University of Washington bioengineering researchers are using the latest microfabrication techniques to develop and test miniature devices that may revolutionize the way blood is analyzed in critical care situations.
These microdevices -- modules, filters and optical detectors -- bypass current steps in blood analysis such as centrifugation, a process that requires blood samples to be sent to labs where the lighter and heavier molecules are separated with centrifugal force.
The module researchers are testing is constructed of Pyrex, a heat-resistant glass, and silicon wafers. Molecules in blood flowing into the module are separated as they pass through an H-filter, so-called because it consist of miniature channels etched into one of the silicon wafers in the shape of the letter H. As the molecules separate, they are read by optical detectors attached to one side of the module.
"You cannot shrink a device and expect it to work the same way it did at full size. But at small sizes, new types of devices can be made that don't function at the large scale," said lead investigator Dr. Paul Yager, a UW professor in the Center for Bioengineering.
Researchers are converting these microdevices into larger instruments about the size of laptop computers that will be able to analyze blood in situations that call for immediate diagnoses.
Yager first began designing the technology with support from Senmed Medical Ventures, a Cincinnati, Ohio, medical technology company, and Defense Advanced Research Projects Agency (DARPA), the Department of Defense1s central research and development organization.
The project has another grant pending with DARPA that would allow researchers to specifically look at how the devices identify chemical and biological warfare agents.
Steve Gailar, director of venture projects for Senmed, said he and his colleagues see a number of commercial applications for the technology. Indeed, on the basis of Yager1s research, they have started a new company, Micronics, through which they will continue to support the project.
"We feel the Yager work will have a significant impact on bringing these diagnostics to the patient level," Gailar said.
Micronics expects to grow eventually into a full operating company, including manufacturing and research and development facilities, in the Seattle area.
The microdevices produce less waste and are less costly than their centrifuge counterparts in labs; they require only very small blood samples and less use of costly reagents, substances used to produce chemical reactions in blood in order to detect other substances. They are being equipped to transmit information electronically to remote clinicians and databases.
In ambulances, helicopters, hospitals and elsewhere, these microdevices would constitute portable stat labs that could aid physicians in making immediate determinations, said Yager. They could be used to identify antigens in blood that result from tumors and infections.
At the heart of the project are miniaturization techniques called microfabrication being used in the Microfabrication Lab at the Washington Technology Center, a state facility established on the UW campus in 1983 to foster and commercialize university research of benefit to Washington companies.
Special equipment in the Microfabrication Lab is allowing scientists to etch miniature channels of different depths into silicon wafers and bond Pyrex to silicon wafers in order to form hermetically sealed channels.
The team working on the project has grown to include researchers from the UW Center for Bioengineering, the departments of Electrical Engineering and Mechanical Engineering in the College of Engineering, and the Department of Laboratory Medicine in the School of Medicine.