Peroxidase-like activity of Fe-N-C single-atom nanozyme based colorimetric detection of galactose

Single atom nanozymes are the artificial enzymes with enzyme-like activity, which have attracted a great deal attention in recent years due to their unique merits such as remarkable stability, excellent atom utilization and low cost. Herein, a convenient and sensitive colorimetric strategy was developed for the sensing of galactose based on Fe-N-C single-atom nanozyme (Fe-SAzyme). The Fe-SAzyme was prepared through "isolation-pyrolysis" method that exhibited intrinsic peroxidase mimicking activity, which can quickly catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to produce blue-colored oxTMB in the presence of hydrogen peroxide (H₂O₂). Galactose can be oxidized by galactose oxidase (Gal Ox) to generate H₂O₂, and Fe-SAzyme can be utilized for quantitative colorimetric detection of galactose. A good linearity between absorbance and the galactose concentration in the range of 50-500 μM was obtained with a detection limit of (LOD) 10 μM. The Fe-SAzyme based colorimetric strategy offered a rapid, convenient and economic way for galactose quantification detection, which could be used as an alternative method for galactosemia diagnosis.