Microfluidics-Based Environmental Testing Equipment for Monitoring Air Quality

Microfluidics is an exciting new field of science and engineering that enables very small-scale fluid control and analysis, allowing instrument manufacturers to develop smaller, more cost-effective and more powerful systems. With this lab-on-a-chip technology, entire complex chemical management and analysis systems can be created in a microfluidic chip and interfaced with, for example, electronics and optical detection systems.

Headed by Professor Alastair Lewis, the team from the National Centre for Atmospheric Science is undertaking initial studies to evaluate the feasibility of developing a portable microfluidics-based environmental testing module. Today’s air monitoring procedure usually requires the collection of air samples at remote locations, which then have to be returned to a laboratory for analysis using large and expensive gas chromatography instruments. The procedure is slow and costly. Professor Lewis’s research is aimed at developing a small-scale portable analysis system that will enable air quality to be analyzed and recorded in-situ. Such a system would have a dramatic effect on the speed of response to adverse changes in air quality.

"This is a great application of our technology," said Gillian Davis Regional Manager at Dolomite. "This is what microfluidics does best. It enables smaller, yet more powerful systems to be developed. Systems that may have been laboratory-based, can become more portable or even hand held, and at the same time can have increased accuracy and repeatability."

For this project Dolomite had to create a microfluidic device with an amazing 7.5m of micro-channel running through a 10cm square piece of glass. This is one of the largest devices and longest channels so far developed by Dolomite (this technology tends to be based in a smaller format). The fabrication processes used to create such a microfluidic device have some similarity to those used in the electronics industry. The channels through which the fluids flow and interact are etched into materials such as glass or polymers using similar photolithography processes, for example. The patterned layers are then very accurately aligned and fused together and drilled to provide microscopic ports through which the chemicals or gases can enter and leave the device.

"The real challenge with this project was the fusing of such large etched glass plates," said Gillian Davis. "Aligning the plates to ensure the etched microchannels were perfectly matched took a great deal of experience and put our capabilities to quite a test."

Dolomite is now considered to be a worldwide leader in Microfluidics. So much so, that in 2005 they won funding from the UK Department of Trade and Industry's Micro and Nano Technology (MNT) Manufacturing Initiative. This £2m funding, allowed Dolomite to establish excellent microfabrication facilities, with cleanrooms, precision glass processing facilities and applications laboratories.

"We are very pleased with both the progress of our development and the excellent support we have received from Dolomite," said Professor Alastair Lewis. "Dolomite has been very responsive to our demanding requests and has helped us make significant progress in recent months. It's clear from our research that microfluidics is very much an enabling technology for the next generation of environmental testing equipment. It offers us an exciting step forward in providing in-situ environmental monitoring capabilities with the possibility of more rapid response to adverse changes in air quality."

Posted August 22nd, 2008