Sebastian Knust¹, Andy Sischka¹, Andre Spiering¹, Christoph Pelargus¹, and Dario Anselmetti¹
¹: Experimental Biophysics & Applied Nanoscience, Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany
We developed and included video-based axial force analysis into our previously described optical tweezers setup . By measuring the radius of a trapped microbead
we achieve an overall force resolution along the z-axis in the range of 0.2pN with a bandwidth of 120Hz, only limited by our CCD camera. With this video-based method
we overcome the remaining weak interference effects in backscattered light based force analysis when operating a microsphere in the vicinity of an interface.
We tested our setup by investigating the controlled threading and translocation of individual lambda-DNA molecules with and without attached DNA-binding ligands
through solid-state nanopores and comparing these results with previous measurements realized with photodiode intensity detection [2, 3].
The setup, methods and results described in this poster are elaborated in the follow-up publication in Rev. Sci. Instrum. 83, 103704 (2012).