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Technology addresses global health challenge

June 04, 2007

An ASU research team's work is highlighted on the cover of the May issue of the Analyst, an international journal that reports on new analytical and bioanalytical techniques.

Joseph WangThe edition's featured article, written by the group led by Ira A. Fulton School of Engineering faculty members Antonio Garcia and Joseph Wang, details progress toward solving a bioanalytical problem identified by the American Association for the Advancement of Science as one of the “Grand Challenges in Global Health.”

The challenge is to develop technologies to assess multiple aspects of a patient's health using diagnostic tests that can be conducted quickly, and without requiring the facilities of a clinic or hospital.

Antonio GarciaThe ASU researchers' solution is described in the article (“Discrete microfluidics with electrochemical detection”) as a new strategy for rapid detection of biochemicals and proteins that are indicators of a patient's health, and which can be performed with portable testing devices that require less infrastructure to operate, says Garcia, a professor in the Harrington Department of Bioengineering.

The article gives examples of chemicals that mimic biological fluids that can each be processed, separated and directed to electrodes that provide a precise determination of amounts of a patient's “clinically relevant biomolecules,” such as glucose and dopamine.

The electrodes are the critical element in the detection system. Chemical reactions that occur on the surfaces of the electrodes generate electrical signals. The signal strength indicates the concentrations of biochemicals in fluid samples, Garcia says, adding that the new technology overcomes a barrier that has prevented droplet microfluidics systems from using electrochemistry for analysis.

Use of electrochemistry is now possible because the team's method eliminates the need to cover biological and aqueous drops with oil and instead relies on an “open-drop” format known as digital magnetofluidics, says Wang, a professor in the Department of Chemical Engineering. He also is director of the Center for Bioelectronics and Biosensors in ASU's Biodesign Institute.

Garcia and Wang explain that when an electrode is placed in oil, the oil molecules coat the surface. To provide measurements, the biological fluid drop must come into contact with the electrode. But the electrode cannot make a proper reading because the oil molecules stay on the surface and prevent the reactions that generate the electrical signal to occur properly on the electrode surface. The digital magnetofluidic method solves the problem.

The research team is working on expanding the capabilities of the technology to do such things as separate proteins and add immunoassays to the analysis system, which includes the microfluidic component.

Such an advance would open the way to the development of analytical tools that provide speedier and more flexible medical analyses while keeping devices inexpensive, since such tools won't rely on more expensive and slower conventional spectoscopic and chromatographic methods.

Other co-authors of the article are Solitaire Lindsay, who was a visiting scientist in the engineering school's Harrington Department of Bioengineering and worked at ASU as a postdoctoral fellow through INEST, the Interdisciplinary Network for Emerging Science and Technology; Terannie Vazquez, a graduate student in the Department of Chemistry and Biochemistry in the College of Liberal Arts and Sciences; Ana Egatz-Gomez, a doctoral candidate in the bioengineering department; and Suchera Loypraset, a visiting graduate researcher working in the Center for Bioelectronics and Biosensors.