Combining fluorescence and atomic force microscopy (AFM) to image individual microtubules in vitro

Atomic force microscopy (AFM) can be used in buffer, to image samples at a resolution superior to light-based microscopy techniques, and, unlike electron microscopy (EM), under physiological conditions [1]. However, the heterogeneity of most biological samples requires that, to distinguish specific components within a system, a label must be used. The lack of such labelling techniques for AFM makes it difficult to characterize structures in complex biological systems using AFM alone. An imaging setup capable of combining multiple imaging techniques, such as the JPK NanoWizard AFM mounted on an inverted light microscope enables the correlation of images generated on a single sample by multiple microscopy techniques. While this set up is clearly essential for the characterization of cell surface structures [2,3], it is also useful for the study of individual cellular components used in in vitro assays.