Implications of heterogeneous bead behavior on cell mechanical properties measured with magnetic twisting cytometry

Magnetic twisting cytometry (MTC) measures cellular mechanical properties, such as cell stiffness and viscosity, by applying mechanical stress to specific cell surface receptors via ligand-coated ferromagnetic beads. MTC measures simultaneously the rotation of approximately 50,000 beads attached to 20,000-40,000 cells. Here we show direct evidence of heterogeneous bead behavior and examine its consequences in the interpretation of cell mechanical properties. (C) 1999 Elsevier Science B.V. All rights reserved.