Study of carbon nanotube for scanning probe microscopy

Atomic force microscopy (AFM) has become an indispensable tool due toits ability to image and manipulate matter at the nanometer scale in air,liquid, or vacuum. The AFM uses a micromachined silicon or silicon nitride probe mounted on a flexible cantilever that can sense or generate forcesbetween the probe tip and a sample surface. The AFM can thus be used aseither an imaging instrument or a manipulation device.Because it can acquire high-resolution topographical images in physiologically relevantaqueous environments, AFM has become especially important for structural biology and biophysics. AFM is distinct from other highly sensitive techniques for measuringintermolecular forces, such as the surface force apparatus and optical tweezers,due to the high spatial resolution possible and the capability to dynamicallymeasure and control time-dependent forces. In addition to obtainingtopographic images of biological structures, AFM can probe dynamic processesin solution, such as chemically and mechanically induced unfoldingmechanisms in proteins and DNA. The level of resolution possible in AFM for both single-molecule imagingand force transduction is ultimately limited by the structure of the tip. KeywordsAtomic force microscope (AFM), carbon nanotubes, optical tweezers, micromachined silicon, silicon-nitride probe,