DEVELOPING NANOPHOSPHORS FOR BIOLOGICAL ASSAYS

Persistent luminescence in inorganic phosphors is an optical phenomenon that provides a pathway for visible or infrared photon emission to occur for several seconds to hours after photoexcitation. The emission lifetimes of these compounds are orders of magnitude longer than the spin-forbidden transitions in phosphorescent or metal-chelate molecules. This makes them ideal for “glow-in-the-dark” applications like safety signs, emergency displays, luminescent paints, and, more recently, as optical reporters in biological applications. Unfortunately, only a few compounds like alkaline earth aluminates possess such long lifetimes, and most of these decompose in aqueous environments limiting biological application. The Brgoch group develops new, water-stable persistent luminescent phosphors by applying band-gap engineering to exploit the interaction between the luminescence centers and trap states for biological use.

The compounds prepared by students in the Brgoch group are used in collaboration with Richard Willson's group in Chemical Engineering in their invention of a phosphor-based immuno-chromatographic lateral flow assay (LFA) as a robust point-of-care diagnostic test. The use of phosphors effectively eliminates the need for expensive and cumbersome optical hardware that are typically required for a sensitive readout with conventional fluorescent molecules. The current research project focuses on developing persistent nanophosphors that emit at different wavelengths to allow the concurrent detection of multiple analytes, called multiplexing.