title: Rapid colorimetric sensing platform for the detection of Listeria monocytogenes foodborne pathogen.
abstract: Listeria monocytogenes is a serious cause of human foodborne infections worldwide, which needs spending billions of dollars for inspection of bacterial contamination in food every year. Therefore, there is an urgent need for rapid, in-field and cost effective detection techniques. In this study, rapid, low-cost and simple colorimetric assay was developed using magnetic nanoparticles for the detection of listeria bacteria. The protease from the listeria bacteria was detected using D-amino acid substrate. D-amino acid substrate was linked to the carboxylic acid on the magnetic nanoparticles using EDC/NHS chemistry. The cysteine residue at the C-terminal of the substrate was used for the self-assembled monolayer formation on the gold sensor surface, which in turn the black magnetic nanobeads will mask the golden color. The color will change from black to golden color upon the cleavage of the specific peptide sequence by the Listeria protease. The sensor was tested with serial dilutions of Listeria bacteria. It was found that the appearance of the gold surface area is proportional to the bacterial concentrations in CFU/ml. The lowest detection limit of the developed sensor for Listeria was found to be 2.17×10(2) colony forming unit/ml (CFU/ml). The specificity of the biosensor was tested against four different foodborne associated bacteria (Escherichia coli, Salmonella, Shigella flexnerii and Staphylococcus aureus). Finally, the sensor was tested with artificially spiked whole milk and ground meat spiked with listeria.
authors.affiliation: Department of Chemistry, Alfaisal University, Al Zahrawi Street, Al Maather, Al Takhassusi Road, Riyadh 11533, Saudi Arabia.
authors.forename: Sahar
authors.initials: S
authors.lastname: Alhogail
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Pharmacy, The University of Jordan, Amman 11942, Jordan.
authors.forename: Ghadeer A R Y
authors.initials: GARY
authors.lastname: Suaifan
authors.affiliation: Department of Chemistry, Alfaisal University, Al Zahrawi Street, Al Maather, Al Takhassusi Road, Riyadh 11533, Saudi Arabia; King Faisal Specialist Hospital and Research Center, Zahrawi Street, Al Maather, Riyadh 12713, Saudi Arabia. Electronic address: mzourob@alfaisal.edu.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Zourob
mesh_terms: D015373:Bacterial Typing Techniques / Q000295:instrumentation; D003124:Colorimetry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology / Q000295:instrumentation*; D008089:Listeria monocytogenes / Q000145:classification / Q000201:enzymology / Q000302:isolation & purification*; D058185:Magnetite Nanoparticles / Q000737:chemistry; D010447:Peptide Hydrolases / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013045:Species Specificity
chemical_list: D058185:Magnetite Nanoparticles; D010447:Peptide Hydrolases
keywords: Biosensors; Colorimetric assay; Listeria monocytogenes; Listeriosis; Magnetic nanoparticles; Self-assembled monolayer