Micro-optofluidic manipulation of particles

• Main Author: Soh, Kok Hong.
• Other Authors: Nguyen Nam-Trung
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Optics, optoelectronics, photonics
• Online Access: http://hdl.handle.net/10356/16191
• Institution: Nanyang Technological University

The method of optical manipulation of micro particles using optical tweezers was discovered many years ago. Since then, the field of optical tweezers went through many trials and experiments and had progress tremendously. The introduction of new techniques in optical tapping and manipulation was expanded to the trapping of live virus and bacteria using laser radiation pressure. This played a play a major role in the revolution in the field of biophysical and biochemical processes. This project will look at the techniques at the manipulation of micro particles using micro-optofluidic technologies where the micro particles could be cells, bacteria or normal particles. The author will also carry out a number of experiments and evaluate their suitability for various applications. The experiments will also look at varying the different parameters such as the size of the particles, laser power and fluid medium. The particle sizes for this experiment are 1.0µm, 2.9µm and 4.3µm. The laser intensities are set at 1.2w, 1.5w and 1.8w. As for the fluid medium, the particles will be mixed liquids such as water, glycerol and ethanol. Through the experiment, the aims will be to investigate on how each parameter will affect the optical trapping of each particle. In addition, the results from the experiments will be processed to highlight the position, velocity and acceleration with respect to time. In conclusion, after the experiments and the interpretation of the results, the goals objectives set before the experiment was largely achieved. The trapping ability performed its best when the fluid medium and laser intensity were at its ideal (ie water and high laser intensity). The trapping ability loses some of its shine when faced upon the high viscosity of glycerol. This ability was made worse when the laser intensity was adjusted to a lower setting with a smaller particle size. The future for the field of optical trapping will largely depend on the innovation of instrumentation and techniques with the continued improvement of established methods.