Peroxidase-like activity of apoferritin paired gold clusters for glucose detection

The discovery and application of noble metal nanoclusters have received considerable attention. In this paper, we reported that apoferritin paired gold clusters (Au-Ft) could efficiently catalyze oxidation of 3.3',5.5'-tetramethylbenzidine (TMB) by H₂O₂ to produce a blue color reaction. Compared with natural enzyme, Au-Ft exhibited higher activity near acidic pH and could be used over a wide range of temperatures. Apoferritin nanocage enhanced the reaction activity of substrate TMB by H₂O₂. The reaction catalyzed by Au-Ft was found to follow a typical Michaelis-Menten kinetics. The kinetic parameters exhibited a lower K_m value (0.097mM) and a higher K_cat value (5.8×10⁴s^-1) for TMB than that of horse radish peroxidase (HRP). Base on these findings, Au-Ft, acting as a peroxidase mimetic, performed enzymatic spectrophotometric analysis of glucose. This system exhibited acceptable reproducibility and high selectivity in biosening, suggesting that it could have promising applications in the future.