Bayer Professor of Engineering

                  Director,Center for Micro-fluidics and Medical Diagnostics

                                         University of Notre Dame

                        Department of Chemical and Biomolecular Engineering

                                              University of Notre Dame
                                                 Notre Dame, IN 46556

                                                    hchang@nd.edu

                                                   Phone: 574 631 5697
                                                    Fax: 574 631 8366

Our current microfluidic and nanofluidic research is in the area of electrokinetics.  We use theoretical analyses, MD simulation, micro/nano fabrication/synthesis, biofunctionalization, nancolloid flocculation, nanostructure plasmonics, optical and mechanical fields at geometric singularities etc to study ion transport/storage/depletion in nanoporous ion-selective media, ion condensation/dissociation, molecular conformation transition and various other peculiar electrokinetic phenomena at high-intensity DC and AC fields. We are able to fabricate nanofluidic transistor circuits that exhibit oscillatory, excitatory, inhibitory and hysteretic ion current/voltage features. We also develop new integrated biochip technologies, based on our fundamental studies, to manipulate/lyse/transfect cells and to concentrate/identify/detect/separate molecules/chemicals. A particularly exciting new direction is the integration of cone plasmonics of individually addressable optical fiber tips with nanocolloid and Janus nanowire reporters for massive parallel detection of molecules. Photoconductive tip dielectrophoresis is used to eliminate diffusion limitation of target molecules to allow sub-minute detection time.

Editor: Biomicrofluidics, an American Institute of Physics journal <bmf.aip.org>

Fighting for Innovative Health Care <NBC Video>

Chief Scientific Advisor: FCubed LLC <fcubed.iviehost.com>

Channeling Microfluidic Devices into Point-of-Care Diagnostics <QMed>

Feature Article in Bioscience Technology (PDF)<news>

Books: "Complex Wave Dynamics on Thin Films",H-C Chang and E A Demehkin, Elsevier (2002) <link>

            "Electrokinetically Driven Microfluidics and Nanofluidics", H-C Chang and L Yeo, Cambridge Press(2009)<link>

Publications : 6230 citations  h-index: 44 (detailed breakdown: Google Scholar)

(over 100 citations)   (over 75 citations)

Earlier Representative Papers

     (See Publications for Complete List Prior to 2005)

Ratulowski, J. and Chang, H.-C., "Transport of Air Bubbles in Capillaries", Phys Fluids, 1,1642(1989). (pdf)

Ratulowski, J. and Chang, H.-C., "The Effect of Surfactant Transport on the Motion of Gas Bubbles in Capillaries", J Fluid Mech, 210, 303(1990). (pdf)

Chang, H.-C., Demekhin, E. A. and Kopelevich, D. I., "Nonlinear Evolution of Waves on a Falling Film", J. Fluid Mech, 250, 433-480 (1993). (pdf)

Yuzhakov, V., Chang, H.-C. and Miller, A. E., "Pattern Formation During Electropolishing", Phys Rev B, 56, 12608 (1997).(pdf)

Veretennikov, I., Indeikina, A. and Chang, H.-C., "Front Dynamics and Fingering of a Driven Contact Line", J Fluid Mech, 373, 81(1998). (pdf)

Chang, H.-C., Demekhin, E. A. and Kalaidin, E., "Iterated Stretching of Viscoelastic Jets", Phys Fluids, 11, 1717 (1999). (pdf)

Ye, Y. and Chang, H.-C., "A Spectral Theory for Fingering on a Wetted Plane", Phys Fluids, 11, 2494 (1999). (pdf)

Arya, G., Chang, H.-C. and Maginn, E. J. "A Critical Comparison of Equilibrium, non-Equilibrium and Boundary Driven Molecular Dynamics Techniques for Studying Transport in Microporous Material", J Chem Phys, 115, 8112 (2001) (pdf)

Kopelevich, D. I. and Chang, H.-C., "Does Lattice Vibration Drive Diffusion in Zeolite", J Chem Phys, 114, 3776 (2001). (pdf)

