1
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Tekkis NP, Rafi D, Brown S, Courtney A, Kawka M, Howell AM, McLean K, Gardiner M, Mavroveli S, Hutchinson P, Tekkis P, Wilkinson P, Sam AH, Savva N, Kontovounisios C, Tekkis N, Rafi D, Brown S, Courtney A, Kawka M, Howell A, McLean K, Gardiner M, Mavroveli S, Hutchinson P, Tekkis P, Wilkinson P, Sam AH, Savva N, Kontovounisios C, Tekkis N, Rafi D, Brown S, Courtney A, Kawka M, Howell A, McLean K, Gardiner M, Mavroveli S, Hutchinson P, Tekkis P, Wilkinson P, Sam AH, Savva N, Kontovounisios C, Tekkis N, Brown S, Kawka M, Mclean K, Savva N, Wilkinson P, Sam AH, Singal A, Chia C, Chia W, Ganesananthan S, Ooi SZY, Pengelly S, Wellington J, Mak S, Subbiah Ponniah H, Heyes A, Aberman I, Ahmed T, Al-Shamaa S, Appleton L, Arshad A, Awan H, Baig Q, Benedict K, Berkes S, Citeroni NL, Damani A, de Sancha A, Fisayo T, Gupta S, Haq M, Heer B, Jones A, Khan H, Kim H, Meiyalagan N, Miller G, Minta N, Mirza L, Mohamed F, Ramjan F, Read P, Soni L, Tailor V, Tas RN, Vorona M, Walker M, Winkler T, Bardon A, Acquaah J, Ball T, Bani W, Elmasry A, Hussein F, Kolluri M, Lusta H, Newman J, Nott M, Perwaiz MI, Rayner R, Shah A, Shaw I, Yu K, Cairns M, Clough R, Gaier S, Hirani D, Jeyapalan T, Li Y, Patel CR, Shabir H, Wang YA, Weatherhead A, Dhiran A, Renney O, Wells P, Ferguson S, Joyce A, Mergo A, Adebayo O, Ahmad J, Akande O, Ang G, Aniereobi E, Awasthi S, Banjoko A, Bates J, Chibada C, Clarke N, Craner I, Desai DD, Dixon K, Duffaydar HI, Kuti M, Mughal AZ, Nair D, Pham MC, Preest GG, Reid R, Sachdeva GS, Selvaratnam K, Sheikh J, Soran V, Stoney N, Wheatle M, Howarth K, Knapp-Wilson A, Lee KS, Mampitiya N, Masson C, McAlinden JJ, McGowan N, Parmar SC, Robinson B, Wahid S, Willis L, Risquet R, Adebayo A, Dhingra L, Kathiravelupillai S, Narayanan R, Soni J, Ghafourian P, Hounat A, Lennon KA, Abdi Mohamud M, Chou W, Chong L, Graham CJ, Piya S, Riad AM, Vennard S, Wang J, Kawar L, Maseland C, Myatt R, Tengku Saifudin TNS, Yong SQ, Douglas F, Ogbechie C, Sharma K, Zafar L, Bajomo MO, Byrne MHV, Obi C, Oluyomi DI, Patsalides MA, Rajananthanan A, Richardson G, Clarke A, Roxas A, Adeboye W, Argus L, McSweeney J, Rahman-Chowdhury M, Hettiarachchi DS, Masood MT, Antypas A, Thomas M, de Andres Crespo M, Zimmerman M, Dhillon A, Abraha S, Burton O, Jalal AHB, Bailey B, Casey A, Kathiravelupillai A, Missir E, Boult H, Campen D, Collins JM, Dulai S, Elhassan M, Foster Z, Horton E, Jones E, Mahapatra S, Nancarrow T, Nyamapfene T, Rimmer A, Robberstad M, Robson-Brown S, Saeed A, Sarwar Y, Taylor C, Vetere G, Whelan MK, Williams J, Zahid D, Chand C, Matthews M. The impact of the COVID-19 pandemic on UK medical education. A nationwide student survey. Med Teach 2022; 44:574-575. [PMID: 34428109 DOI: 10.1080/0142159x.2021.1962835] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
| | - Damir Rafi
- School of Medicine, Imperial College London, London, UK
| | - Sam Brown
- Leicester Medical School, University of Leicester, Leicester, UK
| | - Alona Courtney
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Michal Kawka
- School of Medicine, Imperial College London, London, UK
| | - Ann-Marie Howell
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Kenneth McLean
- Division of Clinical and Surgical Sciences, University of Edinburgh, Edinburgh, UK
| | - Matthew Gardiner
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | | | - Peter Hutchinson
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Paris Tekkis
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Paul Wilkinson
- School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Amir H Sam
- School of Medicine, Imperial College London, London, UK
| | - Nicos Savva
- Division of Management Science and Operations, London Business School, London, UK
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- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - T Ball
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - W Bani
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - A Elmasry
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - F Hussein
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - M Kolluri
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - H Lusta
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - J Newman
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - M Nott
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - M I Perwaiz
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - R Rayner
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - A Shah
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - I Shaw
