Carolyn Ren

Professor, Mechanical and Mechatronics Engineering; Canada Research Chair in Droplet Microfluidics and Lab-on-a-Chip (LOC) Technology

Research interests: micro/nano-fluidics; lab-on-a-chip; protein separation; live-colony detection

Biography

Waterloo Microfluidics Laboratory operates under the direction of Professor Carolyn L. Ren. The ultimate goal of our lab is to gain fundamental understanding of microfluidics and nanofluidics and develop integrated Lab-on-a-Chip or BioChip devices for biological, chemical and biomedical diagnosis and analysis. Specifically, Waterloo Microfluidics Lab is interested in the development of design and optimization tools, advanced microfabrication techniques for rapid prototyping, characterization methodologies for Lab-on-a-Chip or BioChip devices. Both experimental investigation and numerical simulation are practical tools for their investigations.

A typical Lab-on-a-Chip device is a piece of palm-sized glass or plastic plate with a network of microchannels etched onto its surface. It is able to perform integrated chemical and biomedical processes on a single chip by employing electrokinetic methods to transport liquids in microchannels. As compared to their traditional counterparts, such miniaturized devices require a very small amount of biological samples (i.e. protein), reduce operation and analysis time by integrating parallel processes, and increase integration and portability. Therefore, the development of microfluidic chips can save the cost of chemical and biomedical diagnosis significantly and has the potential revolutionize the current level of medical diagnosis and treatment.

Education

PhD, Mechanical Engineering, University of Toronto, 2004
MASc, Thermal Engineering, Harbin Institute of Technology, 1995
BSc, Thermal Engineering, Harbin Institute of Technology, 1992

Research

Development of Microfluidic chips for protein separation

Isoelectrical focusing (IEF) is a high-resolution microfluidic separation method that requires the use of carrier ampholytes (CAs) to set up continuous pH gradients in a medium. However, these CAs are very expensive. Ren’s Group develops novel microfluidic chips and takes a different approach to set up pH gradients using an electrical field applied to the liquid in a diverging microchannel. The axial variation of the channel cross-sectional area will induce non-uniform Joule heating and set up temperature gradients, which will generate pH gradients when a proper medium is used. This method avoids the use of expensive CAs and is a very promising alternative for IEF applications.

Design and Modeling of Microfluidic chips for DNA amplification

Polymerase chain reaction (PCR) is an important technology used to amplify DNA. Continuous flow PCR chip is where samples and reagents are continuously pumped through three designed temperature regions for reactions. Our lab develops sets of analysis tools for the optimized design and precise control of continuous flow microfluidic PCR chips.

Living Cell Analysis

Living cell microfluidic culture systems have been developed; however, most rely on external fluid control from off-chip valves and pumps. Most microfluidic chips for cell culture applications use Pressure Driven Flow (PDF) where the flow rate through a syringe pump is fixed by the relative hydrodynamic resistance of the channels resulting in long delay times and a lack of flexibility in multi-function devices. Alternatively, Elecctro-Osmotic Flow (EOF) is a compact method of pumping fluids in microfluidic chips where flow rate and direction can be accurately controlled by manipulating applied voltages at the reservoirs. However, EOF also has several limitations for cell culture which include high electric fields, joule heating and high shear stress which is applied to the cells. Consequently, standard EOF pumping which applies an electrical field directly through the working liquid cannot be applied for cell culture applications.

Ren’s group proposes that these problems can be solved by an Electro Osmotic Pump (EOP) which generates an induced pressure driven flow from EOF flow. EOPs provide pulse free flow, almost instant flow control, and precise movement of minute volumes of fluid (µL-pL). The integration of internal pumps onto the chip also opens up the possibility of multi-fluid control on the chip without valves.

