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.
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.
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. (graphic: m-cantilevers coated with the enantio-selective antibodies responding (bending) to amino acids; deflections measured by reflecting diode laser beam onto position sensitive detector)
Dr. Sepaniak received his B.S. in Chemistry from Northern Illinois University in 1974 and his Ph.D. in Analytical Chemistry from Iowa State University in 1980. He joined the faculty of the University of Tennessee in 1981 and has been affiliated with Oak Ridge National Laboratory throughout his time at Tennessee. He is a former Head of the Department of Chemistry and is a Paul and Wilma Ziegler Professor of Chemistry.
B.S., Northern Illinois University (1974)
Ph.D., Iowa State University (1980)
Awards and Recognitions
- Chemistry Teacher, Southeastern Community H.S., Augusta, IL, 1974-1975
- Analytical Chemist, Dow Chemical Co., Midland, MI, 1977-1978
- Assistant Professor, University of Tennessee, 1981-1986
- Summer Faculty Research Participant, ORNL, Analytical Division, 1981
- Consultant, ORNL, 1981-present
- Eli Lilly Promising Analytical Chemist Award, 1986
- Science Alliance Awards, UTK, 1986-2001
- Associate Professor, University of Tennessee, 1986-1991
- IR 100 Research and Development Award 1987
- Professor, University of Tennessee, 1991-1996
- Chancellor's Research Scholar, UTK, 1991
- Hoechst Celanese Corporation Teaching and Research Award, UTK, 1995
- Professor & Department Head, University of Tennessee, 1996-2003
- Ziegler Professor of Chemistry, University of Tennessee, 1998-present
- Northern Illinois University Distinguished Alumnus, 2009
- American Association for the Advancement of Science Fellow, 2010
- R&D 100 Research and Development Award, 2011
Z. Long, John Story, Samuel Lewis, and M.J. Sepaniak “Landfill Siloxane Gas Sensing Using Differentiating, Responsive Phase Coated Microcantilever Arrays” Anal. Chem., 81, 2575-2580 (2009).
S.M.Wells, S.D. Retterer, J.M. Oran, and M.J. Sepaniak “Controllable Nanofabrication of Aggregate-Like Nanoparticle Substrates and Evaluation for Surface Enhanced Raman Spectroscopy,” ACS Nano, 3, 3845-3853 (2009).
N.V. Lavrik, L. Taylor, and M.J. Sepaniak, “ Fabrication of enclosed pillar arrays integrated on a fluidic platform for on-chip separations and analysis”, Lab-on-a-Chip, 10, 1086-1094 (2010).
Z. Long, K.L. Hill and M. J. Sepaniak, “Aluminium Oxide Nanostructured Microcantilever Arrays for Chemical and Biological Sensing” Anal. Chem., 82, 4114-4121 (2010).
J. Patton, M.J. Sepaniak, D. B. Smith, P. G. Daskos and S. R. Hunter “Palladium Metal Alloy Functionalized Hydrogen Microsensor” Sensors and Actuators 163, 464-470 (2010).
L. Taylor, N.L. Lavrik, and M.J. Sepaniak, “High Aspect Ratio, Silicon Oxide-Enclosed Pillar Structures in Microfluidic Liquid Chromatography” Anal. Chem., 82, 9549-9556 (2010).
S.M. Wells, A. Polemi, N.V. Lavrik, K.L. Shuford, and M.J. Sepaniak “Disk on Pillar Substrates for SERS ” Chem. Comm., 47, 3814-3816 (2011).
K.L. Hill, P. Dutta, M.L. Z. Long, and M.J. Sepaniak, “Microcantilever-based Nanomechanical Studies of the orphan nuclear receptor PXR” J. Biomaterials Nanobiotech., 2, 133-142 (2011).
N.V. Lavrik, L. Taylor, and M.J. Sepaniak "Nanotechnology and chip level systems for pressure driven and emerging analytical separation techniques" Analytica Chimica Acta, 694, 6-20 (2011).
D. Bhandari, I.I. Kravchencho, N.V. Lavrik, and M.J. Sepaniak, “In Situ Plasma Deposited Octafluorocyclobutane-(Teflon)-Mediated Nanotransfer Printing, JACS, 133, 7722-7724 (2011).
L.C. Taylor, T.B. Kirchner, N.V. Lavrik, and M.J. Sepaniak, “Surfaced Enhanced Raman Spectroscopy in Microfluidic Pillar Arrayed Separation Chips”, Analyst,137, 1005-1012 (2012).
