Real-time and sensitive detection of Salmonella Typhimurium using an automated quartz crystal microbalance (QCM) instrument with nanoparticles amplification.
The accidental contamination of Salmonella in raw and processed foods is a major problem for the food industry worldwide. At present many of the currently used methods for Salmonella detection are time and labour intensive. Therefore, rapid detection is a key to the prevention and identification of problems related to health and safety. This paper describes the application of a new quartz crystal microbalance (QCM) instrument with a microfluidic system for the rapid and real time detection of Salmonella Typhimurim. The QCMA-1 bare gold sensor chip which contain two sensing array was modified by covalently immobilising the monoclonal capture antibody on the active spot and a mouse IgG antibody on the control spot using a conventional amine coupling chemistry (EDC-NHS). The binding of the Salmonella cells onto the immobilised anti-Salmonella antibody alters the sensor frequency which was correlated to cells concentration in the buffer samples. Salmonella cells were detected using direct, sandwich, and sandwich assay with antibody conjugated gold-nanoparticles. The performance of the QCM immunosensor developed with gold-nanoparticles gave the highest sensitivity with a limit of detection (LOD) ~10-20 colony forming unit (CFU) ml(-1) compared to direct and sandwich assay (1.83 × 10(2) CFU ml(-1) and 1.01 × 10(2) CFU ml(-1), respectively). The sensor showed good sensitivity and selectivity for Salmonella in the presence of other bacteria in real food samples and helped in reducing the pre-enrichment step, hence, demonstrating the potential of this technology for the rapid and sensitive microbial analysis.
Cranfield Health, Cranfield University, Cranfield, Bedfordshire, MK43 0AL England, United Kingdom.
Faridah
F
Salam
Yildiz
Y
Uludag
Ibtisam E
IE
Tothill
D000818:Animals; D000907:Antibodies, Bacterial / Q000737:chemistry* / Q000276:immunology; D055910:Antibodies, Immobilized / Q000737:chemistry / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques; D002645:Chickens; D005506:Food Contamination / Q000032:analysis*; D006046:Gold / Q000737:chemistry; D007118:Immunoassay; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology; D057230:Limit of Detection; D008460:Meat / Q000382:microbiology*; D053768:Metal Nanoparticles / Q000737:chemistry; D051379:Mice; D046210:Microfluidic Analytical Techniques; D058525:Quartz Crystal Microbalance Techniques; D012486:Salmonella typhimurium / Q000302:isolation & purification*
D000907:Antibodies, Bacterial; D055910:Antibodies, Immobilized; D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D006046:Gold
Bacteria detection; Food monitoring; Immunosensor; Nanoparticle; Quartz crystal microbalance (QCM); Salmonella