Highly selective non-enzymatic electrochemical sensor based on a titanium dioxide nanowire–poly(3-aminophenyl boronic acid)–gold nanoparticle ternary nanocomposite

Abstract

A novel three component (titanium dioxide nanowire (TiO₂ NW), poly(3-aminophenyl boronic acid) (PAPBA) and gold nanoparticles (Au NPs)) based ternary nanocomposite (TNC) (designated as TiO₂ NW/PAPBA–Au TNC) was prepared by a simple two-stage synthetic approach and utilized for the fabrication of a non-enzymatic (enzyme-free) glucose (NEG) sensor. In stage 2, the PAPBA–Au NC was formed by oxidative polymerization of 3-APBA using HAuCl₄ as oxidant on the surface of pre-synthesized TiO₂ NW via electrospinning (stage 1). The formation of PAPBA–Au NC as the shell on the surface of the TiO₂ NW (core) was confirmed by field emission scanning electron microscopy (FE-SEM). Notably, we obtained a good peak to peak separation, and a high peak current for the redox Fe(CN)₆^3−/4− process indicating excellent electron transfer capability at the glassy carbon electrode (GCE)/TiO₂ NW/PAPBA–Au TNC interface. Also, the fabricated TiO₂ NW/PAPBA–Au TNC provides excellent electrocatalytic activity towards glucose detection in neutral (pH = 7.0) phosphate buffer solution. The detection of glucose was monitored using differential pulse voltammetry. The obtained sensitivity and detection limits are superior to many of the TiO₂ based enzymatic and non-enzymatic glucose sensors reported in the literature. Furthermore, the TiO₂ NW/PAPBA–Au TNC sensor is preferred because of its high selectivity to glucose in the presence of co-existing interfering substances and practical application for monitoring glucose in human blood serum samples.