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | - K Yu
- Plymouth University Peninsula Schools of Medicine and Dentistry
| | | | | | - S Gaier
- Queen Mary University of London
| | | | | | - Y Li
- Queen Mary University of London
| | | | | | | | | | - A Dhiran
- St George's Hospital Medical School
| | - O Renney
- St George's Hospital Medical School
| | - P Wells
- St George's Hospital Medical School
| | | | - A Joyce
- The Queen's University of Belfast
| | | | | | - J Ahmad
- The University of Birmingham
| | | | - G Ang
- The University of Birmingham
| | | | | | | | - J Bates
- The University of Birmingham
| | | | | | | | | | - K Dixon
- The University of Birmingham
| | | | - M Kuti
- The University of Birmingham
| | | | - D Nair
- The University of Birmingham
| | | | | | - R Reid
- The University of Birmingham
| | | | | | | | - V Soran
- The University of Birmingham
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- The University of Cambridge
| | | | | | | | | | - W Chou
- The University of East Anglia
| | | | | | - S Piya
- The University of Edinburgh
| | | | | | - J Wang
- The University of Edinburgh
| | | | | | | | | | | | | | | | | | | | | | | | - C Obi
- The University of Leicester
| | | | | | | | | | | | | | | | - L Argus
- The University of Manchester
| | | | | | | | | | | | | | | | | | | | | | | | | | - B Bailey
- University of Brighton and Sussex
| | - A Casey
- University of Brighton and Sussex
| | | | - E Missir
- University of Brighton and Sussex
| | - H Boult
- University of Exeter Medical School
| | - D Campen
- University of Exeter Medical School
| | | | - S Dulai
- University of Exeter Medical School
| | | | - Z Foster
- University of Exeter Medical School
| | - E Horton
- University of Exeter Medical School
| | - E Jones
- University of Exeter Medical School
| | | | | | | | - A Rimmer
- University of Exeter Medical School
| | | | | | - A Saeed
- University of Exeter Medical School
| | - Y Sarwar
- University of Exeter Medical School
| | - C Taylor
- University of Exeter Medical School
| | - G Vetere
- University of Exeter Medical School
| | | | | | - D Zahid
- University of Exeter Medical School
| | - C Chand
- University of Hull and the University of York
| | - M Matthews
- University of Hull and the University of York
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2
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Piro B, Pham MC, Bazzaoui EA, Lacroix JC, Lacaze PC, Novak P, Hass O. Un nouveau film conducteur poly(aminoquinone) pour le stockage de l'énergie. ACTA ACUST UNITED AC 2017. [DOI: 10.1051/jcp:1998320] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Nguyen TD, Dang TTH, Thai H, Nguyen LH, Tran DL, Piro B, Pham MC. One-step Electrosynthesis of Poly(1,5-diaminonaphthalene)/Graphene Nanocomposite as Platform for Lead Detection in Water. ELECTROANAL 2016. [DOI: 10.1002/elan.201501075] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- T. Dung Nguyen
- Institute for Tropical Technology; Vietnam Academy of Science and Technology; 18 Hoang Quoc Viet Hanoi Vietnam
| | - T. T. Huyen Dang
- Institute for Tropical Technology; Vietnam Academy of Science and Technology; 18 Hoang Quoc Viet Hanoi Vietnam
| | - Hoang Thai
- Institute for Tropical Technology; Vietnam Academy of Science and Technology; 18 Hoang Quoc Viet Hanoi Vietnam
| | - L. Huy Nguyen
- School of Chemical Engineering; Hanoi University of Science and Technology; 1 Dai Co Viet Hanoi Vietnam
| | - D. Lam Tran
- Institute of Material Sciences; Vietnam Academy of Science and Technology; 18 Hoang Quoc Viet Hanoi Vietnam
| | - B. Piro
- Univ. Paris Diderot; Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS; 15 rue J-A de Baïf 75205 Paris Cedex 13 France
| | - M. C. Pham
- Univ. Paris Diderot; Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS; 15 rue J-A de Baïf 75205 Paris Cedex 13 France
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Strzemińska I, Sainte Rose Fanchine S, Anquetin G, Reisberg S, Noël V, Pham MC, Piro B. Grafting of a peptide probe for Prostate-Specific Antigen detection using diazonium electroreduction and click chemistry. Biosens Bioelectron 2016; 81:131-137. [PMID: 26938492 DOI: 10.1016/j.bios.2016.02.060] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/23/2016] [Indexed: 11/28/2022]
Abstract
