Nanowire-based Surface Plasmon Resonance Research Articles

Direct detection of dopamine using zinc oxide nanowire-based surface plasmon resonance sensor

This study uses an angle interrogation approach to propose an SF11 Prism- Ag– ZnO nanowires-CeO2-Sensing layer-based surface plasmon resonance sensor. The proposed multilayer structure has been used for the concentration measurement of dopamine in human blood. The thicknesses of the ZnO nanowire (ZnO-NW) and cerium oxide (CeO2) layer have been taken as 50 nm and 0.5 nm, respectively, and the thickness of the metal layer is 50 nm considered. The characteristics and parameters are also measured for the proposed sensor. The sensitivity, full width at half maximum (FWHM), detection accuracy (DA), and quality factor (QF) are obtained as 95 deg/RIU, 14.34 deg, 0.06578 deg−1, and 6.24 RIU−1, respectively. Numerous neurological illnesses are brought on by abnormalities of dopamine (D. A.), a crucial neurotransmitter in the brain's neural circuits. Quick and sensitive sensors for D. A. detection are needed to diagnose these illnesses early. The significance of this sensor in the biomedical field.

Experimental study of sensitivity enhancement in surface plasmon resonance biosensors by use of periodic metallic nanowires

We have experimentally confirmed sensitivity enhancement of a nanowire-based surface plasmon resonance (SPR) sensor structure. Gold nanowires with periods of 200 and 500 nm were fabricated, respectively, by electron-beam and interference lithography on a gold/SF10 substrate. Sensitivity enhancement was measured to be 44% compared with a conventional thin-film-based SPR structure for nanowires of 200 nm period and 31% for 500 nm when evaluated using ethanol at a varied concentration. This result is consistent with numerical data. Surface roughness is responsible for sensitivity reduction by more than 10%. More significant sensitivity improvement can be achieved by inducing strong localized plasmon coupling with finer nanowires.

Sensitivity analysis of a nanowire-based surface plasmon resonance biosensor in the presence of surface roughness

We have investigated the effect of surface roughness on the sensitivity of conventional and nanowire-based surface plasmon resonance (SPR) biosensors. The theoretical research was conducted using rigorous coupled-wave analysis with Gaussian surface profiles of gold films determined by atomic force microscopy. The results suggest that, when surface roughness ranges near 1 nm, the sensitivity of a conventional SPR system is not significantly affected regardless of the correlation length. For a nanowire-based SPR biosensor, however, we have found that the sensitivity degrades substantially with decreasing correlation length. In particular, at a correlation length smaller than 100 nm, a random rough surface may induce destructive coupling between excited localized surface plasmons, which can lead to prominent reduction of sensitivity enhancement.

Effect of resonant localized plasmon coupling on the sensitivity enhancement of nanowire-based surface plasmon resonance biosensors

A nanowire-based surface plasmon resonance (SPR) is investigated as a structure that offers improved sensor performance. The results calculated by rigorous coupled-wave analysis on a model using a hexanedithiol self-assembled monolayer (SAM) indicate that the resonant coupling between localized surface plasmons (LSPs) of nanowires affects the sensitivity enhancement substantially, while the LSP resonance in a single nanowire also contributes. SPR characteristics change significantly by applying a SAM, which can give rise to zero sensitivity for a given SAM. The results suggest that a properly designed nanowire-based SPR biosensor can enhance sensitivity by an order of magnitude with reasonable detection properties.

Design study of highly sensitive nanowire-enhanced surface plasmon resonance biosensors using rigorous coupled wave analysis

In this study, we investigated the sensitivity enhancement in nanowire-based surface plasmon resonance (SPR) biosensors using rigorous coupled wave analysis (RCWA). The enhancement, enabled by the excitation of localized surface plasmons in gold nanowires, offers improved performance in sensitivity as well as in reproducibility and customizability. Calculation results found that a T-profile provides higher sensitivity than an inverse T-profile in general and also determined optimum design parameters. Our study on a nanowire-enhanced SPR biosensor demonstrates the potential for significant improvement in the sensitivity through the nanowire-mediated localized SPR.