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Amr AEGE, Kamel AH, Almehizia AA, Sayed AYA, Abd-Rabboh HSM. Solid-Contact Potentiometric Sensors Based on Main-Tailored Bio-Mimics for Trace Detection of Harmine Hallucinogen in Urine Specimens. Molecules 2021; 26:molecules26020324. [PMID: 33435196 PMCID: PMC7826799 DOI: 10.3390/molecules26020324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 11/21/2022] Open
Abstract
All-solid-state potentiometric sensors have attracted great attention over other types of potentiometric sensors due to their outstanding properties such as enhanced portability, simplicity of handling, affordability and flexibility. Herein, a novel solid-contact ion-selective electrode (SC-ISE) based on poly(3,4-ethylenedioxythiophene) (PEDOT) as the ion-to-electron transducer was designed and characterized for rapid detection of harmine. The harmine-sensing membrane was based on the use of synthesized imprinted bio-mimics as a selective material for this recognition. The imprinted receptors were synthesized using acrylamide (AA) and ethylene glycol dimethacrylate (EGDMA) as functional monomer and cross-linker, respectively. The polymerization process was carried out at 70 °C in the presence of dibenzoyl peroxide (DBO) as an initiator. The sensing membrane in addition to the solid-contact layer was applied to a glassy-carbon disc as an electronic conductor. All performance characteristics of the presented electrode in terms of linearity, detection limit, pH range, response time and selectivity were evaluated. The sensor revealed a wide linearity over the range 2.0 × 10−7–1.0 × 10−2 M, with a detection limit of 0.02 µg/mL and a sensitivity slope of 59.2 ± 0.8 mV/hamine concentration decade. A 40 mM Britton–Robinson (BR) buffer solution at pH of 6 was used for all harmine measurements. The electrode showed good selectivity towards harmine over other common interfering ions, and maintained a stable electrochemical response over two weeks. After applying the validation requirements, the proposed method revealed good performance characteristics. Method precision, accuracy, bias, trueness, repeatability, reproducibility, and uncertainty were also evaluated. These analytical capabilities support the fast and direct assessment of harmine in different urine specimens. The analytical results were compared with the standard liquid chromatographic method. The results obtained demonstrated that PEDOT/PSS was a promising solid-contact ion-to-electron transducer material in the development of harmine-ISE. The electrodes manifested enhanced stability and low cost, which provides a wide number of potential applications for pharmaceutical and forensic analysis.
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Affiliation(s)
- Abde El-Galil E. Amr
- Pharmaceutical Chemistry Department, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia;
- Applied Organic Chemistry Department, National Research Center, Dokki, Giza 12622, Egypt; (A.A.A.); (A.Y.A.S.)
| | - Ayman H. Kamel
- Department of Chemistry, Faculty of Science, Ain Shams University, Cairo 11566, Egypt
- Correspondence: (A.H.K.); (H.S.M.A.-R.); Tel.: +966-565-148-750 (H.S.M.A.-R.)
| | - Abdulrahman A. Almehizia
- Applied Organic Chemistry Department, National Research Center, Dokki, Giza 12622, Egypt; (A.A.A.); (A.Y.A.S.)
| | - Ahmed Y. A. Sayed
- Applied Organic Chemistry Department, National Research Center, Dokki, Giza 12622, Egypt; (A.A.A.); (A.Y.A.S.)
| | - Hisham S. M. Abd-Rabboh
- Department of Chemistry, Faculty of Science, Ain Shams University, Cairo 11566, Egypt
- Chemistry Department, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
- Correspondence: (A.H.K.); (H.S.M.A.-R.); Tel.: +966-565-148-750 (H.S.M.A.-R.)
