Particle Focusing on a Lab on a Disk System

Heydarabadipour, Adel | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48433 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Shamloo, Amir
  7. Abstract:
  8. In many microfluidic devices, focusing particles into a narrow stream is usually an essential step prior to counting, detecting, and sorting them. By installation of microfluidic laboratory functions on a rotating disk, new devices called Lab-on-a-disks, which have plenty of advantages in comparison to ordinary Lab-on-a-chips, shape. In this study, to the best of our knowledge for the first time, a Lab-on-a-disk device is designed and fabricated in order to focus particles prior to detecting them by a conventional CD-ROM as a strong optical system. Hydrophoresis method, using slanted obstacles to induce transverse pressure gradients, is utilized to focus particles. In this regard, the behavior of the particles flowing over a microchannel in which variety of obstacle geometries are used is simulated. Among all, four triangular slanted obstacles show better performance in focusing particles. Using this kind of obstacles makes it possible to focus particles in wider microchannels. The effect of parameters such as microchannel length, obstacle size, flow rate, and the ratio of obstacle length to the gap between two successive ones on the path of the particles is investigated. Afterwards, by using selected obstacles into the drawn path for the microchannel, ultimate particle focusing device, placed on a disk, is designed. The behavior of the particles passing through that is simulated and the effect of microchannel and obstacle width; particle diameter, and angular velocity of the disk rotation is examined too. This shows that appropriate utilization of the forces originate from disk rotation causes particles focus into a narrower area. Finally, designed device is fabricated by Soft Lithography technique and it is shown experimentally that how particles pass through the microchannel. Also, it is figured out that the experimental and simulation results acceptably correspond
  9. Keywords:
  10. Microparticles ; Lithography ; Microfluidic System ; Lab-on-a-Chip ; Focusing Particles ; Hydrophoresis Method

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