Research interests

Lab-on-a-Chip design, fabrication and characterization
Micro/Nano-scale fluid mechanics
Computational Fluid Dynamics (CFD)

Publications

Refereed journal articles

X. Chen, T. Glawdel, N. Cui, C. L. Ren, "Model of Droplet Generation in Flow Focusing Devices Operating in the Squeezing Regime", submitted (2013)
K. M. Schreiter, T. Glawedel, J. A. Forrest, C. L. Ren, "Robust Thin-film Fluorescence Thermometry for Prolonged Measurements in Microfluidic Devices", RSC Adv. 3 (2013) 17236-17243
M.S. Boybay, A. Jiao, T. Glawdel, C. L. Ren, "Microwave sensing and heating over individual droplets in microfluidic devices", Lab Chip, 13 (2013) 3840-3846
S. M. Shameli, T. Glawdel, V. Fernand, C. L. Ren, "Micellar Affinity Gradient Focusing in a Microfluidic Chip with Integrated Bilinear Temperature Gradients", Electrophoresis, 33 (2012) 2703–2710
Z. Almutairi, C. L. Ren, L. Simon, "Evaluation of Polydimethylsiloxane (PDMS) Surface Modification Approaches for Microfluidic Applications", Colloid Surface A:Physicochemical Eng Aspects, 415 (2012) 406-412
L. Li, X. Bi, J. Yu, C. L. Ren, Z. Liu, "A new soft-lithographic route for the facile fabrication of hydrophilic and easy-to-UV detect sandwich microchips", Electrophoresis, 33 (2012) 2591-2597
T. Glawdel, C. L. Ren, "Droplet Formation in Microfluidics T-junction Generators Operating in the Transitional Regime: Part III - Dynamic Surfactant Effects", Phy Review E, 86, 026308 (2012)
T. Glawdel, C. L. Ren, "Global Network Design for Robust Operation of Microfluidic Droplet Generators with Pressure Driven Flow”, Microfluidics and Nanofluidics, 13 (2012) 469-480
S. M. Shameli, T. Glawdel, Z. Liu, C. L. Ren, "Bilinear Temperature Gradient Focusing in a Hybrid PDMS/Glass Microfluidic Chip Integrated with Planar Heaters for Generating Temperature Gradients", Anal Chem, 84 (2012) 2968-2973
T. Glawdel, C. Elbuken, C. L. Ren, "Droplet Formation in Microfluidics T-junction Generators Operating in the Transitional Regime: Part II - Theoretical and Numerical Modelling", Phy Review E, 85, 016323 (2012) (12 pages)
T. Glawdel, C. Elbuken, C. L. Ren, "Droplet Formation in Microfluidics T-junction Generators Operating in the Transitional Regime: Part I - Experimental Observations", Phy Review E, 85, 016322 (2012)
T. Glawdel, C. Elbuken, C. L. Ren, "Passive Droplet Trafficking at Microfluidic Junctions Under Geometric and Flow Asymmetries", Lab Chip, 11 (2011) 3774-3784 [featured on cover page, highlighted on the LOC blog]
C. Elbuken, T. Glawdel, D. Chan, C. L. Ren, "Detection of Microdroplet Size and Speed Using Capacitive Sensors", Sens Actuator A: Phys, 171 (2011), 55-62 [Most downloaded article in the past 90 days reported in Feb. 2012 by Elsevier].
B. Y. Yu, C. Elbuken, C. L. Ren, J. P. Huissoon, “Image Procesing and Classification Algorithm for Yeast Cell Morphology in a Microfluidic Chip”, J Biomed Opt, 16 (2011), 066008 [selected for the June 15. 2011 issue of virtual Journal of Biological Physics Research].
L. Gui, C. L. Ren, “Exploration and Evaluation of Embedded Shape Memory Alloy (SMA) Microvalves for High Aspect Ratio Microchannels”, Sens Actuator A: Phys, 168 (2011) 155-161
S. M. Shameli, C. Elbuken, J. Ou, C. L. Ren, J. Pawliszyn, "Fully Integrated PDMS/SU-8/quartz Microfluidic Chip with a Novel Macroporous Polydimethylsiloxane (PDMS) Membrane for Isoelectric Focusing of Proteins using Whole-channel Imaging Detection", Electrophoresis, 32 (2011) 333-339
L. Gui, B. Y. Yu, C. L. Ren, J. P. Huissoon, “Microfluidic Phase Change Valve with a Two-level Cooling/Heating System”, Microfluidics Nanofluidics, 10 (2011) 435-445
