Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NIST's simple microfluidic devices now have valves

03.04.2014

Researchers at the National Institute of Standards and Technology (NIST) have added yet another innovation—miniature valves—to their ever-growing collection of inexpensive, easy-to-manufacture and highly efficient microfluidic devices made from plastic films and double-sided tape.

Traditionally, microfluidic devices—tiny gadgets with fluid-carrying channels used in medical diagnostics, DNA forensics and "lab-on-a-chip" chemical analyzers—have been fabricated like microchips using photolithography.


Double-sided tape is cut with channels and ports that will align when folded (A). The polymer membrane that supplies the valve function for the microfluidic device is sandwiched between (B). The completed apparatus (C) has ports for fluid flow into and out of the device, as well as a valve inlet for air. Air pressure pushes the membrane into the flow channel, blocking fluid movement.

Credit: Gregory A. Cooksey/National Institute of Standards and Technology

A desired pattern of micrometer-sized channels and ports is created on top of a silicon substrate, which can then be replicated many times by techniques such as molding or embossing. However, the process requires specialized cleanroom equipment and can take several days to complete.

If valves are needed in the system, they traditionally have been made from silicones. Unfortunately, silicones are not the best materials to use with particular laboratory assays or for manufacturing lab-on-a-chip structures.

NIST researchers have spent the past few years developing and refining a method for making microfluidic devices using plastic films and double-sided tape that produces a functional apparatus in hours rather than days and requires only simple tools to create channels and ports.

The NIST designs allow for folding the films to make multilayer or three-dimensional structures, can be used to make devices with multiple functions, and cost a fraction of traditional fabrication techniques.

But until now, there has not been a practical way to incorporate valves for dynamic control of fluid flow in these devices. In a new paper in the journal Lab on a Chip,* NIST bioengineer Gregory Cooksey and research engineer Javier Atencia describe the first-ever technique for building pneumatic microvalves into 2-D and 3-D microfluidic devices made with plastic films and tape.

Like previous NIST systems,** the new valved microfluidic device is built in layers. Narrow slits and holes are cut into pieces of double-sided tape that become tiny channels and ports when the tape is folded on itself.

The microvalve is made by sandwiching a flexible membrane between two channels that intersect, one on top of the other. Applying air pressure to the top channel pushes the membrane down like a diaphragm valve, closing the lower channel.

Cooksey and Atencia have demonstrated that their novel microvalve also can work with more complex configurations of the NIST microfluidic system. These include devices with different designs for performing different tasks simultaneously, multiple layers with different flow rates, and single units with multiple "microfluidic walls" that can fold together to form a 3-D shape.

In one trial with a cubed-shaped device, the researchers filled it with agar and grew nematodes (Caenorhabditis elegans) inside. Using the microchannels, ports and valves built into the cube's walls, they injected chemicals at controlled concentrations that either attracted or repelled the worms. This showed that the cube was a unique setup for studying a living organism's response to chemical stimuli within a closed environment.

###

*G.A. Cooksey and J. Atencia. Pneumatic valves in folded 2-D and 3-D fluidic devices made from plastic films and tapes. Lab on a Chip (March 2014). DOI:10.1039/C4LC00173G

**See NIST Tech Beat issue of Feb. 7, 2012, "New NIST 'Cell Assay on a Chip': Solid Results from Simple Means" at http://www.nist.gov/mml/bbd/fluidics-020712.cfm.

Michael E. Newman | EurekAlert!

Further reports about: NIST Pneumatic Technology materials microfluidic plastic silicones structures techniques valves walls

More articles from Life Sciences:

nachricht A Fluttering Accordion
04.08.2015 | Friedrich-Schiller-Universität Jena

nachricht Molecular Spies to Fight Cancer - Procedure for improving tumor diagnosis successfully tested
03.08.2015 | Helmholtz-Zentrum Dresden-Rossendorf

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Greenhouse gases' millennia-long ocean legacy

Continuing current carbon dioxide (CO2) emission trends throughout this century and beyond would leave a legacy of heat and acidity in the deep ocean. These...

Im Focus: Glaciers melt faster than ever

Glacier decline in the first decade of the 21st century has reached a historical record, since the onset of direct observations. Glacier melt is a global phenomenon and will continue even without further climate change. This is shown in the latest study by the World Glacier Monitoring Service under the lead of the University of Zurich, Switzerland.

The World Glacier Monitoring Service, domiciled at the University of Zurich, has compiled worldwide data on glacier changes for more than 120 years. Together...

Im Focus: Quantum Matter Stuck in Unrest

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Success 4.0 – Is Your Company Fit for the Future? New Series of Events for Executives

04.08.2015 | Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

 
Latest News

Small tilt in magnets makes them viable memory chips

04.08.2015 | Information Technology

New Design Brings World’s First Solar Battery to Performance Milestone

04.08.2015 | Power and Electrical Engineering

Magnetism at Nanoscale

04.08.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>