Balakotaiah, V. and Chang, H.-C. "Hyperbolic Homogenized Models for Thermal and Solutal Dispersion", SIAM J App Math, 63, 1231-1258(2003). (pdf)

Review Articles

Chang, H.-C., "Wave Evolution on a Falling Film", Annual Review of Fluid Mechanics, 26, 103-136 (1994). (pdf) (>300 citations)

Yeo, L. and Chang, H.-C., "Static and Spontaneous Electrowetting", Modern Phys Lett. B ,19 ,549 (2005). (PDF)

Chang, H.-C., "Nanobead Electrokinetics: The Enabling Microfluidic Platform for Rapid Multi-Target Detection" AIChE J., 53, 2486(2007) (pdf)

Sengupta, S., Gordon, J. E. and Chang, H.-C., "Microfluidic Diagnostic Systems for the Rapid Detection and Quantification of Pathogens", Chap 9 of "Microfluidics for Biological Applications",Editors: W-C Tien and E. Finehout, Springer (2008) (pdf)

Chang, H.-C., " Rapid and Portable Genetic Identification Kits for World Health Care Applications", Feature Article, Chinese American Chemical Society Communications, Summer Issue (2008). (pdf)

Chang, H.-C. and Yossifon, G., "Understanding Electrokineitcs at the Nanoscale--a Perspective", Biomicrofluidics, 3, 012001 (2009) (pdf)

Maheshwari, S., Chetwani, N. and Chang, H.-C., "Alternating Current Electrospraying", Ind. Eng. Chem. Res., 48, 9358 (2009). (pdf)

Yeo, L. Y., Chang, H.-C., Chan, P. P. Y. and Friend, J. R. , "Microfluidic Devices for Bioapplications", Small, 7, 12 (2011)(pdf)

Senapati, S., Basuray, S., Slouka, Z., Cheng, L.-J. and Chang, H.-C., "A Nanomembrane-Based Nucleic Acid Sensing Platform for Portable Diagnostics", Topics in Current Chemistry,  304, 153-170 (2011). (pdf)

Chang, H.-C., Yossifon, Y. and Demekhin, E. A., "Nanoscale Electrokinetics and Microvortices: How Hydrodynamics Affects Nanofluidic Ion Flux", Annual Review of Fluid Mechanics, 44, 401-426(2012). (pdf)

Revzin, A., Maverakis, E. and Chang, H.-C., "Biosensors for Immune Cell Analysis---A Perspective", Biomicrofluidcs, 6, 021301 (2012). (pdf)

Electrokinetics of Nanoporous Membranes and Nanochannels

Ben, Y. and Chang, H.-C., "Nonlinear Smoluchowski Slip Velocity and Vortex Generation", J. Fluid Mech., 461, 229(2002).(PDF)

Ben, Y., Demekhin, E. A. and Chang, H.-C., "Superfast Nonlinear Electrokinetics and Electrophoresis", J of Collid and Interface Sci ., 276 , 483-497 (2004). (pdf)

Wang, S.-C., Wei, H.-H., Chen, H.-P., Tsai, M.-H., Yu, C.-C, and Chang, H.-C., "Dynamic     Superconcentration at Critical Point Double-layer Gates of Conducting Nanoporous Granules due to Asymmetric Tangential Fluxes" Biomicrofluidics , 2 , 014012 (2008). (PDF)

Yossifon, G. and Chang, H.-C., "Selection of Nonequilibrium Overlimiting Currents: Universal Depletion Layer Formation Dynamics and Vortex Instability", Phys. Rev. Lett,101, 254501(2008). (PDF)

Yossifon, G., Mushenheim, P., Chang, Y-C. and Chang, H.-C.,"Nonlinear Current-Voltage Characteristics of Nanochannels" Phys Rev E, 79, 046305 (2009). (PDF)

