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My research is dedicated to developing and deploying advanced micro and nanotechnology (e.g., microfluidics and Lab on a Chip) to improve and facilitate disease diagnosis and therapeutics. My research aims not only at exploring and elucidating the fundamental physics that could expand the boundary of knowledge but also at addressing real-life challenges in biomedicine by providing cutting-edge microfluidic technology.
My research is dedicated to developing and deploying advanced micro and nanotechnology (e.g., microfluidics and Lab on a Chip) to improve and facilitate disease diagnosis and therapeutics. My research aims not only at exploring and elucidating the fundamental physics that could expand the boundary of knowledge but also at addressing real-life challenges in biomedicine by providing cutting-edge microfluidic technology.
Master and PhD positions at the group are opening. The potential research projects include 1) Fundamental physics of fluid flow in micro/nano-structures, 2) flexible and stretchable miniaturized devices, 3) portable miniaturised systems for disease diagnosis and therapeutics. Candidates with backgrounds in engineering (e.g., mechanical, mechatronics, materials, chemical and biomedical etc.), physics and biomedicine are welcome to enquiry.
Master and PhD positions at the group are opening. The potential research projects include 1) Fundamental physics of fluid flow in micro/nano-structures, 2) flexible and stretchable miniaturized devices, 3) portable miniaturised systems for disease diagnosis and therapeutics. Candidates with backgrounds in engineering (e.g., mechanical, mechatronics, materials, chemical and biomedical etc.), physics and biomedicine are welcome to enquiry.
The accurate manipulation and separation of bioparticles (such as cells, bacteria, cellular exosomes and virus) promise a vast potential for applications in clinical diagnosis and biomedical research. My research explores passive fluid dynamics and fluid rheology, active external force fields (such as magnetic and electrical fields) and combinations to implement the accurate manipulation of bioparticles in rigid and flexible microfluidic systems. The research will offer informative knowledge of manipulating micro and nanoparticles that can guide the design and optimisation of medical devices. In addition, the research will provide cost-effective and efficient devices that can facilitate disease diagnosis and therapeutics.
The accurate manipulation and separation of bioparticles (such as cells, bacteria, cellular exosomes and virus) promise a vast potential for applications in clinical diagnosis and biomedical research. My research explores passive fluid dynamics and fluid rheology, active external force fields (such as magnetic and electrical fields) and combinations to implement the accurate manipulation of bioparticles in rigid and flexible microfluidic systems. The research will offer informative knowledge of manipulating micro and nanoparticles that can guide the design and optimisation of medical devices. In addition, the research will provide cost-effective and efficient devices that can facilitate disease diagnosis and therapeutics.
1. Fundamental mechanism of inertial focusing
1. Fundamental mechanism of inertial focusing
My work is among the pioneering investigations of the fundamental mechanism of inertial focusing and separation in symmetric serpentine microchannels. Particle inertial focusing in spiral channels has been extensively studied due to its relative simplicity. Because the curvature of this channel type follows a single direction, secondary flow can reach the steady state and is consistent in all channel cross-sections. Analysis of particle behaviour can be approximated by the static superposition of inertial lift force field with a secondary flow field. However, in serpentine channels with alternating curvatures, the situation becomes more complicated. Secondary flow and the corresponding kinematic movement of particles may not reach the steady state after each turn of alternating curvatures. Accumulation of this unsteady condition causes unpredictable and non-intuitive behaviour of particles. I developed an analytical model for focusing mechanism of particles in serpentine channels and experimentally investigated the effects of particle size, Reynolds number and particle inertia on the focusing process. My research discovered that particle focusing positions can shift from channel sidewalls to the centreline with increasing Reynolds number, and that this transformation is highly sensitive to particle size. This unique differential focusing phenomenon was later innovatively adapted for the complete separation of cells. My works initiated this discovery and pioneered the application of this unique phenomenon to cell separation.
2. High-throughout bioparticle separation using inertial microfluidics
2. High-throughout bioparticle separation using inertial microfluidics
Based on the discovery of the above unique inertial focusing phenomenon in serpentine microchannels, I have developed several innovative inertial microfluidic platforms for the manipulation, filtration and separation of cells. For example, I developed a microfluidic device with eight parallel serpentine channels for the filtration of blood cells and the extraction of blood plasma with a high filtration efficiency (>99.95%) and a high throughput (7×108 cells/min). Furthermore, I also demonstrated the highly efficient separation of white blood cells and red blood cells based on their distinct focusing positions, which could potentially serve as an alternative to conventional centrifugation and filtration methods. The inertial microfluidic system was also applied to the classification of nerve cells. Neurons and glial cells are two typical nerve cells. As both nerve cells play significant roles in the development and therapy of schizophrenia, it is difficult to identify their specific contributions. Traditional medium-based methods to separate neurons and glial cells are ineffective and inefficient. I applied the developed inertial microfluidic platform to sort neurons and glial cells based on their morphological differences in a continuous and label-free manner. The separation purity for neurons and glial cells was as high as 92 ± 1.5% and 81 ± 1.4%, respectively. The functionality of sorted nerve cells such as neurite growth, neuroplasticity and neuron metabolism were verified to demonstrate the biocompatibility of the technology.
3. Hybrid DEP-inertial microfluidics
3. Hybrid DEP-inertial microfluidics
Furthermore, my recent work is the first to explore the coupling of dielectrophoresis (DEP) and inertial focusing in microfluidics. The preliminary results demonstrated the feasibility of the innovative combination of these two concepts. In general, inertial focusing and dielectrophoresis are not compatible because the working flow speed for two physics is as different as three orders. The linear flow speed is ~ O(1) m/s in inertial focusing, whereas, the flow speed in DEP is limited on the order of mm/s. Above this limitation, DEP force exerting on target particles is so weak that the separation devices fail to function. My works innovatively address this challenge by coupling DEP force and inertial force delicately along the vertical direction, along which a tiny vertical movement can amplify the displacement along the lateral direction. I developed the counterbalance theory to explain the mechanism of DEP and inertial focusing coupling in the curvilinear channels. The theory can qualitatively explain the experimental observations. Next, I developed a hybrid DEP-inertial microfluidic device based on the coupling scheme. The device enables tuneable separation of microparticles based on size in real time. The proposed concept expands the scope of inertial microfluidic technology and may lead to a new research area in microfluidics.
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