A disposable aptasensing device for label-free detection of fumonisin B1 by integrating PDMS film-based micro-cell and screen-printed carbon electrode

Abstract A disposable aptasensing device for specific detection of fumonisin B1 (FB1), the most toxic of fumonisin B-series, has been fabricated. In this design, the pretreated screen-printed carbon electrode (SPCE) has been firstly covered by a polydimethylsiloxane (PDMS) film with a hole to construct a micro-cell with the conventional three electrodes at the bottom. Subsequently, well-dispersed gold nanoparticles (AuNPs) have been electrodeposited on the working electrodes to serve as excellent matrices for thiolated aptamer immobilization. Since a single nanoparticle could be conjugated with a large number of aptamer probe, the dense decoration of AuNPs on SPCE provided abundant binding sites for aptamer anchoring, finally enhancing the impedance signal effectively. A high affinity between FB1 and its aptamer has been demonstrated by a small association constant ( K a ) of 1.19 × 10 9  M −1 calculated by Langmuir adsorption isotherm. The developed aptasensor showed a good linearity in the range from 10 pg mL −1 to 50 ng mL −1 with a low detection limit of 3.4 pg mL −1 (S/N = 3). The developed aptasensing device is cost-effective, simple in operation, high-sensitive, less reagent consumption, and can be easily expand to other mycotoxins if the specific aptamer is available.