J. Ou, C. L. Ren, J. Pawliszyn, “A Simple Method for Preparation of Macroporous Polydimethylsiloxane Membrane for Microfluidic Chip-based Isoelectric Focusing Applications”, Anal Chim Acta,662 (2010) 200 – 205.
T. Glawdel, C. Elbuken, L. Lee, C. L. Ren, "Microfluidic System with Integrated Electroosmotic Pumps, Concentration Gradient Generator and Fish Cell Line (RTgill-W1)-Towards Water Toxicity Testing" Lab Chip, 9 (2009), 3243 – 3250.
Z. Shao, C. L. Ren, G. E. Schneider, “A Complete Numerical Model for Electrokinetic Flow and Species Transport in Microchannels”, Eur Phys J Appl Phys: Special Topics, 171 (2009), 189–194.
J. Ou, T. Glawdel, C. L. Ren, J. Pawliszyn, “Fabrication of a Hybrid PDMS/SU-8/quartz Microfluidic Chip for Enhancing UV Absorption Whole-channel Imaging Detection Sensitivity and Application for Isoelectric Focusing of Proteins”, Lab Chip, 9 (2009), 1926 – 1932.
Z. Almutairi, T. Glawdel, C. L. Ren, D. A. Johnson, “A Y-channel Design for Improving Zeta Potential and Surface Conductivity Measurements using the Current Monitoring Method”, Microfluidics Nanofluidics, 6 (2009) 241 – 251.
T. Glawdel, Z. Almutairi, S. Wang, C. L. Ren, “Photobleachingabsorbed Rhodamine B to improve temperature measurements in PDMS microchannels”, Lab Chip, 9 (2009) 171 – 174.
(invited paper) T. Glawdel, C. L. Ren, “Electroosmotic Flow Control for Living Cell Analysis in Microfluidic PDMS Chips ”, Mech Res Comm: Special Issue of Recent Advances in Microfluidics, 36 (2009) 75 – 81.
J. Ou, T. Glawdel, R. Samy, S. Wang, Z. Liu, C. L. Ren, J. Pawliszyn “Integration of dialysis membranes into a poly(dimethylsiloxane) microfluidic chip for isoelectric focusing of proteins using whole-channel imaging detection”, Anal Chem, 80 (2008) 7401 – 7407.
Z. Liu, J. Ou, R. Samy, T. Glawdel, T. Huang, C. L. Ren, J. Pawliszyn “Side-side Comparison of Disposable Microchips with Commercial Capillary Cartridges for Applications in Capillary Isoelectric Focusing with Whole Column Imaging Detection”, Lab Chip, 8 (2008) 1738 – 1741.
(invited paper) J. Taylor, C. L. Ren, G.D. Stubley, “Numerical and Experimental Evaluation of Microfluidic Sorting Devices”, Biotechnol Progr, 24 (2008) 981 – 991.
R. Samy, T. Glawdel, C. L. Ren, “Method for Microfluidic Whole-Chip Temperature Measurement Using Thin-Film Poly(dimethylsiloxane)/Rhodamine B”,Anal Chem, 80 (2008), 369 – 375.
C. Elbuken, L. Gui, C. L. Ren, M. Yavuz, B. Khamesee. “Design and Analysis of a Polymeric Photo-thermal Microactuator”, Sensor Actuator Phy, 147(2008) 292-299.
J. Taylor, G.D. Stubley, C. L. Ren, “Experimental Determination of Sample Stream Focusing with Fluorescent Dye”, Electrophoresis, 29 (2008) 2953 – 2959.
L. Gui, C. L. Ren, “Analytical and numerical study of Joule heating effects on electrokinetically pumped continuous flow PCR chips”, Langmuir, 24 (2008), 2938-2946.
L. Gui, C. L. Ren, “Temperature Measurement in Microfluidic Chips Using Photobleaching of a Fluorescent Thin Film”, Appl Phys Lett, 92 (2008), 024102,[This article has been selected by Virtual Journal of Nanoscale Science & Technology, 17 (2008) 4]
W-G Hou, C. L. Ren, “Evaluation of Intrinsic Ionization and Complexation Constants of TiO2 and Mg-Fe Hydrotalcite-like Compounds”, Chin J Chem, 24 (2006) 1336-1341.
L. Gui, C. L. Ren, “Numerical Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-based Continuous Flow PCR Chip”, Anal Chem, 78 (2006) 6215-6222.
Z. Shao, C. L. Ren, G. E. Schneider, “3D Electrokinetic Flow Structure of Solution Displacement in Microchannels for on-Chip Sample Preparation Applications”, J Micromech Microeng, 16 (2006) 589-600.
