Rapid and multiple detections of staphylococcal enterotoxins by two-dimensional molecularly imprinted film-coated QCM sensor

A quartz crystal microbalance with dissipation biosensor based on two-dimensional (2D) molecularly imprinted film-coated by organosilanes and the template protein staphylococcal enterotoxins (SEs) in situ synthesizing on the surface of the piezoelectric quartz crystal (PQC) as transducer was developed for the detection of SEs in real samples. By incorporated with the sensor, frequency shifts (Δfs) and dissipation shifts (ΔDs) were recorded and monitored in real time for the evaluation of the property of the sol-gel imprinted films for the detection of targets. Both of the working ranges for the detection of SEA and SEB were 0.1-1000 μg/mL with the lowest detection limits 7.97 and 2.25 ng/mL, respectively. Performances and surface structures of the fabricated 2D sol-gel films were also observed and confirmed by atomic force microscopy. Results demonstrated that the 2D molecularly imprinted film-coated QCM could give repeated usage and selective recognition to the template SEs. The intelligentized biosensor was employed to SEA and SEB detection in milk samples after pre-treatment. The recoveries ranged from 97.00% to 114.20% and it can be used for ten times indicating that the developed method was feasible and applicable in the detection of SEs.