光镊与差动共焦显示术整合系统在蛋白质弹性研究中的应用

Application of the integrated system composed of optical tweezers and differential con-focal microscopy in protein elasticity research

由于光镊对被操纵物的轴向位移检测技术尚不成熟,因此引入差动共焦显微术与光镊相结合,并以肌凝蛋白与肌动蛋白为样本,测量蛋白质对微球在缓冲液中自然扰动的影响.结果表明,微球在蛋白质环境中有较大的扰动现象,但此扰动在肌凝蛋白-肌动蛋白的结合影响下随轴向抬升而明显降低.此外,还即时检测到肌凝蛋白-肌动蛋白的结合会延迟微球的轴向运动的特性.本系统的动态测量范围可达3μm以上,结合其纳米解析度,适合应用于蛋白质的弹性研究中.

The precise measurement of axial motion of a trapped object in optical tweezers is not well developed. In this paper the differential con-focal microscopy （DCM） is introduced into optical tweezers for the axial detection and the effect of myosin–actin binding to the fluctuations of a trapped bead is measuring by this system. The result shows the fluctuations of a bead are lager with the presence of protein in solution. However, as myosin–actin bonds formed, the fluctuations of the myosin-coated bead gradually decreased when the bead is elevated from actin-coated dish bottom. In addition, the motion retardation of bead caused by the tension of myosin–actin binding between the bead and the bottom is observed. The detection dynamic range of this system is lager than 3μm, which makes it be very suitable for the application of protein elasticity research.