Experimental Technique Sorts DNA, Cells, Molecules in a Split Second

October 17, 2007

A simple device just a few millimeters across can separate microscopic objects such as DNA or cells in a fraction of a second—thousands of times faster than conventional methods.

University of Rochester researchers have patented the device, which they hope will make tests such as identifying proteins in a tiny sample of blood as simple as placing a drop on a handheld device. Laboratories and hospitals all over the world use similar, albeit cumbersome, hours-long processes in efforts to identify everything from DNA fragments to pathogens.

"We see this as a powerful technique for biochemical analysis. It's very quick and we can work with incredibly small sample sizes," says Michael King, associate professor of biomedical engineering. "This process can separate proteins, and in theory it can separate them even when they are the same size and have the same electric charge."

King and Thomas Jones, professor of electrical and computer engineering, induce an electrical field around the droplet to be analyzed, and in one-tenth of a second the droplet elongates along an electrode into an electrified, liquid string. As the fluid is stretched, the electrical field separates the molecules laterally along the edges of the long droplet. Stretching the droplet along a specially prepared detector can lay down one set of molecules directly onto the detector, making their recognition highly efficient, says King.

King and Jones found that a micro-liter of fluid or less is enough for the process to work with great efficiency. The most common method of separating proteins, called gel electrophoresis, requires more liquid and can take several hours, says King.

As outlined in Jones's 1995 book, Electromechanics of Particles, the frequency of an electric field can be tuned to send one subset of particles in one direction, and another set of particles in the reverse direction based on the way they behave in an electric field.

"We get a little droplet from a micropipette; all you have to do is load the thing," says Jones. "It's much simpler than other microfluidic schemes being used."

Jones had conducted research in microfluids and the dielectrophoretic force for decades when King suggested adding particles to the liquid experiments. They experimented with a variety of substrates and voltages, finally finding a coated electrode structure comprised of two parallel strips each thinner than a human hair. The strips allowed them the necessary control over the movement of the fluid and particles within. The discovery was first documented in 2005 in the Journal of Applied Physics.

The team is now looking into building electrodes with integrated particle detectors, and using fluorescence-marked proteins to see if they can increase the speed and accuracy of the process further yet.

Source: University of Rochester

4.7 /5 (33 votes)  

Filter


Move the slider to adjust rank threshold, so that you can hide some of the comments.


Display comments: newest first

manifespo
Oct 17, 2007

Rank: 4 / 5 (1)
What about integrating ligand-linked quantum dots into the particle detectors?
Quantum_Conundrum
Oct 18, 2007

Rank: not rated yet
This is neat. It could have all sorts of applications in medicine and forensics by speeding up diagnosis time.
Rank 4.7 /5 (33 votes)
Tags

Related Stories
Relevant PhysicsForums posts
  • Pith balls problem
    created34 minutes ago
  • Electrostatics
    created35 minutes ago
  • what is phase constant
    created47 minutes ago
  • Basics In electromagnetic wave
    created56 minutes ago
  • How to calculate theoretical initial velocity?
    created1 hour ago
  • Question about Gravity?
    created3 hours ago
  • More from Physics Forums - General Physics

More news stories

Putting the squeeze on planets outside our solar system

(PhysOrg.com) -- Using high-powered lasers, scientists at Lawrence Livermore National Laboratory and collaborators discovered that molten magnesium silicate undergoes a phase change in the liquid state, abruptly ...

Physics / Condensed Matter

created 11 hours ago | popularity 4.3 / 5 (7) | comments 0 | with audio podcast

Hovering not hard if you're top-heavy, researchers find

Top-heavy structures are more likely to maintain their balance while hovering in the air than are those that bear a lower center of gravity, researchers at New York University's Courant Institute of Mathematical Sciences ...

Physics / General Physics

created 12 hours ago | popularity 5 / 5 (1) | comments 1 | with audio podcast

SLAC, Stanford team focuses on high-energy electrons to treat cancer

Accelerator physicists at SLAC and cancer specialists from Stanford are working on a new technology that could dramatically reduce the time needed for cancer radiation treatments. The team ran an initial experiment ...

Physics / General Physics

created 15 hours ago | popularity 5 / 5 (2) | comments 0

Measurements from high-energy collisions lead to better understanding of why meson particles disappear

For several years, physicists at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), USA, have studied an unusual state of matter called the quark–gluon plasma, which they ...

Physics / General Physics

created 16 hours ago | popularity 4.5 / 5 (4) | comments 0

Explained: Sigma

It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but ...

Physics / General Physics

created Feb 09, 2012 | popularity 5 / 5 (16) | comments 53


Anonymous knocks CIA website offline (Update)

The website of the Central Intelligence Agency was inaccessible on Friday after the hacker group Anonymous claimed to have knocked it offline.

Google users warned of threat to smartphone wallets

Users of Google smartphone wallets were being warned on Friday that there is a way to crack pass codes intended to thwart thieves from going on illicit shopping sprees.

New error-correcting codes guarantee the fastest possible rate of data transmission

Error-correcting codes are one of the triumphs of the digital age. They’re a way of encoding information so that it can be transmitted across a communication channel — such as an optical fiber o ...

Humans may have helped the decline of African rainforests 3000 years ago

(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...

New power source discovered

(PhysOrg.com) -- Researchers at the Massachusetts Institute of Technology (MIT) and RMIT University have made a breakthrough in energy storage and power generation.

The power of estrogen -- male snakes attract other males

A new study has shown that boosting the estrogen levels of male garter snakes causes them to secrete the same pheromones that females use to attract suitors, and turned the males into just about the sexiest ...