Background:

• Research Staff, Oak Ridge National Laboratory, 1995-2003
• Postdoctoral Fellow, Oak Ridge National Laboratory, 1992-1995
• Award for Excellence in Technology Transfer, Federal Laboratory Consortium, 2004
• R&D 100 Top 40 Award, R&D Magazine, 2001
• R&D 100 Award, R&D Magazine, 1996
• Significant Event Award, Lockheed Martin Energy Research, 1996
• Technical Achievement Award, Lockheed Martin Energy Research, 1996
• Alexander Hollaender Distinguished Postdoctoral Fellow, 1992-1995

An exciting area that continues to grow is interdisciplinary research at the interface between chemistry, physics, and biology. Because of the breadth and complexity of this research, faster, more precise, and more sensitive strategies are needed to study these systems. One approach that could contribute significantly to this research uses micromachining techniques to build miniature platforms, i.e., lab-on-a-chip technologies, to conduct chemical and biological experiments. On these platforms, fluids can be precisely manipulated in the nanoliter (10^-9 L) to attoliter (10^-18 L) range by controlling the applied force, geometry of the structure, and properties of the materials.

The benefit of microfabricated devices comes from being able to evaluate and understand physical and chemical interactions on micro- and nanometer length scales. Our research projects focus on developing micro- and nanoscale tools for manipulating and interrogating molecules, fluids, and particles. These projects require developing the necessary micro- and nanoscale devices using lithography, thin film deposition, and chemical etching (see Figure 1), and evaluating device performance using spectroscopy and electrochemistry.

Whether identifying peptides and proteins, conducting cell-based assays, or evaluating host-guest interactions, an advantage of miniature systems is that the performance tends to increase as dimensions are reduced. For example, with electrokinetically driven separations, the reduced dimensions provide shorter injection plugs and higher electric field strengths resulting in higher separation efficiencies. In addition to separations, evaluating transport properties through micro- and nanometer scale conduits and mimicking cellular processes in artificial environments are areas of interest.

	Mapping of the light intensity transmitted through nanometer scale apertures. Scanning electron micrograph of two features (nano-pillars) formed by photopolymerizing a negative tone resist with UV radiation through 480 nm diameter apertures in a metal film. This project is in collaboration with Prof. Dragnea.

Selected Publications:

E.-S. Kwak, T.-D. Onuta, D. Amarie, R. Potyrailo, B. Stein, S.C. Jacobson, W.L. Schaich, and B. Dragnea, "Optical Trapping with Integrated Near-Field Apertures," The Journal of Physical Chemistry B, in press.

C.D. Thomas, S.C. Jacobson, and J.M. Ramsey, "A Strategy for Repetitive Pinched Injections on a Microfluidic Device," Analytical Chemistry, in press.

M.A. McClain, C.T. Culbertson, S.C. Jacobson, N.L. Allbritton, C.E. Sims, and J.M. Ramsey, "Microfluidic Devices for the High Throughput Chemical Analysis of Cells," Analytical Chemistry, 75, 5646-5655, 2003.

J.D. Ramsey, S.C. Jacobson, C.T. Culbertson, and J.M. Ramsey, "High Efficiency, Two-Dimensional Separations of Protein Digests on Microfluidic Devices," Analytical Chemistry, 75, 3758-3764, 2003.

B.S. Broyles, S.C. Jacobson, and J.M. Ramsey, "Sample Filtration, Concentration, and Separation Integrated on Microfluidic Devices," Analytical Chemistry, 75, 2761-2767, 2003.