Atomic Force Microscopy

Atomic Force Microscopy is essentially an imaging instrument consisting of a tip at the end of a cantilever with which to scan a molecule on a surface. This technique can be used to map individual molecules and their dynamics to a high temporal resolution. It can also be applied to manipulate and measure forces in real time; in particular, it has been used to measure the force–extension curve of dsDNA, but due to the relatively high stiffness of the cantilevers, AFM is more suited for the detection of events at higher forces (e.g., bond strengths). Its design also makes it less convenient to produce torque. We used this technique in imaging mode mostly as a control method to analyze single molecules prior to their mechano-chemical analysis by optical tweezers. As part of the IMDEA Nanoscience facilities, we use a JPK Nanowizard® II, which combines fluorescence and AFM, and a Nanotec Cervantes®.