Surface Plasmon resonance (SPR) provides an efficacious and label-free detection method for optical fiber bio-sensing. MoSe2 is one of the transition metal dichalcogenides (TMDCs) which has broad applications in detecting specific reactions. Cysteamine hydrochloride with enriched groups can generate self-assemble films for tight attachment. In this study we aimed to combine the rapid response of optical fiber SPR sensors with the enhanced sensitivity of MoSe2 nano-films. An optical fiber SPR biosensor with MoSe2-Au nanostructure was proposed and implemented, and a sensitivity of 2821.81 nm/RIU was achieved, which was approximately 98.7% higher than that of conventional SPR sensor without using MoSe2 nanostructure. Furthermore, Bovine Serum Albumin (BSA) was utilized as the target molecule to test the bioaffinity of the biosensor with MoSe2 deposition cycles from 0 to 8. Weighing the sensitivity and the figure of merit (FOM), the best deposition cycle of MoSe2 was 4 with the sensitivity of 2793.36 nm/RIU and FOM of 37.24 RIU-1. At last, immunization experiments were carried out using Goatanti-Rabbit IgG and a detection limit of 0.33 µg/mL was achieved. The rapid response and the high bioaffinity showed a strong applicability of the proposed MoSe2-Au SPR immune-sensor in specific interactions and immunization therapy.

A polypeptide nanofibers (PNs) modified optical fiber surface plasmon resonance (SPR) biosensor for specific detecting of rabbit IgG were proposed in this paper. Based on the optical properties, biochemical properties, and programmable characteristics of PNs, the proposed SPR biosensor has the advantages of ease preparation, low toxicity, a large surface area, and high bio-sensitivity. In this study, the SPR biosensor was specifically developed to detect rabbit IgG. The bio-sensitivity of 1.36 nm/(μg/mL) and limit of detection (LOD) 0.015 μg/mL are achieved experimentally. Compared with other single nanomaterial modified SPR biosensors, the developed biosensor has the higher bio-sensitivity and lower LOD. These findings indicate a significant improvement in the performance of PNs modified biosensors. Furthermore, based on the programmable characteristics, the proposed sensor can be applied in various biosensing environments (such as nucleic acid, biological small molecules, glucose, etc), providing customized solutions for diverse sensing needs. This significantly expands the potential applications of PNs modified optical fiber SPR biosensors.

In this paper, we proposed an all-fiber waveguide coupled surface Plasmon resonance (SPR) sensor which was designed and fabricated with Au-ZnO-Au sandwich multi-layer structure. Based on the transfer matrix method (TMM), the theoretical modeling of the proposed sensor structure was investigated. The influence of the layer thickness on the transmission spectrum of the sensor was studied numerically, in order to optimize each layer thickness, leading to sensitivity enhancement in the infrared spectral range. Meanwhile, an experimental testbed for the refractive index measurement was implemented based on the proposed all-fiber waveguide coupled SPR sensor. Using this waveguide coupled SPR sensor, the refractive index sensing was realized with a sensitivity enhancement of 7%—131% compared with conventional SPR sensors.

An optical fiber biosensor based on tapered noncore fiber (NCF) and coupling effect between surface plasmon resonance (SPR) and localized surface plasmon resonance is proposed in this paper. The sensor consists of two multimode fibers and a tapered NCF spliced in the middle. The tapered fiber with a waist diameter of 40 μm is fabricated by flame-heated drawing technology, and then a layer of Au film of 50 nm thickness is deposited on the surface of the taper waist. Au nanoparticles (AuNPs) are immobilized on the surface of the Au film by using the rich functional groups of polydopamine (PDA). The sensitivity is improved by reducing the diameter of the NCF and the electric field coupling between the Au film and AuNPs. The refractive index sensitivity of the sensor is increased to 3558 nm/RIU in the detection range of 1.335–1.365, which is about 1.8 times higher than that of Au-NCF sensor without tapering and AuNPs. Goat anti-rabbit IgG was fixed on the sensor surface through the adhesion effect of PDA and used for the specificity detection of rabbit IgG. The sensitivity and limit of detection (LOD) of the proposed biosensor are 1.16 nm/(μg/ml) and 0.017 μg/ml, respectively. The proposed biosensor has low manufacturing cost and high biological sensitivity, which has potential applications in low concentration biomolecular detection and human health monitoring.