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Rapid Detection of Salmonella typhimurium in Drinking Water by a White Light Reflectance Spectroscopy Immunosensor

Biosensors represent an attractive approach for fast bacteria detection. Here, we present an optical biosensor for the detection of Salmonella typhimurium lipopolysaccharide (LPS) and Salmonella bacteria in drinking water, based on white light reflectance spectroscopy. The sensor chip consisted of a...

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Autores principales: Angelopoulou, Michailia, Tzialla, Konstantina, Voulgari, Angeliki, Dikeoulia, Mary, Raptis, Ioannis, Kakabakos, Sotirios Elias, Petrou, Panagiota
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8069642/
https://www.ncbi.nlm.nih.gov/pubmed/33920297
http://dx.doi.org/10.3390/s21082683
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author Angelopoulou, Michailia
Tzialla, Konstantina
Voulgari, Angeliki
Dikeoulia, Mary
Raptis, Ioannis
Kakabakos, Sotirios Elias
Petrou, Panagiota
author_facet Angelopoulou, Michailia
Tzialla, Konstantina
Voulgari, Angeliki
Dikeoulia, Mary
Raptis, Ioannis
Kakabakos, Sotirios Elias
Petrou, Panagiota
author_sort Angelopoulou, Michailia
collection PubMed
description Biosensors represent an attractive approach for fast bacteria detection. Here, we present an optical biosensor for the detection of Salmonella typhimurium lipopolysaccharide (LPS) and Salmonella bacteria in drinking water, based on white light reflectance spectroscopy. The sensor chip consisted of a Si die with a thin SiO(2) layer on top that was transformed into a biosensor through the immobilization of Salmonella LPS. The optical setup included a reflection probe with seven 200 μm fibers, a visible and near-infrared light source, and a spectrometer. The six fibers at the reflection probe circumference were coupled with the light source and illuminated the biosensor chip vertically, whereas the central fiber collected the reflected light and guided it to the spectrometer. A competitive immunoassay configuration was adopted for the analysis. Accordingly, a mixture of LPS or bacteria solution, pre-incubated for 15 min, with an anti-Salmonella LPS antibody was pumped over the chip followed by biotinylated secondary antibody and streptavidin for signal enhancement. The binding of the free anti-Salmonella antibody to chip-immobilized LPS led to a shift of the reflectance spectrum that was inversely related to the analyte concentration (LPS or bacteria) in the calibrators or samples. The total assay duration was 15 min, and the detection limits achieved were 4 ng/mL for LPS and 320 CFU/mL for bacteria. Taking into account the low detection limits, the short analysis time, and the small size of the chip and instrumentation employed, the proposed immunosensor could find wide application for bacteria detection in drinking water.
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spelling pubmed-80696422021-04-26 Rapid Detection of Salmonella typhimurium in Drinking Water by a White Light Reflectance Spectroscopy Immunosensor Angelopoulou, Michailia Tzialla, Konstantina Voulgari, Angeliki Dikeoulia, Mary Raptis, Ioannis Kakabakos, Sotirios Elias Petrou, Panagiota Sensors (Basel) Article Biosensors represent an attractive approach for fast bacteria detection. Here, we present an optical biosensor for the detection of Salmonella typhimurium lipopolysaccharide (LPS) and Salmonella bacteria in drinking water, based on white light reflectance spectroscopy. The sensor chip consisted of a Si die with a thin SiO(2) layer on top that was transformed into a biosensor through the immobilization of Salmonella LPS. The optical setup included a reflection probe with seven 200 μm fibers, a visible and near-infrared light source, and a spectrometer. The six fibers at the reflection probe circumference were coupled with the light source and illuminated the biosensor chip vertically, whereas the central fiber collected the reflected light and guided it to the spectrometer. A competitive immunoassay configuration was adopted for the analysis. Accordingly, a mixture of LPS or bacteria solution, pre-incubated for 15 min, with an anti-Salmonella LPS antibody was pumped over the chip followed by biotinylated secondary antibody and streptavidin for signal enhancement. The binding of the free anti-Salmonella antibody to chip-immobilized LPS led to a shift of the reflectance spectrum that was inversely related to the analyte concentration (LPS or bacteria) in the calibrators or samples. The total assay duration was 15 min, and the detection limits achieved were 4 ng/mL for LPS and 320 CFU/mL for bacteria. Taking into account the low detection limits, the short analysis time, and the small size of the chip and instrumentation employed, the proposed immunosensor could find wide application for bacteria detection in drinking water. MDPI 2021-04-10 /pmc/articles/PMC8069642/ /pubmed/33920297 http://dx.doi.org/10.3390/s21082683 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Angelopoulou, Michailia
Tzialla, Konstantina
Voulgari, Angeliki
Dikeoulia, Mary
Raptis, Ioannis
Kakabakos, Sotirios Elias
Petrou, Panagiota
Rapid Detection of Salmonella typhimurium in Drinking Water by a White Light Reflectance Spectroscopy Immunosensor
title Rapid Detection of Salmonella typhimurium in Drinking Water by a White Light Reflectance Spectroscopy Immunosensor
title_full Rapid Detection of Salmonella typhimurium in Drinking Water by a White Light Reflectance Spectroscopy Immunosensor
title_fullStr Rapid Detection of Salmonella typhimurium in Drinking Water by a White Light Reflectance Spectroscopy Immunosensor
title_full_unstemmed Rapid Detection of Salmonella typhimurium in Drinking Water by a White Light Reflectance Spectroscopy Immunosensor
title_short Rapid Detection of Salmonella typhimurium in Drinking Water by a White Light Reflectance Spectroscopy Immunosensor
title_sort rapid detection of salmonella typhimurium in drinking water by a white light reflectance spectroscopy immunosensor
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8069642/
https://www.ncbi.nlm.nih.gov/pubmed/33920297
http://dx.doi.org/10.3390/s21082683
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