Point-of-care diagnostics have the potential to improve the quality of healthcare by providing simple, low-cost systems for the detection of infectious pathogens. Many diagnostic platforms use fluorescent labels which require expensive optical filters. Strontium aluminate doped with rare earth metals is an inorganic phosphorescent material with a high quantum efficiency and long luminescence lifetime, allowing for its use as an optical label in assays without fluorescence filters. We purchased luminescent strontium aluminate powder, reduced the mean particle size by wet-milling, and isolated small particles by settling. The phosphors were made water-stable by silica encapsulation via a modified St�ber process, and triethoxysilyl butyraldehyde and 3-aminopropyl triethoxysilane were used to functionalize the phosphors with reactive groups for covalent conjugation of antibodies. A microplate reader could detect ca. 1000 700-900 nm particles, and experimental results with various antibody-antigen model systems show that the phosphors are a promising new label for diagnostic immunoassays.

Rare-earth-doped strontium aluminate particles as reporters in point-of-care diagnostics

245th National Meeting (2013)

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