The main objective of this work was to validate a label-free electrochemical method of protein detection using peptides as capture probes. As a proof-of-concept, we used a 7 amino acids sequence (HSSKLQL) specific for Prostate Specific Antigen. We investigated various electrografting conditions of two anilines (2-[(4-aminophenyl)sulfanyl]-8-hydroxy-1,4-naphthoquinone and 4-azidoaniline) further converted in situ into their corresponding diazonium salts on glassy carbon electrodes. It was demonstrated that the best method to obtain a mixed layer is the simultaneous electroreduction of the two diazonium salts. 4-azidoaniline was used to covalently immobilize the ethynyl-functionalized peptide probe by click coupling, and the hydroxynaphthoquinone derivative plays the role of electrochemical transducer of the peptide-protein recognition. The proteolytic activity of PSA towards a small peptide substrate carrying streptavidin at its distal end was also investigated to design an original sensing architecture leading to a reagentless, label free, and "signal-on" PSA sensor. Without optimization, the limit of quantification can be estimated in the nM to pM range.
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Affiliation(s)
- I Strzemińska
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - S Sainte Rose Fanchine
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - G Anquetin
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - S Reisberg
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - V Noël
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - M C Pham
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - B Piro
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
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Souada M, Piro B, Reisberg S, Anquetin G, Noël V, Pham MC. Label-free electrochemical detection of prostate-specific antigen based on nucleic acid aptamer. Biosens Bioelectron 2014; 68:49-54. [PMID: 25569871 DOI: 10.1016/j.bios.2014.12.033] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/01/2014] [Accepted: 12/15/2014] [Indexed: 12/17/2022]
Abstract
We report a label-free aptasensor to make direct detection of prostate specific antigen (PSA, a biomarker of prostate cancer) using a quinone-containing conducting copolymer acting as redox transducer and grafting matrix for immobilization of the short aptamer strands. It is shown that capture of PSA generates a current decrease (signal-off) measured by Square Wave Voltammetry. This current decrease is specific for PSA above a limit of quantification in the ng mL(-1) range. The change in current is used to determine the PSA-aptamer dissociation constant K(D), of ca. 2.6 nM. To consolidate the proof of concept, a heterogeneous competitive exchange with a complementary DNA strand which breaks PSA-aptamer interactions is studied. This double-check followed by a current increase provides full assurance of a perfectly specific recognition.
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Affiliation(s)
- M Souada
- Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - B Piro
- Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
| | - S Reisberg
- Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - G Anquetin
- Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - V Noël
- Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - M C Pham
- Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
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6
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Tran HV, Piro B, Reisberg S, Huy Nguyen L, Dung Nguyen T, Duc HT, Pham MC. An electrochemical ELISA-like immunosensor for miRNAs detection based on screen-printed gold electrodes modified with reduced graphene oxide and carbon nanotubes. Biosens Bioelectron 2014; 62:25-30. [PMID: 24973539 DOI: 10.1016/j.bios.2014.06.014] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 06/06/2014] [Accepted: 06/10/2014] [Indexed: 11/17/2022]
Abstract
We design an electrochemical immunosensor for miRNA detection, based on screen-printed gold electrodes modified with reduced graphene oxide and carbon nanotubes. An original immunological approach is followed, using antibodies directed to DNA.RNA hybrids. An electrochemical ELISA-like amplification strategy was set up using a secondary antibody conjugated to horseradish peroxidase (HRP). Hydroquinone is oxidized into benzoquinone by the HRP/H2O2 catalytic system. In turn, benzoquinone is electroreduced into hydroquinone at the electrode. The catalytic reduction current is related to HRP amount immobilized on the surface, which itself is related to miRNA.DNA surface density on the electrode. This architecture, compared to classical optical detection, lowers the detection limit down to 10 fM. Two miRNAs were studied: miR-141 (a prostate biomarker) and miR-29b-1 (a lung cancer biomarker).
