Sensors 2011, 11(12), 11335-11342; doi:10.3390/s111211335
Article

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

Harri Härmä 1,* email, Juha Toivonen 1,2 email, Juhani T. Soini 1,3 email, Pekka Hänninen 1 email and Wolfgang J. Parak 4 email
1 Laboratory of Biophysics, University of Turku, 20520 Turku, Finland 2 Department of Physics, Tampere University of Technology, 33101 Tampere, Finland 3 Turku University of Applied Sciences, 20520 Turku, Finland 4 Fachbereich Physik and Wissenschaftliches Zentrum für Materialwissenschaften, Philipps Universität Marburg., 35037 Marburg, Germany
* Author to whom correspondence should be addressed.
Received: 24 August 2011; in revised form: 18 October 2011 / Accepted: 14 November 2011 / Published: 28 November 2011
(This article belongs to the Special Issue Sensing with Quantum Dots)
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Abstract: 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: colloidal nanoparticles; quantum dots; time-gated fluorescence; sensing; bioaffinity assays

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MDPI and ACS Style

Härmä, H.; Toivonen, J.; Soini, J.T.; Hänninen, P.; Parak, W.J. Time-Resolved Fluorescence Immunoassay for C-Reactive Protein Using Colloidal Semiconducting Nanoparticles. Sensors 2011, 11, 11335-11342.

AMA Style

Härmä H, Toivonen J, Soini JT, Hänninen P, Parak WJ. Time-Resolved Fluorescence Immunoassay for C-Reactive Protein Using Colloidal Semiconducting Nanoparticles. Sensors. 2011; 11(12):11335-11342.

Chicago/Turabian Style

Härmä, Harri; Toivonen, Juha; Soini, Juhani T.; Hänninen, Pekka; Parak, Wolfgang J. 2011. "Time-Resolved Fluorescence Immunoassay for C-Reactive Protein Using Colloidal Semiconducting Nanoparticles." Sensors 11, no. 12: 11335-11342.

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