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 Quick, Precise, but not Cold
17.05.2017 | Fraunhofer-Institut für Lasertechnik ILT

nachricht A laser for divers
03.05.2017 | Laser Zentrum Hannover e.V.

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>