title: Optical biosensors with an integrated Mach-Zehnder Interferometer for detection of Listeria monocytogenes.
abstract: In this work, we have demonstrated an efficient optical immunoassay technique for the detection of a food-borne pathogen, Listeria monocytogenes, using a Mach-Zehnder Interferometer (MZI) configuration. We have investigated ten different MZI configurations with angular and Sbend Y-junction geometries. An efficient Hydrofluoric acid (HF) based technique was used for rapid and specific binding of L. monocytogenes to the sensor arm of the MZI biosensor. The MZI biosensor was able to detect L. monocytogenes at concentrations of the order of 10(5) CFU/ml, which is lower than the infection dose for healthy human beings. SEM analysis and light intensity measurements showed the biosensor is highly selective to L. monocytogenes over other microbial species (such as Escherichia coli). Finally, a novel calibration scheme of the MZI biosensor was developed from experimental data that can be used for determining unknown concentrations of L. monocytogenes.
authors.affiliation: Department of Mechanical Engineering, University of Alberta, Edmonton, T6G 2G8, Canada.
authors.forename: Dibyo
authors.initials: D
authors.lastname: Sarkar
authors.forename: Naga Siva Kumar
authors.initials: NS
authors.lastname: Gunda
authors.forename: Iqbal
authors.initials: I
authors.lastname: Jamal
authors.forename: Sushanta K
authors.initials: SK
authors.lastname: Mitra
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D018914:Cells, Immobilized / Q000382:microbiology; D015169:Colony Count, Microbial; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D005976:Glutaral / Q000737:chemistry; D007118:Immunoassay / Q000379:methods; D057230:Limit of Detection; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties
chemical_list: D005976:Glutaral