B. Kates, C. L. Ren, “Study of Joule Heating Effects on Temperature Gradient in Diverging Microchannels for Isoelectric Focusing Application”, Electrophoresis, 27 (2006) 1967 – 1976.
C. L. Ren, D. Li, “Sample Transport Control in a Microchannel with Spatial Electrical Conductivity Gradients”, J Colloid Interface Sci, 294 (2006) 482 – 491.
J. Taylor, C. L. Ren, “Application of Continuum Mechanics to Fluid Flow in Nanochannels”, Microfluidics Nanofluidics, 1, (2005) 356-363.
J. N. McMullin, H. Qiao, S. Goel, C. L. Ren, D. Li, “Integrated Optical Measurement of Microfluid Velocity”, J Micromech Microeng, 15 (2005) 1810 – 1816. [Hot article! According to the publisher, the above article was downloaded 250 times within the first three months of appearance.]
C. L. Ren, D. Li, “Improved Understanding of the Effect of Electrical Double Layer on Pressure-Driven Flow in Microchannels”, Anal Chim Acta, 531(2005) 15-23.
J. S. Lee, C. L. Ren and D. Li, “Effects of Surface Heterogeneity on Flow Circulation in Electroosmotic Flow in Microchannels”, Anal Chim Acta, 530 (2005) 273-282.
C. L. Ren, Y. Hu, C. Werner, D. Li, “A New Model for the Total Interaction Energy Between Two Surfaces in Aqueous Solutions”, J Adhesion, 80 (2004) 831-849.
C. L. Ren, D. Li, “Effects of Spatial Gradients of Electrical Conductivity on Chip-based Injection Processes”, Anal Chim Acta, 518 (2004), 59-68.
C. L. Ren, D. Li, “Electroviscous Effects on Pressure-driven Electrokinetic Flow in Small Microchannels”, J Colloid Interface Sci, 274 (2004) 319-330.
L. Ren, D. Sinton, D. Li, “Numerical Simulation of Microfluidic Injection Processes in Crossing Microchannels”, J. Micromech. Microeng., 13 (2003) 739 – 747.
L. Ren, J. Masliyah, D. Li, “Experimental and Theoretical Study of the Displacing Processes Between Two Electrolyte Solutions in a Microchannel”, J. Colloid Interface Sci., 257 (2003) 85 – 92.
D. Sinton, L. Ren, X. Xuan, D. Li, “Liquid Conductivity Differences in Microfluidic Chips: Injection, Pumping and Stacking”, Lab on a Chip, 3 (2003) 173 – 179.
D. Sinton, L. Ren, D. Li, “A Dynamic Sample Loading Step for Microfluidic Chip Applications,” J. Colloid Interface Sci., 266 (2003) 448 – 456.
D. Sinton, L. Ren, D. Li, “Visualization and Numerical Modeling of Microfluidic On-Chip Injection Processes”, J. Colloid Interface Sci., 260 (2003) 431-439.
A. Sze, D. Erickson, L. Ren, D. Li, “Zeta-Potential Measurement of Flat Solid Surfaces Using Electroosmotic Flow and the Slope of Current-Time Method” J. Colloid Interface Sci., 261 (2003) 401 – 410.
L. Ren, D. Li, “Theoretical Studies of Microfluidic Dispensing Process”, J. Colloid Interface Sci., 254 (2002) 384 – 395.
L. Ren, C. Escobedo, D. Li, “A New Method of Evaluating the Average Electro-Osmotic Velocity in Microchannels”, J. Colloid Interface Sci., 250 (2002) 238 – 242.
D. Sinton, C. Escobedo, L. Ren , D. Li, “Direct and Indirect Electroosmotic Flow Velocity Measurements in Microchannels”, J. Colloid Interface Sci., 254 (2002)184 – 189.
L. Ren, C. Escobedo, D. Li, “Electro-osmotic Flow in a Micro-capillary with One Solution Displacing Another Solution”, J. Colloid Interface Sci., 242 (2001) 264 – 271.
L. Ren, D. Li, “Electro-Osmotic Flow in Heterogeneous Microchannels”, J. Colloid Interface Sci.,243 (2001) 255 – 261.
L. Ren, W. Qu, D. Li, “Interfacial Kinetic Effects on Liquid Flow in Microchannels”, Int. J. Heat Mass Transfer, 44 (2001) 3125 – 3134.
L. Ren, D. Li, W. Qu, “Electro-Viscous Effects on Liquid Flow in Microchannels”, J. Colloid Interface Sci., 233 (2001) 12 – 22.
L. Ren, B. Chen, J. Liu, “Study of Heat Transfer Correlation of Two-Phase Closed Thermosyphon”, J. Dalian University of Technology, 39 (1999) 532 – 537.