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Chen SS, Han PC, Kuok WK, Lu JY, Gu Y, Ahamad T, Alshehri SM, Ayalew H, Yu HH, Wu KCW. Synthesis of MOF525/PEDOT Composites as Microelectrodes for Electrochemical Sensing of Dopamine. Polymers (Basel) 2020; 12:polym12091976. [PMID: 32878082 PMCID: PMC7564993 DOI: 10.3390/polym12091976] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/25/2022] Open
Abstract
Dopamine (DA) is an important neurotransmitter responsible for the functions and activities of multiple systems in human. Electrochemical detection of DA has the advantages of fast analysis and cost-effectiveness, while a regular electrode probe is restricted to laboratory use because the probe size is too large to be suitable for an in vivo or in vitro analysis. In this study, we have developed porphyrin-based metal organic framework (MOF525) and poly(3,4-ethylenedioxythiophene) (PEDOT)-based composites to modify microelectrode for DA detection. Two types of PEDOT monomers with different functional groups were investigated in this study. By varying the monomer ratios, electrolyte concentrations, and electropolymerization temperature, it was found that the PEDOT monomer containing carboxylic group facilitated the formation of regular morphology during the electropolymerization process. The uniform morphology of the PEDOT promoted the electron transmission efficiency in the same direction, while the MOF525 provided a large reactive surface area for electrocatalysis of DA. Thus, the MOF525/PEDOT composite improved the sensitivity-to-noise ratio of DA signaling, where the sensitivity reached 11 nA/μM in a good linear range of 4–100 µM. In addition, porphyrin-based MOF could also increase the selectivity to DA against other common clinical interferences, such as ascorbic acid and uric acid. The as-synthesized microelectrode modified with MOF525/PEDOT in this study exhibited great potential in real time analysis.
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Affiliation(s)
- Season S. Chen
- Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan; (S.S.C.); (W.-K.K.)
| | - Po-Chun Han
- Program of Green Materials and Precision Devices, National Taiwan University, Taipei 10617, Taiwan;
| | - Wai-Kei Kuok
- Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan; (S.S.C.); (W.-K.K.)
| | - Jian-Yu Lu
- Department of Chemical and Materials Engineering, Tunghai University, No. 1727, Sec. 4, Taiwan Boulevard, Xitun District, Taichung City 407224, Taiwan; (J.-Y.L.); (Y.G.)
| | - Yesong Gu
- Department of Chemical and Materials Engineering, Tunghai University, No. 1727, Sec. 4, Taiwan Boulevard, Xitun District, Taichung City 407224, Taiwan; (J.-Y.L.); (Y.G.)
| | - Tansir Ahamad
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; (T.A.); (S.M.A.)
| | - Saad M. Alshehri
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; (T.A.); (S.M.A.)
| | - Hailemichael Ayalew
- Smart Organic Materials Laboratory, Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan;
| | - Hsiao-hua Yu
- Smart Organic Materials Laboratory, Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan;
- Correspondence: (H.-h.Y.); (K.C.-W.W.)
| | - Kevin C.-W. Wu
- Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan; (S.S.C.); (W.-K.K.)
- Correspondence: (H.-h.Y.); (K.C.-W.W.)
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Kamel AH, Amr AEGE, Abdalla NS, El-Naggar M, Al-Omar MA, Almehizia AA. Modified Screen-Printed Potentiometric Sensors based on Man-Tailored Biomimetics for Diquat Herbicide Determination. Int J Environ Res Public Health 2020; 17:E1138. [PMID: 32053930 PMCID: PMC7068347 DOI: 10.3390/ijerph17041138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/04/2020] [Accepted: 02/10/2020] [Indexed: 11/22/2022]
Abstract
Screen-printed platforms integrated with molecularly imprinted polymers (MIP) were fabricated and characterized as potentiometric sensors for diquat (DQ). The synthesized MIP beads were studied as sensory carriers in plasticized poly(vinyl chloride) membranes. The sensors were constructed by using poly(3,4-ethylenedioxythiophene) (PEDOT) as solid-contact material to diminish charge-transfer resistance and water layer potential. Conventional ion-selective electrodes (ISEs) with internal filling solution were used for comparison. The designed electrodes showed near Nernstian slopes of 28.2 ± 0.7 (r² = 0.999) over the concentration range of 1.0 × 10-6-1.0 × 10-2 M with the limit of detection 0.026 µg/mL over the pH range 4.2-9.0. The electrode exhibited good selectivity for diquat cations over a large number of organic and inorganic cations. The sensor was successfully introduced for direct measurement of diquat content in commercial pesticide preparations and different spiked potato samples. The results showed that the proposed electrode has a fast and stable response, good reproducibility, and applicability for direct assessment of diquat content. The proposed potentiometric method is simple and accurate in comparison with the reported HPLC methods. Besides, it is applicable to turbid and colored sample solutions.
