High-force NdFeB-based magnetic tweezers device optimized for microrheology experiments.
We present the design, calibration, and testing of a magnetic tweezers device that employs two pairs of permanent neodymium iron boron magnets surrounded by low-carbon steel focusing tips to apply large forces to soft materials for microrheology experiments. Our design enables the application of forces in the range of 1-1800 pN to ∼4.5 μm paramagnetic beads using magnet-bead separations in the range of 0.3-20 mm. This allows the use of standard coverslips and sample geometries. A high speed camera, custom LED-based illumination scheme, and mechanically stabilized measurement platform are employed to enable the measurement of materials with viscoelastic moduli as high as ∼1 kPa.
Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, USA.
Jun
J
Lin
Megan T
MT
Valentine
D000180:Acrylic Resins / Q000737:chemistry; D001896:Boron Compounds / Q000737:chemistry*; D055119:Elastic Modulus; D058085:Iron Compounds / Q000737:chemistry*; D060328:Magnetic Phenomena; D008863:Microspheres; D055616:Microtechnology / Q000295:instrumentation*; D036103:Nanotechnology; D009354:Neodymium / Q000737:chemistry*; D012212:Rheology / Q000295:instrumentation*; D014783:Viscosity; D000099166:Polyacrylamides
D000180:Acrylic Resins; D001896:Boron Compounds; D058085:Iron Compounds; D009354:Neodymium; D000099166:Polyacrylamides