Sensor Promises Rapid Detection of Dangerous Heavy Metal Levels

UC researcher, Ian Papautsky, and doctoral student Xing Pei, displays how the lab-on-a-chip sensor works to provide fast feedback regarding levels of the heavy metal manganese in humans.University of Cincinnati (UC) researchers are developing the first lab-on-a-chip sensor to provide fast feedback regarding heavy metal exposure in humans. Reports of the development appeared in the August 2011 issue of the international journal, Biomedical Microdevices.

This low-cost, disposable lab-on-a-chip sensor detects highly electronegative heavy metals quicker than current technology generally available in healthcare settings. Researchers envision use of the new UC sensor technology in point-of-care devices to provide needed feedback on heavy-metal levels within about 10 minutes.

Ian Papautsky, UC associate professor of electrical and computer engineering, is co-author of the published research, "Lab-on-a-Chip Sensor for Detection of Highly Electronegative Heavy Metals by Anodic Stripping Voltammetry." Other co-authors are Erin Haynes, assistant professor of environmental health; William Heineman, distinguished research professor of chemistry; and just-graduated electrical and computer engineering doctoral student Preetha Jothimuthu, just-graduated chemistry doctoral student Robert Wilson, and biomedical engineering undergraduate research co-op student Josi Herren.

How the Sensor Works
The new UC sensor uses a technology called anodic stripping voltammetry that incorporates three electrodes: a working electrode, a reference electrode, and an auxiliary electrode.

A critical challenge for such sensors is the detection of electronegative metals like manganese. Detection is difficult because hydrolysis, the splitting of a water molecule, at the auxiliary electrode severely limits a sensor's ability to detect a strongly electro-negative metal.

To resolve this challenge, the UC team developed an environmentally friendly thin-film bismuth working electrode vs. the conventional mercury or carbon electrode. The favorable performance of the bismuth-working electrode combined with its environmentally friendly nature means the new sensor will be especially attractive in settings where a disposable lab-on-a-chip is wanted.

In addition, the UC team also optimized the sensor layout and working-electrode surface in order to reduce the effects of hydrolysis and to boost the reliability and sensitivity in detecting heavy metals. The new sensor layout better allowed for its functioning, which consists of the taking of a blood serum sample, stripping out the heavy metal, and then measuring that heavy metal.
 

Field Testing
One specific motivation for developing the sensor was an ongoing project by UC's Erin Haynes, who is studying the effect of air quality on children's health in Marietta, OH. Manganese and other metals are emitted in that area because it is home to a ferromanganese refinery.

Funding
The National Institute of Environmental Health Sciences, the National Institute of Occupational Safety and Health Pilot Research Project Training Program, and the University of Cincinnati have provided funding for this research.

University of Cincinnati http://www.uc.edu/news/ NR.aspx?id=13977v