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Affiliation(s)
- H V Tran
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France; USTH, University of Science and Technology of Hanoi, 18 Hoang Quoc Viet, Hanoi, Vietnam; School of Chemical Engineering, Hanoi University of Science and Technology, 1st Dai Co Viet Road, Hanoi, Vietnam
| | - B Piro
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - S Reisberg
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - L Huy Nguyen
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - T Dung Nguyen
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France
| | - H T Duc
- Université Paris 11, INSERM U-1014, Hôpital Paul Brousse 94800 Villejuif, France
| | - M C Pham
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
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7
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Tran HV, Piro B, Reisberg S, Anquetin G, Duc HT, Pham MC. An innovative strategy for direct electrochemical detection of microRNA biomarkers. Anal Bioanal Chem 2013; 406:1241-4. [PMID: 23963573 DOI: 10.1007/s00216-013-7292-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/24/2013] [Accepted: 08/05/2013] [Indexed: 01/10/2023]
Abstract
We report an electrochemical method for direct, reagentless, and label-free detection of microRNA, based on a conjugated copolymer, poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-2-carboxyethyl-1,4-naphthoquinone), acting as hybridization transducer. Hybridization between the oligonucleotide capture probe and a microRNA target of 22 base pairs generates an increase in the redox current ("signal-on"), which is evidenced by square wave voltammetry. Selectivity is good, with little hybridization for non-complementary targets, and the limit of detection reaches 650 fM. It is also evidenced that this sensitivity benefits from the high affinity of DNA for RNA.
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Affiliation(s)
- H V Tran
- Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205, Paris Cedex 13, France
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8
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Tran HV, Reisberg S, Piro B, Nguyen TD, Pham MC. Label-Free Electrochemical Immunoaffinity Sensor Based on Impedimetric Method for Pesticide Detection. ELECTROANAL 2013. [DOI: 10.1002/elan.201200331] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Zhang QD, March G, Noel V, Piro B, Reisberg S, Tran LD, Hai LV, Abadia E, Nielsen PE, Sola C, Pham MC. Label-free and reagentless electrochemical detection of PCR fragments using self-assembled quinone derivative monolayer: application to Mycobacterium tuberculosis. Biosens Bioelectron 2011; 32:163-8. [PMID: 22186165 DOI: 10.1016/j.bios.2011.11.048] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 09/29/2011] [Accepted: 11/30/2011] [Indexed: 11/17/2022]
Abstract
We report a signal-on, label-free and reagentless electrochemical DNA biosensor, based on a mixed self-assembled monolayer of thiolated hydroxynaphthoquinone and thiolated oligonucleotide. Electrochemical changes resulting from hybridization were evidenced with oligonucleotide targets (as models), as well as with polymerase chain reaction (PCR) products related to different lineages of Mycobacterium tuberculosis strains. With pure oligonucleotides, this system achieves high sensitivity (∼300 pM of DNA target, i.e. 30 fmol in a 100 μL sample) and excellent selectivity, allowing to detect a single mismatch on a sequence of 20 bases. With PCR products, current changes are specific to the bacterial strain from which the PCR fragment is produced. In addition, the sensor response is of the signal-on type, giving a positive signal change upon hybridization, and therefore does not suffer from false positive responses due to non-specific adsorption of DNA.
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Affiliation(s)
- Q D Zhang
- Interfaces, Traitement, Organisation et Dynamiques des Systèmes, UMR CNRS 7086, Université Paris Diderot, Sorbonne Paris Cité 15 rue Jean Antoine de Baïf, 75205 Paris Cedex 13, France
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10
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Reisberg S, Dang LA, Nguyen QA, Piro B, Noel V, Nielsen PE, Le LA, Pham MC. Label-free DNA electrochemical sensor based on a PNA-functionalized conductive polymer. Talanta 2008; 76:206-10. [PMID: 18585264 DOI: 10.1016/j.talanta.2008.02.044] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 02/08/2008] [Accepted: 02/20/2008] [Indexed: 11/26/2022]
Abstract
An electrochemical hybridization biosensor based on peptide nucleic acid (PNA) probe is presented. PNA were attached covalently onto a quinone-based electroactive polymer. Changes in flexibility of the PNA probe strand upon hybridization generates electrochemical changes at the polymer-solution interface. A reagentless and direct electrochemical detection was obtained by detection of the electrochemical changes using square wave voltammetry (SWV). An increase in the peak current of quinone was observed upon hybridization of probe on the target, whereas no change is observed with non-complementary sequence. In addition, the biosensor is highly selective to effectively discriminate a single mismatch on the target sequence. The sensitivity is also presented and discussed.
