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__**ESC471H1 F: Engineering Science Capstone Design**__

This is a new lab that has been tested, but there is no provision for laser safety. "Thor labs optical trap kit"
 * Optical Tweezers**
 * Test current setup
 * Design ways to make this system laser safe for use by undergraduate students
 * Design experiments relevant to bio or nano

Descriptions of the current versions of some of these labs are available here: http://www.physics.utoronto.ca/~phy326/explist.htm

The optical tweezer system we will be working with: http://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=3959

Thorlabs cites the following article that their system is based on:


 * Description of Optical Tweezers from the Biomechanics text:**

Photons carry momentum; consequently when light shines on a surface there is an effective force exerted on that surface. Usually this effect is very small and can be neglected. However, for intense light shining on a small particle, forces in the range of 1 to 200 pN can be generated. An extension of this concept is to create a specially focussed light beam that creates a potential “well” that traps a bead or small particle, typically 1–2 μm in diameter. This principle can be used for biological measurements by coating the bead with fibronectin (or some other molecule that will bind to receptors on the cell surface) so that the bead adheres to a given location on the cell. The beam is then moved laterally, and the motion of the bead is observed microscopically (Fig. 2.21). From knowledge about the characteristics of the light trap, the force exerted on the bead by the moving light beam can be determined from the bead position relative to the center of the optical trap. Since the displacement of the bead is simultaneously monitored, this information can be used to determine the local stiffness of the cell. Essentially the same technique can be used to measure the force exerted by individual molecules. Optical trap techniques have been used for a variety of biomechanical measurements; for reviews see [36–38].