Atomic force microscopy for imaging and nanomechanical characterisation of live nematode epicuticle: A comparative Caenorhabditis elegans and Turbatrix aceti study

Highlights: • PeakForce tapping Atomic Force microscopy was applied to image live nematodes in native environments. • Nanomechanical mapping demonstrates non-uniform modulus and adhesion force distribution in adult nematodes. • High-resolution images and nanomechanical maps of Caenorhabditis elegans and Turbatrix aceti nematodes were comparatively investigated. Atomic force microscopy (AFM), a powerful tool in interdisciplinary biomedical research, has been applied here to investigate the surface of live nematodes epicuticle. We have used AFM in PeakForce Tapping non-resonant imaging and nanomechanical characterisation mode to investigate and compare the surface features of epicuticle of two free-living microscopic nematodes, Caenorhabditis elegans and Turbatrix aceti. We have successfully immobilised live anesthetized adult nematodes on glass supports using either layer-by-layer-deposited polyelectrolyte films or bioadhesive coatings, which allowed for imaging the living nematodes in native environment. We have obtained AFM images and corresponding nanomechanical maps of annular rings and furrows, demonstrating the differences in topography and structure between the species. Our results demonstrate that AFM in PeakForce Tapping mode can be used to image and characterise surfaces of relatively-large live immobilised multicellular organisms, which can be further applied to a number of invertebrates.