Yossifon, G., Chang, Y.-C. and Chang, H.-C., "Rectification, Gating Voltage and Interchannel Communication due to Asymmetric Entrance Space Charge Polarization", Phys Rev  Lett., 103, 154502(2009). (PDF)

Yossifon, G., Mushenheim P., Chang, Y.-C. and Chang, H.-C., "Eliminating the Limiting-Current Phenomenon by Geometric Field Focusing into Nanopores and Nanoslots", Phys Rev E, 81, 046301 (2010) (pdf)

Yossifon, G. and Chang, H.-C., "Changing Nanoslot Ion Flux with a Dynamic Nanocolloid Ion-Selective Filter: Secondary Overlimiting Currents due to Nanocolloid-Nanoslot Interaction", Phys Rev E, 81, 066317 (2010) (pdf)

Yossifon, G., Mushenheim, P and Chang, H.-C., "Controlling Nanoslot Overlimiting Current with the Depth of a Connecting Microchamber", Europhys Lett, 90, 64004(2010) (pdf)

Cheng, L.-J. and Chang, H.-C., "Microscale pH Regulation by Water Splitting",  Biomicrofluidics, 5, 046502 (2011) (pdf)

Chang, H.-C., Demekhin, E. A. and Shelistov, V. S., "Competition Between Dukhin's and Rubinstein's Electrokinetic Modes", Phys Rev E, 86, 046319(2012). (pdf)

Anomolous Electrokinetics

Thamida, S. and Chang, H.-C., "Nonlinear Electrokinetic Ejection and Entrainment due to Polarization at Nearly Insulated Wedges",Phys of Fluids, 14, 4315(2002).(PDF)

Takhistov, P., Duginova, K. and Chang, H.-C., "Electrokinetic Mixing Vortices due to Electrolyte Depletion at Microchannel Junctions", J. of Colloid and Interfacial Science , 263 ,133-143 (2003).  (PDF)

Yeo, L. and Chang, H.-C.,"Electro-Wetting Films on Parallel Line Electrodes", Phys Rev E,73,011605(2006)   (PDF)

Hou, D. and Chang, H.-C., "Electrokinetic particle aggregation patterns in microvorticesdue to particle-field interaction", Phys. of Fluids , 18 , 071702 (2006). (PDF)

Hou, D. and Chang, H.-C., "AC Field-Enhanced Protein Crystallization", Applied Phys Lett, 92, 223902 (2008) (PDF)

Maheshwari, S., Zhang, L., Y. Zhu and Chang, H.-C., " Coupling between Precipitation an Contact-line Dynamics: Multi-ring Stains and Stick-Slip Motion", Phys Rev Lett , 100 , 044503 (2008). (PDF)

F. Plouraboue and Chang, H.-C., "Symmetry Breaking and Electrostatic Attraction Between Two Identical Surfaces", Phys. Rev. E, 79, 041404(2009). (PDF)

Gagnon, Z. and Chang, H.-C., "Electrothermal ac Electro-osmosis", Applied Phys Lett., 94, 024101(2009) (pdf)

Dielectrophoresis

Minerick, A., Takhistov, P., Zhou, R. and Chang, H-C, "Manipulation and Characterization of Red Blood Cells with AC Fields in Micro Devices", Electrophoresis, 24, 3703-3717 (2003). (pdf)

Gagnon, Z. and Chang, H.-C., "Aligning fast alternating current electroosmotic flow fields and characteristic frequencies with dielectrophoretic traps to achieve rapid bacteria detection", Electrophoresis , 26 , 3725-3737(2005). (PDF)

Zhou, R., Wang, P. and Chang, H.-C., "Bacteria capture, concentration and detection by AC dielectrophoresis and self-assembly of dispersed single-wall carbon nanotubes",Electrophoresis,27, 1375(2006)(PDF) <news item>

Zhou, R., Chang, H.-C., Protasenko, V., Kuno, M., Singh, A. K. and Jena, D., ""CdSe Nanowires with Illumination Enhanced Conducitivity: Induced Dipoles, DielectrophoreticAssembly and Field-Sensitive Assembly", J App Phys , 101 , 073704(2007). (PDF)

