Lab-on-chip tests DNA

A microfabricated sensor is poised to become the key component in portable DNA analysis. Researchers at the University of Michigan College of Engineering (Ann Arbor, MI) have developed a miniature “laboratory on a chip” that automatically analyzes DNA samples and reports the results electronically. The sensor is a glass-and-silicon chip that is far less expensive than conventional methods of analyzing DNA–which require specialized laboratories, equipment, and personnel–yet just as quick and sensitive.

This “laboratory on a chip” sensor automatically analyzes DNA samples
and reports the results electronically, replacing conventional methods
of analyzing DNA at a significantly lower cost.

All the steps for retrieving genetic information from a DNA sample occur within the self-contained device, which includes systems for metering, measuring, and mixing microscopic liquid samples of DNA with reagents. It moves the mixtures to an integrated, temperature-controlled reaction chamber, separates DNA molecules by size (through gel electrophoresis), and determines the results with an on-board fluorescence detector.

Fluidic components are linked using a surface-tension-gradient pumping mechanism in which discrete droplets are differentially heated and propelled through channels. Since all the components are made using conventional photolithographic techniques, they can be assembled into integrated systems.

Preliminary estimates suggest that the cost of producing the DNA-testing chip in research-sized quantities may be approximately $6 per sensor. For more information, call Professor Mark Burns, University of Michigan College of Engineering, at 734-764-4315, e-mail him at maburns@mich.edu.