Longitudinal surface plasmon resonance assay enhanced by magnetosomes for simultaneous detection of Pefloxacin and Microcystin-LR in seafoods

• A simple UV assay for the simultaneous detection of Pefloxacin and Microcystin-LR was developed.
• Modified gold nanorods exhibiting two different peaks were applied to simultaneous UV detection.
• Artificial antigen (antigen-OVA) modified biological magnetosome as signal amplification probes.

A simple longitudinal surface plasmon resonance (LSPR) assay for the simultaneous detection of Pefloxacin and Microcystin-LR in seafoods has been developed for the first time using antibody-functionalized gold nanorods as signal probes and antigen-ovalbumin modified biological magnetosomes as signal amplification probes. The gold nanorods exhibit two different LSPR peaks, at around 695 nm and 863 nm, the positions of which were sensitive to changes in the local environment but can be subjected to simultaneous UV–vis detection. The biological magnetosomes produced by the magnetotactic bacteria not only act as a substrate for the immobilization of artificial antigen, but also enable signal enhancement and rapid separation, because of good dispersivity, biocompatibility and superparamagnetic properties. Under optimal conditions, magnetosome-enhanced LSPR assays showed a good linear response over the range 1–20 ng mL−1 (R2=0.9978 and R2=0.9992) with little adsorption to Enrofloxacin, Sarafloxacin, Ciprofloxacin, Norfloxacin, Microcystin-RR, Microcystin-LW, and Microcystin-LF, and compared with magnetosome-free LSPR assays, the response signal was amplified 2.5–5.0 fold. Furthermore, LSPR assays were successful in the analysis of Pefloxacin and Microcystin-LR in naturally contaminated seafood samples and high recoveries were achieved. Indications are that this LSPR assay promises reliable simultaneous detection of Pefloxacin and Microcystin-LR in seafoods, and holds the potential of novel applications in exploiting this multiple simultaneous UV–vis detection.