Corporate Banner
Satellite Banner
Technology
Networks
Scientific Communities
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Oscillating Microscopic Beads Could be Key to Biolab on a Chip

Published: Tuesday, September 25, 2012
Last Updated: Tuesday, September 25, 2012
Bookmark and Share
MIT team finds way to manipulate and measure magnetic particles without contact, potentially enabling multiple medical tests on a tiny device.

If you throw a ball underwater, you’ll find that the smaller it is, the faster it moves: A larger cross-section greatly increases the water’s resistance. Now, a team of MIT researchers has figured out a way to use this basic principle, on a microscopic scale, to carry out biomedical tests that could eventually lead to fast, compact and versatile medical-testing devices.

The results, based on work by graduate student Elizabeth Rapoport and assistant professor Geoffrey Beach, of MIT’s Department of Materials Science and Engineering (DMSE), are described in a paper published in the journal Lab on a Chip. MIT graduate student Daniel Montana ’11 also contributed to the research as an undergraduate.

The balls used here are microscopic magnetic beads that can be “decorated” with biomolecules such as antibodies that cause them to bind to specific proteins or cells; such beads are widely used in biomedical research. The key to this new work was finding a way to capture individual beads and set them oscillating by applying a variable magnetic field. The rate of their oscillation can then be measured to assess the size of the beads.

When these beads are placed in a biological sample, biomolecules attach to their surfaces, making the beads larger — a change that can then be detected through the biomolecules effect on the beads’ oscillation. This would provide a way to detect exactly how much of a target biomolecule is present in a sample, and provide a way to give a virtually instantaneous electronic readout of that information.

This new technique, for the first time, allows these beads — each about one micrometer, or millionth of a meter, in diameter — to be used for precise measurements of tiny quantities of materials. This could, for example, lead to tests for disease agents that would need just a tiny droplet of blood and could deliver results instantly, instead of requiring laboratory analysis.

In a paper published earlier this year in the journal Applied Physics Letters, the same MIT researchers described their development of a technique for creating magnetic tracks on a microchip surface, and rapidly transporting beads along those tracks. (The technology required is similar to that used to read and write magnetic data on a computer’s hard disk.) An operational device using this new approach would consist of a small reservoir above the tracks, where the liquid containing the magnetic beads and the biological sample would be placed.

Rather than pumping the fluid and the particles through channels, as in today’s microfluidic devices, the particles would be controlled entirely through changes in applied magnetic fields. By controlling the directions of magnetic fields in closely spaced adjacent regions, the researchers create tiny areas with extremely strong magnetic fields, called magnetic domain walls, whose position can be shifted along the track. “We can use the magnetic domain walls to capture and transport the beads along the tracks,” Beach says.

In the researchers’ most recent paper, Rapoport explains, they have now shown that once a bead is captured, a magnetic field can be used to shake it back and forth. Then, the researchers measure how fast the bead moves as they change the frequency of the oscillation. “The resonant frequency is a function of the bead size,” she says — and could be used to reveal whether the bead has grown in size through attachment to a target biomolecule.

Besides being potentially quicker and requiring a far smaller biological sample to produce a result, such a device would be more flexible than existing chip-based biomedical tests, the researchers say. While most such devices are specifically designed to detect one particular kind of protein or disease agent, this new device could be used for a wide variety of different tests, simply by inserting a fresh batch of fluid containing beads coated with the appropriate reactant. After the test, the material could be flushed out, and the same chip used for a completely different test by inserting a different type of magnetic beads. “You’d just use it, wash it off, and use it again,” Rapoport says.

There are dozens of types of magnetic beads commercially available now, which can be coated to react with many different biological materials, Beach explains, so such a test device could have enormous flexibility.

The MIT team has not yet used the system to detect biological molecules. Rather, they used magnetic beads of different sizes to demonstrate that their system is capable of detecting size differences corresponding to those between particles that are bound to biological molecules and those that are not. Having succeeded in this proof of concept, the researchers’ next step will be to repeat the experiment using biological samples.

“We now have all the elements required to make a sensing device,” Beach says. The next step is to combine the pieces in an operational device and demonstrate its performance.

R. Sooryakumar, a professor of physics at Ohio State University who was not involved in this research, calls this an “innovative approach.”

