Enhanced features of the Atomic Force Microscope

A new study demonstrates that the new experimental technology based on flexible membranes can replace the cantilevers of the Atomic Force Microscopy (Cantilever) AFM) in applications such as fast-lance photography, material characterization and single-molecule measurement.

(Photo by Gary Meek)

Together with the standard AFM technique, these new test tools simultaneously determine the properties of the material including adhesion, stiffness, elasticity and viscosity.

Levent Degertekin, a professor at Georgetown University's George W. Woodruff School of Engineering, says the testers' tools are tied directly to existing AFM systems on the market and can be collected. Fast shear measurements are at least 50 times longer than traditional Cantilever because they use electrostatic force between the membrane and the electrode to move the transducer. The team consists of Guclu Onaran graduates and Hamdi Torun, of the College of Electrical and Computer Engineering, Georgia Tech.

Details of the new Force Sensing Integrated Readout and Active Force (FIRAT) sensor and its biological applications were demonstrated at the American Physical Society 3 past. The study was funded by the National Institutes of Health and the National Science Foundation.

In present AFM systems, the sample surface is scanned by Cantilever with a sophisticated probe that is only a few nanometers in diameter. An optical beam is projected at the cantilever's probe to measure the deviation of the cantilever as the transducer moves over the surface and interacts with the material to be analyzed to determine the geometry of the surface.

The new instrument replaces Cantilever with a drum-like diaphragm, from which the probe protrudes to scan the specimen. In a scan, when the transducer moves over the surface, it gently slides the material. With each incision, the tool collects accurate information about both the position of the probe and the force acting on it, sensing the shape of the material and the hardness and adhesion of the material.

The output signal is generalized only when there is an interactive force on the instrument. In other words, the transient interaction forces can be measured in each of the transducers ' processes of high resolution and without any background signal.