Ag‐CNT Architectures for Attomolar Dopamine Detection and 100‐Fold Fluorescence Enhancements with Cellphone‐Based Surface Plasmon‐Coupled Emission Platform

Abstract

We report cellphone-based detection of dopamine with attomolar sensitivity in clinical samples with the use of a surface plasmon-coupled emission (SPCE) platform. To this end, silver-coated carbon nanotubes were used as spacer and cavity materials on SPCE substrates to obtain up to 100-fold fluorescence enhancements. The presence of silver on the carbon nanotubes helped to overcome fluorescence quenching arising due to π-π interactions between the carbon nanotube and rhodamine 6G. The competing adsorption of dopamine versus rhodamine 6G on graphene oxide was utilized to develop this sensing platform.

Femtomolar Detection of Spermidine Using Au Decorated SiO2 Nanohybrid on Plasmon-Coupled Extended Cavity Nanointerface: A Smartphone-Based Fluorescence Dequenching Approach

“…Unlike the cost intensive spectrophotometer detection platforms that are commonly used for this purpose, in this study we demonstrate a label-free smartphone-based SPCE detection technique that is portable and economically viable for resource-limited settings. SPCE has been used for studying spectral shifts in fluorescence emission patterns to gather noteworthy information such as DNA-hybridization, attomolar sensitivity and influence of Purcell factor on quantum confinement from nanointerfaces. − In this regard, we also present a consistent shift in molecular fluorescence from AuSil-spermidine ensemble in SPCE with increasing concentration of spermidine. This spectral red shift in fluorescence was found to be in excellent agreement with shift in the color observed in CIE chromaticity diagram obtained using smartphone-based detection technique.…”

“…After the first time utilization of silver nanoparticles (AgNPs) as spacer material by Lakowicz et al to realize 60-fold increase in SPCE, there has been extensive use of this plasmonic architecture in biochemical research for multifarious applications. − In this context, several templates such as DNA, proteins, intermetallics (like TiC, TiN, and TiCN), low dimensional carbon substrates and graphene (Dirac Fermions) decorated with AgNPs have been explored to comprehend the modulation in hot-spot intensities at the nanointerface due to interaction of these templates with AgNPs. − These investigations have provided novel insights into physicochemical aspects of plasmonic coupling at interfaces pertaining to Purcell effect, Casimir force, Fabry–Perot mode-coupling, quantum confinement, and Rabi splitting to name a few. − However, these assessments have been restricted to the use of AgNPs as the primary plasmonic material. Silver suffers from quick oxidation and parasitic material Ohmic losses due to coarseness of the surface.…”

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

“…In the context of polymer-based basic research, so many methods are developed for all kinds of analyte detection. A 1 fM limit of detection of mercury ions (Hg 2+ ) arrived relying on a Rh6G D-Hg 2+ complex-based 30 nm poly­(vinyl alcohol) (PVA) spacing layer, and attomolar dopamine detection is achieved upon PVA-supported silver–carbon nanotube architectures . And Liu et al also realize a highly sensitive Hg 2+ detection on an SPCE platform with a poly­(allylamine hydrochloride) (PAH) and poly­(4-sodium sulfonatestyrene) (PSS) assembly .…”

“…A 1 fM limit of detection of mercury ions (Hg 2+ ) arrived relying on a Rh6G D-Hg 2+ complex-based 30 nm poly(vinyl alcohol) (PVA) spacing layer, 115 and attomolar dopamine detection is achieved upon PVA-supported silver−carbon nanotube architectures. 116 And Liu et al also realize a highly sensitive Hg 2+ detection on an SPCE platform with a poly(allylamine hydrochloride) (PAH) and poly(4-sodium sulfonatestyrene) (PSS) assembly. 117 With this PAH−PSS matrix, an LOD of 34 pg mL −1 human IgG in unfractionated human serum is achieved.…”

Localized and Surface Plasmons Coupling for Ultrasensitive Dopamine Detection by means of SPR‐Based Perylene Bisimide/Au Nanostructures Thin Film

“…[18] Considering the low sensitivity typical of this kind of techniques, many efforts have been devoted to the implementation and the optimization of the active layer/ transducer for DA detection at least down to the physiological concentration. [19][20][21] With this aim, in this work, an SPR transducer has been ad hoc designed and developed in order to gain sub-nanomolar DA recognition even in complex matrix, as artificial CSF (aCSF). An amphiphilic perylene bisimide derivative bearing a positive charge (perylene bisimide, PBI, Figure 1) has been used for anchoring citrate-capped Au nanostructures, through the layer-by-layer (LbL) method, onto solid supports including SPR slides.…”