School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa, Japan.
Langmuir. 2010 Jan 19;26(2):1002-7. doi: 10.1021/la902472h.
In single molecule force measurements with soft atomic force microscope (AFM) cantilevers, the force sensitivity is limited by the Brownian motion of the cantilever. When a cantilever is close to the surface, the hydrodynamic interaction between the cantilever beam and the surface, called the "squeezing effect", becomes significant, and the resonance peak of the thermal oscillation of the cantilever is heavily broadened and shifted to lower frequency which makes it difficult to eliminate the thermal noise by low-pass filtering. In this study, we propose an easy and low-cost method to improve the force sensitivity. We demonstrate that by bringing a tip of a cantilever onto the edge of a micropillar structure a significant reduction of the damping and an enhancement of force sensitivity are achieved.
在使用软原子力显微镜（AFM）悬臂进行单分子力测量时，力灵敏度受到悬臂布朗运动的限制。当悬臂靠近表面时，悬臂梁与表面之间的流体动力学相互作用，称为“挤压效应”，变得显著，悬臂热振动的共振峰被严重展宽并移至较低频率，这使得通过低通滤波消除热噪声变得困难。在这项研究中，我们提出了一种简单且低成本的方法来提高力灵敏度。我们证明，通过将悬臂的尖端置于微柱结构的边缘上，可以显著降低阻尼并提高力灵敏度。