Book chapters

J. Ou, C. L. Ren, “Microchip UV Absorption Detection Applied to Isoelectric Focussing of Proteins”, a chapter in Methods in Molecular Biology – Microfluidic Diagnostics, (accepted 2011) Humana Press, Springer publishing group.
T. Glawdel, C. L. Ren, “Electrokinetic Focusing”, a short chapter in Encyclopedia of Microfluidics and Nanofluidics, Springer-Verlag Heidelberg, Germany, 2008, 516 – 516.
L. Gui, C. L. Ren, “Thermalmechanical Microvalves”, a chapter in Encyclopaedia of Microfluidics and Nanofluidics, Springer-Verlag Heidelberg, Germany, 2008, 2047 – 2061.
T. Glawdel, C. L. Ren, “Zeta Potential Measurements”, a chapter in Encyclopaedia of Microfluidics and Nanofluidics, Springer-Verlag Heidelberg, Germany, 2008, 2199 – 2206.
C. L. Ren, “Electrical Current Monitoring Methods”, a chapter in Encyclopaedia of Microfluidics and Nanofluidics, Springer-Verlag Heidelberg, Germany, 2008, 435 – 444.
C. L. Ren, “Electrokinetic Dispensing”, a chapter in Encyclopaedia of Microfluidics and Nanofluidics, Springer-Verlag Heidelberg, Germany, 2008, 482 – 489.

Conference articles and presentations (refereed)

