Development of Localized Surface Plasmon Resonance-Based Optical Fiber Biosensor for Immunoassay Using Gold Nanoparticles and Graphene Oxide Nanocomposite Film

In this study, the development of a reflected-type localized surface plasmon resonance (LSPR) based optical fiber biosensor is presented. The gold nanoparticles (AuNPs) and graphene oxide (GO) are sequentially modified on the surface of fiber probes to form a nanocomposite film using self-assembly method. Compared with AuNPs fiber probe, the refractive index sensitivity (RIS) of GO/AuNPs fiber probe is improved from 29.6 nm/RIU to 79 nm/RIU in the refractive index range from 1.33 to 1.38. After that, the fiber probes are immobilized with anti-mouse IgG for the immunoassay, and the response time is 30 minutes. Due to the advantages of good biocompatibility as well as physical and optical properties of GO, the GO/AuNPs fiber probe shows a quicker reaction and larger resonant wavelength shift, which are compared with AuNPs fiber probe in measuring different concentrations of mouse IgG. In addition, the GO/AuNPs fiber probe exhibits a better sensitivity (150.4 nm/
$\mu \text{g}$
mL
⁻¹
), linearity (R
²
= 0.998) and a lower limit of detection (4.3 ng/mL) in a low concentration of mouse IgG detection, which suggests that GO has huge potentials of biosensing applications in the future.