An ultrasensitive immunosensor array for determination of staphylococcal enterotoxin B

Staphylococcal enterotoxin B (SEB) is a potent gastrointestinal toxin and is heat resistant. SEB is also a potential bioterrorism agent. The ability to measure accurately very low amounts of staphylococcal enterotoxin B in food and other samples is very important. A highly sensitive and stable sandwich fluorescence immunoassay based on a pair of monoclonal antibodies against SEB which were produced by us was developed. Classical sandwich immunoassay was adopted and the glass slides were used as the base of the immunologic reaction. The functionalized fluorescent core–shell silica nanoparticles were used as labels. The fluorescence issued from the labels was detected by a laser-induced fluorescence millimeter sensor array detection platform. The fluorescence intensity has a linear relationship with the amount of SEB in the range of 50 pg/mL–5 ng/mL, and the detection limit of SEB was 20 pg/mL (the absolute detection limit was 0.02 pg). The relative standard deviation (RSD) for 5 parallel measurements of SEB (1 ng/mL) was 9.2%.