Micellar catalysis of an iron(iii)-MOF: enhanced biosensing characteristics

Abstract

Recent years have seen an enormous growth of interest in enzyme mimics based on porous materials as a substitute for natural enzymes. This interest has been increased to a considerable extent due to the fact that they have outstanding chemical and structural features. Herein, Zr₆O₈(H₂O)₈(FeCl-tcpp)₂(PCN-222(Fe)) was synthesized via a solvothermal approach with Zr₆ clusters as nodes and Fe–TCPP (TCPP = tetrakis(4-carboxyphenyl)porphyrin) as a heme-like ligand and was characterized by various techniques such as XRD, TEM, SEM, XPS, UV-vis and IR. Also, since the achievement of high enzyme-like activity of some nanoparticles has attracted widespread interest in recent years, for the first time, we have applied a significant approach by modifying PCN-222(Fe) with sodium dodecyl sulfate (SDS) micelles (SDS/PCN-222(Fe)). In an attempt to explore the significance of this procedure, initially, peroxidase and catalase-like activity were investigated through a reaction with a chromogenic substrate 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). Based on the high peroxidatic activity of SDS/PCN-222(Fe), a visual, sensitive and reliable method was established for detection of H₂O₂ with a linear range of 3–200 μM and limit of detection (LOD) of 2 μM. Also, as an implication of these findings, the SDS/Zr₆O₈(H₂O)₈(FeCl-tcpp)₂ (SDS/PCN-222(Fe)) based system could also be used for glucose assay with a LOD of 3 μM indicating potential applications in clinical medicine. In order to prove this hypothesis, the glucose detection in human serum was determined. Finally, on the basis of SDS/PCN-222(Fe) performance, three natural antioxidants, gallic acid (GA), tannic acid (TA), and ascorbic acid (AA) were applied to explore antioxidant capabilities.