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Affiliation(s)
- S Reisberg
- Laboratoire Interfaces-Traitements-Organisation et Dynamique des Systèmes, Université Paris 7-Denis Diderot, associé au CNRS, UMR 7086, 1 rue Guy de la Brosse, Paris 75005, France
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11
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Gabrielli C, Perrot H, Rose D, Rubin A, Toqué JP, Pham MC, Piro B. New frequency/voltage converters for ac-electrogravimetric measurements based on fast quartz crystal microbalance. Rev Sci Instrum 2007; 78:074103. [PMID: 17672777 DOI: 10.1063/1.2751093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A better understanding of the mechanisms located at the solid/electrolyte interface is becoming essential to the development of new applications in the electrochemical fields. The fast quartz crystal microbalance is an attractive and powerful gravimetric sensor which can be used in the dynamic regime to determine a mass/potential transfer function. The principle is equivalent to classical electrochemical impedance measurements; the only difference is the determination of mass changes given by the quartz crystal microbalance rather than current changes following sine wave modulations of the applied potential. This function appears very well adapted to characterize ionic exchanges at the electrochemical interface. Frequency/voltage converters are the key devices in translating the microbalance frequency response in terms of a continuous voltage change. The latter allows the transfer function to be obtained via a frequency response analyzer. Different converters were tested in this work in order to improve the performances of the experimental setup.
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Affiliation(s)
- C Gabrielli
- LISE-UPR 15 du CNRS, Université Pierre et Marie Curie-Paris 6, 4, place Jussieu (case 133), 75252 Paris Cedex 05, France
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12
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Piro B, Reisberg S, Noel V, Pham MC. Investigations of the steric effect on electrochemical transduction in a quinone-based DNA sensor. Biosens Bioelectron 2007; 22:3126-31. [PMID: 17363240 DOI: 10.1016/j.bios.2007.02.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 01/19/2007] [Accepted: 02/06/2007] [Indexed: 11/29/2022]
Abstract
Electrochemical biosensors for DNA hybridization are receiving increasing interest. A key point for their efficiency is to obtain a high signal level for low DNA concentration. This implies the design of an efficient transducing surface. Conducting polymers are interesting for this purpose but the great majority of conducting polymer-based electrodes present a signal decrease upon hybridization (a "signal-off" behavior), which impedes their response and makes them sensitive to false positive ones. The sensor described here presents a "signal-on" behavior, due to the use of a quinone group as the transducing agent. The specific aim of this work is to study the steric effect on transduction. To this end, the electrochemical response was monitored versus the DNA target length, for a constant DNA probe length. The results indicate that the current depends on the length of the double strand. A model which can explain the electrochemical behavior takes into account the steric hindrance of the ODN strands.
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Affiliation(s)
- B Piro
- Laboratoire Interfaces-Traitements-Organisation et Dynamique des Systèmes (ITODYS), Université Paris 7-Denis Diderot, associé au CNRS, UMR 7086, 1 rue Guy de la Brosse, 75005 Paris, France
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Haccoun J, Piro B, Noël V, Pham MC. The development of a reagentless lactate biosensor based on a novel conducting polymer. Bioelectrochemistry 2006; 68:218-26. [PMID: 16263338 DOI: 10.1016/j.bioelechem.2005.09.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 08/26/2005] [Accepted: 09/02/2005] [Indexed: 10/25/2022]
Abstract
A reagentless lactate biosensor is described, based on an electropolymerized copolymer film poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-3-acetic acid-1,4-naphthoquinone). The quinone group, as part of the polymer backbone, is electroactive and very stable in neutral aqueous medium. It can therefore act as an immobilized mediator for the enzyme recycling, at a working potential much lower than those commonly reported in the literature for other mediators. Experimental conditions for amperometric measurements (temperature, pH) are studied, especially the interference between quinone and molecular oxygen to investigate the enzyme/quinone recycling kinetic. Some well-known interferents are shown to have no measurable effect on the amperometric curves.
