Cantilever-Based Optical Interfacial Force Microscopy

Atomic force microscopy (AFM) is one of the most important tools that lead current nanoscience and nanotechnology in many diverse areas including physics, chemistry, material engineering, and nano-biology. The current AFM technique has been routinely applied to forced unbinding processes of biomolecular complexes such as antibody-antigen binding, ligand-receptor pairs, protein unfolding, DNA unbinding, and RNA unfolding studies (Butt et al., 2005; Fritz & Anselmetti, 1997; Schumakovitch et al., 2002). AFMs have also been applied to intermolecular friction studies (Carpick et al., 1997; Colchero et al., 1996; Fernandez-Torres et al., 2003; Goddenhenrich et al., 1994; Goertz et al., 2007; B.I. Kim et al., 2001; Major et al., 2006). These previous techniques of measuring friction employed a lateral modulation of the sample relative to the cantilever as a means to measure normal force and friction force at the same time (Burns et al., 1999a; Carpick et al., 1997; Colchero et al., 1996; Goddenhenrich et al., 1994; Goertz et al., 2007; Major et al., 2006).