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Srinivas S, Ashokkumar K, Sriraghavan K, Senthil Kumar A. A prototype device of microliter volume voltammetric pH sensor based on carbazole-quinone redox-probe tethered MWCNT modified three-in-one screen-printed electrode. Sci Rep 2021; 11:13905. [PMID: 34230547 PMCID: PMC8260652 DOI: 10.1038/s41598-021-93368-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/14/2021] [Indexed: 11/30/2022] Open
Abstract
As an alternate for the conventional glass-based pH sensor which is associated with problems like fragile nature, alkaline error, and potential drift, the development of a new redox-sensitive pH probe-modified electrode that could show potential, current-drift and surface-fouling free voltammetric pH sensing is a demanding research interest, recently. Herein, we report a substituted carbazole-quinone (Car-HQ) based new redox-active pH-sensitive probe that contains benzyl and bromo-substituents, immobilized multiwalled carbon nanotube modified glassy carbon (GCE/MWCNT@Car-HQ) and screen-printed three-in-one (SPE/MWCNT@Car-HQ) electrodes for selective, surface-fouling free pH sensor application. This new system showed a well-defined surface-confined redox peak at an apparent standard electrode potential, Eo' = - 0.160 V versus Ag/AgCl with surface-excess value, Γ = 47 n mol cm-2 in pH 7 phosphate buffer solution. When tested with various electroactive chemicals and biochemicals such as cysteine, hydrazine, NADH, uric acid, and ascorbic acid, MWCNT@Car-HQ showed an unaltered redox-peak potential and current values without mediated oxidation/reduction behavior unlike the conventional hydroquinone, anthraquinone and other redox mediators based voltammetry sensors with serious electrocatalytic effects and in turn potential and current drifts. A strong π-π interaction, nitrogen-atom assisted surface orientation and C-C bond formation on the graphitic structure of MWCNT are the plausible reasons for stable and selective voltammetric pH sensing application of MWCNT@Car-HQ system. Using a programed/in-built three-in-one screen printed compatible potentiostat system, voltammetric pH sensing of 3 μL sample of urine, saliva, and orange juice samples with pH values comparable to that of milliliter volume-based pH-glass electrode measurements has been demonstrated.
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Affiliation(s)
- Sakthivel Srinivas
- Nano and Bioelectrochemistry Research Laboratory, Carbon Dioxide Research and Green Technology Centre, Vellore Institute of Technology, Vellore, 632 014, India
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632 014, India
| | - Krishnan Ashokkumar
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632 014, India
| | - Kamaraj Sriraghavan
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632 014, India.
| | - Annamalai Senthil Kumar
- Nano and Bioelectrochemistry Research Laboratory, Carbon Dioxide Research and Green Technology Centre, Vellore Institute of Technology, Vellore, 632 014, India.
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632 014, India.
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Ma X, Deng D, Xia N, Hao Y, Liu L. Electrochemical Immunosensors with PQQ-Decorated Carbon Nanotubes as Signal Labels for Electrocatalytic Oxidation of Tris(2-carboxyethyl)phosphine. NANOMATERIALS 2021; 11:nano11071757. [PMID: 34361143 PMCID: PMC8308108 DOI: 10.3390/nano11071757] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 06/30/2021] [Accepted: 07/01/2021] [Indexed: 11/16/2022]
Abstract
Nanocatalysts are a promising alternative to natural enzymes as the signal labels of electrochemical biosensors. However, the surface modification of nanocatalysts and sensor electrodes with recognition elements and blockers may form a barrier to direct electron transfer, thus limiting the application of nanocatalysts in electrochemical immunoassays. Electron mediators can accelerate the electron transfer between nanocatalysts and electrodes. Nevertheless, it is hard to simultaneously achieve fast electron exchange between nanocatalysts and redox mediators as well as substrates. This work presents a scheme for the design of electrochemical immunosensors with nanocatalysts as signal labels, in which pyrroloquinoline quinone (PQQ) is the redox-active center of the nanocatalyst. PQQ was decorated on the surface of carbon nanotubes to catalyze the electrochemical oxidation of tris(2-carboxyethyl)phosphine (TCEP) with ferrocenylmethanol (FcM) as the electron mediator. With prostate-specific antigen (PSA) as the model analyte, the detection limit of the sandwich-type immunosensor was found to be 5 pg/mL. The keys to success for this scheme are the slow chemical reaction between TCEP and ferricinum ions, and the high turnover frequency between ferricinum ions, PQQ. and TCEP. This work should be valuable for designing of novel nanolabels and nanocatalytic schemes for electrochemical biosensors.
