Surface Plasmon Resonance-Based Highly Sensitive Hollow-Core Fiber Dopamine Sensor Using Dual-Recognition Strategy

The dual recognition method has been applied extensively as an attractive strategy, which effectively improved the specificity of detection. Herein, a novel silver-coated hollow fiber (HF) surface plasmon resonance (SPR) sensor based on a dual-recognition strategy for high-sensitivity detection of dopamine (DA) was presented. The 4-mercaptophenylboronic acid (PMBA) monolayer was self-assembled on the silver film surface in the sensor as the recognition layer. Meanwhile, 4-mercaptobenzoic acid (4-MBA)-modified gold nanoparticles (AuNPs) were adopted as the signal amplification tag to enhance the wavelength shift of the SPR phenomenon excited by the light transmitted in the wall of the HF sensor. Experiments of detection for DA were taken in the concentration range of 0.1 nM– $10~\mu \text { M}$ to investigate the performance of the biosensor. The influences of concentrations of palladium chloride (PdCl2) in pretreatment and the AuNPs size were investigated to improve the performance of the HF SPR sensor. The experimental results showed that the limit of detection (LOD) for DA achieved as low as 0.1 nM. The presented HF SPR sensor with a dual-recognition structure based on self-assembled recognition monolayer and AuNPs shows a large potential for the detection of small biomolecules in biosensing.