Michael J. Sepaniak	Analytical Chemistry	msepaniak@utk.edu
Ziegler Professor	Buehler Room 420	865-974-8023

The Sepaniak Research Group contributes innovative research in the three broad areas of chemical analysis described below. Themes that permeate our efforts include molecular recognition in analysis and the use of micro- and nano-technologies and materials in the development of a wide range of new analytical approaches.

Microfluidics. Our current microfluidics (MF) research program is dedicated to the development of capillary electrokinetic lab-on-a-chip separation and sample manipulation techniques for chemical analysis. Fundamental work focuses on studies involving highly ordered assemblies (micelles, cyclodextrins, etc.) as selective reagents for capillary electrophoresis (CE) separations and to expand the versatility of electrophoretic separations. Recently, we have begun using lab-on-a-chip MF separation devices (see figure at right) fabricated using lithographic techniques. The development of new and improved optical detection methods, particularly SERS, is also a focus of our efforts (see below). Our separations work is applied to samples of environmental, forensic, biological, and industrial significance. [ See CV 106, 110, 124, 126, 143, 158, 159, 160, 165, 168]
Microfluidic

Optical Spectroscopy. Sensitive methods of detection for lab-on-a-chip devices are being developed based on laser optical methods. The inherent sensitivity of laser induced fluorescence detection has been exploited for a wide variety of applications. A major effort involves exploiting the potential for high sensitivity and exceptional selectivity of surface enhanced Raman scattering (SERS) for detection in MF. Approaches have included the use of novel metal-PDMS nanocomposities for integrated MF-SERS. Methods to improve the questionable reproducibility and dynamic range of SERS are being pursued and involve unique lithographically-prepared and nanocomposite substrates to increase sensitivity and dynamic range, and sample translation to improve reproducibility. We have demonstrated for the first time nano-transfer printing and an unusual approach to electron beam lithography that borrows from bio-medically inspired concepts to create unique SERS substrates (see at left). [See CV 130, 135, 138, 147, 161, 163, 166, 167]

Chemical Sensing. Methods to impart selectivity to micro-electro-mechanical sensors (MEMS) are being developed. Methods of depositing and immobilizing polysiloxane phases, chelating resins and imprinted sol gels, and macrocylic reagents on m-dimension cantilever-based MEMS are being developed. The macrocycle compounds developed and characterized through molecular recognition studies serve as tunably selective sequestering phases when immobilized on the planar substrate. These various phases are used to increase response factors and add chemical specificity to analyte-induced surface stresses that cause the cantilevers to bend. Methods of developing nano-structured surface features enhance the response characteristics of the sensors by orders of magnitude. Applications for these novel sensing technologies abound in the environmental, homeland security, and medical fields. For example, chiral discrimination has been achieved by immobilizing antibodies on m-cantilevers (see figure at right). The response signatures from arrays of differentially functionalized cantilevers are being used with data mining techniques to identify analytes. The coupling of these arrays with chemical separation techniques is also underway. By putting different nuclear receptor proteins on adjacent cantilevers on a chip we are developing mimics of whole biological systems. [See CV 122, 127, 128, 132, 140, 149, 152, 155, 157, 161, 163]

See the Sepaniak group web page for more information and recent noted CV publications