Poster Presentations
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Assessment of passive and active approaches for circulating tumor cell isolation in an on-disk microfluidic device
Amir Shamloo, Professor, Sharif University of technology
One of the challenging steps in cancer research is separating circulating tumor cells (CTC). Since CTCs are very rare compared to the other blood cells, the efficacy and efficiency of the isolating devices are of great importance. In this study, a microfluidic device was designed and tested for separating CTCs from the other cells based on their size difference. Geometrical features such as successive contraction-expansions and channel bifurcation were implemented in this device together with the speed-controlled centrifugal driving force. An active version of this device was also developed replacing the bifurcation feature with an external magnetic field using two 0.34T magnets. Experimental tests were performed on this device after numerically optimizing the design. In these in-vitro tests, MCF7 human breast cancer cells as target cells with/without magnetite nanoparticle labels and L929 mouse fibroblast cells imitating the blood cells were used as experimental samples. Performing the tests in different rotational speeds, the maximum target cell recoveries of 76% and 85% were reported at rotational speeds of 1200rpm and 2100rpm for the passive and active device, respectively. The active device is more efficient whereas the passive device does not need the complex sample preparation and occupies smaller radial space on disk.
Design of an inertial microfluidic device by combining the contraction-expansion and curved channels for CTCs separation from blood
Amir Shamloo, Professor, Sharif University of technology
Circulating tumor cells (CTCs) separation has a crucial importance in cancer research and drug discovery. Microfluidic cell separation offers a great promise in separation of target cells from heterogeneous population of cells by exploiting different properties of cells. Among the microfluidic cell separation methods, inertial method offers a high throughput and high efficiency, label-free and low-cost applications with minimum damage on the cells. In this work, an inertial contraction-expansion microchannel device, capable of passively separating two cells with different sizes, was numerically studied and the numerical model was validated with experimental data. Then, to explore the combination of curved channel with contraction-expansion channel for cancer cells separation from blood, another numerical simulation was performed and different aspect ratio for channel investigated in terms of purity and separation efficiency. Also, it is found that this combination reinforces the secondary flow effects on migration of cells in cross section of channel and leads to separation of cells in shorter length in comparison to only straight contraction-expansion arrays. This device works based on fluid dynamic forces including wall effect lift, shear gradient lift and secondary flow induced drag force, so the balance of these forces leads to equilibrium positions for different cells.
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