3D renderings of F-actin filaments acquired in fluid with a Cypher AFM. Height image (left) and phase channel overlaid onto the height image (right). 340 nm scan. The periodic structure of the filament is more pronounced in the overlaid image. The actin sample was a gift from Prof. Emil Reisler's laboratory (UCLA) and prepared by Elena Grintsevich (UCLA) as described in Nanoscale, 2013, 5, 5692.