title: 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.
authors.affiliation: Key Laboratory of Coastal Zone, Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), YICCAS, Yantai Shandong 264003, PR China.
authors.forename: Xuewei
authors.initials: X
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Qin
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D001881:Borates / Q000737:chemistry*; D021881:DNA, Catalytic / Q000032:analysis*; D054856:G-Quadruplexes; D006735:Horseradish Peroxidase / Q000032:analysis*; D057230:Limit of Detection; D008567:Membranes, Artificial; D010084:Oxidation-Reduction; D010655:Phenylenediamines / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011199:Potentiometry; D012680:Sensitivity and Specificity; D013917:Thrombin / Q000032:analysis
chemical_list: D052157:Aptamers, Nucleotide; D001881:Borates; D021881:DNA, Catalytic; D008567:Membranes, Artificial; D010655:Phenylenediamines; D011108:Polymers; C081676:thrombin aptamer; C034193:1,2-diaminobenzene; D006735:Horseradish Peroxidase; D013917:Thrombin
keywords: biosensors; intermediate-sensitive membranes; peroxidase; peroxidase mimetics; potentiometry