Scanning Probe Microscope (SPM)
Application in Microscopy
Advantages and Disadvantages
The scanning probe microscope gives researchers imaging tools for the future as these specialized microscopes provide high image magnification for observation of three-dimensional-shaped specimens.
This renders not only enhanced images but specimen properties, response and reaction or non-action when specimens are stimulated or touched.
Working in an IBM research laboratory in Zurich, Switzerland Dr. Gerd K. Binning and Dr. Heinrich Rohrer conducted the first successful scanning tunneling microscopic observation at the atomic level.
Rohrer and Binning were awarded the Nobel Prize in Physics in 1986 for their work in bringing scanning probe microscope technology from the drawing board to the laboratory.
Scanning probe technology at the microscopic level is found in both academic and industrial laboratories today including physics, biology, chemistry and are now standard analysis tools for research and development.
The ability to observe a specimen in three dimensions, in real time plus manipulating specimens through the application of an electrical current with a physical interaction using the tip of the probe has incredible potential for research.
Viewing a specimen in a variety of environments is why scanning probe microscopes, SPMs, are so widely used.
Specimens can now be viewed at the nanometer level and instead of light waves or electrons, SPMs use a delicate probe to scan a specimen’s surface eliminating many of the restrictions that light waves or electron imaging has.
How Does a Scanning Probe Microscope work?
Tracing the surface of a specimen is done through the use of a sharp, electrically charged probe, much in the way an old record player created sound through a needle following the grooves on an LP.
Unlike a record player needle, the SPM probe does not touch the surface but traces the specimen nanometers above the surface.
Plus, the probe can be used to interact with a specimen allowing researchers to observe how a substance attracts or detracts, responds to electrical currents. Since SPM technology can operate in a wide variety of environments even non-conductive specimens can be manipulated and observed.
Development of scanning probe microscopes has allowed specialized microscopes to be created including:
The scanning tunneling microscopes use a piezo-electrically charged wire, a very small space between the charged wire and the surface and the specimen to produce enhanced images of the specimen.
The charged wire forces energy across the small space and onto the specimen where the current meets with the specimens surface and decays.
This decay is measured and a high resolution image is produced from the information collected.
Tunneling microscopy allows imaging at the atomic level to be produced plus different types of information can be obtained by altering the environment that the specimen is observed in such as a gaseous environment, vacuum, or a liquid environment.
Atomic force microscopy uses a cantilever with a sharp probe that scans the surface of the specimen allowing for a resolution that you can measure in fractions of a nanometer; in other words "feeling" the surface of an object in order to produce a visual image.
The flexibility of these types of microscopes are allowing for additional specialized instruments including the near field scanning optical microscope that utilizes optical fibers to stimulate specimens.
Advantages of SPM Technology
Scanning Probe Microscopy provides researchers with a larger variety of specimen observation environments using the same microscope and specimen reducing the time required to prepare and study specimens.
Specialized probes, improvements and modifications to scanning probe instruments continues to provide faster, more efficient and revealing specimen images with minor effort and modification.
Disadvantages of SPM Technology
Unfortunately, one of the downsides of scanning probe microscopes is that images are produced in black and white or grayscale which can in some circumstances exaggerate a specimens actual shape or size.
Computers are used to compensate for these exaggerations and produce real time color images that provide researchers with real time information including interactions within cellular structures, harmonic responses and magnetic energy.
SPM Technological Evolution
As researchers continue to improve and expand the abilities of scanning probe microscopes the technological evolution will include better observation equipment, improved data analysis, and processing equipment.
Additionally, micro-manipulation of molecules, DNA, biological and organic specimens using these precision instruments will produce a greater understanding of and new methods for:
- Treating disease
Scanning probe microscopes have improved microscopy research in many ways like the invention of the microscope improved the world.
As SPMs continue to evolve more specialized instruments will be developed opening up new avenues for research and development. Thus, the field of Nanotechnology will become all the more fascinating.
For further information, please follow the links below...
Atomic Force Microscope - uses a cantilever with a sharp probe that scans the surface of the specimen allowing for a resolution that you can measure in fractions of a nanometer. That is serious resolution!
Scanning Tunneling Microscope - is commonly used in fundamental and industrial research offering a three dimensional profile of a surface looking at microscopic characteristics to your astonishment.
Nanonics Optometronic 4000 - Companies such as Nanonics have lead the way in SPM technologies, and continue to provide researchers systems with previously unimaginable potential. Check out this systems meld of the most powerful and versatile devices available.
Magnetic Force Microscopy - A variant of Atomic Force Microscopy
See Also: Atom under the Microscope for more info
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