Basuray, S. and Chang, H.-C., "Induced Dipoles and Dielectrophoresis of Nano-Colloids in Electrolytes", Phys Rev E., 75, 060501-060504(2007). (PDF)

Gordon, J. E., Gagnon, Z. and Chang, H.-C., "Dielectrophoretic Discrimination of Bovine Red Blood Cell Starvation Age by Buffer Selection and Membrane Cross-linking", Biomicrofluidics , 1 , 044102 (2007). (PDF)

Gagnon, Z. and Chang, H.-C., "Dielectrophoresis of Ionized Gas Microbubbles: Dipole Reversal due to Diffusive Double Layer Polarization", Applied Phys Lett, 93, 224101(2008). (pdf)

Gagnon, Z., Senapati, S., Gordon, J. and Chang, H.-C., "Dielectrophoretic Detection and Quantification of Hybridized DNA Molecules on Nano-Genetic Beads", Electrophoresis, 29, 4808 (2008). (fast track and feature cover) (pdf)

Gagnon, Z., Gordon, J., Sengupta, S. and Chang, H.-C., "Bovine Red Blood Cell Starvation Age Discriminatin through a Glutaraldehyde Amplified Dielectrophoretic Approach with Buffer Selection and Membrane Cross-Linking", Electrophoresis , 29 , 2272 (2008). (PDF)

Gagnon, Z., Mazur, J. and Chang, H.-C., "Glutaraldehyde Enhanced Dielectrophoretic Yeast Cell Separation", Biomicrofluidics, 3, 044108 (2009). (link)

Basuray, S., Wei, H.-H. and Chang, H.-C., "Dynamic Double-Layer Effects on AC-Induced Dipoles of Dielectric Nanocolloids", Biomicrofluidics, 4, 022801 (2010). (link)

AC and DC Electrosprays, Surface Acoustic Wave Nanodrops and Mass Spectrometry

Yeo, L., Lastochkin, D., Wang, S.-C. and Chang, H.-C., "A New ac Electrospray Mechanism by Maxwell-Wagner Polarization andCapillary Resonance", Phys Rev Lett , 92,133902-133904 (2004). (PDF)

Chen. Z.. Wang, P. and Chang, H.-C., "An Electro-osmotic Micropump based on Monolithic Silica for Micro-flow Analyses and Electrosprays", Anal. Bioanal. Chem ., 382 , 817(2005). (PDF)<news>

Yeo, L., Gagnon, Z. and Chang, H.-C., "AC Electrospray Biomaterial Synthesis", Biomaterials , 26 ,  6122( 2005). (PDF)

Wang, P., Chen, Z. and Chang, H.-C., "An integrated micropump and electrospray emitter system based on porous silica monoliths", Electrophoresis , 27 , 3964 (2006). (PDF)<news>

Yeo, L. and Chang, H.-C., "Static and Spontaneous Electrowetting", Modern Phys Lett. B ,19 ,549 (2005). (PDF)

Wang, P., Maheshwari, S. and Chang, H-C, "Polyhedra formation and transient cone ejection of a resonant microdrop forced by an ac electric field", Phys Rev Lett, 96, 254502 (2006)(PDF)<news>

Maheshwari, S. and Chang, H.-C., " Anomalous conical menisci under an ac field-departure from the dc Taylor cone", App Phys Lett, 89, 234103(2006). (PDF)

Maheshwari, S. and Chang, H.-C., "Effects of bulk charge and momentum relaxation times on ac electrospraying". J. App. Phys., 102,034902(2007). (PDF)

Chen, Z., Bogess, B. and Chang, H.-C., "Open-tubular Capillary Electrochromatography Mass Spectrometry with Sheathless Nanoflow Electrospray Ionization for the Analysis ofAmino Acids and Peptides", J of Mass Spectrometry , 42 , 244-253 (2007). (PDF) <news>

