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

Abstract

The integration of surface plasmon resonance and fluorescence yields a multiaspect improvement in surface fluorescence sensing and imaging, leading to a paradigm shift of surface plasmonassisted fluorescence techniques, for example, surface plasmon enhanced field fluorescence spectroscopy, surface plasmon coupled emission (SPCE), and SPCE imaging. This Review aims to characterize the unique optical property with a common physical interpretation and diverse surface architecture-based measurements. The fundamental electromagnetic theory is employed to comprehensively unveil the fluorophore−surface plasmon interaction, and the associated surfacemodification design is liberally highlighted to balance the surface plasmon-induced fluorescence-enhancement efforts and the surface plasmon-caused fluorescence-quenching effects. In particular, all types of surface structures, for example, silicon, carbon, protein, DNA, polymer, and multilayer, are systematically interrogated in terms of component, thickness, stiffness, and functionality. As a highly interdisciplinary and expanding field in physics, optics, chemistry, and surface chemistry, this Review could be of great interest to a broad readership, in particular, among physical chemists, analytical chemists, and in surface-based sensing and imaging studies.

Dynamic Cryptography through Plasmon‐Enhanced Fluorescence Blinking

“…[ 7b ] Plasmonic nanostructures have emerged as promising functional materials in fundamental and technologically relevant studies of optical, electronic, and optoelectronic devices, whose unique properties are enabled by localized surface plasmons. [ 5l,8 ] Early experiments have shown that plasmonic nanoantennas are able to promote both absorption and emission of single molecules under high‐power light excitation (such as 2.4 kW cm −2 ) through producing highly localized electromagnetic near‐field enhancement and the Purcell effect, leading to high‐brightness fluorophore blinking. [ 9 ] However, it has remained challenging to realize fluorophore blinking through low‐power light excitation, for instance, by a mercury lamp, simply because its excitation power density (typically on the order of 1 W cm −2 ) is too low to achieve sufficient photon emissions from single molecules.…”

Multiplexed Profiling of Extracellular Vesicles for Biomarker Development

“…In another recent study, Min et al explored long-range (> 100 nm) SPR-enhanced fluorescence on a periodic array instead of the localized "hotspot" surfaces (< 20 nm). This approach is more suitable for measurements with intact EVs given their dimension (30-1000 nm) [118,119]. Four fluorescent dyes (AF488, Cy3, Cy5, and Cy5.5) were conjugated with streptavidin separately in order to code biotinylated EV membrane proteins (CD9, CD63, CD81, GAPDH, EGFR, EGFRvIII) after their capture on neutravidin-PEG layers (Fig.…”

Titanium nitride as an alternative and reusable plasmonic substrate for fluorescence coupling

“…Plasmonic and photonic substrates are being increasingly employed to improve fluorescence properties in multiple ways. 1–7 Useful control over fluorescence emission has been accomplished by integrating fluorophores with thin metal films of silver or gold that support surface plasmon oscillations, and hybrid metal–dielectric configurations that support both plasmonic and optical waveguide modes. 8–12 In these structures, fluorophores placed within near-field distances of the metal surface can create and couple with surface plasmons (and/or waveguide modes), and subsequently radiate through the substrate with narrow angular distribution.…”

“…17–22 To improve the scope of SPCE and benefit from the surface plasmon field enhancement, a number of studies are being carried out to engineer the spacer layer between the metal and the fluorophore with the help of different materials like polymers, silicon, protein/DNA, carbon nanotubes and graphene. 1,22–24 However, the expansion of SPCE for practical applications is still hindered by the metallic component, which is typically limited to the conventional plasmonic materials, silver and gold.…”