Journal Article

FZJ-2015-02515

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Magnetic tweezers with high permeability electromagnets for fast actuation of magnetic beads

Chen, L. ; Offenhäusser, A.FZJ* ; Krause, H.-J. (Corresponding Author)

2015
American Institute of Physics [S.l.]

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Please use a persistent id in citations: http://hdl.handle.net/2128/16752  doi:10.1063/1.4916255

Abstract: As a powerful and versatile scientific instrument, magnetic tweezers have been widely used in biophysical research areas, such as mechanical cell properties and single molecule manipulation. If one wants to steer bead position, the nonlinearity of magnetic properties and the strong position dependence of the magnetic field in most magnetic tweezers lead to quite a challenge in their control. In this article, we report multi-pole electromagnetic tweezers with high permeability cores yielding high force output, good maneuverability, and flexible design. For modeling, we adopted a piece-wise linear dependence of magnetization on field to characterize the magnetic beads. We implemented a bi-linear interpolation of magnetic field in the work space, based on a lookup table obtained from finite element simulation. The electronics and software were custom-made to achieve high performance. In addition, the effects of dimension and defect on structure of magnetic tips also were inspected. In a workspace with size of 0.1 × 0.1 mm2, a force of up to 400 pN can be applied on a 2.8 μm superparamagnetic bead in any direction within the plane. Because the magnetic particle is always pulled towards a tip, the pulling forces from the pole tips have to be well balanced in order to achieve control of the particle’s position. Active video tracking based feedback control is implemented, which is able to work at a speed of up to 1 kHz, yielding good maneuverability of the magnetic beads.

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Contributing Institute(s):

1. Bioelektronik (PGI-8)
2. Bioelektronik (ICS-8)
3. JARA-FIT (JARA-FIT)

Research Program(s):

1. 552 - Engineering Cell Function (POF3-552) (POF3-552)
2. 553 - Physical Basis of Diseases (POF3-553) (POF3-553)
3. 523 - Controlling Configuration-Based Phenomena (POF3-523) (POF3-523)

Appears in the scientific report 2015

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Database coverage:
; ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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