Chetwani, N., Maheshwari, S. and Chang, H.-C."Universal cone angle of ac electrosprays due to net charge entrainment", Phys Rev Lett, 101, 204501(2008). (PDF)

Maheshwari, S. and Chang, H.-C."Assembly of multi-stranded nanofiber threads through ac electrospinning", Adv Mater., 21,349354(2009).  (PDF)

Cheng, X. and Chang, H.-C. "Universal nanocolloid deposition patterns: can you see the harmonics of a Taylor cone ?", New J of Physics, 11, 075023(2009) (PDF)

Chetwani, N., Cassou, C. A., Go, D. B. and Chang, H.-C., "High-Frequency AC Electrospray Ionization for Mass Spectrometry of Biomolecules", J Am Soc Mass Spect, 21, 1852(2010). (pdf)

Chetwani, N., Cassou, C. A., Go, D. B. and Chang, H.-C., "Frequency Dependence of Alternating Current Electrospray Ionization Mass Spectrometry", Analytical Chemistry, 83, 3017 (2011). (pdf)

Ho, J., Tan, M. K., Go, D. B., Friend, J. R. and Chang, H.-C., "A Paper-Based Microfluidic Surfae Acoustic Wave Sample Delivery and Ionization Source for Rapid and Sensitive Ambient Mass Spectrometry", Analytical Chemistry , 83, 3260-3266 (2011) (accelerated article) (pdf).

Wang, Y., Tan, M. K., Go, D. B. and Chang, H.-C., "Electrospray Cone-Jet Breakup and Droplet Production  for Electrolyte Solutions", Europhys Lett, 99, 64003 (2012). (pdf)

Taller, D., Go, D. N. and Chang, H.-C., "Self-Similar Micron-Size and Nanosize Drops of Liquid Generated by Surface Acoustic Waves", Phys Rev Lett, 109, 224301(2012). (pdf)

Molecular Manipulation and Detection

Kreft, J., Chen, Y.-L. and Chang, H.-C., "Conformation and Trapping Rate of   DNA at aConvergent Stagnant Flow", Phys Rev E.,77, 030801(R) (2008). (PDF)

S. Senapati, A. R. Mahon, J. Gordon, C. Nowak, S. Sengupta, T. H. W. Powell, J. Feder, D. M. Lodge and Chang, H.-C., "Rapid on-chip Genetic Detection Microfluidic Platform for Real World Applications", Biomicrofluidics, 3, 022407(2009).(pdf)

Basuray,S., Senapati,S., Aijian, A., Mahon, A.R. and Chang, H.-C., "Shear and AC Field Enhanced Carbon Nanotube Impedance Assay for Rapid, Sensitive and Mismatch-Discriminating DNA Hybridization", ACS Nano, 3, 1823 (2009).(pdf)

Cheng, X., Basuray, S., Senapati, S. and Chang, H.-C., "Identification and Separation of DNA Hybridized Nanocolloids by Taylor Cone Harmonics", Electrophoresis, 30, 3236 (2009). (pdf)

Basuray, S. and Chang, H.-C., "Designing a Sensitive and Quantifiable Nanocolloid Assay with Dielectrophoretic Cross-Over Frequency", Biomicrofluidics, 4, 013205 (2010). (link)

Cheng, I.-F., Senapati, S., Cheng, S.,Basuray, S., Chang, H.-C. and Chang, H.-C., "A Rapid Field-Use Assay for Mismatch Number and Location of Hybridized DNAs", Lab-on-a-Chip, 10, 828-831(2010).(pdf)

Wang, S., Chang, H.-C. and Zhu, Y., "Hysteretic Conformational Transition of Single Flexible Polyelectrolyte under Resonant AC Electric Polarization", Macromolecules, 43, 7402-7405(2010). (pdf)

