Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Purdue engineers develop quick, inexpensive method to prototype microchips

08.01.2004


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 , ladisch@purdue.edu
Nate Mosier, (765)494-6695, mosiern@purdue.edu
Tom Huang, (765)494-0326, huangt@purdue.edu
Bob Armstrong, (202) 685-2532, armstrongre@ndu.edu
Ag Communications: (765) 494-2722; Beth Forbes, bforbes@aes.purdue.edu
Agriculture News Page

Jennifer Cutraro | Purdue News
Further information:
http://news.uns.purdue.edu/html4ever/2004/040107.Ladisch.chip.html
http://engineering.purdue.edu/IIES/LORRE/

More articles from Process Engineering:

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

nachricht Jelly with memory – predicting the leveling of com-mercial paints
15.12.2017 | 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: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

Im Focus: Autonomous 3D scanner supports individual manufacturing processes

Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).

Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Fingerprints of quantum entanglement

16.02.2018 | Information Technology

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers

16.02.2018 | Health and Medicine

Hubble sees Neptune's mysterious shrinking storm

16.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>