Chemistry @ IU

Contact Information:

(812) 855-6620
jacobson@indiana.edu
Simon 002C
Jacobson Group Website

Professor Jacobson received a B.S. in mathematics from Georgetown University in 1988 and a Ph.D. in chemistry from the University of Tennessee in 1992. After graduate school, he was awarded an Alexander Hollaender Distinguished Postdoctoral Fellowship at Oak Ridge National Laboratory (ORNL). In 1995, Stephen became a research staff member at ORNL, and during his stay at ORNL, he participated as an adjunct faculty member in the Genome Science and Technology Program at the University of Tennessee from 2000 to 2003. In 2003, he moved to Indiana University (IU) and joined the faculty as an Associate Professor in the Department of Chemistry.

Research in the Jacobson group focuses on developing microfabricated instrumentation and using this instrumentation to study various chemical and biochemical problems. Current projects are in the areas of microfluidic separations, nanofluidics, photolithographic mapping, and cell-based assays.

Research

Our research focuses on developing microfabricated instrumentation and using this instrumentation to study various chemical and biochemical problems. We are currently pursuing projects which fall into the areas of (1) microfluidic separations, (2) nanofluidics, (3) photolithographic mapping, and (4) cell-based assays. Please feel free to contact us if you would like additional information.

Microfluidic Separations. Microfluidic-based separations benefit from the dexterity with which materials can be manipulated and the ability to fabricate microchannel structures having small volume interconnects. In fact, electrokinetically driven separations on microfluidic devices have generated efficiencies per unit length similar to or exceeding that of conventional capillary separations. We are currently developing microfluidic devices for one- and two-dimensional separations that will shorten analysis times and concurrently improve the peak capacity, accuracy, and reproducibility compared to conventional techniques. With improved analytical performance, assays can be developed to study the onset and progression of diseases.

Nanofluidics. In addition to developing sophisticated microscale analysis systems, of particular interest is how device function scales when one or more of the conduit dimensions is on a nanometer length scale, and what advantages, if any, there might be for separations. Nanofluidic systems can be significantly influenced by phenomena such as double layer overlap, surface charge, diffusion, and entropic forces, which are either insignificant or absent in larger microchannels. To develop analytical functions from these unique nanofluidic phenomena, we are studying fundamental fluid and material transport and applying what is learned to separation and sensing problems, e.g., creating tunable particle/molecular filters and monitoring supramolecular assembly.

Photolithographic Mapping. While evaluating techniques to fabricate feature sizes suitable for our nanofluidic work, we developed a method that provides direct visualization of the three-dimensional light intensity distribution in close proximity to nanoscale apertures. The primary advantages of this method with respect to state-of-the-art techniques using surface probes are higher spatial resolution and non-intrusiveness. Applications employing this method include creating micro- and nanoscale features simultaneously in a single photolithographic exposure and using the optical properties of the polymer (pillar-like) features as detection elements in microfluidic separation devices.

Cell-Based Assays. A long term goal is to be able to screen and analyze cells to determine the chemical basis of cell variability. Microfluidic devices play a key role in handling small quantities of material, delivering those materials to different locations within the device, and controlling the movement of cells within the channels. We have developed microfluidic systems to study sperm chemotaxis, which is oriented cell motion in response to an extracellular chemical concentration gradient, and to produce linear chemical gradients having arbitrary slopes and offsets. Presently, we are exploring bacterial chemotaxis and biofilm formation using similar microfluidic architectures.

(a) Schematic of integrated nanopore/microchannel device, (b) transmitted light image of the microfluidic device with a single nanopore isolated at the channel intersection, and fluorescence images of ion depletion region forming in the vertical microchannel at (c) 0, (d) 2.5, and (e) 5 s after 5 V was applied to reservoirs 1 and 3 with reservoirs 2 and 4 grounded. Arrows depict direction of anionic transport. (J. Am. Chem. Soc. 130, 8614-8616, 2008)

Selected Publications

PubMed

1. K. Zhou, M.L Kovarik, and S.C. Jacobson, “Surface-Charge Induced Ion Depletion and Sample Stacking near Single Nanopores in Microfluidic Devices,” Journal of the American Chemical Society, 130, 8614-8616, 2008. http://dx.doi.org/10.1021/ja802692x.
2. M.L. Kovarik and S.C. Jacobson, “Integrated Nanopore/Microchannel Devices for AC Electrokinetic Trapping of Particles,” Analytical Chemistry, 80, 657-664, 2008. http://dx.doi.org/10.1021.ac701759f.
3. M.A. Lerch, M.D. Hoffman, and S.C. Jacobson, “Influence of Channel Position on Sample Confinement in Two-Dimensional Planar Microfluidic Devices,” Lab on a Chip, 8, 316-322, 2008. http://dx.doi.org/10.1039/b713500a.
4. D. Amarie, J.A. Glazier, and S.C. Jacobson, “Compact Microfluidic Structures for Forming Linear Spatial and Temporal Gradients,” Analytical Chemistry, 79, 9471-9477, 2007. http://dx.doi.org/10.1021/ac0714967.
5. Z. Zhuang, J.A. Starkey, Y. Mechref, M.V. Novotny, and S.C. Jacobson, “Electrophoretic Separations of N-Glycans on Microfluidic Devices,” Analytical Chemistry, 79, 7170-7175, 2007. http://dx.doi.org/10.1021/ac071261v.
6. M.L. Kovarik and S.C. Jacobson, “Attoliter-Scale Dispensing in Nanofluidic Channels,” Analytical Chemistry, 79, 1655-1660, 2007. http://dx.doi.org/10.1021/ac061814m.
7. D. Amarie, N.D. Rawlinson, W.L. Schaich, B. Dragnea, and S.C. Jacobson, “Three-Dimensional Mapping of the Light Intensity Transmitted through Nanoapertures,” Nano Letters, 5, 1227-1230, 2005. http://dx.doi.org/10.1021/nl050891e.

Awards

• Guest Professorship from the Otto Mønsted Foundation, Technical University of Denmark, 2009.
• Trustees Teaching Award, Indiana University, 2006 and 2008.
• Analytical Chemistry Award, Eli Lilly and Company, 2004.
• 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, Oak Ridge National Laboratory, 1992-1995.

Highlights