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Affiliation(s)
- Ayman H. Kamel
- Chemistry Department, Faculty of Science, Ain Shams University, Abbasia, Cairo 11566, Egypt;
| | - Abd El-Galil E. Amr
- Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; (M.A.A.-O.); (A.A.A.)
- Applied Organic Chemistry Department, National Research Center, Dokki, Giza 12622, Egypt
| | - Nashwa S. Abdalla
- Chemistry Department, Faculty of Science, Ain Shams University, Abbasia, Cairo 11566, Egypt;
| | - Mohamed El-Naggar
- Chemistry Department, Faculty of Sciences, University of Sharjah, Sharjah 27272, UAE;
| | - Mohamed A. Al-Omar
- Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; (M.A.A.-O.); (A.A.A.)
| | - Abdulrahman A. Almehizia
- Pharmaceutical Chemistry Department, Drug Exploration & Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; (M.A.A.-O.); (A.A.A.)
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Vomero M, Zucchini E, Delfino E, Gueli C, Mondragon NC, Carli S, Fadiga L, Stieglitz T. Glassy Carbon Electrocorticography Electrodes on Ultra-Thin and Finger-Like Polyimide Substrate: Performance Evaluation Based on Different Electrode Diameters. Materials (Basel) 2018; 11:ma11122486. [PMID: 30544545 PMCID: PMC6316905 DOI: 10.3390/ma11122486] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/03/2018] [Accepted: 12/05/2018] [Indexed: 02/07/2023]
Abstract
Glassy carbon (GC) has high potential to serve as a biomaterial in neural applications because it is biocompatible, electrochemically inert and can be incorporated in polyimide-based implantable devices. Miniaturization and applicability of GC is, however, thought to be partially limited by its electrical conductivity. For this study, ultra-conformable polyimide-based electrocorticography (ECoG) devices with different-diameter GC electrodes were fabricated and tested in vitro and in rat models. For achieving conformability to the rat brain, polyimide was patterned in a finger-like shape and its thickness was set to 8 µm. To investigate different electrode sizes, each ECoG device was assigned electrodes with diameters of 50, 100, 200 and 300 µm. They were electrochemically characterized and subjected to 10 million biphasic pulses—for achieving a steady-state—and to X-ray photoelectron spectroscopy, for examining their elemental composition. The electrodes were then implanted epidurally to evaluate the ability of each diameter to detect neural activity. Results show that their performance at low frequencies (up to 300 Hz) depends on the distance from the signal source rather than on the electrode diameter, while at high frequencies (above 200 Hz) small electrodes have higher background noises than large ones, unless they are coated with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS).
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Affiliation(s)
- Maria Vomero
- Institute of Microsystem Technology (IMTEK), Laboratory for Biomedical Microtechnology, Georges-Koehler-Allee 102, D-79110 Freiburg, Germany.
- Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Georges-Koehler-Allee 80, 79110 Freiburg, Germany.
| | - Elena Zucchini
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia (IIT), Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
- Section of Human Physiology University of Ferrara, Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
| | - Emanuela Delfino
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia (IIT), Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
- Section of Human Physiology University of Ferrara, Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
| | - Calogero Gueli
- Institute of Microsystem Technology (IMTEK), Laboratory for Biomedical Microtechnology, Georges-Koehler-Allee 102, D-79110 Freiburg, Germany.
| | - Norma Carolina Mondragon
- Institute of Microsystem Technology (IMTEK), Laboratory for Biomedical Microtechnology, Georges-Koehler-Allee 102, D-79110 Freiburg, Germany.
| | - Stefano Carli
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia (IIT), Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
| | - Luciano Fadiga
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia (IIT), Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
- Section of Human Physiology University of Ferrara, Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
| | - Thomas Stieglitz
- Institute of Microsystem Technology (IMTEK), Laboratory for Biomedical Microtechnology, Georges-Koehler-Allee 102, D-79110 Freiburg, Germany.
- Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Georges-Koehler-Allee 80, 79110 Freiburg, Germany.
- Bernstein Center Freiburg, University of Freiburg, Hansastrasse 9a, 79104 Freiburg, Germany.
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Su L, Smith PM, Anand P, Reeja-Jayan B. Surface Engineering of a LiMn 2O 4 Electrode Using Nanoscale Polymer Thin Films via Chemical Vapor Deposition Polymerization. ACS Appl Mater Interfaces 2018; 10:27063-27073. [PMID: 30040379 DOI: 10.1021/acsami.8b08711] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Surface engineering is a critical technique for improving the performance of lithium-ion batteries (LIBs). Here, we introduce a novel vapor-based technique, namely, chemical vapor deposition polymerization, that can engineer nanoscale polymer thin films with controllable thickness and composition on the surface of battery electrodes. This technique enables us to, for the first time, systematically compare the effects of a conducting poly(3,4-ethylenedioxythiophene) (PEDOT) polymer and an insulating poly(divinylbenzene) (PDVB) polymer on the performance of a LiMn2O4 electrode in LIBs. Our results show that conducting PEDOT coatings improve both the rate and the cycling performance of LiMn2O4 electrodes, whereas insulating PDVB coatings have little effect on these performances. The PEDOT coating increases 10 C rate capacity by 83% at 25 °C (from 23 to 42 mA h/g) and by 30% at 50 °C (from 64 to 83 mA h/g). Furthermore, the PEDOT coating extends the high-temperature (50 °C) cycling life of LiMn2O4 by over 60%. A model is developed, which can precisely describe the capacity degradation exhibited by the different types of cells, based on the aging mechanisms of Mn dissolution and solid-electrolyte interphase growth. Results from X-ray photoelectron spectroscopy suggest that chemical or coordination bonds form between Mn in LiMn2O4 and O and S in the PEDOT film. These bonds stabilize the surface of LiMn2O4 and thus improve the cycling performance. In contrast, no bonds form between Mn and the elements in the PDVB film. We further demonstrate that this vapor-based technique can be extended to other cathodes for advanced LIBs.
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Chao D, Xia X, Liu J, Fan Z, Ng CF, Lin J, Zhang H, Shen ZX, Fan HJ. A V2O5/conductive-polymer core/shell nanobelt array on three-dimensional graphite foam: a high-rate, ultrastable, and freestanding cathode for lithium-ion batteries. Adv Mater 2014; 26:5794-800. [PMID: 24888872 DOI: 10.1002/adma.201400719] [Citation(s) in RCA: 152] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 03/23/2014] [Indexed: 04/14/2023]
Abstract
A thin polymer shell helps V2O5 a lot. Short V2O5 nanobelts are grown directly on 3D graphite foam as a lithium-ion battery (LIB) cathode material. A further coating of a poly(3,4-ethylenedioxythiophene) (PEDOT) thin shell is the key to the high performance. An excellent high-rate capability and ultrastable cycling up to 1000 cycles are demonstrated.
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Affiliation(s)
- Dongliang Chao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
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Hsiao YS, Luo SC, Hou S, Zhu B, Sekine J, Kuo CW, Chueh DY, Yu H, Tseng HR, Chen P. 3D bioelectronic interface: capturing circulating tumor cells onto conducting polymer-based micro/nanorod arrays with chemical and topographical control. Small 2014; 10:3012-7. [PMID: 24700425 PMCID: PMC4125486 DOI: 10.1002/smll.201400429] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 03/10/2014] [Indexed: 05/20/2023]
Abstract
The three-dimensional (3D) poly(3,4-ethylenedioxythiophene) (PEDOT)-based bioelectronic interfaces (BEIs) with diverse dimensional micro/nanorod array structures, varied surface chemical pro-perties, high electrical conductivity, reversible chemical redox switching, and high optical transparency are used for capturing circulating tumor cells (CTCs). Such 3D PEDOT-based BEIs can function as an efficient clinical diagonstic and therapeutic platform.
