Environmental Factor, September 2011, National Institute of Environmental Health Sciences
UC grantees' lab-on-a-chip detects toxic heavy metals in humans
The new sensor efficiently strips highly electronegative heavy metals out of blood to measure their concentration. In a clinical setting, it can give feedback to researchers and families in only a few minutes. (Photo courtesy of Dottie Stover at UC)
Papautsky, above, and his collaborators have developed a new tool that is not only child friendly, requiring only a few drops of blood for testing, but also environmentally friendly. Instead of mercury, the critical electrodes are made from bismuth, a less toxic compound. (Photo courtesy of Dottie Stover at UC)
An ongoing NIEHS-funded(http://tools.niehs.nih.gov/portfolio/index.cfm?action=portfolio.grantdetail&grant_number=R21ES019255) study at the University of Cincinnati (UC) examining the health effects of manganese on children will soon have a new tool at its disposal - an inexpensive, highly accurate, lab-on-a-chip sensor. This new technology can quickly measure not only manganese, but also other metals such as lead and cadmium, from just a few drops of blood.
That the UC study(http://www.ncbi.nlm.nih.gov/pubmed/21479538) is first to benefit from this innovation is no coincidence. The chip was engineered at UC and its development was also supported by NIEHS.
Portable, inexpensive, and minimally invasive
The sensor, dubbed the multi-metal chip, puts a new spin on traditional whole blood analysis, which is the most common method for determining metal exposure for the assessment of health outcomes. But while conventional methods of sample collection can be traumatic for children and relatively slow to produce results, the UC solution will be capable of rapid analysis, 10-15 minutes, of a blood sample of just two drops from a single lancet puncture.
“The conventional methods for measuring manganese levels in blood currently requires about five milliliters of whole blood sent to a lab, with results back in 48 hours,” said Ian Papautsky, Ph.D. (http://www.biomicro.uc.edu/members.html) , lead researcher and associate professor of electrical and computer engineering at UC. “For a clinician monitoring health effects by measuring these levels in a patient's blood, you want an answer much more quickly about exposure levels, especially in a rural, high-risk area where access to a certified metals lab is limited.”
This low-cost and disposable solution will be portable and usable anywhere, continued Papautsky.
In fact, the concept for a diabetes-like sensor for metals was the brainchild of Papautsky and Erin Haynes, Ph.D., an environmental health researcher with UC, who is studying the exposure and possible effects of manganese on neurological and cognitive development in children. The sensor was initially conceived as a way to easily evaluate the bioaccumulation of manganese in children residing near the Marietta, Ohio area, a rural Appalachian community that is home to a ferromanganese refinery.
Manganese is an essential element in human bodies, but dangerous in excess. Infants and children may be at greater risk for manganese neurotoxicity than adults, and some studies have linked high levels of exposure to movement disorders.
The chip is scheduled for initial field testing in Marietta in 2012 - first on adults, then on children, once the technology has proven safe and effective. Should the practical test be successful, the multi-metals chip will have demonstrated its potential in large-scale settings. Future applications include point-of-care devices where practitioners need immediate feedback on heavy-metal levels such as in clinical, occupational, and research settings.
Public health and research applications
David Balshaw, Ph.D., is the NIEHS program administrator for the grants. “Having a tool like this, that is both cost effective and child friendly, can potentially transform how information is collected in the field,” he said. “Any parent will recognize the benefit of a small pin prick that draws 50 times less blood than typical methods.”
Balshaw added, “Being able to measure a host of metals and possibly other environmental factors down the road really opens the door to endless public health and research applications.”
The concept of the device and its development are profiled in the August issue of the journal Biomedical Microdevices.
Citation: Jothimuthu P, Wilson RA, Herren J, Haynes EN, Heineman WR, Papautsky I(http://www.ncbi.nlm.nih.gov/pubmed/21479538) . 2011. Lab-on-a-chip sensor for detection of highly electronegative heavy metals by anodic stripping voltammetry. Biomed Microdevices 13(4):695-703.
(Ed Kang is a public affairs specialist in the Office of Communications and Public Liaison and a regular contributor to the Environmental Factor.)