ABSTRACT
The optical trapping module is mounted on an inverted microscope for convenient visualization of the trapping and manipulation process. As aforementioned, optical tweezers trapping requires the use of one or multiple highly focused laser beams. The power of the trapping laser varies from a few milliwatts to several watts, depending on the desirable trapping force/torque and the optical transmittance of the actual optical tweezers system. Multiple-point trapping is more favorable in recent optical tweezers applications, cell trapping in particular. Because of its noncontact feature for trapping and manipulation and its accuracy in molecular force measurement, the optical tweezers technique has been quickly used in life science, since its invention. The major optical tweezers application in molecular biology lies in the exploitation of the physical and mechanical properties of various polynucleotide acids, molecular motors, and other subcellular components. Optical tweezers are also widely used to study the intricate mechanics of molecular motors and packaging in viruses.
