FeS2 nanosheets as mimetic peroxidase for sensitive colorimetric detection of biothiols

The preparation and application of nanomaterials with enzyme-like activity have attracted widespread attention from researchers. Herein, we prepared FeS2 nanosheets (FeS2 NSs) with peroxidase mimicking behavior through a simple hydrothermal pathway. Then, a FeS2 NSs-based colorimetric assay for biothiols detection was established. On one hand, FeS2 NSs could catalyze H2O2 to oxidize colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxidized product (ox-TMB) with a characteristic peak at 652 nm. On the other hand, when a biothiol compound including cysteine (CySH), homocysteine (HcySH) and glutathione (GSH) was present, ox-TMB would be reduced, resulting in lighter blue and lower absorbance. Suggesting that the change of absorbance could be used for quantitative detection of biothiols. Taking HcySH as an example, several experimental parameters including pH, incubation time, and TMB concentration were optimized. Under the conditions of pH 4.5, incubation time of 50 min, and TMB of 0.4 mM, the limit of detection for HcySH, CySH and GSH was as low as 0.67, 0.59 and 0.36 μM, respectively. To verify its possible application, this method was further applied for the determination of HcySH in real serum samples, and good recoveries of 95.0 to 103.8% were obtained. KEY WORDS: Nanosheets, Peroxidase‐like activity, Spectrophotometric, Determination Bull. Chem. Soc. Ethiop. 2025, 39(9), 1699-1711. DOI: https://dx.doi.org/10.4314/bcse.v39i9.4