Nano-p–n junction heterostructures enhanced TiO2 nanobelts biosensing electrode

6-Phosphate aminopurine (PA), a purine analog, is usually used in clinical anticancer treatment and biochemical research. Up to now, to the best of our knowledge, no literature about the electrochemical behaviors of PA has been reported. In this study, nano-p–n junction heterostructures based on TiO2 nanobelts were produced by the assembly of p-type semiconducting NiO nanoparticles onto the n-type surface-coarsened TiO2 nanobelts. The electrochemical behaviors of PA were investigated by different voltammetric techniques in a phosphate buffer solution of pH 7.4 using the heterostructures as the sensing electrode. Compared with single-phase TiO2 nanobelt electrodes, the resulting chemically modified electrodes exhibited higher surface accumulation ability and enhanced electrocatalytic activities in the oxidation for PA, with an irreversible oxidation peak at +0.91 V. It is proposed that the nano-p–n junction heterostructures played an important role in the enhancement of charge transport in the sensing electrodes. The results suggest that the nanoengineered TiO2 nanobelts might be a promising candidate for biosensing applications of nucleic acid drugs that will be of significance to diagnostic medicine and molecular biology research.