Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Purdue engineers develop quick, inexpensive method to prototype microchips


Purdue University researchers have developed a new method to quickly and inexpensively create microfluidic chips, analytic devices with potential applications in food safety, biosecurity, clinical diagnostics, pharmaceuticals and other industries.

Purdue University graduate student Tom Huang assembles a new microfluidic chip by placing a thin layer of a flexible polymer on a glass microscope slide. The new method of producing these chips saves time and money and uses materials easily acquired by any research laboratory. (Purdue Agricultural Communications photo/Tom Campbell)

"This development democratizes the preparation of microfluidic biochips," said Michael Ladisch, Distinguished Professor of Agricultural and Biological Engineering and Biomedical Engineering. "This brings the design and manufacture of these devices within reach of scientists in many laboratories who can now easily test their ideas and conduct research within a typical laboratory setting."

Microfluidics is a branch of nanotechnology that involves manipulating minute quantities of liquids, typically in a chip device approximately the size of a postage stamp. The initial design and manufacture of these chips often requires weeks of work, but the new approach developed by Ladisch and Tom Huang, a graduate student in chemical engineering, cuts that time to hours.

Microchips have traditionally been made through a lengthy and expensive process called photolithography, which uses X-rays or ultraviolet light to form a pattern on a glass or silicon wafer that is then etched by washing the wafer with a variety of solvents. The key to controlling the shape and size of the patterns on the wafer is the production of a template, which can take weeks to develop.

Ladisch and his team have developed an alternative method that uses materials easily acquired by any research laboratory, including glass microscope slides, tweezers, thin glass fibers such as those found in glass wall insulation, and a flexible polymer called PDMS that is available from most scientific supply companies.

"What we’ve done is really thinking outside of the box," said Nate Mosier, an assistant professor of agricultural and biological engineering who also contributed to this project. "This is a radical departure from using photolithography to make these devices."

The speed and simplicity of Ladisch’s method gives researchers the flexibility to experiment with the conception and construction of microchips that can test any number of ideas.

"This whole device can be developed and in operation in less than two hours," Ladisch said. "Tools like this that take a lot less time to make and that can be manufactured in any lab are going to speed up the rate of research."

Mosier said, "The capability for rapid prototyping and working out design considerations before the manufacturing step is important to any development, from the micro-scale on up.

"It’s always very difficult to the make the first of anything -- the second through the millionth are much easier."

The new chip assembly method involves placing a fine fiber - approximately one-tenth the width of a human hair - on a glass slide and covering it with a small square of the polymer PDMS. The polymer flexes slightly over the fiber, creating a small channel on either side of the fiber, much the same way that a sheet of plastic wrap placed on top of a pencil would bend, making two channels running the pencil’s length.

A small amount of pressure applied with a finger is enough to cause the PDMS to stick to the glass slide, Mosier said.

"The chemical properties of the PDMS allow it to stick to the glass slide with enough strength to form a tight seal, which permits us to pump liquids through the channel," Ladisch said.

In addition, he said, the small size of the channel - not quite the width of a strand of hair - allows researchers to minimize their use of experimental liquids, which may be costly or difficult to obtain.

In their proof-of-concept paper, published in the November issue of the American Institute of Chemical Engineers Journal, the team showed that coating the fibers with materials that attract different types of molecules allowed them to separate specific proteins from a mixed solution.

By manipulating the fiber’s properties, scientists can identify or separate various types of molecules, such as proteins or antibodies, from solutions pumped through the chip.

Depending on the properties of the fiber, liquids placed at one end of the channel move through the device by "wicking" along the fiber, or by being pulled through by with a weak vacuum at the opposite end of the channel.

"We can control the chemistry inside the channel to determine what flows through, what sticks, and in that way we can separate things out," Huang said.

This ability translates into numerous potential applications, such as the ability to diagnose diseases or detect foodborne pathogens and biological agents.

"These kinds of chips are essential from a security perspective," said Bob Armstrong, senior research fellow at the National Defense University, one of the organizations that funded this research.

"Microfluidic chips are becoming part of a sensor system to detect, for example, biological or chemical agents, or pathogens in the food supply. What is it you want to detect? Your imagination is the only limit on how to use these devices."

Also collaborating on this research were Woo-Jin Chang, research associate in electrical and computer engineering; Demir Akin, senior research scientist in electrical and computer engineering; Rafel Gomez, former graduate student in electrical and chemical engineering; and Rashid Bashir, associate professor of electrical and computer engineering and biomedical engineering.

The research is part of an ongoing project sponsored through the Purdue Center for Food Safety Engineering and the Purdue Laboratory of Renewable Resources Engineering. Funding was provided by the Agricultural Research Service of the U.S. Department of Agriculture, and the Center for Technology and National Security Policy at the National Defense University in Washington, D.C., is contributing to the further development of this concept.

Writer: Jennifer Cutraro, (765)496-2050
Sources: Mike Ladisch, (765)494-702 ,
Nate Mosier, (765)494-6695,
Tom Huang, (765)494-0326,
Bob Armstrong, (202) 685-2532,
Ag Communications: (765) 494-2722; Beth Forbes,
Agriculture News Page

Jennifer Cutraro | Purdue News
Further information:

More articles from Process Engineering:

nachricht No compromises: Combining the benefits of 3D printing and casting
23.03.2018 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA

nachricht Intelligent wheelchairs, predictive prostheses
20.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>