Hemin–amino acid co-assembly nanozymes with dual enzyme-mimicking activities for in situ oxygen generation-enhanced one-step biosensing of glucose and H2O2

Abstract

The co-assembly of amino acids or proteins with active small molecules to prepare biomimetic nanozymes offers a promising strategy for designing novel nanozymes. However, a significant challenge in nanozyme catalysis is the low activity at physiological pH, particularly for oxidase-like and peroxidase-like nanozymes. In this study, we successfully synthesized three biomimetic nanozymes (His@Hemin, Fe-His@Hemin, and Mn-His@Hemin) via the co-assembly of amphiphilic amino acids and hemin. Among these, the spherical Fe-His@Hemin exhibited superior peroxidase-like and catalase-like catalytic activities even in neutral pH systems. Free radical capture experiments revealed that Fe-His@Hemin, as a peroxidase-like nanozyme, generated three reactive oxygen species (O₂˙⁻, ¹O₂, and ˙OH), and as a catalase-like nanozyme produced oxygen during the catalytic process. This excellent catalase activity enabled in situ oxygen generation, which facilitated the oxidation of glucose oxidase within the system, providing a new strategy for one-step analysis of glucose and H₂O₂. The detection limits for glucose and H₂O₂ were as low as 0.25 µM and 0.16 µM, respectively, with linear ranges of 0.5–400 µM for glucose and 0.25–120 µM for H₂O₂. The glucose sensors demonstrated reliable and reproducible results for glucose determination in human serum.