Areas of Research
Dr. Wickramasinghe's Research
Research Interests:
Dr Wickramasinge’s research focuses on the development of membrane based separation processes. Membranes find numerous applications, bioseparations, biomedical engineering and environmental engineering. Examples of current research projects in each of these areas are given below.
Bioseparations: Adsorptive Membranes for Virus capture
Purification of virus particles for viral vaccines and applications of gene therapy is a major large scale separations challenge. While the use of membrane as chromatographic support materials offers a number of advantages especially for virus capture, the capacity of the membranes for virus particles is orders of magnitude less than the manufacturer’s stated capacity for model proteins such as BSA and lysozyme indicating that binding patterns are very different for different sized solutes. Our research focuses on optimizing the structure of the membrane to maximize the capacity of the membrane for virus capture. In order to visualize solute binding confocal laser scanning microscopy (CLSM) has been used to observe binding patters of various model proteins. The figure shows that the binding patterns for of thyroglobulin (MW 600,000), BSA (MW 67,000) and lysozyme (MW 14,300) to cation exchange membranes are very different.
Biomedical Separations: Designing Blood Oxygenators
Extracorporeal blood oxygenators are designed to replace pulmonary function during cardiac surgery requiring cardiopulmonary bypass. Today over 1,000,000 cardiac procedures requiring blood oxygenators are performed throughout the world. The majority of the blood oxygenators used today contain microporous hydrophobic membranes. The objective of our research is to design more efficient or optimized blood oxygenators. There is tremendous clinical and commercial interest in developing better designs which maximize the gas transfer per priming volume of the device and minimize the shear stress on the blood. Increasing the rate of gas transfer will reduce the membrane surface area required and thus lower the cost of the device.
Environmental Engineering: Membranes for treatment of Co-Produced water
Coal bed methane is natural gas associated with coal deposits. The existence of this gas has been know for a long time, however only recently have economical methods to collect it been developed. In Wyoming in 2003, the total value of coal bed methane production was about $1.5 billion. The recent rapid increase in production of coal bed methane has lead to serious concerns regarding the management and disposal of the large volumes of water that are co produced (produced water) with the coal bed methane. The quality of this produced water is highly variable.
We are currently developing smart membranes for low pressure reverse osmosis and nanofiltration application by growing polymer brushes from the surface of the membranes. By controlling both the chemical and environmentally responsive conformational properties of these polymer films at the nanoscale, we will limit biofilm formation and provide an easy way to remove attached biofoulants.
Teaching Interests:
Dr Wickramasinghe has taught the following courses at Colorado State University:
CH 331 Momentum Transfer and Mechanical Separations
This junior level course is designed to introduce students to the fundamental principles underlying the behavior of fluids.
CH 333 Momentum and Heat Transfer Laboratory
This is the first of two unit operations laboratory courses offered by the Department of Chemical and Biological Engineering. The focus of this course is to complement and reinforce knowledge gained in CH 331 and CH 332. Laboratory exercises include rheology of Newtonian and non-Newtonian fluids, double pipe heat exchanger; steam condensation. All experiments are conducted in groups.
CH 443 Mass Transfer and Separations Laboratory
This is the second of two unit operations courses. The aim of this course is to complement and reinforce knowledge gained in the lecture courses on mass transfer and separations. Laboratory exercises include distillation; ion exchange; membrane separations. All experiments are conducted in groups.
CH 503 Transport Phenomena Fundamentals
This graduate level course covers general topics in momentum, heat and mass transfer. Analogies between momentum, heat and mass transfer are highlighted
Dr Wickramasinghe currently teaches the following courses:
CH 332 Heat and Mass Transfer Fundamentals
This junior level course in heat and mass transfer is based on the principles of conversation of energy and mass. A major part of the course is devoted to steady and unsteady conduction and convection of energy and mass. Heat exchanger design is also considered (linked to CH 333). Analogies between heat and mass transfer are highlighted. Numerous examples from biomedical engineering will be used. Examples include analogies between the design of heat exchangers, blood oxygentors and dialyzers.
CH 442 Separation Processes
In this course, the basic principles of phase equilibrium thermodynamics, diffusion, and convective mass transfer are applied to the design and analysis of several separation processes. Processes to be studied included absorption, stripping, distillation, adsorption, ion exchange, gas permeation and reverse osmosis.
CH 522/BE 522 Bioseparation Processes
This graduate level course introduces students to the major unit operations used in the purification of biopharmaceutical products such as microfiltration, ultrafiltration chromatography. In addition students are introduced to newer unit operations such as membrane chromatography and virus filtration
CH 793 Seminar II
The departmental seminar series is offered each semester. Generally speakers are invited from outside the department.
Selected Publications:
Selected Educational publication
Wickramasinghe S. R. & Timpson, W. M. (2006), ‘Mid semester student feed back enhances student learning’, Education for Chemical Engineers, IChme Trans Part D, accepted.
Selected Publications Research 2005-2006
Wickramasinghe, S. R., Carlson J. O., Teske C., Hubbuch J. and Ulbricht M. (2006), ‘Characterizing solute binding to macroporous ion exchange membrane adsorbers using confocal laser scanning microscopy’, Journal of Membrane Science, (available online 28 April 2006).
Wickramasinghe, S. R., Carvalho, W., Canilha, L., Han, B. & McMillan, J. D. (2006), ‘Adsorptive Membranes vs. Resins for acetic acid removal from Biomass Hydrolysates’, Desalination, 193, (1-3), 361-366.
Lubansky, A. S., Yeow Y. L, Leong, Y. K., Wickramasinghe, S. R. & Han, B. (2006), A general method of computing the derivative of experimental data, AIChE J, 52 (1), 323-332.
Han, B., Specht, R., Carlson, J. O. & Wickramasinghe, S. R. (2005), ‘Virus Purification Using Adsorptive Membranes’, Journal of Chromatography A,1092, 114-124.
Wickramasinghe, S. R., Kalbfuß, B., Zimmermann, A., Thom, V. & Reichl, U. (2005), ‘Tangential Flow Microfiltration and Ultrafiltration for Human Influenza A Virus Concentration and Purification’, Biotechnology and Bioengineering, 92(2), 199-208.