WaveFlex Biosensor-Using Novel Tri-Tapered-in-Tapered Four-Core Fiber With Multimode Fiber Coupling for Detection of Aflatoxin B1

Aflatoxins are a kind of fungal toxin that causes great damage to humans and animals due to its wide distribution, secretive nature, and high toxicity. For the purpose of achieving qualitative and quantitative detection of aflatoxin B1 (AFB1), a novel tri-taper-in-taper fiber-optic structure based on core mismatch of four-core fiber with a multimode fiber-based WaveFlex biosensor is developed and tested. The sensor probe's surface is coated with gold nanoparticles (AuNPs). Multi-walled carbon nanotubes and zinc oxide nanoparticles are sequentially immobilized on the sensing probe surface to enhance the sensor's sensing capabilities. Then, the AFB1 antibody is utilized to functionalize the sensor to possess specific selectivity. After the modification of nanomaterials and the corresponding bioreceptors, the final sensor structure is formed. By stimulating the localized surface plasmon resonance phenomenon of AuNPs, different concentrations of AFB1 can be detected. The sensor demonstrates high sensitivity (38.29 nm/μM) as well as low LOD (7.12 nM) within the range of 0–100 nM for detection. The sensor is also found to be stable and reproducible in repeated measurements, indicating its potential for practical application. Additionally, it exhibits satisfactory specific recognition of AFB1. These results show that AFB1 can be detected in food and agricultural products using LSPR-based optical fiber sensors, which could have significant ramifications for public health and food safety.