Combining Tip-Scanning AFM with Super-Resolution Optical Imaging towards Multiparametric Correlative Microscopy

Abstract

The last three decades have established atomic force microscopy (AFM) as an indispensable tool for the high-resolution structural analysis of specimens ranging from single molecules to complex biological systems. AFM currently offers premium spatial resolution of the analysed samples, while simultaneously being able to correlate topography and mechanics at near native/ physiological imaging conditions. In turn, the combination with advanced/customised optics leverages the advantages of immunolabelling techniques for true correlative microscopy. Recording the stimulated emission depletion (STED) microscopy fluorescence delivers a multi-colour image with a 6-10 times enhanced spatial resolution compared to conventional optical methods and, therefore, reaches the same order of magnitude as the spatial resolution of AFM. Furthermore, structured illumination microscopy (SIM) offers a unique possibility to go below the optical diffraction limit while simultaneously operating and acquiring AFM images.