BOSTON Scientists at Pacific Northwest National Laboratory have discovered a way to increase the sensitivity of test strips that will enable creation of a portable biosensor that can address a major concern associated with incidents involving chemical or nerve agents the need to quickly distinguish between individuals who have been exposed and the worried well.
The sensor components resemble a pregnancy test strip and a small glucose testing meter. Its development will be discussed by principal investigator Yuehe Lin at the national meeting of the American Chemical Society.
Every disease has biomarkers, a change in the proteins that announces something is wrong. Lin and his team are creating a nanoparticle label that can increase the ability of a sensor to detect and interpret the message of biomarkers.
Current test strip based-immunoassay technology has very good selectivity, but it can only give a positive or negative response, Lin said.
The researchers are working with an electrochemical immunoassay approach. This involves using the antibody of a specific disease a protein produced in response to an invading bacterium or other foreign substance to attract the biomarker. Lin found that labeling a second antibody with a nanoparticle amplifies the biomarkers signal. Greater amplification means more precise readings.
Researchers at PNNL are developing a portable biomonitor to rapidly evaluate tiny samples of blood or saliva for exposure to nerve agents.
Lin achieves this by removing the iron from a nanoparticle-sized ball of the protein ferrin, creating an empty cage called apoferritin, which he then loads with another metal, such as cadmium. The cadmium-fi lled cage is attached to one end of the reporting antibody, and the immuno-reaction product becomes electroactive.
The electrochemical signal is amplified several hundreds to thousand times because of the metal ions, Lin said. This
|Contact: Geoff Harvey|
DOE/Pacific Northwest National Laboratory