Multiphoton up-converting phosphors for use in rapid immunoassays

There exists increasing demand for rapid in-vitro diagnostic tests capable of detecting pathogens, disease markers, and drugs. Many currently marketed technologies are limiting due to their analytical sensitivity or the number of analytes detected in a single assay. Presented is the use of up-converting phosphors as reporters in rapid point-of-care diagnostic assays using a lateral flow format in a nitrocellulose matrix. Up-converting Phosphor Technology (UPT) utilizes lanthanide-doped ceramic particles that possess anti-Stokes shift emission. These materials absorb multiple IR photons and emit dopant-dependent spectra in the visible range. Their signature spectra allow the development of sensitive, multi-analyte diagnostic tests. Because no biological matrix up-converts in the IR, the sensitivity of the assay is enhanced, being determined by the affinity of the biological constituents (e.g. antigen-antibody interactions) and the level of non-specific binding of the particle reporter. Feasibility data presented below represent a wide range of molecular weight analytes, including drugs of abuse, proteins such as cardiac markers, and pathogenic microorganisms.