Polyoxometalate nanostructured gold surfaces for sensitive biosensing of benzo[a]pyrene

We report the design of a polyoxometalate-nanostructured immunosensor for benzo[a]pyrene (B[a]P) detection. The organic–inorganic hybrid polyoxometalate (POM) (NBu4)3[PW11O39{(SiC6H4NH2)2O}] carrying two amine functions was covalently attached to a functionalized gold substrate to achieve a nanometric organization of amine groups at its surface. Pyrenebutyric acid (PBA) was subsequently grafted to amine groups to create the sensing layer. The detection of B[a]P in the indirect competitive format was carried out using a monoclonal anti-B[a]P antibody whose binding to the immunoprobe was monitored with a quartz crystal microbalance with dissipation measurement (QCM-D). The performances of the POM-nanostructured biosensor were compared to a reference sensor constructed from a cysteamine self-assembled monolayer. QCM-D measurements displayed significant input from POM-nanostructuration. Both the accessibility of the analogue on the surface and the analytical performances were enhanced showing a promising effect of this strategy of nanostructuration for the biosensing of small molecules.