Author:
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Sevim, Semih; Ozer, Sevil; Feng, Luying; Wurzel, Joel; Fakhraee, Arielle; Shamsudhin, Naveen; Jang, Bumjin; Alcantara, Carlos; Ergeneman, Olgaç; Pellicer Vilà, Eva Maria; Sort Viñas, Jordi; Lühmann, Tessa; Pané i Vidal, Salvador; Nelson, Bradley J.; Torun, Hamdi
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Abstract:
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We report for the first time on a novel Atomic Force Microscopy (AFM) technique with dual actuation capabilities using both piezo and magnetic bead actuation for advanced single-molecule force spectroscopy experiments. The experiments are performed by manipulating functionalized magnetic microbeads using an electromagnet against a stationary AFM cantilever. Magnetic actuation has been demonstrated for AFM before to actuate cantilevers, but here we report for the first time a method where we keep the cantilever stationary and accomplish actuation via free-manipulated microstructures. This method leads to a significant reduction of mechanical drift in the system since the experiments are performed without a need for a hard surface and the measured force between the cantilever and the bead is inherently differential. In addition, shrinking the size of the actuator can minimize hydrodynamic forces affecting the AFM cantilever. We conducted single-molecule force spectroscopy and force-clamp experiments with biotin/streptavidin as a model system using the new method. The new method reported herein allows applying constant force on the beads to perform force-clamp experiments without any active feedback, which might be crucial for a deeper understanding of interaction between biomolecules. |