title: Evanescent wave DNA-aptamer biosensor based on long period gratings for the specific recognition of E. coli outer membrane proteins.
abstract: An evanescent wave fiber optic sensor for detection of Escherichia coli (E. coli) outer membranes proteins (EcOMPs) using long period gratings (LPGs) as a refractometric platform is presented. The sensing probes were attained by the functionalization of LPGs inscribed in single mode fiber using two different methods of immobilization; electrostatic assembly and covalent binding. The resulting label-free configuration enabled the specific recognition of EcOMPs in water by monitoring the resonance wavelength shift due to refractive index changes induced by binding events. The sensors displayed linear responses in the range of 0.1 nM to 10 nM EcOMPs with sensitivities of -0.1563±0.005 nm decade(-1) [EcOMP, M] (electrostatic method) and -0.1597±0.004 nm decade(-1) [EcOMP, M] (covalent method). The devices could be regenerated (under low pH conditions) with a deviation less than 0.1% for at least three subsequent detection events. The sensors were also applied to spiked environmental water samples.
authors.affiliation: INESC TEC (Coordinated by INESC Porto), Rua do Campo Alegre, 687, 4150-179 Porto, Portugal. Electronic address: raquelbqueiros@gmail.com.
authors.forename: R B
authors.initials: RB
authors.lastname: Queirós
authors.affiliation: INESC TEC (Coordinated by INESC Porto), Rua do Campo Alegre, 687, 4150-179 Porto, Portugal.
authors.forename: C
authors.initials: C
authors.lastname: Gouveia
authors.affiliation: INESC TEC (Coordinated by INESC Porto), Rua do Campo Alegre, 687, 4150-179 Porto, Portugal; Universidade de Trás-os-Montes e Alto Douro, Apartado 1013, 5001-801 Vila Real, Portugal.
authors.forename: J R A
authors.initials: JR
authors.lastname: Fernandes
authors.affiliation: INESC TEC (Coordinated by INESC Porto), Rua do Campo Alegre, 687, 4150-179 Porto, Portugal.
authors.forename: P A S
authors.initials: PA
authors.lastname: Jorge
mesh_terms: D052157:Aptamers, Nucleotide / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis*; D001483:Base Sequence; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins / Q000032:analysis*; D005336:Fiber Optic Technology; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D055100:Optical Fibers; D012031:Refractometry; D014871:Water Microbiology
chemical_list: D052157:Aptamers, Nucleotide; D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins
keywords: Aptamer; Biosensor; E. coli; LPGs; Label-free