and Nancy L. Allbritton. Anal. Chem., 2012, 84 (24), pp 10614–10620.