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Three-dimensional Simulation of Circulating Tumor Cells Magnetic Isolation Using a Viscoelastic-based Ferrofluid Solution

Mostafavi, Ali | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54778 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Saeedi, Mohammad Saeed
  7. Abstract:
  8. Nowadays cancer is the second major cause of death in the world after cardiovascular diseases and scientists and researchers are making considerable efforts to fight it. Detection and isolation of circulating tumor cells in the blood is of paramount importance as it can be further used to measure the disease severity as well as efficacy of chemical drugs. Magnetophoresis has attracted researchers because of its simplicity, high effectiveness and non-invasiveness. Microfluidic systems have a high potential for implementing conventional biological methods in a microscale for detection, separation and incubation of CTCs, and they also lead to reduction in costs and required samples. Prior to effective magnetic isolation in microfluidic systems, cells need to be focused at the center of the microchannel and this could be done by intrinsic characteristics of viscoelastic fluid without any external force, complex microchannel geometry and sheath flow. After cell focusing, a ferrofluid is used to provide the necessary medium for the magnetic separation and the magnetic field is generated by a permanent magnet. In this study, we used finite element method to simulate the viscoelastic fluid flow and particle focusing. Subsequently, we calculated the magnetic field in the microchannel analytically, which enabled us to trace the microparticles three-dimensionally by solving a coupled ordinary differential equation system. Three key parameters in the magnetic isolation are the sample flow rate, the volumetric concentration of magnetic nanoparticles in the ferrofluid, and magnet distance from the edge of the microchannel, and by adjusting them we can optimize the performance of the system. In the proposed geometry, according to the experimental data, volumetric flow rate of 15 μL/min is the maximum flow rate for three-dimensional particle focusing. Considering this magnitude and the results of our numerical solution, in order to separate CTCs (18 μm in diameter) and white blood cells (13 μm in diameter) utilizing PEO-based ferrofluid with 1000 ppm PEO concentration and 1% magnetic nanoparticles volume concentration, the magnet distance from the edge of microchannel should be 1.35 mm which would result in 126 μm lateral distance between the different cells at the end of the microchannel
  9. Keywords:
  10. Circulating Tumor Cells (CTC) ; Ferrofluid ; Viscoelastic Fluids ; Microfluidic System ; Magnetophoresis

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