Viruses and virus-related processes have been good targets for imaging with AFM especially in the early phase of its biological applications. In such studies AFM complements electron microscopy and diffraction techniques. One of advantages of AFM over other microscopic methods like electron microscopy is its ability to directly give information on the height of the specimens thus allowing quantification of virus dimensions.

Tobacco Mosaic Virus (TMV or Satellite TMV) is the most popular among other numerous mosaic viruses investigated so far. Fig. 1 shows an AFM height image of TMV, which was obtained with a probe of the 14 series. Colloidal solutions of TMV behave similarly to those of commonly studied protein ones and so can be studied the same way.