Rapid electrodeposition of a gold–Prussian blue nanocomposite with ultrahigh electroactivity for dual-potential amperometric biosensing of uric acid

Abstract

We report a new and efficient protocol for rapid electrodeposition of a gold–Prussian blue ((Au–PB)_REd) nanocomposite with ultrahigh electroactivity on an Au electrode by cyclic voltammetry in 0.1 M aqueous K₂SO₄ containing 1 mM K₃Fe(CN)₆, 1 mM HAuCl₄, and 0.1 mM Fe₂(SO₄)₃, and an electrochemical quartz crystal microbalance and scanning electron microscopy were utilized to investigate the electrodeposition. The (Au–PB)_REd/Au electrode was then cast-coated with a urate oxidase (UOx)–poly(anilineboronic acid) (PABA)–Pt nanoparticle (PtNP) bionanocomposite and chitosan (CS) for high-performance amperometric biosensing of uric acid (UA) in the dual-potential mode. The UOx–PABA–PtNP bionanocomposite was prepared through chemical oxidation of anilineboronic acid (ABA) by sodium chloroplatinate in the presence of UOx. The thus-fabricated CS/UOx–PABA–PtNP/(Au–PB)_REd/Au enzyme electrode worked well under optimized conditions through both oxidation and reduction determination of enzyme-generated H₂O₂, which responded linearly to UA concentrations from 0.3 μM to 0.65 mM with a sensitivity of 223 μA mM⁻¹ cm⁻² and a limit of detection (LOD) of 0.2 μM (0.7 V vs. SCE), and from 0.2 μM to 0.25 mM with a sensitivity of 247 μA mM⁻¹ cm⁻² and a LOD of 0.1 μM (−0.05 V vs. SCE), being superior to most analogues hitherto reported for biosensing of UA.