Fiber optic sensor based on ZnO nanowires decorated by Au nanoparticles for improved plasmonic biosensor

Abstract

Fiber-optic-based localized surface plasmon resonance (FO-LSPR) sensors with three-dimensional (3D) nanostructures have been developed. These sensors were fabricated using zinc oxide (ZnO) nanowires and gold nanoparticles (AuNPs) for highly sensitive plasmonic biosensing. The main achievements in the development of the biosensors include: (1) an extended sensing area, (2) light trapping effect by nanowires, and (3) a simple optical system based on an optical fiber. The 3D nanostructure was fabricated by growing the ZnO nanowires on the cross-section of optical fibers using hydrothermal synthesis and via immobilization of AuNPs on the nanowires. The proposed sensor outputted a linear response according to refractive index changes. The 3D FO-LSPR sensor exhibited an enhanced localized surface plasmon resonance response of 171% for bulk refractive index changes when compared to the two-dimensional (2D) FO-LSPR sensors where the AuNPs are fixed on optical fiber as a monolayer. In addition, the prostate-specific antigen known as a useful biomarker to diagnose prostate cancer was measured with various concentrations in 2D and 3D FO-LSPR sensors, and the limits of detection (LODs) were 2.06 and 0.51 pg/ml, respectively. When compared to the 2D nanostructure, the LOD of the sensor with 3D nanostructure was increased by 404%.

Overview of Recent Advances in the Design of Plasmonic Fiber-Optic Biosensors

“…However, Au and Ag nanomaterials suffer from high production costs and low melting points, which can significantly limit the large-scale application of these plasmonic materials in commercial fiber-optic sensors [ 21 , 22 ]. A few of the reported designs already utilized alternative plasmonic materials such as graphene [ 23 ], graphene oxide [ 51 ], titanium nitride [ 21 ], titanium oxide [ 24 ], Molybdenum trioxides [ 52 , 53 ], zinc oxide [ 54 ], platinum based nanocomposites [ 55 ], bi layers of indium tin oxide and platinum [ 56 ], and tungsten oxide [ 57 ] as either the coating materials or the main plasmonic layer. However, further investigations on the performance of these fiber-optic biosensors and comparison between alternative plasmonic materials and Au/Ag nanofilms/NPs are necessary.…”

One-Dimensional Plasmonic Sensors

“…The hybrid NWs with a wrinkled γ-Fe 2 O 3 outer shell and embedded Au NPs [56] exhibit excellent performance in ethanol sensing with high sensitivity and selectivity. Another NPs-decorated MOSs-based sensor [25] is presented for bio-sensing by Kim et al from Dankook University. The sensor is fabricated by growing the ZnO NWs using hydrothermal synthesis and via the immobilization of Au NPs on the NWs.…”

“…In recent years, boosted by the dramatic progress made in micro-and nano-fabrication technology [12][13][14] these years, plasmonic sensors have demonstrated their advantages in various areas, such as chemical sensing [15][16][17], biological species [18,19], environmental monitoring [20,21], food safety [22][23][24], and medical diagnosis [8,[25][26][27]. Notably, these sensors offer distinguishing characteristics in biochemical analyses [28,29].…”

Multi-band MIM refractive index biosensor based on Ag-air grating with equivalent circuit and T-matrix methods in near-infrared region

“…Widespread applications such as food quality control, health, diseases diagnosis, and environmental and molecular monitoring make the biosensors a hot topic for researchers in these years [25][26][27] . The label-based and label-free sensors are two main types of biosensors.…”