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Affiliation(s)
- Xiaohua Ma
- Henan Key Laboratory of Biomolecular Recognition and Sensing, Shangqiu Normal University, Shangqiu 476000, China;
| | - Dehua Deng
- College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang 455000, China; (D.D.); (N.X.)
| | - Ning Xia
- College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang 455000, China; (D.D.); (N.X.)
| | - Yuanqiang Hao
- Henan Key Laboratory of Biomolecular Recognition and Sensing, Shangqiu Normal University, Shangqiu 476000, China;
- Correspondence: (Y.H.); (L.L.)
| | - Lin Liu
- Henan Key Laboratory of Biomolecular Recognition and Sensing, Shangqiu Normal University, Shangqiu 476000, China;
- College of Chemistry and Chemical Engineering, Anyang Normal University, Anyang 455000, China; (D.D.); (N.X.)
- Correspondence: (Y.H.); (L.L.)
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Grushevskaya HV, Krylova NG. Carbon Nanotubes as A High-Performance Platform for Target Delivery of Anticancer Quinones. Curr Pharm Des 2019; 24:5207-5218. [PMID: 30652640 DOI: 10.2174/1381612825666190117095132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 01/11/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND In spite of considerable efforts of researchers the cancer deseases remain to be incurable and a percentage of cancer deseases in the structure of mortality increases every year. At that, high systemic toxicity of antitumor drugs hampers their effective use. Because of this fact, the development of nanosystems for targeted delivery of antitumor drugs is one of the leading problem in nanomedicine and nanopharmacy. OBJECTIVE To critically examine the modern strategies for carbon nanotubes (CNTs)-based delivery of anticancer quinones and to summarize the mechanisms which can provide high effectiveness and multifunctionality of the CNT-based quinone delivery platform. RESULTS Quinones, including anthracycline antibiotics - doxorubicin and daunorubicin, are among the most prospective group of natural and syntetic compounds which exhibit high antitumor activity against different type of tumors. In this review, we focus on the possibilities of using CNTs for targeted delivery of antitumor compounds with quinoid moiety which is ordinarily characterized by high specific interaction with DNA molecules. Quinones can be non-covalently adsorbed on CNT surface due to their aromatic structure and π-conjugated system of double bonds. The characteristic features of doxorubicine-CNT complex are high loading efficiency, pH-dependent release in acidic tumor microenviroment, enough stability in biological fluid. Different types of CNT functionalization, targeting strategies and designs for multifunctional CNT-based doxorubicine delivery platform are disscussed. CONCLUSION Nanosystems based on functionalized CNTs are very promising platform for quinone delivery resulting in significant enhancement of cancer treatment efficiency. Functionalization of CNTs with the polymeric shell, especially DNA-based shells, can provide the greatest affinity and mimicry with biological structures.
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Affiliation(s)
- H V Grushevskaya
- Physics Department, Belarusian State University, 4 Nezavisimosti Ave., Minsk 220030, Belarus
| | - N G Krylova
- Physics Department, Belarusian State University, 4 Nezavisimosti Ave., Minsk 220030, Belarus
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Kaur J, Jiang C, Liu G. Different strategies for detection of HbA1c emphasizing on biosensors and point-of-care analyzers. Biosens Bioelectron 2018; 123:85-100. [PMID: 29903690 DOI: 10.1016/j.bios.2018.06.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/23/2018] [Accepted: 06/06/2018] [Indexed: 12/21/2022]
Abstract
Measurement of glycosylated hemoglobin (HbA1c) is a gold standard procedure for assessing long term glycemic control in individuals with diabetes mellitus as it gives the stable and reliable value of blood glucose levels for a period of 90-120 days. HbA1c is formed by the non-enzymatic glycation of terminal valine of hemoglobin. The analysis of HbA1c tends to be complicated because there are more than 300 different assay methods for measuring HbA1c which leads to variations in reported values from same samples. Therefore, standardization of detection methods is recommended. The review outlines the current research activities on developing assays including biosensors for the detection of HbA1c. The pros and cons of different techniques for measuring HbA1c are outlined. The performance of current point-of-care HbA1c analyzers available on the market are also compared and discussed. The future perspectives for HbA1c detection and diabetes management are proposed.
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Affiliation(s)
- Jagjit Kaur
- Graduate School of Biomedical Engineering, ARC Centre of Excellence in Nanoscale Biophotonics (CNBP), Faculty of Engineering, The University of New South Wales, Sydney 2052, Australia; Australian Centre for NanoMedicine, The University of New South Wales, Sydney 2052, Australia
| | - Cheng Jiang
- Nuffield Department of Clinical Neurosciences, Department of Chemistry, University of Oxford, Oxford OX1 2JD, United Kingdom
| | - Guozhen Liu
- Graduate School of Biomedical Engineering, ARC Centre of Excellence in Nanoscale Biophotonics (CNBP), Faculty of Engineering, The University of New South Wales, Sydney 2052, Australia; Australian Centre for NanoMedicine, The University of New South Wales, Sydney 2052, Australia; International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan 430079, PR China.
