Related Experiment Video
Updated: Apr 27, 2026
Optical Detection of E. coli Bacteria by Mesoporous Silicon Biosensors
Published on: November 20, 2013
Evanescent wave DNA-aptamer biosensor based on long period gratings for the specific recognition of E. coli outer
R B Queirós1, C Gouveia1, J R A Fernandes2
1INESC TEC (Coordinated by INESC Porto), Rua do Campo Alegre, 687, 4150-179 Porto, Portugal.
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.
