title: Dual labeled Ag@SiO₂ core-shell nanoparticle based optical immunosensor for sensitive detection of E. coli.
abstract: An optical nanobiosensor is presented using a fluorescent dye and anti-E. coli McAb anchored Ag@Silica core shell nanoparticles, for rapid and sensitive Escherichia coli detection in environmental samples. The synthesized dual labeled core shell (DLCS) nanoparticle shows intense fluorescence at 620 nm in solution, having a narrow emission with full width at half maxima (FWHM) of 10 nm, as a prerequisite to develop a sensitive detection platform for various biosensing applications. The specific E. coli was captured using an anti-E. coli antibody functionalized quartz glass, followed by a treatment with DLCS, where the photoluminescence spectroscopy was used to detect the target pathogen. The fabrication of the quartz glass based optical-immunosensor was monitored, and the results show changes in the photoluminescent patterns, which substantiate that varied species were immobilized on the surface of the antibody modified quartz glass. Consequently, the optical immunosensor demonstrated specificity and improved sensitivity, as compared to the customary methods, and was able to detect as low as 5CFU/mL. The developed DLCS based optical immunosensor was evaluated with environmental water samples, which showed acceptable precision, reproducibility and stability, and could be readily applied to the routine monitoring of pathogenic microorganisms in the environmental samples, and most importantly, demonstrate the potential of a prototype development of a simple and inexpensive diagnostic technique.
authors.affiliation: Department of Chemistry, MIT Campus, Anna University, Chennai 600 044, India.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Krishnan
authors.affiliation: Division of Proteomics and Nanobiotechnology, Science for Life Laboratory, KTH-Royal Institute of Technology, Stockholm, Sweden.
authors.forename: Thiruppathiraja
authors.initials: T
authors.lastname: Chinnasamy
authors.affiliation: National Environmental Engineering Research Institute, Chennai Zonal Laboratory, CSIR Complex, Chennai 600 113, India.
authors.forename: Saroja
authors.initials: S
authors.lastname: Veerappan
authors.affiliation: National Environmental Engineering Research Institute, Chennai Zonal Laboratory, CSIR Complex, Chennai 600 113, India.
authors.forename: Kamatchiammal
authors.initials: K
authors.lastname: Senthilkumar
authors.affiliation: Department of Chemistry, Thiruvalluvar University, Vellore 632 115, India. Electronic address: kdinakaran.tvu@gmail.com.
authors.forename: Dinakaran
authors.initials: D
authors.lastname: Kannaiyan
mesh_terms: D015374:Biosensing Techniques; D004926:Escherichia coli / Q000302:isolation & purification*; D005456:Fluorescent Dyes / Q000737:chemistry; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D012834:Silver; D012822:Silicon Dioxide
keywords: Core–shell nanoparticle; E. coli; Immunosensor; Optical sensor; Photoluminescence