Constructing the Au nanoparticle multimer on optical fiber end face to enhance the signal of localized surface plasmon resonance biosensors: A case study for deoxynivalenol detection

Localized surface plasmon resonance (LSPR) based optical fiber end-face biosensors have the advantages of convenience, fast, accuracy, and high sensitivity. Because the sensor area (optical fiber end face)) is small, how to improve its signal strength is a challenge faced by researchers. In this study, an Au nanoparticle (AuNP) multimer structure was designed to enhance the LSPR signal by the hot spots effect produced by the AuNP multimers. The fiber end face was coupled with the first batch of AuNPs, on which the second batch of AuNPs was coupled using 3-aminopropyl triethoxysilane as a spacer, then deoxynivalenol (DON) aptamer was coupled on to complete the biosensor. Also, the preparation parameters were optimized. The results showed that this biosensor with the AuNP multimers had a higher signal strength, its LSPR absorbance was 2.1 fold of that of the biosensor with AuNPs. It had a high performance for DON detection, furthermore, the LSPR peak shift value and LOD of this developed biosensor was 3.4 fold and 1/8 of that of LSPR the biosensor with AuNPs. Therefore, it is a good strategy to enhance the signal of the optical fiber LSPR biosensors by constructing the AuNP multimers on the fiber end face.