Fabrication of oxidase-like polyaniline-MnO2 hybrid nanowires and their sensitive colorimetric detection of sulfite and ascorbic acid.

Recently, nanomaterials-based oxidase-like artificial enzymes have attracted much attention due to their unique catalytic efficiency, high environmental stability and low-cost. In this study, we for the first time show the application of polyaniline (PANi)-MnO2 hybrid nanowires for oxidase mimicking. The PANi-MnO2 hybrid nanowires are prepared via a redox reaction between PANi nanowires and KMnO4. The as-prepared PANi-MnO2 hybrid nanowires exhibit an enhanced oxidase-like catalytic activity compared with individual PANi nanowires and MnO2 alone due to the synergistic catalytic effect between the two components. Based on the above findings, we construct PANi-MnO2 hybrid nanowires-based colorimetric assay for sensitive and selective detection of sulfite and ascorbic acid (AA). The detection limits of sulfite and AA are as low as 79 and 26 nM, respectively, which is much lower than many previous reported enzyme mimics-based colorimetric sensors. This work demonstrates a broad potential prospect of PANi-MnO2 hybrid nanowires in biotechnology, environmental science and food safety.