Atomic Force Microscopy: Biomedical Methods And Applications (methods In Molecular Biology)
by Pier Carlo Braga /
2003 / English / PDF
8.7 MB Download
The natural, biological, medical, and related sciences would not be
what they are today without the microscope. After the introduction
of the optical microscope, a second breakthrough in
morphostructural surface analysis occurred in the 1940s with the
development of the scanning electron microscope (SEM), which,
instead of light (i. e. , photons) and glass lenses, uses electrons
and electromagnetic lenses (magnetic coils). Optical and scanning
(or transmission) electron microscopes are called “far-field
microscopes” because of the long distance between the sample and
the point at which the image is obtained in comparison with the
wavelengths of the photons or electrons involved. In this case, the
image is a diffraction pattern and its resolution is wavelength
limited. In 1986, a completely new type of microscopy was proposed,
which, without the use of lenses, photons, or electrons, directly
explores the sample surface by means of mechanical scanning, thus
opening up unexpected possibilities for the morphostructural and
mechanical analysis of biological specimens. These new scanning
probe microscopes are based on the concept of near-field
microscopy, which overcomes the problem of the limited
diffraction-related resolution inherent in conventional
microscopes. Located in the immediate vicinity of the sample itself
(usually within a few nanometers), the probe records the intensity,
rather than the interference signal, thus significantly improving
resolution. Since the most we- known microscopes of this type
operate using atomic forces, they are frequently referred to as
atomic force microscopes (AFMs).
The natural, biological, medical, and related sciences would not be
what they are today without the microscope. After the introduction
of the optical microscope, a second breakthrough in
morphostructural surface analysis occurred in the 1940s with the
development of the scanning electron microscope (SEM), which,
instead of light (i. e. , photons) and glass lenses, uses electrons
and electromagnetic lenses (magnetic coils). Optical and scanning
(or transmission) electron microscopes are called “far-field
microscopes” because of the long distance between the sample and
the point at which the image is obtained in comparison with the
wavelengths of the photons or electrons involved. In this case, the
image is a diffraction pattern and its resolution is wavelength
limited. In 1986, a completely new type of microscopy was proposed,
which, without the use of lenses, photons, or electrons, directly
explores the sample surface by means of mechanical scanning, thus
opening up unexpected possibilities for the morphostructural and
mechanical analysis of biological specimens. These new scanning
probe microscopes are based on the concept of near-field
microscopy, which overcomes the problem of the limited
diffraction-related resolution inherent in conventional
microscopes. Located in the immediate vicinity of the sample itself
(usually within a few nanometers), the probe records the intensity,
rather than the interference signal, thus significantly improving
resolution. Since the most we- known microscopes of this type
operate using atomic forces, they are frequently referred to as
atomic force microscopes (AFMs).