Z. Almutairi, T. Glawdel, C. L. Ren, D Johnson, “Experimental Studies of Liquid/Liquid Droplet Transport in Curved Microchannels”, 64th Annual Meeting of the American Physical Society Division of Fluid Dynamics, Nov. 20-22, 2011, Baltimore, MD, USA.
S. Shameli, T. Glawdel, C. L. Ren, "Bilinear Temperature Gradient for Improving the Separation Performance of Temperature Gradient Focusing in Microfluidic Chips", Gordon Research Conference on the Physics & Chemistry of Microfluidics, Jun.26 – Jul. 1, 2011, Waterville Valley, NH, USA (Poster)
T. Glawdel, C. Elbuken, C. L. Ren, L. E. J. Lee, “Integrated Microfluidic System for Toxicity Testing”, ASME 2009 2nd Micro/Nanoscale Heat & Mass Transfer International Conference, Jan 2010, Shanghai, China (Oral presentation only).
T. Glawdel, C. Elbuken, C. L. Ren, L. E. J. Lee, “Electro-osmotic Pumps With Steady Long-term Performance for Cytotoxicology Studies”The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences (μTAS2009), October 2009, Jeju, South Korea (Poster).
T. Glawdel, C. Elbuken, L. Lee and C. L. Ren,, “Microfluidic System for Toxicity Testing with Integrated Electroosmotic Pumps, Gradient Generator and Fish Cell Line (RTgill-W1) p towards a point-of-care device”, Gordon Research Conference on the Physics & Chemistry of Microfluidics, June 2009, Lucca, Italy (Poster).
C. Elbuken, L. Gui, C. L. Ren, M. Yavuz, M. Behrad Khamesee, “Design and Characterization of a Polymeric Photo-thermal Microgripper for Micromanipulation”, 2008 ASME International Mechanical Engineering Congress and R&D Expo (IMECE), Boston, MA, Oct.30- Nov. 6, 2008.
T. Glawdel, Z. Almutairi, S. Wang, C. L. Ren, “Improving Rhodamine B Fluorescence Thermometry in PDMS Microchannels by Photobleaching Absorbed Dye”, 2008 ASME International Mechanical Engineering Congress and R&D Expo (IMECE), Boston, MA, Oct.30- Nov. 6, 2008.
Z. Shao, C. L. Ren, G. E. Schneider, “Multi-step Dynamic Control for Enhanced Electrokinetic Transport Characteristics in Microchip Capillary Electrophoresis”, 2008 ASME International Mechanical Engineering Congress and R&D Expo (IMECE), Boston, MA, Oct. 30- Nov. 6, 2008.
T. Glawdel, C. L. Ren, “Exploration of the Feasibility using Electroosmotic Pump in Cell Culture”, 2007 ASME International Mechanical Engineering Congress and R&D Expo, Seattle, WA, Nov. 11-15, 2007.
R. Samy, T. Glawdel, C. L. Ren, “Whole-Chip Temperature Measurements Using Thin-film PDMS/Rhodamine B For Microfluidic Chip Design”, 2007 ASME International Mechanical Engineering Congress and R&D Expo, Seattle, WA, Nov. 11-15, 2007.
J. Taylor, C. L. Ren, G.D. Stubley, “Evaluation of Microfluidic-based Cell-sorting Devices”, 2007 ASME International Mechanical Engineering Congress and R&D Expo, Seattle, WA, Nov. 11-15, 2007.
Z. Almutairi, T. Glawdel, C. L. Ren, D. Johnson, “A Novel Y-Channel Design for Measuring The Zeta Potential using the Current Monitoring Technique”, 2007 ASME International Mechanical Engineering Congress and R&D Expo, Seattle, WA, Nov. 11-15, 2007
Z. Shao, G. E. Schneider, C. L. Ren, “Theoretical Investigation of On-chip Multi-species Transport in Microchannels for Analysis Applications”, 2007 ASME International Mechanical Engineering Congress and R&D Expo, Seattle, WA, Nov. 11-15, 2007.
Z. Shao, G. E. Schneider, C. L. Ren, “Theoretical study on Unsteady Multi-species Transport in Electrokinetic Flows”, The 16th Discrete Simulation of Fluid Dyanmics (DSFD 2007): Micro, Nano and Multiphysics for Emerging Technologies Conference, July 23-27, Banff, Canada, 2007.
Z. Almutairi, T. Glawdel, C. L. Ren, D. Johnson, “Area-averaged Method for Velocity Measurements in Microchannels”, 21st Canadian Congress of Applied Mechanics, June 3-7, 2007
Z. Shao, C. L. Ren, G. E. Schneider. “Theoretical Study of Electroosmotic Flow with Replacement Solutions”, 2005 ASME International Mechanical Engineering Congress and Exposition, Orlando, USA, Nov 5-11 2005.
J. Taylor, C. L. Ren “Electroosmotic Flow in Nanao Channels”, 3rd International Conference on Microchannels and Minichannels, June 13-15, 2005, Toronto, Ontario, Canada
Z. Shao, C. L. Ren, G. E. Schneider, “Control of Laminar Flow and Mass Transport in Crossing Linked Microchannels for Micro Fabrication”, 3rd International Conference on Microchannels and Minichannels, June 13-15, 2005, Toronto, Ontario, Canada
C. L. Ren, D. Li, “Sample Manipulation in Microfluidic Devices With Electrical Conductivity Difference”, ASME 2nd International Conference on Microchannels and Minichannels, Rochester, NY, USA, June 17 – 19, 2004.
L. Ren, D. Li, “Theoretical Study of On-Chip Microfluidic Dispensing Processes with Spatial Gradients of Electrical Conductivity”, 2003 ASME International Mechanical Engineering Congress and R&D Expo, Washington D.C., USA, Nov. 15 – 21, 2003.
L. Ren, D. Li, “ Numerical Studies of Injection Process Control with Spatial Gradients of Electrical Conductivity”, ASME Summer Heat Transfer Conference, Rio All Suite Hotel & Casino Las Vegas, Nevada, USA, July 21 – 23, 2003.
L. Ren, D. Li, “Numerical Studies of Microfluidic Transport Phenomena”, Third International Conference on Computational Heat and Mass Transfer, Banff, Canada, May 26-30, 2003.
L. Ren, D.Li, “Evaluation of Electro-Osmotic Flow Velocity in Microchannels by Monitoring the Current Change”, CSME 2002 Forum, Kingston, Ontario, May 21-24, 2002.

