Magnetic Fe3O4@NH2-MIL-101(Fe) nanocomposites with peroxidase-like activity for colorimetric detection of glucose

Abstract

In order to improve the stability and reduce the cost of natural enzymes, the design and development of nanomaterials-based artificial enzymes with low-cost and highly stable properties have become a research hotspot. Herein, composite material Fe3O4@NH2-MIL-101(Fe) was prepared by ultrasonic self-assembly strategy, and its mimicking peroxidase-like activity was investigated in detail. In the presence of H2O2, Fe3O4@NH2-MIL-101(Fe) can catalyze chromogenic substrate 3,3′,5,5′-tetramethyl-benzidine (TMB) to produce blue oxidation product (oxTMB) and the kinetic assay indicates that the composite material had higher affinity towards both the substrate TMB and H2O2 than horseradish peroxidase (HRP). Under the optimized conditions, the absorbance of oxTMB at 652 nm had a good linear relationship with the concentration of H2O2 in a certain range, the linear range was 1.0 μM to 80.0 μM (R2 = 0.9973), 80.0 μM to 250 μM (R2 = 0.9927), and the detection limit was 0.45 μM. Moreover, the combination of Fe3O4@NH2-MIL-101(Fe) with glucose oxidase (GOx) can be further used for the determination of glucose. The detection range was 1.67 μM to 167 μM (R2 = 0.9960), 167 μM to 750 μM (R2 = 0.9943), and the detection limit was 0.22 μM. It was proved that the established method can be successfully applied to detect the concentration of glucose in human serum samples. The detection result was consistent with that of commercial glucose meters, indicating that the method with high selectivity and acceptable reproducibility was accurate, reliable and applicable. Importantly, the synthesized magnetic material had excellent recyclability with high activity. These results suggest that the proposed method based on Fe3O4@NH2-MIL-101(Fe) as peroxidase mimic may be one of the promising candidates for glucose detection in biomedical fields.