Sensors (Nov 2011)

Time-Resolved Fluorescence Immunoassay for C-Reactive Protein Using Colloidal Semiconducting Nanoparticles

  • Pekka Hänninen,
  • Harri Härmä,
  • Juha Toivonen,
  • Juhani T. Soini,
  • Wolfgang J. Parak

DOI
https://doi.org/10.3390/s111211335
Journal volume & issue
Vol. 11, no. 12
pp. 11335 – 11342

Abstract

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Besides the typical short-lived fluorescence with decay times in the nanosecond range, colloidal II/VI semiconductor nanoparticles dispersed in buffer also possess a long-lived fluorescence component with decay times in the microsecond range. Here, the signal intensity of the long-lived luminescence at microsecond range is shown to increase 1,000-fold for CdTe nanoparticles in PBS buffer. This long-lived fluorescence can be conveniently employed for time-gated fluorescence detection, which allows for improved signal-to-noise ratio and thus the use of low concentrations of nanoparticles. The detection principle is demonstrated with a time-resolved fluorescence immunoassay for the detection of C-reactive protein (CRP) using CdSe-ZnS nanoparticles and green light excitation.

Keywords