title: Porous Silicon-Based Biosensors: Towards Real-Time Optical Detection of Target Bacteria in the Food Industry.
abstract: Rapid detection of target bacteria is crucial to provide a safe food supply and to prevent foodborne diseases. Herein, we present an optical biosensor for identification and quantification of Escherichia coli (E. coli, used as a model indicator bacteria species) in complex food industry process water. The biosensor is based on a nanostructured, oxidized porous silicon (PSi) thin film which is functionalized with specific antibodies against E. coli. The biosensors were exposed to water samples collected directly from process lines of fresh-cut produce and their reflectivity spectra were collected in real time. Process water were characterized by complex natural micro-flora (microbial load of >107cell/mL), in addition to soil particles and plant cell debris. We show that process water spiked with culture-grown E. coli, induces robust and predictable changes in the thin-film optical interference spectrum of the biosensor. The latter is ascribed to highly specific capture of the target cells onto the biosensor surface, as confirmed by real-time polymerase chain reaction (PCR). The biosensors were capable of selectively identifying and quantifying the target cells, while the target cell concentration is orders of magnitude lower than that of other bacterial species, without any pre-enrichment or prior processing steps.
authors.affiliation: Department of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
authors.forename: Naama
authors.initials: N
authors.lastname: Massad-Ivanir
authors.affiliation: The Interdepartmental Program of Biotechnology, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
authors.forename: Giorgi
authors.initials: G
authors.lastname: Shtenberg
authors.affiliation: Department of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
authors.forename: Nitzan
authors.initials: N
authors.lastname: Raz
authors.affiliation: Microbiome Ltd, Amsterdam, the Netherlands.
authors.forename: Christel
authors.initials: C
authors.lastname: Gazenbeek
authors.affiliation: Department of Medical Microbiology, VU medical Center, Amsterdam, the Netherlands.
authors.forename: Dries
authors.initials: D
authors.lastname: Budding
authors.affiliation: Microbiome Ltd, Amsterdam, the Netherlands.
authors.forename: Martine P
authors.initials: MP
authors.lastname: Bos
authors.affiliation: Department of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.|The Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
authors.forename: Ester
authors.initials: E
authors.lastname: Segal
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D004926:Escherichia coli / Q000235:genetics*; D019649:Food Industry / Q000379:methods; D049329:Nanostructures / Q000737:chemistry; D016062:Porosity; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D012825:Silicon / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D012825:Silicon