title: Detection of ESAT-6 by a label free miniature immuno-electrochemical biosensor as a diagnostic tool for tuberculosis.
abstract: Tuberculosis is a worldwide disease considered as a major health problem with high morbidity and mortality rates. Poor detection of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis remains a major obstacle to the global control of this disease. Here we report the development of a new test based on the detection of the major virulent factor of Mtb, namely the early secreted antigenic target 6-kDa protein or ESAT-6. A label free electrochemical immunosensor using an anti-ESAT-6 monoclonal antibody as a bio-receptor is described herein. Anti-ESAT-6 antibodies were first covalently immobilized on the surface of a gold screen-printed electrode functionalized via a self-assembled thiol monolayer. Interaction between the bio-receptor and ESAT-6 antigen was evaluated by square wave voltammetry method using [Fe(CN)6]3-/4-as redox probe. The detection limit of ESAT-6 antigen was 7ng/ml. The immunosensor has also been able to detect native ESAT-6 antigen secreted in cell culture filtrates of three pathogenic strains of Mtb (CDC1551, H37RV and H8N8). Overall, this work describes an immune-electrochemical biosensor, based on ESAT-6 antigen detection, as a useful diagnostic tool for tuberculosis.
authors.affiliation: Institut Pasteur de Tunis, LR11IPT03, Laboratory of Epidemiology and Veterinary Microbiology (LEMV), Tunis-Belvédère 1002, Tunisia; Institut Pasteur de Tunis, LR11IPT02, Laboratory of Transmission, Control and Immunobiology of Infections (LTCII), Tunis-Belvédère 1002, Tunisia; Faculty of Sciences of Bizerte, University of Carthage, Bizerte 7021, Tunisia. Electronic address: fethi.diouani@pasteur.rns.tn.
authors.forename: Mohamed Fethi
authors.initials: MF
authors.lastname: Diouani
authors.affiliation: Prince Sattam Bin Abdulaziz University, Saudi Arabia; Université Tunis El Manar, Tunis 1068, Tunisia.
authors.forename: Oussama
authors.initials: O
authors.lastname: Ouerghi
authors.affiliation: Institut Pasteur de Tunis, LR11IPT02, Laboratory of Transmission, Control and Immunobiology of Infections (LTCII), Tunis-Belvédère 1002, Tunisia; Université Tunis El Manar, Tunis 1068, Tunisia.
authors.forename: Amira
authors.initials: A
authors.lastname: Refai
authors.affiliation: Institut Pasteur de Tunis, LR11IPT03, Laboratory of Epidemiology and Veterinary Microbiology (LEMV), Tunis-Belvédère 1002, Tunisia; Université Tunis El Manar, Tunis 1068, Tunisia.
authors.forename: Kamel
authors.initials: K
authors.lastname: Belgacem
authors.affiliation: Institut Pasteur de Tunis, LR11IPT03, Laboratory of Epidemiology and Veterinary Microbiology (LEMV), Tunis-Belvédère 1002, Tunisia; Research Center for Precision Medicine and Single Molecule Diagnostics, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
authors.forename: Chaker
authors.initials: C
authors.lastname: Tlili
authors.affiliation: Institut Pasteur de Tunis, LR11IPT02, Laboratory of Transmission, Control and Immunobiology of Infections (LTCII), Tunis-Belvédère 1002, Tunisia; Université Tunis El Manar, Tunis 1068, Tunisia.
authors.forename: Dhafer
authors.initials: D
authors.lastname: Laouini
authors.affiliation: Institut Pasteur de Tunis, LR11IPT02, Laboratory of Transmission, Control and Immunobiology of Infections (LTCII), Tunis-Belvédère 1002, Tunisia; Université Tunis El Manar, Tunis 1068, Tunisia.
authors.forename: Makram
authors.initials: M
authors.lastname: Essafi
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology; D000942:Antigens, Bacterial / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D004566:Electrodes; D005292:Ferricyanides / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D008904:Miniaturization; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology
chemical_list: D055910:Antibodies, Immobilized; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D005292:Ferricyanides; D011994:Recombinant Proteins; C007931:hexacyanoferrate III
keywords: Biosensor; Diagnosis; ESAT-6; Immuno-sensor; Square wave voltammetry; Tuberculosis