title: Wedged AFM-cantilevers for parallel plate cell mechanics.
abstract: The combination of atomic force microscopy (AFM) and optical microscopy has gained popularity for mechanical analysis of living cells. In particular, recent AFM-based assays featuring tipless cantilevers and whole-cell deformation have yielded insights into cellular function, structure, and dynamics. However, in these assays the standard ≈10° tilt of the cantilever prevents uniaxial loading, which complicates assessment of cellular geometry and can cause cell sliding or loss of loosely adherent cells. Here, we describe an approach to modify tipless cantilevers with wedges and, thereby, achieve proper parallel plate mechanics. We provide guidance on material selection, the wedge production process, property and geometry assessment, and the calibration of wedged cantilevers. Furthermore, we demonstrate their ability to simplify the assessment of cell shape, prevent lateral displacement of round cells during compression, and improve the assessment of cell mechanical properties.
authors.affiliation: Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland.
authors.forename: Martin P
authors.initials: MP
authors.lastname: Stewart
authors.forename: Adrian W
authors.initials: AW
authors.lastname: Hodel
authors.forename: Andreas
authors.initials: A
authors.lastname: Spielhofer
authors.forename: Cedric J
authors.initials: CJ
authors.lastname: Cattin
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Müller
authors.forename: Jonne
authors.initials: J
authors.lastname: Helenius
mesh_terms: D001696:Biomechanical Phenomena; D048430:Cell Shape; D019245:Compressive Strength; D006367:HeLa Cells; D006801:Humans; D018625:Microscopy, Atomic Force / Q000295:instrumentation / Q000379:methods*; D024462:Myosin Type II / Q000037:antagonists & inhibitors / Q000502:physiology; D013312:Stress, Physiological
chemical_list: D024462:Myosin Type II