Organophosphonic acid and cerium functionalized antimonotungstate with electrochemical promise in biosensing bacterial dissimilatory sulfite reductase gene sequence

Abstract

The rational design and synthesis of organically functionalized cluster-based materials has always been a hot topic. Polyoxometalates (POMs) have become primary candidates for fabricating novel organic–inorganic hybrid cluster-based materials owing to their multiple coordination sites and modes, unique electronic configurations and variable constituents. Herein, an unprecedented organophosphonic acid and cerium functionalized antimonotungstate [H₂N(CH₃)₂]₉Na₁₂H₆{[Ce₃(H₂O)₂W₈(Hgps)₂O₂₀][B-α-SbW₉O₃₃]₄}·66H₂O (1, H₅gps = glyphosine) was synthesized in CH₃COOH–CH₃COONa buffer solution. Its tetrameric polyanion [Ce₃(H₂O)₂W₈(Hgps)₂O₂₀][SbW₉O₃₃]₄²⁷⁻ consists of four Keggin [B-α-SbW₉O₃₃]⁹⁻({SbW₉}) segments linked by a dumbbell-shaped [Ce₃(H₂O)₂W₈(Hgps)₂O₂₀]⁹⁺ core. Furthermore, we prepared a ternary composite material (denoted as Au-rGO-1) containing 1, reduced graphene oxide (rGO) and Au nanoparticles, which exhibits remarkable electrical conductivity and long-term stability. Subsequently, Au-rGO-1 was applied as an electrode modification material to construct an electrochemical DNA biosensor (EDB) for detecting the bacterial dissimilatory sulfite reductase (DSR) gene from sulfate-reducing bacteria, and the MB/dsDNA/Au-rGO-1/GCE EDB shows outstanding sensitivity, selectivity and anti-interference capability for detecting the DSR DNA sequence. This research provides an accessible strategy for synthesizing organophosphonic acid and lanthanide functionalized POMs and also demonstrates the great potential of POM-based materials in the application of detecting the DSR gene sequence.