Optimization and Application of Reflective LSPR Optical Fiber Biosensors Based on Silver Nanoparticles

Abstract

In this study, we developed a reflective localized surface plasmon resonance (LSPR) optical fiber sensor, based on silver nanoparticles (Ag NPs). To enhance the sensitivity of the LSPR optical sensor, two key parameters were optimized, the length of the sensing area and the coating time of the Ag NPs. A sensing length of 1.5 cm and a 1-h coating time proved to be suitable conditions to produce highly sensitive sensors for biosensing. The optimized sensor has a high refractive index sensitivity of 387 nm/RIU, which is much higher than that of other reported individual silver nanoparticles in solutions. Moreover, the sensor was further modified with antigen to act as a biosensor. Distinctive wavelength shifts were found after each surface modification step. In addition, the reflective LSPR optical fiber sensor has high reproducibility and stability.

Ag fractals formed on top of a porous TiO2 thin film

“…However, the reflectance is far below the unit for both as‐deposited and annealed samples, which might result from two main reasons: (i) non‐specular scattering and (ii) discontinuity of the metallic structure, i.e., its fractal geometry. Well defined shapes of Ag clusters would manifest themselves by their characteristic spectral features, for instance, spherical NPs (not too small) would show LSPR close to 400 nm , which would be split into two distinct resonances in nanorods. Fractal aggregates incorporate a plenitude of shapes and spatial scales and therefore their spectral response is very broad and almost featureless, as predicted theoretically and shown experimentally for specially prepared agglomerates of Ag NPs .…”

Polydopamine-Assisted Fabrication of Stable Silver Nanoparticles on Optical Fiber for Enhanced Plasmonic Sensing

“…In the RI range of 1.328-1.401, the sensor shows brilliant optical performance with the enhanced sensitivity of 961 nm/RIU. As shown in Table 1, the Ag NPs prepared by photodeposition, physical lithography, and electrostatic self-assembly show lower sensitivity than two constructed sensors in this work [26][27][28][29]. Moreover, the sandwich-structured PDA/Ag/PDAbased sensor presents higher sensitivity compared with the PDA/Ag-based sensor.…”

“…2(d), the sensor shows a sensitivity up to 555 nm/RIU. This sensitivity was higher than that of the Ag NPs prepared by photodeposition, physical lithography, and electrostatic self-assembly [26][27][28][29], as shown in Table 1.…”

Near-IR Plasmons in Micro and Nanoparticles with a Semiconductor Core

“…The wavelength of the LSPR depends on the material, size, shape of nanoparticles and its surroundings. The LSPR properties of silver nanoparticles are exploited in applications such as surface-enhanced Raman scattering [2], optical fiber biosensors [3], and sensing platforms [4]. Yet, metals suffer losses in the visible and near-IR regimes [5].…”