title: Micro magnetic tweezers for nanomanipulation inside live cells.
abstract: This study reports the design, realization, and characterization of a multi-pole magnetic tweezers that enables us to maneuver small magnetic probes inside living cells. So far, magnetic tweezers can be divided into two categories: I), tweezers that allow the exertion of high forces but consist of only one or two poles and therefore are capable of only exerting forces in one direction; and II), tweezers that consist of multiple poles and allow exertion of forces in multiple directions but at very low forces. The magnetic tweezers described here combines both aspects in a single apparatus: high forces in a controllable direction. To this end, micron scale magnetic structures are fabricated using cleanroom technologies. With these tweezers, magnetic flux gradients of nablaB = 8 x 10(3) T m(-1) can be achieved over the dimensions of a single cell. This allows exertion of forces up to 12 pN on paramagnetic probes with a diameter of 350 nm, enabling us to maneuver them through the cytoplasm of a living cell. It is expected that with the current tweezers, picoNewton forces can be exerted on beads as small as 100 nm.
authors.affiliation: Biophysical Engineering, Faculty of Science and Technology, Institute for Biomedical Technology, University of Twente, 7500 AE Enschede, The Netherlands.
authors.forename: Anthony H B
authors.initials: AH
authors.lastname: de Vries
authors.forename: Bea E
authors.initials: BE
authors.lastname: Krenn
authors.forename: Roel
authors.initials: R
authors.lastname: van Driel
authors.forename: Johannes S
authors.initials: JS
authors.lastname: Kanger
mesh_terms: D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D002478:Cells, Cultured; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006098:Granulocytes / Q000502:physiology*; D006801:Humans; D008280:Magnetics; D008846:Micromanipulation / Q000295:instrumentation* / Q000379:methods; D008863:Microspheres; D008904:Miniaturization; D015336:Molecular Probe Techniques / Q000295:instrumentation*; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D010812:Physical Stimulation / Q000295:instrumentation* / Q000379:methods; D013314:Stress, Mechanical