Electromagnetic Miniatures

Simultaneous production of microchannels with parallel, electrically conducting metal wires

09-Oct-2006

Magnetic components that can be controlled by the application of an external electric field are useful in many different applications. They can serve as microfluidic pumps, mixers, or valves in miniature lab-on-chip systems, or they can help in sorting and arranging magnetic particles. Biochemistry and cellular biology in particular benefit from many possible uses: for example, antibodies or other ligands that bind to individual biomolecules or to surface structures of cells can be coupled to magnetic beads in order to recognize and bind to their specific bonding partner even in complex mixtures. They can subsequently be fished out of the mixture with an electromagnet. Electromagnets have an additional advantage over permanent magnets: they can easily be switched on and off with an electric current. Also, the field strength can be adjusted to the desired value and can be changed as required. However, electromagnets do have the disadvantage of generating weaker magnetic fields, meaning that they must be very close to the place where they are to be used.

G. M. Whitesides and his co-workers at Harvard University in Cambridge, USA, have now developed an uncomplicated method for producing a microfluidic channel along with two metal cables parallel to it and only 10 µm away. First, a structure consisting of a 40-µm-wide and 40-µm-deep inner channel between two 120-µm-wide and 40-µm-deep outer channels was lithographically engraved into a polydimethylsiloxane resin. Treatment with 3-mercaptopropyltrimethoxysilane silanized the surfaces of the outer channels. This allowed them to be coated with molten solder that was poured into the heated forms in the next step. Upon cooling, the liquid metal solidified, forming two stable metal cables to the left and right of the inner channel. Application of an electrical field to these two wires generates magnetic fields of up to 2.8 mT within the central channel.

It was also possible to steer magnetic spheres through the channel: the scientists again made a channel with parallel wires on either side, but this time the channel forked after a few millimeters. A suspension of magnetic spheres flowed through the channel. If current was allowed to flow through wire on the right, the spheres flowed to the right as they reached the fork, and vice versa.

Original publication: George M. Whitesides et al.; "Cofabrication of Electromagnets and Microfluidic Systems in Poly(dimethylsiloxane)"; Angewandte Chemie International Edition 2006, 45, No. 41, 6877-6882.

Other news from the department science

These products might interest you

Impulsmischer

Impulsmischer by Hybrid Chemie

Pneumatic mixer for homogenizing solutions, suspensions and emulsions

Gentle, efficient mixing, regardless of the fill level, even for high viscosities

pneumatic mixers
2mag Magnetic Stirrers Catalogue 2024

2mag Magnetic Stirrers Catalogue 2024 by 2mag

Wear-free magnetic stirrers for laboratory and cell culture

Request the 2mag catalogue 2024 with innovative stirring solutions now

THINKY ARE-250

THINKY ARE-250 by C3 Prozess- und Analysentechnik

Perfect mixing and effective degassing in record time - Discover the revolutionary solution for your mixing and degassing needs

planetary centrifugal mixer
THINKY ARE-500

THINKY ARE-500 by C3 Prozess- und Analysentechnik

Efficient mixing and degassing in minutes - The revolutionary mixer and disperser without stirrer

planetary centrifugal mixer
YSTRAL Conti-TDS

YSTRAL Conti-TDS by ystral

YSTRAL Conti-TDS: The No. 1 in Powder Wetting

Induct, wet and disperse powder

powder wetting systems
OHAUS Laboratory equipment

OHAUS Laboratory equipment by Ohaus

Do More with OHAUS Laboratory Equipment

Do Not Limit Yourself to Just Measurement! Discover Ingenious Portfolio

lab equipment
Mini Vortex Mixers

Mini Vortex Mixers by Ohaus

Your vortex mixer for perfect mixing in any application

Your durable laboratory assistant for everyday mixing and vortexing

mixers
MultiDrive

MultiDrive by IKA Werke

The Universal Crusher: Weigh and Crush Using the Same Mixing Cup!

Mix, grind, disperse – no matter whether your samples are hard, soft or fibrous

grinders
Innovative Magnetic Stirrers

Innovative Magnetic Stirrers by 2mag

Magnetic stirrer of the future - for laboratories and pilot plants

Individually configurable, 100 % wear-free, 3-year guarantee

Loading...

Most read news

More news from our other portals

So close that even
molecules turn red...