A new fullerene-C<inf>60</inf> – Nanogold composite for non-enzymatic glucose sensing

A new functionalized fullerene C60 – thiol capped gold nanoparticle based nanocomposite using 3-amino-5-mercapto-1,2,4-triazole as the ligand was designed and synthesized following electronic structure calculation via DFT formalism. The electrostatic potential map from the DFT optimized geometry implied C60 core of the composite to remain electron deficient, and a much reduced HOMO-LUMO energy gap for the composite towards enhanced electron-transport ability was noted. Experimentally, first, fullerene-C60 was functionalized with the multipolar group containing ligand 3-amino-5-mercapto-1,2,4-triazole, making it hydrophilic and its aqueous dispersion was subsequently used to make a composite with in-situ prepared aqueous phase gold nanoparticles. The composite modified glassy carbon electrode showed electrocatalytic behaviour towards sensing of glucose, studied via cyclic voltammetry and electrochemical impedance spectroscopy. Thus, the highly stable and low onset potential non-enzymatic sensor exhibited high electro-catalytic activity and effective electron transfer from the electro-catalyst to the substrate electrode in a linear concentration range spanning over 0.025–0.8 mM and a higher sensitivity response of 1.2 μA mM−1 cm−2 with good reproducibility, long term stability, anti-interference ability and chloride poisoning resistance.