The surface-confined assay format is one of the most convenient detection formats used in many immunoassays. Fluorescence emission from monolayers of dyes requires a strong excitation and good detection system. Such samples are susceptible to artifacts due to background fluorescence from substrates. We demonstrate that using silver nanostructures deposited on the slide substrate can significantly enhance measured fluorescence, reduce unwanted background and increase photostability of the used probes. Using thin layers of polymer doped with fluorescein, we tested two nanostructures—silver island films (SIFs) deposited on glass slides and self-assembled colloidal structures (SACS) deposited on thin silver film. The SACS surfaces show extraordinary fluorescence enhancements: over 100-folds in hot spots. We applied these surfaces for enhanced Alexa488 model immunoassay.
Key wordsFluorescence enhancement Alexa488 Silver nanoparticles Immunoassay Plasmonics
This work was supported by Texas Emerging Technologies Fund Grant, NIH HG 004364 and R01AR048622, NSF DBI-0649889, and ARPATP Project 000130-0042-2007. RL is the recipient of the Research Mobility program from the Polish Ministry of Science and Higher Education. TS was supported by Research Corporation for Science Advancement (CCSA 7748) and The Welch Foundation (BP-0037).
- 14.Geddes CD, Aslan K, Gryczynski I, Malicka J, Lakowicz JR (2004) Noble-metal surfaces for metal-enhanced fluorescence. In: Geddes CD, Lakowicz JR (eds) Reviews in fluorescence. Kluwer Academic/Plenum Publishers, New York, Boston, Dordrecht, London, MoscowGoogle Scholar
- 15.Lakowicz JR (2006) Principles of fluorescence spectroscopy, 3rd edn. Springer, New York, NY, ch 25, pp 841–859Google Scholar
- 16.Matveeva EG, Gryczynski I, Gryczynski Z, Goldys EM (2009) Immunochemical detection of analytes by using fluorescence. In: Goldys EM (ed) Fluorescence applications in biotechnology and life science. WileyGoogle Scholar
- 22.Sorensen TJ, Laursen BW, Luchowski R, Shtoyko T, Akopova I, Gryczynski Z, Gryczynski I (2009) Enhanced fluorescence emission of Me-ADOTA by self-assambled silver nanoparticles on a gold film. Chem Phys Lett (in press)Google Scholar