Mechanical properties analyzer for nano-size protein with optically driven nano-beam

There is growing demand for a novel tool that measures mechanical properties of cellular proteins such as cytoskeletal protein. Conventionally, for such studies, optical tweezers using micro-beads has widely utilized. This method, however, has two significant problems: unchanged contact-area, and irradiation of strong laser close to the proteins. First, this method cannot change contact-area between micro-beads and target proteins because the moved micro-beads are only spherical shape. Secondly, the irradiation of strong laser thermally damages protein because the laser approaches near target. To solve these problems, herein we developed “optically driven nano-beam”. It is specialized to perform quasi-static mechanical analysis about cellular proteins. The nano-beam had a movable plate and a fixed wall which are same sizes. The plate has cylindrical object named “trap-point” for moved by optical tweezers. The movable plate was contacted to a fixed block by a thin beam. The beam was 20μm long, 647nm height, and 147nm wide in average. When target proteins were placed between the palate and wall, the nano-beam could mechanically analyze elastic modulus of target proteins by slowly moved the plate using optical tweezers. The nano-beam had two advantages; variable contact-area and strong laser far from the target proteins. Therefore, our device can reveal cellular life phenomena which conventional method cannot perform.