title: An electrochemical immunosensor for efficient detection of uropathogenic E. coli based on thionine dye immobilized chitosan/functionalized-MWCNT modified electrode.
abstract: Uropathogenic Escherichia coli (UPEC) is the major cause of 150 million Urinary Tract Infections (UTI) reported annually world-wide. High prevalence of multi-drug-resistance makes it dangerous and difficult to cure. Therefore simple, quick and early diagnostic tools are essential for effective treatment and control. We report an electrochemical immunosensor based on thionine dye (Th) immobilized on functionalized-multiwalled carbon nanotube+chitosan composite coated on glassy carbon electrode (GCE/f-MWCNT-Chit@Th) for quick and sensitive detection of UPEC in aqueous solution. This immunosensor was constructed by sequential immobilization of UPEC, bovine serum albumin, primary antibody and Horse Radish Peroxidase (HRP) tagged secondary antibody on the surface of GCE/f-MWCNT-Chit@Th. When analyzed using 2.5mM of hydrogen peroxide reduction reaction using cyclic voltammetry in phosphate buffer, pH 7.0, the immunosensor showed excellent linearity in a range of 10(2)-10(9)cfu of UPEC mL(-1) with a current sensitivity of 7.162μA {log(cfumL(-1))}(-1). The specificity of this immunosensor was tested using other UTI and non-UTI bacteria, Staphylococcus, Klebsiella, Proteus and Shigella. The clinical applicability of the immunosensor was also successfully tested directly in UPEC spiked urine samples (simulated sample).
authors.affiliation: Centre for Biotechnology, Anna University, Guindy, Chennai 600025, Tamil Nadu, India.
authors.forename: Chandran Hema
authors.initials: CH
authors.lastname: Gayathri
authors.affiliation: Environmental and Analytical Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu, India; Nano and Bioelectrochemistry Research Laboratory, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu, India.
authors.forename: Pinapeddavari
authors.initials: P
authors.lastname: Mayuri
authors.affiliation: Centre for Biotechnology, Anna University, Guindy, Chennai 600025, Tamil Nadu, India. Electronic address: ksankran@yahoo.com.
authors.forename: Krishnan
authors.initials: K
authors.lastname: Sankaran
authors.affiliation: Environmental and Analytical Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu, India; Nano and Bioelectrochemistry Research Laboratory, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu, India. Electronic address: askumarchem@yahoo.com.
authors.forename: Annamalai Senthil
authors.initials: AS
authors.lastname: Kumar
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D002417:Cattle; D048271:Chitosan / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D054308:Enteropathogenic Escherichia coli / Q000302:isolation & purification*; D004867:Equipment Design; D004927:Escherichia coli Infections / Q000175:diagnosis / Q000382:microbiology / Q000652:urine*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D037742:Nanotubes, Carbon / Q000737:chemistry; D010640:Phenothiazines / Q000737:chemistry; D014552:Urinary Tract Infections / Q000175:diagnosis / Q000382:microbiology / Q000652:urine*
chemical_list: D004396:Coloring Agents; D037742:Nanotubes, Carbon; D010640:Phenothiazines; D048271:Chitosan; C009469:thionine
keywords: Electrochemical Immunosensor; Thionine dye; Urine; Uropathogenic E. coli; functionalized MWCNT