Tetra(p‐tolyl)borate‐Functionalized Solvent Polymeric Membrane: A Facile and Sensitive Sensing Platform for Peroxidase and Peroxidase Mimetics

Abstract

The determination of peroxidase activities is the basis for enzyme‐labeled bioaffinity assays, peroxidase‐mimicking DNAzymes‐ and nanoparticles‐based assays, and characterization of the catalytic functions of peroxidase mimetics. Here, a facile, sensitive, and cost‐effective solvent polymeric membrane‐based peroxidase detection platform is described that utilizes reaction intermediates with different pKa values from those of substrates and final products. Several key but long‐debated intermediates in the peroxidative oxidation of o‐phenylenediamine (o‐PD) have been identified and their charge states have been estimated. By using a solvent polymeric membrane functionalized by an appropriate substituted tetraphenylborate as a receptor, those cationic intermediates could be transferred into the membrane from the aqueous phase to induce a large cationic potential response. Thus, the potentiometric indication of the o‐PD oxidation catalyzed by peroxidase or its mimetics can be fulfilled. Horseradish peroxidase has been detected with a detection limit at least two orders of magnitude lower than those obtained by spectrophotometric techniques and traditional membrane‐based methods. As an example of peroxidase mimetics, G‐quadruplex DNAzymes were probed by the intermediate‐sensitive membrane and a label‐free thrombin detection protocol was developed based on the catalytic activity of the thrombin‐binding G‐quadruplex aptamer.

Recent advances in potentiometric biosensors

“…By selecting proper substrates, the enzyme activities can be determined by detecting ions generated by the enzymatic reactions using corresponding ISEs. Potentiometric assays for horseradish peroxidase [108], alkaline phosphate [109], butyrylcholinesterase [90], thrombin [110], and trypsin [111] are available. For example, Ding et al reported a simple, general and label-free potentiometric method to measure nuclease activities in a homogeneous solution using a polycation-sensitive membrane electrode [112].…”

Potentiometric Detection of Listeria monocytogenes via a Short Antimicrobial Peptide Pair-Based Sandwich Assay

“…The potential change, which is closely related to the amount of LM, can be used for the quantification of LM. It should be noted that ophenylenediamine 34 and other C-derivatives of benzidine (such as N,N′,N,N′-tetramethylbenzidine, 3,3′-dimethoxybenzidine, and m,m′-ditolylamine) can also be used as the substrates for the developed methodology. 32 An original long peptide (WGEAFSAGVHRLAN) has been identified, which can recognize and capture the bacterial cells by interacting with the specific receptor on the membrane of LM to form a helical conformation.…”

“…The potential change, which is closely related to the amount of LM, can be used for the quantification of LM. It should be noted that o -phenylenediamine and other C-derivatives of benzidine (such as N , N ′, N , N ′-tetramethylbenzidine, 3,3′-dimethoxybenzidine, and m , m ′-ditolylamine) can also be used as the substrates for the developed methodology …”

Pulsed Chronopotentiometric Detection of Thrombin Activity Using Reversible Polyion Selective Electrodes

“…However, due to the irreversible nature of their response, these sensors are limited to single‐use devices. Recently, a novel polymeric membrane electrode‐based potentiometric sensing platform was reported for the detection of thrombin activity . This sensor was based on peroxide‐like DNAzyme function and was found to have high sensitivity and rapid regeneration.…”