Fluorescence Enhancement Using Bimetal Surface Plasmon-Coupled Emission from 5-Carboxyfluorescein (FAM)

Abstract

We demonstrate the enhancement of fluorescence emission from a dye, 5-carboxyfluorescein (FAM), which couples with surface plasmons at the spectral channels of excitation and emission. Experiments and calculations revealed that bimetallic (gold-silver) plasmon, as compared to the monometallic ones, allowed such coupling to be enhanced, at both the spectral channels. We achieved the maximum fluorescence enhancement level of 46.5-fold, with markedly high reproducibility (coefficient of variation ~ 0.5%) at a FAM concentration of 10 nM. We also found that higher fluorescence enhancement was more likely to be reproducible. This encourages the use of this technology for practical applications in fluorescence-based biochemical assays. Moreover, we investigated a FAM concentration-dependent enhancement of fluorescence. It was found that fluorescence enhancement decreased and saturated at above 10 nM concentration possibly due to partial photo-bleaching of FAM molecules.

Ultrasensitive biosensors based on waveguide-coupled long-range surface plasmon resonance (WC-LRSPR) for enhanced fluorescence spectroscopy

“…In estimating the optical power of pure fluorescence, which must be used for fluorescence enhancement analysis, dark noise power included in the detected fluorescence power needs to be subtracted. 60,61 Fig. 8 shows the fluorescence optical power measured via the optical systems described in Fig.…”

Label-free localized surface plasmon resonance biosensor composed of multi-functional DNA 3 way junction on hollow Au spike-like nanoparticles (HAuSN) for avian influenza virus detection

“…However, in the case of FAM/SH-DNA 3 W J, a substantially increased LSPR band was observed compared to that with SH-DNA 3 W J. Presumably, the results showed that the fluorescent dye molecule in the DNA could couple with the surface plasmon that confers a high refractive index onto the DNA 3 W J-modified hAuSN substrate [21]. Based on the combined result, the prepared nanobio heterolayer can be used to effectively detect HA protein.…”

“…The electron oscillation originating from electromagnetic waves triggers a binding interaction event in the nanoparticle interface, thus providing high sensitivity [19]. Moreover, this plasmonic event can be tuned to excite the fluorescence dye-labeled bioprobe that exhibits ultra-sensitivity in order to detect the H5N1 virus [20,21]. Advanced bioprobes have been developed to detect H5N1 accurately with high sensitivity.…”

“…The 5′ end of DNA 3 W Jb was labeled with FAM dye (FAM/3 W Jb) for signal enhancement. It is reported that the fluorescence dye can be excited by a plasmonic field, which increases the detection sensitivity effectively [20,21]. To increase the LSPR enhancement effect, FAM dye was introduced.…”

Surface Plasmon-Assisted Fluorescence Enhancing and Quenching: From Theory to Application

“…150 It is the first reusable SPCE device for an ultrafast and sensitive DNA detection in whole blood. The great compatibility of the DNA component allows for a further extension of the DNA architecture with silver nanoparticles, 151 carbon dots, 152 or a bimetallic substrate 153,154 in SPCE measurements.…”