Effect of small forces on microsphere under optical trap

In this era of technological development, greater impact of nanotechnology now can be seen in many fields due to better properties and precise control. Many functions are being executed by bio nano-materials or biomolecules in living systems in a very efficient manner. The functional behaviour and their properties need to be examined to use them for various nano-device applications. The mechanical properties of the biomolecules can be studied by attaching them with microspheres and measuring forces on these microspheres through optical trap. Microspheres of three-micrometer diameter were trapped at the focus of infrared laser and viscous drag forces were applied to measure the effect of these forces on the trapped microsphere. It was observed that with 28mW intensity Laser, the trapped microsphere was displaced by 0.19 μm at 2.1 pN force and trap stiffness was determined as 0.011pN/nm. The findings can be useful while attaching these microspheres as cargos along the bionanomotors for nanorobotics and drug delivery applications.