“It is very interesting how the researchers combine technologies that are well understood for applications in computing and data storage, and apply them to something completely different,” Sooryakumar says. He adds, “These magnetic devices are potentially valuable tools that could go well beyond how one may normally expect them to be used. The ramifications, for example in food safety and health care, such as pathogen or cancer detection, are indeed exciting.”


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 3,300+ scientific posters on ePosters
  • More Than 4,800+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

New Device can Study Electric Field Cancer Therapy
Microfluidic device allows study of electric field cancer therapy through low-intensity fields, preventing malignant cells spreading.
Friday, July 08, 2016
Programmable RNA Vaccines
Tests in mice show the vaccines work against Ebola, influenza, and a common parasite.
Wednesday, July 06, 2016
Seeing RNA at the Nanoscale
MIT researchers have developed a new way to image proteins and RNA inside neurons of brain tissue.
Wednesday, July 06, 2016
Tough New Hydrogel Hybrid Doesn’t Dry Out
Water-based material could be used to make artificial skin, longer-lasting contact lenses.
Friday, July 01, 2016
Wireless, Wearable Toxic-Gas Detector
Inexpensive sensors could be worn by soldiers to detect hazardous chemical agents.
Friday, July 01, 2016
New System for Detecting Explosives
Spectroscopic system with chip-scale lasers cuts detection time from minutes to microseconds.
Wednesday, June 01, 2016
Illuminating Hidden Gene Regulators
New super-resolution technique visualizes important role of short-lived enzyme clusters.
Friday, May 27, 2016
Controlling RNA in Living Cells
Modular, programmable proteins can be used to track or manipulate gene expression.
Wednesday, April 27, 2016
Long-Term Drug Release
New tablet attaches to the lining of the GI tract, resists being pulled away.
Thursday, April 07, 2016
Pharmacy on Demand
New, portable system can be configured to produce different drugs.
Monday, April 04, 2016
A Programming Language for Living Cells
New language lets researchers design novel biological circuits.
Monday, April 04, 2016
Why Some Tumors Withstand Treatment
Mechanism uncovered that allows cancer cells to evade targeted therapies.
Thursday, March 17, 2016
Cancer Cells Remodel Environments Before Spreading
Researchers at MIT have found that the cancer cells remodel their environment to make it easier to reach nearby blood vessels.
Wednesday, March 16, 2016
Paving the Way for Metastasis
Cancer cells remodel their environment to make it easier to reach nearby blood vessels.
Tuesday, March 15, 2016
A New Way to Discover DNA Modifications
Researchers systematically find molecules that help regulate and protect DNA.
Wednesday, March 02, 2016
Scientific News
Liquid Biopsies: Miracle Diagnostic or Next New Fad?
Thanks to the development of highly specific gene-amplification and sequencing technologies liquid biopsies access more biomarkers relevant to more cancers than ever before.
Core-Shell Columns in HPLC: Food Analysis Applications
Explore the most recent applications of core-shell columns in food analysis.
Review of the Analysis of Haemoglobin A1c for Diabetes Diagnostics
This paper aims to clarify methods, units, quality requirements, reference and cutoff limits for hemoglobin A1c (HbA1c) and ratio of blood glucose/HbA1c on the basis of the results from Finnish quality control surveys by comparing them to the literature.
Colon Cancer Blocked in Mice
Case Western Reserve University Researchers block common type of colon cancer tumour in mice, laying groundwork for human clinical trial.
New Centre Offers Ultra-Speed Protein Analysis
UW-Madison researchers to establish development centre for next-gen protein measurement technologies.
Disrupting Tumour-Promotion in Humans
Researchers have modified an existing protein to represses a specific cancer-promoting ‘message’ within cells.
Protein Nanocages Could Improve Drug Design and Delivery
HHMI scientists have designed and built 10 large protein icosahedra that are similar to viral capsids that carry viral DNA.
Vaccine Strategy Targets Multiple Influenza Viruses
Scientists have identified vaccine-induced antibodies that can neutralize strains of influenza virus that infect humans.
Connectome Map More Than Doubles Human Cortex’s Known Regions
Researchers at NIH have developed software that automatically detects the “fingerprint” of each of these areas in an individual’s brain scans.
Discovered Through ‘Big Data’ Analysis
Researchers at the SBP have identified over 100 new genetic regions that affect the immune response to cancer.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
3,300+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,800+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!