Fig. 4: Examples of studies combining AFM with other biophysical methods.

A Representation of mass spectrometry (MS) technique, which can be combined with AFM to provide a characterization of viral particles. B, C Images adapted from Baclayon et al.¹¹⁵, to show: (B) native nanoelectrospray mass spectra for NVLPs (0.2 μM capsid concentration) and (C) AFM images and height profiles of NVLP (top left panel; solid line) and mutant CT303 particle (bottom left panel; dashed line)¹¹⁵. D Representaion of fluorescence microscopy, that has been used in the study of Bally et al.¹¹⁶ as a complementary technique to AFM in the study of NoV (E). E, F Images adapted from Bally et al.¹¹⁶ showing (E) a correlation of NVLP binding with ___domain features given by fluorescence micrographs of GalCer bilayers, as well as (F) an AFM topography image of a bilayer GalCer ___domain, with corresponding height profile (white line in the image)¹¹⁶. G Representation of MD simulations technique, which has been combined with AFM in the study of Arkhipov et al.¹²⁰ to perform both experiments and simulations of AFM indentation (H). H Schematics of AFM nanoidentation of a HBV capsid, in which an AFM tip is pushed against a viral capsid anchored on a substrate surface (I, J) Images adapted from Arkhipov et al.¹²⁰ showing (I) Force-indentation curves obtained from experiments (gray) and simulations in different pushing directions (colored). Curves are obtained as measurement of the AFM tip position and the force experienced by the tip. Taking into account initial capsid height, the AFM tip position can be translated into indentation depth. Data represents average of multiple simulations or experiments. Error bars are RMSD values. J Exemplary force-indentation curves from individual simulations, each in a different color¹²⁰. Schematics in panels A, D, G, and H were created in BioRender.com.