Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

'No muss, no fuss' miniaturized analysis for complex samples developed

19.11.2009
The goal of an integrated, miniaturized laboratory analysis system, also known as a "lab-on-a-chip," is simple: sample in, answer out.

However, researchers wanting to use these microfluidic devices to analyze complex solutions containing particulates or other contaminating materials often find that the first part of the process isn't so easy.

Effective sample preparation from these solutions can be laborious, expensive and time-consuming, involving complicated laboratory methods that must be performed by skilled technicians. This can significantly diminish the benefits associated with using miniaturized analytical techniques. Recent work at the National Institute of Standards and Technology (NIST) could help change that.

NIST researchers Elizabeth Strychalski and David Ross, in collaboration with Alyssa Henry of Applied Research Associates Inc. (Alexandria, Va.), have developed a novel and simple way to analyze samples that are complex mixtures, such as whole milk, blood serum and dirt in solution. In a paper published recently in Analytical Chemistry,* the team describes its latest enhancement to a NIST-developed separation technique called gradient elution moving boundary electrophoresis (GEMBE) (see "New Miniaturized Device for Lab-on-a-Chip Separations" in NIST Tech Beat, Jan. 19, 2007).

GEMBE relies on a combination of electrophoresis and variable pressure-driven flow through a microchannel. Electrophoresis uses electricity to push a mixture in solution through a channel, forcing the individual components to separate as they move at specific rates based on their individual properties, such as size and electrical charge. Complex samples can be difficult to separate cleanly because components in these samples (for example, the fat globules in milk or proteins in blood) can "foul" microfluidic channels in a way that prevents reliable detection of the desired sample components.

The new technique solves this problem by pumping a buffer solution under controlled pressure in the opposite direction. This opposing pressure flow acts as a "fluid gate" between the sample reservoir and the microchannel. Gradually reducing the pressure of the counterflow opens the "gate" a little bit at a time. A specific sample component is detected when the pressure flow becomes weak enough—when the "gate" opens wide enough—that the component's electrophoretic motion pushes it against the pressure flow and into the channel for detection. In this way, different components enter the channel at different times based on their particular electrophoretic motion. Most importantly, the channel doesn't become fouled because the unwanted material in the sample is held out during the analysis by the pressure flow.

In their paper, the researchers validated their GEMBE analysis technique by testing it with solutions of whole milk, dirt, estuarine sediment, coal fly ash, pulverized leaves and blood serum. In all cases—and without the muss and fuss of pre-analysis sample preparation—the system was able to reproducibly separate and quantify specific components from the solutions, including potassium, calcium, sodium, magnesium, lithium and melamine.

"GEMBE is well-suited to the microfluidic analysis of 'real-world' samples," Strychalski says. "We have shown that the method can handle solutions containing particulates, proteins and other materials that would confound the majority of other microfluidic techniques."

Because of its ability to easily and rapidly characterize complex mixtures with minimal preparation, the researchers believe that GEMBE shows enormous promise for diverse applications, such as monitoring contaminants in food or water supplies, determining nutrient levels in soil, detecting biochemical warfare agents, and diagnosing medical conditions. The next steps, they say, are to miniaturize the desktop equipment now used in the system and integrate all of the parts to develop a true "lab-on-a-chip" field analyzer that can rival the effectiveness of a full-scale facility.

* E. Strychalski, A. Henry and D. Ross. Microfluidic analysis of complex samples with minimal sample preparation using Gradient Elution Moving Boundary Electrophoresis. Analytical Chemistry, Vol. 81, No. 24, Dec. 15, 2009; published online Nov. 10, 2009.

Michael E. Newman | EurekAlert!
Further information:
http://www.nist.gov

More articles from Life Sciences:

nachricht Enzyme with surprising dual function
24.01.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Flexibility and arrangement - the interaction of ribonucleic acid and water
24.01.2018 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Optical Nanoscope Allows Imaging of Quantum Dots

Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.

Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Physicists have learned to change the wavelength of Tamm plasmons

24.01.2018 | Physics and Astronomy

When the eyes move, the eardrums move, too

24.01.2018 | Health and Medicine

Deaf children learn words faster than hearing children

24.01.2018 | Health and Medicine

VideoLinks Science & Research
Overview of more VideoLinks >>>