S.M. Wells, N.V. Lavrik, Igor Merkulov, and M.J. Sepaniak, “Silicon Nanopillars for Field Enhanced Surface Spectroscopy” ACS Nano 6, 2948-2959 (2012).
J. F. Patton, N. V. Lavrik, D. C. Joy, S.R. Hunter, P.G. Datskos, D.B. Smith, and M. J. Sepaniak, “Characterization of Hydrogen Responsive Nanoporous Films Synthesized via Spontaneous galvanic Displacement Reaction” Nanotechnology, 23, DOI:10.1088/0957-4484/23/46/465403 (2012).
J. Charlton, M.J. Sepaniak, G. Schaff, and J. Bradshaw, “Automated SPE-ICP-MS as a tool for the high throughput determination of aqueous actinide levels” J. Anal. At. Spectrom., 28, 711 – 718 (2013).
Z. Long, X. Hou, and M.J. Sepaniak, "Recent Advance of Gas-phase Microcantilever Based Sensing". Reviews in Analytical Chemistry, 32, 135-158 (2013).
J. Jia, F. Xu, P. Z. Long, X. Hou, and M.J. Sepaniak “Metal-Organic framework MIL-53(Fe) for Highly Selective and Ultrasensitive Direct Sensing of MeHg+” Chem. Comm. 49, 4670-4672 (2013).
C.E. Freye, N.A. Crane, T.B. Kirchner, and M.J. Sepaniak, “ SERS Imaging of Developed TLC Plates” Analytical Chemistry, 85, 3991-3998 (2013).
J. Olavarría-Fullerton, S.M. Wells, R. A. Velez, M. J. Sepaniak and M. A. De Jesús “Hybrid morphology nanoarrays as plasmonic Raman probes for the detection of arsenic antimicrobials” Appl. Spectrosc. 67, 1315-1322 (2013).
Michael Kandziolkaa , Jennifer J. Charltonb,c , Ivan I. Kravchenkoa, James A. Bradshawc , Igor A. Merkulova, Michael J. Sepaniak, Nickolay V. Lavrik, “Silicon nanopillars as a platform for enhanced fluorescence analysis” Analytical Chemistry, 85. 9031-9038 (2013).
Teresa B. Kirchner, Nickolay V. Lavrik, and Michael J. Sepaniak, Photolithographic Development of Highly-Ordered Silicon Pillar Arrays for use in Chromatographic Separations, Analytical Chemistry, 85, 11802-11808 (2013).
Z. Long, J. Jia, S. Wang, L. Kou,, M.J. Sepaniak, and X. Hou, “Visual Enantioselective Probe Based on Metal Organic Framework Incorporating Quantum Dots, ” Microchemical Journal 110, 764-769 (2013).
Rebecca L. Agapov1, Bernadeta Srijanto1, Chris Fowler1, Dayrl Briggs1, Nickolay V. Lavrik1*, Michael J. Sepaniak, Lithography-free approach to highly efficient, scalable SERS substrates based on disordered clusters of disk on pillar structures”, Nanotechnology, 24. Article # 505302 (2014).
S.D. Gilman and M.J. Sepaniak, “Capillary Electrophoresis Techniques in Biomedical Analysis,” in Biomedical Photonics Handbook, 2nd Edition, CRC Press, T. Vo Dinh Editor (2014).
J.J Charlton, N.V. Lavrik, J.A. Bradshaw, and M.J. Sepaniak, “Fabrication and characterization of versatile wicking nanopillar arrays with superhydrophobic hierarchal roughness for selective compound transport and fluorescence measurements” J. Appl. Materials and Interfaces, 6, 17894-17901, (2014).
R. A. Wallace, N. V. Lavrik, and M. J. Sepaniak, “Superhydrophobic analyte concentration utilizing colloid-pillar array SERS substrates” Analytical Chemistry, 86, 11819-11825, (2014).
T. B. Kirchner, J. J. Charlton, N. A. Hatab, R. Stricthouser I. I. Kravchenko, N. V. Lavrik, and J. Sepaniak, “Nanoscale pillar arrays for separations” Analyst, 2015, 140, 3347 – 3351 (2015).
J. J. Charlton, N.C. Jones, R.A. Wallace, R. Smithwick, J. A. Bradshaw, I.I. Kravchenko3, N.V. Lavrik, and M.J. Sepaniak1*.”Nanopillar based enhanced fluorescence detection of surface immobilized beryllium”, Analytical Chemistry, doi.org/10.1021/acs.analchem.5b01035, (2015).
Lab Address: 439 Buehler Hall