An Ultrasensitive Fluorescent Platform for Detection of Metal- Nanoparticles, Proteins and Nucleic Acids

ÁLVAREZ CERIMEDO, M. SOLEDAD; ZABALEGUI, NICOLÁS; CADRANEL, ALEJANDRO; HODAK, JOSÉ H.

Córdoba

Congreso; 16th International Congress on Photobiology; 2014

International Union of Photobiology

The detection of specific sequences of DNA, proteins of interest or metal nanoparticles is key to developing novel bioanalytical methods for diagnosing diseases and for early detection of allergenic agents and toxins. Detection of very low concentrations of bioanalytes is a challenge. Thus, it is of great importance to engineer strategies to improve the quantification limits, ultimately reaching the detection of individual molecules. In this direction, gold nanoparticles are an interesting option as they can be functionalized with several types of biomolecules, such as DNA strains, antigens or proteins [1,2], allowing for the amplification of a fluorescent signal through a catalytic reaction. In this work, we developed a single molecule optical detection scheme (Figure 1), capable of detecting single fluorescent molecules with diffraction limited resolution. Fluorescent correlation measurements as well as submicron resolved images have been carried out in order to accurately know the point spread function and sensitivity of the optical system. Based on this strategy, we have been able to detect individual gold nanoparticles, immobilized on a glass substrate (Figure 2).