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Affiliation(s)
| | - Shyh-Chyang Luo
- Responsive Organic Materials Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
- Department of Materials Science and Engineering, National Cheng Kung University, Tainan (Taiwan)
| | - Shuang Hou
- Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging (CIMI), California NanoSystems Institute (CNSI), University of California, Los Angeles, 570 Westwood Plaza, Building 114, Los Angeles, CA 90095-1770 (USA)
| | - Bo Zhu
- Responsive Organic Materials Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai (China)
| | - Jun Sekine
- Responsive Organic Materials Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
| | - Chiung-Wen Kuo
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529 (Taiwan)
| | - Di-Yen Chueh
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529 (Taiwan)
| | - Hsiaohua Yu
- Fax: (+81) (0)48-462-1659, Web: http://www.riken.jp/lab/yuiru/,
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Imae I, Nakamura Y, Komaguchi K, Ooyama Y, Ohshita J, Harima Y. Development of a simple method for fabrication of transparent conductive films with high mechanical strength. Sci Technol Adv Mater 2012; 13:045005. [PMID: 27877505 PMCID: PMC5090561 DOI: 10.1088/1468-6996/13/4/045005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 07/10/2012] [Indexed: 06/06/2023]
Abstract
We have developed a simple method of fabricating transparent conductive films with a high mechanical strength on glass and indium tin oxide substrates. It does not require a large excess of organic solvents and polymerization catalysts and can yield smooth films by spin-coating of a mixture of a commercially available aqueous dispersion of poly(3,4-ethylenedioxythiophene)-poly(4-styrene sulfonate) and a neat liquid of tetraethyl orthosilicate. Preparation conditions such as feed ratio, kinds of additives, and annealing temperature and time were optimized to give highly conductive, transparent and mechanically strong films.
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Olowu RA, Arotiba O, Mailu SN, Waryo TT, Baker P, Iwuoha E. Electrochemical aptasensor for endocrine disrupting 17β-estradiol based on a poly(3,4-ethylenedioxylthiopene)-gold nanocomposite platform. Sensors (Basel) 2010; 10:9872-90. [PMID: 22163445 PMCID: PMC3231014 DOI: 10.3390/s101109872] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 09/17/2010] [Accepted: 10/11/2010] [Indexed: 11/23/2022]
Abstract
A simple and highly sensitive electrochemical DNA aptasensor with high affinity for endocrine disrupting 17β-estradiol, was developed. Poly(3,4-ethylenedioxylthiophene) (PEDOT) doped with gold nanoparticles (AuNPs) was electrochemically synthesized and employed for the immobilization of biotinylated aptamer towards the detection of the target. The diffusion coefficient of the nanocomposite was 6.50 × 10−7 cm2 s−1, which showed that the nanocomposite was highly conducting. Electrochemical impedance investigation also revealed the catalytic properties of the nanocomposite with an exchange current value of 2.16 × 10−4 A, compared to 2.14 × 10−5 A obtained for the bare electrode. Streptavidin was covalently attached to the platform using carbodiimide chemistry and the aptamer immobilized via streptavidin—biotin interaction. The electrochemical signal generated from the aptamer–target molecule interaction was monitored electrochemically using cyclic voltammetry and square wave voltammetry in the presence of [Fe(CN)6]−3/−4 as a redox probe. The signal observed shows a current decrease due to interference of the bound 17β-estradiol. The current drop was proportional to the concentration of 17β-estradiol. The PEDOT/AuNP platform exhibited high electroactivity, with increased peak current. The platform was found suitable for the immobilization of the DNAaptamer. The aptasensor was able to distinguish 17β-estradiol from structurally similar endocrine disrupting chemicals denoting its specificity to 17β-estradiol. The detectable concentration range of the 17β-estradiol was 0.1 nM–100 nM, with a detection limit of 0.02 nM.
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Affiliation(s)
- Rasaq A Olowu
- Sensor Lab, Department of Chemistry, University of the Western Cape, Bellville 7535, South Africa.
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