Hsiao, P.-Y., Wei, Y.-F. and Chang, H.-C., "Unfolding Collapsed Polyelectrolytes in Alternating-Current Electric Fields" , Soft Matter, 7, 1207 (2011). (pdf)

Mahon, A. R., Barnes, M.A., Senapati, S., Feder, J., Chang, H.-C. and Lodge, D. M., "Molecular Detection of Invasive Species in Heterogeneous Mixtures using a Microfluidic Carbon Nanotube Platform", PLOS One, 6, 17280 (2011). (pdf)

Drops/Bubbles, Blood Flow and Microfluidic Pumps/Mixers

Ratulowski, J. and Chang, H.-C., "Transport of Gas Bubbles in Capillaries", Phys of Fluids, 1, 1314 (1989) (pdf)

Ratulowski, J. and Chang, H.-C., "The Effect of Surfactant Transport on the Motion of Gas Bubbles in Capillaries", J Fluid Mech, 210, 303 (1990).(pdf)

Chang, H.-C., Demekhin, E. A. and Kalaidin, E., "Iterated Stretching of Viscoelastic Jets", Phys Fluid, 11, 1717 (1999)(pdf)

Takhistov, P., Indeikina, A. and Chang, H.-C., "Electrokinetic Displacement of Air Bubbles in Microchannels", Physics of Fluids, 14, 1(2002).(PDF)

Minerick, A., Ostafin, A. and Chang, H.-C., "Electrokinetic Transport of Red Blood Cells in Microcapillaries", Electrophoresis, 23, 2165 (2002). (pdf)

Wang, S. C,, Lai, Y. W., Ben, Y. and Chang, H.-C., "Microfluidic Mixing by DC and AC Nonlinear Electrokinetic Vortices", Ind. Eng. Fund. Res., 43, 2902-2911(2004).(PDF)

Lastochkin, D., Zhou, R., Wang, P., Ben, Y. and Chang, H.-C., "Electrokinetic Micropump and Micromixer Design Based on AC Faradaic Polarization", J. of Applied Physics , 96 , 1730 (2004). (PDF)

Zhou, R. and Chang, H.-C.,"Capillary Penetration Failure of Blood Suspensions", J of Colloidand Interfacial Sci ., 287 ,647 (2005.)   (PDF)

Wang, P., Chen, Z. and Chang, H.-C., "A New Electro-osmotic Pump Housed in Silica Monolith", Sensors  and Actuators, 113, 500(2006)  (PDF).<news>

Zhou, R., Gordon, J., Palmer, "A. and Chang, H.-C.,"Role of Eruthrocyte Deformability During Capillary Wetting", Biotechnologyand Bioengineering, 93, 201-211(2006).  (PDF)

Berrouche, Y., Avenas, Y., Schaeffer, C., Chang, H.-C. and Wang, P., "Design of a Porous Electro-osmotic Pump Used in Power Electronic Cooling", IEEE Trans on Industry App., 45, 2073(2009) (pdf)

Cell Concentration, Separation and Detection

Wu, J., Ben, Y., Battigelli, D. and Chang, H.-C., "Long-Range AC Electroosmotic Trapping and Detection of Bioparticles", Ind. Eng. Chem. Res ., 44 , 2815(2005). (PDF)

Wu, J., Ben, Y. and Chang, H.-C., “Particle detection by electrical impedance spectroscopy with asymmetric-polarization ac electroosmotic trapping”, Microlfuid. And Nanofluid., 1, 161-167(2005)

Chen, Z., Hsu, F.-C.,Battigelli, D. and Chang, H.-C., "Capture and release of viruses using amino functionalized silica particles",Anal. Chim. Acta, 569, 76-82(2006). (PDF)

Yeo, L. Y., Hou, D., Maheshwari, S. and Chang, H.-C., "Electrohydrodynamic surface microvortices for mixing and particle trapping", Appl. Phys. Lett., 88 , 233512 (2006). (PDF)<news item> <news>

