Demand for rapid, highly sensitive diagnostic tests in medicine and clinical chemistry has inspired the development of novel photoluminescent labels like fluorescent nanoparticles and quantum dots. Persistent luminescence materials are a class of inorganic phosphors that exhibit intense light emission for minutes to hours after excitation, and are found in numerous applications including electroluminescent displays and luminescent paint, but are not widely used for in vitro diagnostics. Inorganic phosphors offer several advantages over conventional photoluminescent reporters including the potential for increased analytical sensitivity when used in time-resolved luminescence assays due to reduced background autofluorescence, facile surface modification and bioconjugation schemes, and exceptional resistance to photobleaching. Strontium aluminate doped with europium and dysprosium is an inorganic phosphor with a luminescence intensity ten times greater and an emission lifetime ten times longer than the more common zinc sulfide based phosphors, making it one of the brightest known persistent luminescence materials. We obtained luminescent strontium aluminate powder from commercial suppliers and isolated nanoparticles by wet milling and differential sedimentation. Silica encapsulation by a modified St�ber process made the particles water stable, and surface modification with trialkoxysilanes allowed bioconjugation of antibodies and other molecular recognition elements to the particles. We have demonstrated that the particles can be effectively incorporated as highly sensitive labels in lateral flow assays and other formats using various model analyte systems. Future experimentation with persistent luminescence materials could open new opportunities for clinical and point-of-care diagnostics.

Persistent luminescence strontium aluminate nanoparticles as reporters in diagnostics

247th National Meeting (2014)

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