High-force magnetic tweezers with force feedback for biological applications.
Magnetic micromanipulation using magnetic tweezers is a versatile biophysical technique and has been used for single-molecule unfolding, rheology measurements, and studies of force-regulated processes in living cells. This article describes an inexpensive magnetic tweezer setup for the application of precisely controlled forces up to 100 nN onto 5 microm magnetic beads. High precision of the force is achieved by a parametric force calibration method together with a real-time control of the magnetic tweezer position and current. High forces are achieved by bead-magnet distances of only a few micrometers. Applying such high forces can be used to characterize the local viscoelasticity of soft materials in the nonlinear regime, or to study force-regulated processes and mechanochemical signal transduction in living cells. The setup can be easily adapted to any inverted microscope.
Zentrum für Medizinische Physik und Technik, Universität Erlangen-Nürnberg, Henkestrasse 91, 91052 Erlangen, Germany.
Philip
P
Kollmannsberger
Ben
B
Fabry
D001695:Biology / Q000295:instrumentation* / Q000379:methods; D002469:Cell Separation / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D018189:Immunomagnetic Separation / Q000295:instrumentation*; D008280:Magnetics / Q000295:instrumentation*; D008846:Micromanipulation / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000295:instrumentation* / Q000379:methods; D013314:Stress, Mechanical