Transcript Slide 1

Design of Magnetic Field
Concentrators
By: Mohammed Zuned Desai
Koji Hirota
Michael Wong
Areio Hashemi
Background
• Magnetic tweezers is a research tool for studying
molecular and cellular mechanics
• Commonly used to study force regulated processes in
biological systems
• Good resolution through a CCD (charged couple device) camera
• Exert no thermal or physical damage
• Functionality:
• Ability to measure forces on a particle using a magnetic field
gradient.
• Simplicity:
• Simple models consist of a pair of magnets that are placed on top of
the sample holder on an inverted microscope
Over all Purpose
• Design a magnetic tweezers device that is capable of
obtaining force measurements up to at least 100 pN
• The tweezers should be designed in a way in that the
sample will be able to be imaged using a bright-field
transmission microscopy.
Clients
• Universities, Research Institutes, Biotech Companies,
Laboratories
• Reason
• Device itself must be calibrated before its used, which
implies the person must have some knowledge of the field
• If the customer were to buy all of the components it would
be far too expensive for their budget i.e. cameras and
microscope
Objectives
• Using FEMM (Finite Element Methods Magnetics) to
predict the geometry and alignment of the magnets
that will produce the largest possible magnetic field
gradient.
• Machine and assemble the designs of four or six
magnets that produce the largest field gradients using
the FEMM results
• Calibrate the electromagnet assemblies, using
procedures previously developed
Methods
Determining the Best
Design of the Apparatus
Fabrication of the
Apparatus
Calibration of the
Apparatus
Using FEMM
General Design
Proper Placement of
Mirrors/Objectives
Determine the Best
Core Size
Order Necessary Parts
Determine the Best
Coil Size
Designing and
Attaching the Magnet
Tip
Determine the Best
Shape the Magnet Tip
Determine the Best
Alignment of two
Magnets
Setup Microscope and
Bright-Field
Transmission
Setup of Camera and
Computer
Design and Setup of
the Magnets
Finding Linear Region
of the Magnetic Fields
Focusing Camera for
Viewing Bead
Movement
Calculating Velocity
of Beads from
Measured Distance
and Time and use
Stokes Equation to
fine the Force Exerted
on the Beads
Setup Design
Ibrahim UCR Bien June 2009
Design Innovations
1) Angle
2) Arc
3) Cocave
Angle
4) Flat
Objective: Obtain design that will produce the largest magnetic field gradient
Sample Results
Objective: Generate fine magnetic field lines
Sample Results
Objective: Look for shape that provides the largest change in magnetic field
Magnet Design
1) Potential Problem
2) Experimentations
Budget
Component
Price (US)
In Stock
Electromagnetic Magnets
$20-$50 each
Yes
Magnet Power Supply
$200
Yes
Aluminum plate
$50-$200
No
Steel Rods (0.5inch
diameter)
$50-$100 each
No
CCD Camera
$1,000-$10,000
Yes
Microscope
$30,000-$40,000
Yes
Super paramagnetic beads
$100-$500
Yes
Potential Problems
• Machining the conical tip
• Fabrications of tip
• Too small, might crack
• How glue will affect results
• Working with a feasible distance
• Angular positioning of magnets
• Magnet coil turns
• Shipping time of magnets
• Calibrations
• Budget
Conclusion
• Design magnetic tweezers that can exert as much force as
possible, preferable at least 100pN
• Using FEMM to determine the best theoretical model d
• Fabricate based on that model
• Calibrate to maximize the force output from the instrument
• Remarks:
• What makes our project unique from the other designs that are
currently used is that we will be designing it in such a way that it
will be compatible for the sample to be imaged using bright field
transmission microscopy
• Being able to apply large forces
Can We Do It?
• We believe that we can achieve anything
that we set our minds to achieve.
- Anonymous
Questions?
References
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Neuman, Keri C, and Nagy, Attila. “Single-molecule force spectroscopy: optical tweezers, magnetic tweezers and atomic
force microscopy.” Nature Publishing Group Vol. 5, NO. 6. June 2008.
Danilowicz, Claudia, Greefield, Derek and Prentiss, Mara. “Dissociation of Ligand-Receptor Complexes Using Magnetic
Tweezers.” Analytical Chemistry Vol. 77, No. 10. 15 May. 2005.
Humphries; David E., Hong; Seok-Cheol, Cozzarelli; Linda A., Pollard; Martin J., Cozzarelli; Nicholas R. “Hybrid magnet
devices fro molecule manipulation and small scale high gradient-field applications”. United States Patent and Trademark
Office, An Agency of The United States Department of Commerce. <http://patft.uspto.gov>. January 6, 2009.
Ibrahim, George; Lu, Jyann-Tyng; Peterson, Katie; Vu, Andrew; Gupta, Dr. Sharad; Vullev, Dr. Valentine. “Magnetic
Tweezers for Measuring Forces.” University of California Riverside. Bioengineering Senior Design June 2009.
Startracks Medical, “Serves Business, Education, Government and Medical Facilities Worldside.” American Solution.
Startracks.org, Inc. Copyright 2003.
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