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Affiliation(s)
- J Haccoun
- Laboratoire Interfaces-Traitements-Organisation et DYnamique des Systèmes (ITODYS), de l'Université Paris 7-Denis Diderot, associé au CNRS, UMR 7086, 1 rue Guy de la Brosse, 75005 Paris, France
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14
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Pham MC, Piro B, Tran LD, Ledoan T, Dao LH. Direct electrochemical detection of oligonucleotide hybridization on poly(5-hydroxy-1,4-naphthoquinone- co-5-hydroxy-3-thioacetic acid-1,4-naphthoquinone) film. Anal Chem 2004; 75:6748-52. [PMID: 14640757 DOI: 10.1021/ac034770f] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe the construction of a new DNA-modified electrode based on an electroactive film. 5-Hydroxy-1,4-naphthoquinone is coelectrooxidized with 5-hydroxy-3-thioacetic acid-1,4-naphthoquinone to give a copolymer, presenting both electroactive and chemically reactive groups. The carboxylic function acts as a precursor for the covalent grafting of ODN probes while the quinone group acts as the transduction element of hybridization. Electrochemical detection was performed by differential pulse voltammetry in the electroactivity domain of the quinone group (i.e., at very low potentials, 0 to -0.8 V vs SCE). A very clear modification of the redox activity is observed between unmodified and probe-modified films and especially upon addition of target ODN.
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Haccoun J, Piro B, Tran LD, Dang LA, Pham MC. Reagentless amperometric detection of l-lactate on an enzyme-modified conducting copolymer poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-3-thioacetic acid-1,4-naphthoquinone). Biosens Bioelectron 2004; 19:1325-9. [PMID: 15046766 DOI: 10.1016/j.bios.2003.11.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2003] [Revised: 11/13/2003] [Accepted: 11/14/2003] [Indexed: 11/29/2022]
Abstract
We have constructed a reagentless lactate sensor using lactate oxidase (LOD) covalently attached to an electropolymerized copolymer film, poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-3-thioacetic acid-1,4-naphthoquinone), poly(JUG-co-JUGA). Around 10(-12)Mcm(-2) of covalently bound enzymes are immobilized on these films. In aerated medium, the amperometric response versus lactate concentration shows a sensitivity of 350 +/- 50 microAM(-1)cm(-2) for an applied potential of +0.5V versus Ag|AgCl on a film-coated Pt electrode. In deaerated medium, the quinone group, conjugated with the polymer backbone, acts as an immobilized mediator. An amperometric response is observed on film-coated glassy carbon (GC) electrode at a potential as low as -0.1V versus Ag|AgCl, with a sensitivity of 110 +/- 40 microAM(-1)cm(-2).
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Affiliation(s)
- J Haccoun
- Laboratoire Interfaces Traitements Organisation et Dynamique des Systèmes (ITODYS) de l'Université Paris 7-Denis Diderot, associé au CNRS, UMR 7086, 1 rue Guy de la Brosse, 75005 Paris, France
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Abstract
Oligonucleotides were incorporated into conducting films of poly(3, 4-ethylene dioxythiophene) by an electrochemical method that involves two steps. The electrode is first coated with the polymer film by electropolymerization followed by electrooxidation of the formed polymer in the presence of the oligonucleotide. Neutral water soluble polymers such as poly(vinylpyrrolidone) or poly(ethylene glycol) were added to the polymerizing medium resulting in higher incorporation yields of oligonucleotides. The results showed that a payload of about 1.5 nmol/cm2 can be achieved in an 8 micron thick film for an oligomer concentration of about 70 microM in the working solution. Various physical methods were used to analyze the surface of the polymer-coated electrodes. Results showed the presence of domains of varying sizes at the film surface, corresponding to the insertion of the hydrophilic polymer within the matrix of the conductive polymer. The release of entrapped oligonucleotides from the coated film exhibited a three-step profile: a "burst" period during the first 5 min followed by an intermediate and a very slow release period lasting several days. Such polymer films could be exploited as useful reservoirs of biologically active substances for in vivo delivery to targeted tissues. For example, coated stents that can release antiproliferative agents such as antisense oligonucleotides at the site of balloon dilatation may be of interest in the treatment of postangioplasty restenosis.
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Affiliation(s)
- B Piro
- ITODYS, Université Paris VII, 1 Rue Guy de la Brosse, 75005 Paris, France
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Galland MC, Brun A, Camboulives J, Pham MC, Schops M, Tournigand T, Jouglard J. [Side effects from the use of formaldehyde solutions during the surgical removal of hydatid cysts (author's transl)]. Therapie 1980; 35:443-6. [PMID: 7423438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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