Atomic Force Spectroscopy (AFM) is
a powerful technique that can be used
to quantify the elastic properties of
materials or to measure single molecule
unfolding or unbinding interactions on
the picoNewton scale. AFM probes
are composed of ? exible, triangular or
rectangular cantilevers with a sharp
tip near the end of the cantilever. They
can be manufactured from a variety of
materials, but most AFM probes are
made from silicon and/or silicon nitride
(Si3N4) wafers using semiconductor-
based etching processes.
An AFM probe’s sensitivity, or spring
constant (k), is the force required to
bend the cantilever per unit distance
(usually reported in Newtons/meter;
N/m). It is an important factor in AFM
probe behavior and performance for
imaging applications and an essential
parameter when attempting to quantify
intra- or inter-molecular interactions
or the compliance of materials with
the AFM.