Chitosan-coated iron(III) oxide nanoparticles and tungsten disulfide quantum dots-immobilized Fiber-based WaveFlex Biosensor for Staphylococcus Aureus bacterial detection in real food samples
Xianzheng Lang, Ragini Singh, Qinghua Zeng, Jun Li, Daniele Tosi, Jan Nedoma, Carlos Marques, Bingyuan Zhang, Santosh Kumar
Abstract
• Ultra-sensitive WaveFlex biosensor detects S. aureus in real food samples. • Novel SMF structure with AuNPs triggers LSPR for enhanced sensitivity. • Fe3O4–CS NPs and WS2-QDs further enhance biosensor sensitivity. • Antibody functionalization enables specific S. aureus detection. • Achieves maximum sensitivity of 2.74 nm/lg(CFU/mL) and LOD of 1.47 CFU/mL. The research proposes and investigates an extraordinarily sensitive, label-free WaveFlex biosensor utilizing optical fiber technology for the detection of Staphylococcus aureus ( S. aureus ), a common foodborne bacterium. The WaveFlex biosensor (plasmon Wave based Flexible optical fiber Biosensor) is based on a novel flexible tapered single-mode fiber structure, utilizing gold nanoparticles (AuNPs) to trigger the phenomenon of localized surface plasmon resonance (LSPR). Additionally, the sensitivity is further enhanced using chitosan-coated iron(III) oxide nanoparticles (Fe 3 O 4 –CS NPs) and tungsten disulfide quantum dots (WS 2 -QDs). The optical fiber surface is functionalized with antibodies to achieve specific detection of S. aureus . For S. aureus concentrations at 1 × 10 8 CFU/mL (colony-forming units per milliliter), the sensor's maximum sensitivity of 2.74 nm/lg (CFU/mL), and a detection limit (LOD) of 6.67 CFU/mL. This ultra-sensitive biosensor holds great potential for widespread applications in various fields, including disease detection, medical diagnostics, and food safety inspection.