Time-resolved fluorescence immunoassay for C-reactive protein using colloidal semiconducting nanoparticles

: Härmä H, Toivonen J, Soini J, Hänninen P, Parak W

: 2011

: Sensors

: 12

: 11

: 12

: 11335

: 11342

: 8

: 1424-8220

DOI: https://doi.org/10.3390/s111211335

: http://api.elsevier.com/content/abstract/scopus_id:84255191213

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. © 2011 by the authors; licensee MDPI, Basel, Switzerland.