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Effect of Aptamer Binding on the Electron-Transfer Properties of Redox Cofactors. J Mol Evol 2015; 81:186-93. [PMID: 26498628 DOI: 10.1007/s00239-015-9707-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 10/17/2015] [Indexed: 10/22/2022]
Abstract
In vitro selection or SELEX has allowed for the identification of functional nucleic acids (FNAs) that can potentially mimic and replace protein enzymes. These FNAs likely interact with cofactors, just like enzymes bind cofactors in their active sites. Investigating how FNA binding affects cofactor properties is important for understanding how an active site is formed and for developing useful enzyme mimics. Oxidoreductase enzymes contain cofactors in their active sites that allow the enzymes to do redox chemistry. In certain applications, these redox cofactors act as electron-transfer shuttles that transport electrons between the enzymes' active sites and electrode surfaces. Three redox cofactors commonly found in oxidoreductases are flavin adenine dinucleotide, nicotinamide adenine dinucleotide (NAD(+)), and pyrroloquinoline quinone (PQQ). We are interested in investigating how DNA aptamers that bind these cofactors influence the cofactors' redox abilities and if these aptamer-cofactor complexes could serve as redox catalysts. We employed cyclic voltammetry and amperometry to study the electrochemical properties of NAD(+) and PQQ when bound to DNA aptamers. Our results suggest that the aptamers provide a stable environment for the cofactor to participate in redox reactions, although enhanced redox activity was not observed. This work provides a foundation for the development of new FNAs capable of redox activity.
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Zhou Y, Dong H, Liu L, Hao Y, Chang Z, Xu M. Fabrication of electrochemical interface based on boronic acid-modified pyrroloquinoline quinine/reduced graphene oxide composites for voltammetric determination of glycated hemoglobin. Biosens Bioelectron 2015; 64:442-8. [DOI: 10.1016/j.bios.2014.09.058] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/09/2014] [Accepted: 09/22/2014] [Indexed: 10/24/2022]
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Flexer V, Mano N. Wired Pyrroloquinoline Quinone Soluble Glucose Dehydrogenase Enzyme Electrodes Operating at Unprecedented Low Redox Potential. Anal Chem 2014; 86:2465-73. [DOI: 10.1021/ac403334w] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Victoria Flexer
- Centre de Recherche
Paul Pascal, UPR 8641, CNRS, F-33600 Pessac, France
- Université de Bordeaux, CRPP, UPR 8641, F-33600 Pessac, France
| | - Nicolas Mano
- Centre de Recherche
Paul Pascal, UPR 8641, CNRS, F-33600 Pessac, France
- Université de Bordeaux, CRPP, UPR 8641, F-33600 Pessac, France
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Lee PT, Harfield JC, Crossley A, Pilgrim BS, Compton RG. Significant changes in pKa between bulk aqueous solution and surface immobilized species: ortho-hydroquinones. RSC Adv 2013. [DOI: 10.1039/c3ra00164d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Flexer V, Durand F, Tsujimura S, Mano N. Efficient direct electron transfer of PQQ-glucose dehydrogenase on carbon cryogel electrodes at neutral pH. Anal Chem 2011; 83:5721-7. [PMID: 21662989 DOI: 10.1021/ac200981r] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a comprehensive study of the direct electron transfer reaction of soluble PQQ-GDH from Acinetobacter calcoaceticus. Wild-type PQQ-sGDH nonspecifically adsorbed on carbon cryogel electrodes retained its enzymatic activity for glucose and maltose oxidation at pH 7.2 and 37 °C. The cyclic voltammograms in the absence of enzymatic substrate showed 2 redox peaks that suggest a two-step, one-electron oxidation/reduction of PQQ. Calibration curves showed a linear amperometric response for a wide glucose concentration range, including the values normally found in blood. At saturation, the catalytic current reached 0.93 mA cm(-2). Altogether the experimental results suggest that the amperometric output of the electrodes and the shape of the calibration curves represent a combination of the intrinsic enzyme kinetics, the maximum rate of heterogeneous electron transfer and the substrate accessibility to the enzyme's active center caused by the confinement of the enzyme into the mesoporous structure. A new mutant enzyme, N428C, developed in our group that shows almost twice the maximum catalytic activity in homogeneous experiments in solution, also showed a DET signal on carbon cryogel electrodes for glucose electro-oxidation. The higher activity for the mutant enzyme was also verified on the electrode surface.
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Affiliation(s)
- Victoria Flexer
- Université de Bordeaux, Centre de Recherche Paul Pascal, CRPP-UPR 8641-CNRS, Pessac, France
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