Bio-inspired nanozymes with smartphone-assisted sensor platform for colorimetric detection of ascorbic acid in fruits and supplements

Nanozymes have become one of the key applications in the analysis and sensing of food. However, nanozymes presented have shortcomings that limit their further application, such as complex raw material sources, and high condition requirements for synthesis. Cu-GSSG nanozymes under green preparation conditions were synthesized inspired by the detoxification process of glutathione in living organisms. Cu-GSSG nanozymes were further loaded onto filter paper to construct a smartphone-assisted colorimetric sensor test strip for ascorbic acid (AA) detection. As the excellent peroxidase-like enzymes, Cu-GSSG nanozymes showed low AA detection limit of 2.9 μM with a wide linear range of 10–300 μM. Cu-GSSG nanozymes exhibited excellent anti-interference, accuracy, and biocompatibility performances for reliable detection AA in prickly pear juice and 10 supplements. The intelligent colorimetric sensor platform based on the bio-inspired Cu-GSSG nanozymes showed the great potential in rapid detection and large-scale screening of AA in fruits and supplements.