Polyelectrolyte-Enhanced Localized Surface Plasmon Resonance Optical Fiber Sensors: Properties Interrogation and Bioapplication

Abstract

Localized surface plasmon resonance (LSPR) and lossy mode resonance (LMR) are excited simultaneously by the gold nanoparticle (AuNP) arrays and the top-coated polyelectrolyte layer on optical fibers. The well-dispersed and dense AuNP arrays ordered by the diblock copolymer-template have LSPR sensing characteristics, whereas the layer-by-layer coated polyelectrolyte film carries LMR-based sensitivity enhancement. Both the experimental and simulation results illustrated that the thickness of the polyelectrolyte layer is the key factor affecting the optical properties of the proposed polyelectrolyte-enhanced LSPR sensor, and the sensor with a thicker polyelectrolyte layer presents a higher refractive index (RI) sensitivity because the lossy mode of the polyelectrolyte layer enhances the plasmonic resonance of AuNP arrays. The optimal sensor, which self-assembles with 50 nm AuNPs and 20 PAH/PSS bilayers, shows higher sensitivity and stability, with an RI sensitivity of 1312 nm/RIU and a detection limit for human IgG of 32.1 μg/mL. In addition, we observed an abnormally enhanced peak with an invariable wavelength, which has great potential to eliminate interference as a self-reference signal.

Multimodal Biomedical Implant with Plasmonic and Simulated Body Temperature Responses

“…It can combine minimally invasive detection, [15] by using cutting edge developed flexible Raman fiber detectors, with perfectly compatible imaging techniques. [15][16][17] Since the discovery of surface enhanced Raman scattering (SERS) effect in 1974 by Fleischmann et al [18,19] and the rise of employment of Au NPs in biomedicine (for drug delivery, [20,21] cancer therapy, [22][23][24] bacterial inhibition, [25][26][27][28] or bioimaging [16,29] ), diagnostic therapy with such spectroscopy technique represents a promising alternative to photothermal therapy (PTT), which employ near infrared light (NIR) sources with high intensity. [30,31] Contrarily to NIR light-responsive NPsbased PTT, which exhibits both constraints of light penetration and local problems of cell damage can appear due to the source heating itself, SERS probes are not restricted to superficially accessible organs and there is no local heating if appropriated sources are used.…”

“…It can combine minimally invasive detection, [ 15 ] by using cutting edge developed flexible Raman fiber detectors, with perfectly compatible imaging techniques. [ 15–17 ]…”

Research Progress of Resonance Optical Fiber Sensors Modified by Low‐Dimensional Materials

“…In the field of the sensing region, the coupling effect between the LSPR characteristic of noble metal nanoparticles and the plasma wave on the surface of SPR sensor, the tips of these special structures can have the effect of local strong binding enhancing the field strength, which is attributed to the LSPR effect, which is one of the reasons for the sensitization effect of nanoparticles. [164][165][166][167] In addition, the adsorption of nanoparticles on the fiber surface increases the roughness of the sensing surface, and increases the surface area of the sensing region, thus improving the sensitivity of the sensor. [141] In addition to its own sensitization effect, porous nanoparticles can also fill their holes with sensitive materials, and the porous structure is conducive to the entry of the object to be measured into the particle and the full interaction with sensitive materials, thus facilitating the improvement of sensitivity.…”

Enhanced Fiber Long‐Range Surface Plasmon Sensing Enabled by Resonance Coupling to Surface Plasmon Polaritons

“…[4] Compared with the chipbased sensors, fiber optic (FO) sensing probe has the advantages of miniaturized, real-time monitoring, and portability. [8,9] So far, a variety of side-coated FO probes have been designed, and the introduction of some functional materials including gold nanoparticles, [10] nanorod monolayer, [11,12] nanodonuts, [13] graphene, [14,15] polyelectrolyte, [16] Teflon, [17] and metal oxides [18][19][20] not only improve the sensitivity of the SPR sensors but also broaden their functional detection applications such as protein-specific binding and DNA detection. Modified D-shaped and U-bent FO sensors also achieve protein-specific binding and other biosensing detection with excellent detection limits.…”