A nanoporous palladium(II) bridged coordination polymer acting as a peroxidase mimic in a method for visual detection of glucose in tear and saliva

Abstract

A nanoporous coordination polymer (NPCP) was prepared from palladium(II) chloride and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole and is shown to act as a peroxidase mimetic. It can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by HO which is formed on enzymatic oxidation of glucose by glucose oxidase. Based on these findings, a sensitive glucose test was worked out at 652 nm where the intensity if the greenish-blue product is related to the actual concentration of glucose. Figures of merit include (a) rather low Km value (30 μM) which evidences the strong binding affinity of the NPCP toward glucose, (b) a high v (8.5 M·s), (c) a 47 nM detection limit, (d) a lifetime of a month, (e) a wide working pH range (2-10), and (f) a 25-80 °C temperature range. The assay was applied to non-invasive determination of glucose assay in tear, saliva where the detection limits are found to be 61 and 91 nM, respectively. Graphical abstract DSchematic of the mechanism of the peroxidase like catalytic activity of AHMT-Pd NPCP that was applied in a selective colorimetric method for glucose detection based on TMB oxidation in the presence of enzymatically generated HO.

Polyethyleneimine-Stabilized Platinum Nanoparticles as Peroxidase Mimic for Colorimetric Detection of Glucose

“…Saliva was used as the real sample to test the glucose concentration. The glucose concentration was 0.15 mM, which was within a normal glucose concentration of human saliva (0.008–0.21 mM) . This confirmed the validity of this method.…”

Ultrasensitive Poly(boric acid) Hydrogel-Coated Quartz Crystal Microbalance Sensor by Using UV Pressing-Assisted Polymerization for Saliva Glucose Monitoring

“…As shown in Figure c, as the glucose concentration changed, the △ F of the control hydrogel did not show any obvious changes. In contrast, the boric acid hydrogel showed △ F response to glucose in the concentration range of 0–160 mg/L, which encompasses the concentration range of glucose in saliva of both healthy people and diabetics . When the glucose concentration gradually increased from 0 to 160 mg/L, the absolute value of △ F increased rapidly, suggesting rapid binding between boric acid groups of the hydrogel and glucose molecules.…”

Tunable Polymeric Scaffolds for Enzyme Immobilization

“…Protein-NCP hybrids have been applied to a wide range of applications, such as sensing ( Wang et al, 2016 ; Gao et al, 2017 ; Vinita et al, 2018 ; Wu et al, 2019 ; Xiong et al, 2020 ), microfluidic systems ( Hu et al, 2020 ), removal of pollutants ( Shen et al, 2019 ), photodynamic therapies ( Cheng et al, 2016 ; Li et al, 2017 ; You et al, 2019 ; He et al, 2020 ), protein delivery ( Chen et al, 2018 ; Yang et al, 2019 ; Zhang et al, 2019a ; Alyami et al, 2020 ) or even for the optimization of the polymerase chain reaction (PCR) ( Sun et al, 2020 ). Undoubtedly, the nature of the ligands and metals used for the synthesis of the MOFs has a direct impact on the final structure of the hybrid and eventually on the activity of the enzyme.…”