Saliva Monitor Offers Quick and Painless Exposure Results

Every day, people are exposed to a variety of chemical contaminants in food, air, and even the materials in homes and the workplace. Researchers at the Pacific Northwest National Laboratory (PNNL) are developing and applying new monitoring technologies to determine within minutes whether children or adults have been exposed to harmful chemicals. With simplicity of use in mind, the non-invasive technique is structured around the collection and analysis of saliva samples.

Typically, chemical exposures are nominal, producing no recognizable health impact. But some exposures such as high-lead concentrations in aging homes are a critical health concern, especially when children are exposed. The most effective method for assessing chemical exposure is biomonitoring, or the analysis of biological fluids like blood, urine or breath. This method generally requires an invasive technique such as taking a blood specimen, which must be sent to a laboratory for analysis with the results not available for days or weeks.

PNNL’s non-invasive saliva monitoring approach, currently undergoing bench-scale laboratory testing, offers several promising benefits. The technology is designed to be portable, highly reliable, quick in providing results, and cost-effective for on-site monitoring of trace metals and organics. Initial efforts are focused on lead monitoring. The monitor is developed based on the integration of microfluidics with an electrochemical sensor that measures lead in biological specimens. The use of saliva is particularly beneficial, as samples are readily attainable and can be used to quickly screen more children than conventional approaches allow.

Saliva lead concentrations have been shown to correlate with blood lead levels based upon analysis of a “spot” saliva specimen. The microfluidic/electrochemical detection device for lead analysis has excellent sensitivity (low parts per billion range) and reproducibility, and the response is comparable to currently accepted analytical approaches.

To adequately interpret results, PNNL scientists have developed and applied mathematical models for estimating how much lead is in the body based upon a single saliva analysis. The use of saliva for biomonitoring, coupled with real-time measurements of lead and modeling, represents a novel approach with broad application for evaluating both occupational and environmental lead exposures.

Saliva has been proposed as a biological matrix for monitoring a broad range of drugs and environmental contaminants. PNNL scientists are extending the approach to evaluate occupational and environmental exposure to complex mixtures of toxic metals and chlorinated organic compounds. The eventual goal is to develop a suite of integrated, sensitive and portable micro-analytical systems that can be used to monitor a broad range of chemical exposures in workers and high-risk populations.

For more information contact Dr. Charles Timchalk at (509) 376-0434, charles.timchalk@pnl.gov.