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8 December 2004 Maximizing dye fluorescence via incorporation of metallic nanoparticles in solution
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Proceedings Volume 5591, Lab-on-a-Chip: Platforms, Devices, and Applications; (2004)
Event: Optics East, 2004, Philadelphia, Pennsylvania, United States
Gram-negative bacteria initiate a stress response in which the cells efflux potassium when electrophilic toxins are introduced into their environment. Hence, measurement of K+ concentration in the surrounding water using a fluorescence-based potassium-selective optode has been proposed for environmental and homeland security applications. Unfortunately, the fluorophore commonly used in such an optode is inefficient. Surface enhanced fluorescence (SEF) can be used to increase its fluorescence efficiency, which will improve the sensor's performance. To understand this phenomenon before applying it to the optode system, Rose Bengal (RB), an inexpensive and well characterized dye, in solution with gold and silver nanoparticles was studied. As expected, fluorescence from RB-gold solutions was low since alignment of gold's surface plasmon resonance (SPR) peak and absorption and fluorescence energies in RB favored energy transfer from RB to the gold nanoparticles. The alignment of the silver's SPR peak and the RB transitions favored transfer from silver to RB. SEF was observed in solutions with large dye-to-silver separation. However, little fluorescence was observed when the solution was pumped at the silver's SPR peak. Fluorescence from the dye decreased as dye-to-silver separation decreased. An explanation for these observations is presented; additional research is needed to develop a complete understanding.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yang Xu, Guangyin Lei, Annette C. Booker, Katherine A. Linares, Dara L. Fleming, Kathleen Meehan, Guo-Quan Lu, Nancy G. Love, and Brian J. Love "Maximizing dye fluorescence via incorporation of metallic nanoparticles in solution", Proc. SPIE 5591, Lab-on-a-Chip: Platforms, Devices, and Applications, (8 December 2004);

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