Invited presentations

C. L. Ren, United Nations University - Institute for Water, Environment and Health, Jun. 2013.
C. L. Ren, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Apr. 2013.
C. L. Ren, Institute of Biomedical Engineering, National Cheng Kung University, Taiwan, Jan. 2013.
C. L. Ren, Mechanical Engineering, Massachusetts Institute of Technology, USA, Nov. 2012.
C. L. Ren, Chemical Engineering, Queen's University, Sept. 2012.
C. L. Ren, Harbin Institute of Technology, China, Aug. 2012.
C. L. Ren, University of Bordeaux, France, Dec. 2011.
C. L. Ren, Patheon Inc. (Pharmaceutical company), Mississauga, Ontario, Nov. 2011.
C. L. Ren, The School of Naval Architecture, Ocean and Civil Engineering Seminar, Shanghai Jiaotong University, Shanghai, China, Dec. 2009.
C. L. Ren, Mechanical Engineering Department Seminar, Tongji University, Shanghai, China, Dec. 2009.
C. L. Ren, Chemistry Department Seminar, Nanjing University, Nanjing, China, Dec. 2009.
C. L. Ren, Mechanical Engineering Department Seminar, University of Massachusetts, Lowell, MA, U.S.A., Nov. 2008.
C. L. Ren, The Frontiers of Science plenary session of the Fifth Science Center World Congress, Toronto Science Center, Toronto, ON, Canada, Jun. 2008.
C. L. Ren, ASME 2nd Integration & Commercialization of Micro & Nanosystems International Conference & Exhibition, Hong Kong, Jun. 2008.
C. L. Ren, Chemistry Department Seminar, University of Toronto, Toronto, Ontario, Canada, Oct. 2007.
C. L. Ren, Chemical Engineering Department Seminar, University of Alberta, Alberta, Canada, Mar. 2007
C. L. Ren, Mechanical Engineering Department Seminar, Purdue University, West Lafayette, IN, U.S.A., Mar. 2005.
C. L. Ren, Mechanical Engineering Department Seminar, Columbia University, New York, NY, U.S.A., Sept. 2003.
C. L. Ren, Mechanical Engineering Department Seminar, University of Waterloo, Waterloo, ON, Canada, Sept. 2003.
C. L. Ren, Mechanical Engineering Department Seminar, University of Toronto, Toronto, ON, Canada, Feb. 2003.
C. L. Ren, Mechanical Engineering Department Seminar, University of Victoria, Victoria, BC, Canada, Feb. 2003.