Sengupta, S, Battigelli, D. A. and Chang, H.-C., "A micro-scale multi-frequency reactance measurment technique to detect bacterial growth at low-bioparticle concentrations", Lab-on-a-Chip, 6,682(2006) (PDF)

Cheng, I-F.,Chang, H.-C., Hou, D. and Chang, H.-C., "An Integrated Dielectrophoretic Chip for Continuous Bioparticle Filtering, Focusing, Trapping and Detecting", Biomicrofluidics, 1, 021503(2007).(link)

Hou, D., Maheshwari, M. and Chang, H.-C., "Rapid Bioparticle Concentration and Detection by Combining a Discharge Driven Vortex with Surface Enhanced Raman Scattering", Biomicrofluidics, 1, 014016(2007). (pdf)

Cheng, I-F., Froude, V. E., Zhu, Y., Chang, H.-C. and Chang, H.-C., "A Continuous High-Throughput Bioparticle Sorter Based on 3D Traveling-Wave Dielectrophoresis", Lab-on-a-Chip, 9, 3193 (2009). (pdf)

Gagnon, Z., Mazur, J. and Chang, H.-C., "Integrated AC Electrokinetic Cell Separation in a Closed-Loop Device", Lab-on-a-Chip, 10, 718-726(2010) (pdf)

Liu, H.J., Wei, H.-H., Hwang, S.-H. and Chang, H.-C., "Dynamic Particle Trapping, Release and Sorting by Microvortices", Phys Rev E, 82, 026308 (2010). (pdf)

Education

BS Chemical Engineering, Caltech 1976

PhD Chemical Engineering, Princeton 1980

Awards and Lectures

Wallace Memorial Honor Award, Princeton University, 1978
Regent's Junior Faculty Award, University of California, Santa Barbara, 1980
Presidential Young Investigator Award, National Science Foundation, 1985
Sigma Xi Outstanding Research Award, University of Notre Dame, 1990
Francois N. Frenkiel Award, Division of Fluid Dynamics of American Physical Society, 1991
Fellow of the American Physical Society, Elected 1997

Distinguished Visiting Fellow, Royal Society of Engineering, UK, 2011

Colburn Lectureship, University of Delaware, 1988
Keynote Lecture Second Joint US/China Chemical Engineering Conference, Beijing, 1997
Keynote Lecture 13th International Congress of Chemical and Process Engineering CHISA'98, Prague, 1998
Stanley Corrsin Hydrodynamics Lecture, Johns Hopkins University, 2002

Keynote Lecture, ASME Mini and Micro Channel Conference, Rochester, 2004

Keynote Lecture, Annual Biomedical Engineering Symposium, Tainan,Taiwan, 2004

Invited Lecture, BioSensor Symposium, Indianapolis, 2005.

Invited Lecture, International NanoEngineering Symposium, Tao Yuan,Taiwan,2005.

Keynote Lecture, Annual Meeting of the Korean Society of Analytical Science and Technology, Mokpo, 2006.
Plenary Speaker, Advances in Microfluidics and Nanofluidics, HKUST, 2009; Singapore, 2011; Dalian 2012.
Keynote Speaker, 83rd ACS Colloid & Surface Science Symposium, Columbia University, New York,2009.
Keynote Lecture, ASME Mini and Micro Channel Conference, Pohang, 2009.
Keynote Lecture, 2nd ASME Micro and Nanoscale Heat/Mass Tranfer, Jiaotung University Shanghai, 2009.

Keynote Lecture, Asia-Pacific Lab-on-Chip Conference, Fudan University, Shanghai, 2009.

Plenary Speaker, Wave Phenomena IV, Edmonton, Canada, 2010.

Plenary Speaker, China-Japan-Korea Analytical Chemistry Conference, Wuhan, October,2010.

Plenary Speaker, Electrokinetics Workshop, Technion, Israel, December, 2010.

Plenary Speaker, American Electrophoresis Society, Salt Lake City, November, 2010.

Plenary Speaker, Electrokinetics Workshop, Imperial College, June, 2011.