Researchers at Los Alamos National Laboratory (Los Alamos, NM) and the University of California (Los Angeles, CA) have developed a highly sensitive assay that could be used to detect a wide range of biological and non-biological compounds. The polymer, known as MPS-PPV, has been the focus of intense interest for its possible uses in light-emitting diodes and other electronic devices, but the new study (Proc. Natl. Acad. Sci. USA 96, 12287–12292, 1999) puts the compound's unusual fluorescence characteristics to a different use. The scientists found that certain small molecules could bind to the polymer backbone in an aqueous solution and efficiently quench the compound's fluorescence. The team then conjugated biotin to the small-molecule quencher and demonstrated that avidin binding to the biotin efficiently sequesters the quencher and allows the MPS-PPV to fluoresce. "The performance and sensitivity we...have achieved are comparable to several different assay techniques such as ELISA [and] PCR," explains David Whitten, a researcher at Los Alamos and senior author on the paper. Unlike ELISA and PCR, the new technique is rapid and requires minimal equipment, making it well-suited to detecting biological weapons, hazardous chemicals, or antibodies in field or clinical settings.