NiCo2S4 microflowers as peroxidase mimic: A multi-functional platform for colorimetric detection of glucose and evaluation of antioxidant behavior

The regular design of atomic composition of materials endows a diverse range of enzyme mimics types and increases a broader application prospect. In this study, we designed a nickel-cobalt mixed metal sulfide and demonstrated that the as-prepared NiCo2S4 microflowers possessed intrinsic peroxidase-like activity. Nickel-cobalt sulfide (NiCo2S4) possessed high electron transfer capacity, which lead to good peroxidase-like activity. Compared with the reported enzyme-like materials, NiCo2S4 exhibited a smaller Km and a stronger affinity with substrate. A colorimetric assay was developed for the direct detection of hydrogen peroxide and indirect detection of glucose over a wide linear range (H2O2 was 20-200 mu M, and glucose was 20-1000 mu M) with a low detection limit (H2O2 was 5.19 mu M, and glucose was 8.24 mu M). Furthermore, a NiCo2S4 based platform was established to study the antioxidant behavior of three antioxidants. The antioxidant capacities of the antioxidants were found to rank in the order: tannic acid (TA) > ascorbic acid (AA)> gallic acid (GA). Moreover, the three antioxidants showed different inhibition mechanisms. This study indicated a new and important application field for NiCo2S4 and provides a basis for the rational design of enzyme-like mimics in future research.

Automated summary

The study demonstrated the peroxidase-like activity of a nickel-cobalt mixed metal sulfide, NiCo2S4, with high electron transfer capacity. A colorimetric assay was developed for direct detection of hydrogen peroxide and indirect detection of glucose. Moreover, NiCo2S4 was utilized to study the antioxidant behavior of three antioxidants, revealing their capacities and inhibition mechanisms.