Up until now, this website has been funded by Google text adverts that appear on the right of the page. I don’t control what ads appear there, except that I can remove some categories of ads. Beginning soon, I expect to have actual ads from AFM companies appearing there.
The advertisers do not influence any of the other text I write here. Although I do work with some AFM manufacturer’s equipment more than others (and my co-author on the book, Paul West has been owner/CEO of various AFM companies), I do not really favour instruments of one manufacturer over others. I have used many (more than ten) different AFM instruments over the years and this has led me to think that -
ALL AFM instruments can produce great results.
What is necessary to get great results are a certain level of skill on the part of the operator, a good probe, careful sample preparation, patience, use of the right modes and settings, and sometimes, a dash of luck! While newer instruments certainly offer amazing new modes, and in some cases lower noise levels, increased ease of use, or faster scanning, in my experience 99% of AFM could actually be done on just about any instrument. In my teaching, I hope I explain things that are useful to users of all instruments. Furthermore, although I am happy to get new listings, and factual corrections for the “Where to buy instruments” and “Probes” and “Calibration artifacts” pages, I do not accept copy written by the companies for inclusion on those pages. Any inaccuracies, or opinions are mine alone.
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This article contains a small extract from Chapter 7 of “Atomic Force Microscopy”. Chapter 7 contains descriptions of applications of AFM in materials science, chemistry and physics, biology and the life sciences, nanotechnology, and in industry. This short section describes some examples of applications of AFM in bacteriology. References lists, and the second figure can be found in the full book.
AFM is a highly suitable tool to examine bacteria, and has been widely applied to their study. Bacteria are commonly studied by optical microscopy, which can give an overall idea about gross cell morphology (via a two-dimensional projection), and is also useful for cell-counting studies. In comparison, AFM is slower, and thus is less useful for quantitative cell-counting, but allows measurement of a variety of other cellular properties, particularly by nanoindentation and force spectroscopy experiments . In addition, the greatly increased resolution of AFM allows for the imaging of finer details of cell morphology and sub-cellular features such as pili and fimbriae . The three dimensional information from AFM can also be useful in differentiating morphologies which would look the same in optical microscopy . Various other micro-organisms have been studied by AFM such as spores [178, 613–615], fungi [616, 617], including yeasts [171, 618], viruses [287, 619], and others  but here we concentrate on bacteria for the sake of brevity.
Fig. 7.20. Studies of bacterial morphology. Top left: Streptococcus, showing typical linear clusters. Top right: large clusters of Staphylococcus aureus. Bottom left: Salmonella biofilm showing pili-like fimbrial structures. Bottom right: E. coli. All these images were measured in air. Reproduced with permission from  (top left) and  (bottom left). Right hand images the author's own work.
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I have this poster up in the AFM lab here. I made it to save me drawing out how AFMs work everytime I need to explain it to new students or visitors! I saw someone photographing it the other day, so I though I'd make it available here. Click the image below to get the .pdf of the full poster.
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UPDATE: The site has been upgraded to new back-end code. This should help stability and enable new features in the future. Hopefully all the old pages are working now on the new code. If you see any problems, let me know!
The design of the site was changed a little, it looks kind of plain now, maybe I'll revert to the old look later.
There is now a new AFM Image Gallery, which contains more images than before, organised in categories and a few by instrument.
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