Surface plasmon resonance immunosensor for the detection of Salmonella typhimurium

Salmonella Typhimurium is one of the leading causes of foodborne diseases worldwide. Biosensors and immunoassays utilizing monoclonal antibodies are widely used for the detection and subtyping of S. Typhimurium. However, due to insufficient information on the nature of binding with S. Typhimurium flagellin, the selection of appropriate antibodies for assay development is a cumbersome task. Hence, we aimed to compare the binding kinetics of a panel of monoclonal antibodies and their relative binding sites to flagellin antigen using a surface plasmon resonance biosensor. Initially, the flagellin was captured on the sensor surface through an immobilized anti-flagellin antibody. The interactions of different concentrations of monoclonal antibodies to flagellin were determined, and binding curves were fitted using 1:1 bio-interaction model to calculate the kinetic parameters. For epitope mapping, pairwise comparisons were completed to determine the binding inhibition of each paired combination of monoclonal antibodies. It was found that these monoclonal antibodies differed significantly (p < 0.05) in association rate, dissociation rate, and equilibrium dissociation constants. Of the five monoclonal antibodies, only two interfered with the binding of each other. Four distinct epitopes located within a 23 kDa domain of flagellin were identified. Findings from this study provide crucial information needed for the further development and optimization of biosensors and other immunoassays for the detection and subtyping of Salmonella.

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Detection of Salmonella Typhimurium in Romaine Lettuce Using a Surface Plasmon Resonance Biosensor

Biosensors ◽

10.3390/bios9030094 ◽

2019 ◽

Vol 9 (3) ◽

pp. 94 ◽

Cited By ~ 6

Author(s):

Devendra Bhandari ◽

Fur-Chi Chen ◽

Roger C. Bridgman

Keyword(s):

Surface Plasmon Resonance ◽

Salmonella Typhimurium ◽

Surface Plasmon ◽

Plasmon Resonance ◽

High Specificity ◽

Leafy Vegetables ◽

Detection Sensitivity ◽

Sandwich Assay ◽

Romaine Lettuce ◽

Accurate Identification

Leafy vegetables have been associated with high-profile outbreaks causing severe illnesses. Timely and accurate identification of potential contamination is essential to ensure food safety. A surface plasmon resonance (SPR) assay has been developed for the detection of Salmonella Typhimurium in leafy vegetables. The assay utilizes a pair of well characterized monoclonal antibodies specific to the flagellin of S. Typhimurium. Samples of romaine lettuce contaminated with S. Typhimurium at different levels (between 0.9 and 5.9 log cfu/g) were pre-enriched in buffered peptone water. Three SPR assay formats, direct assay, sequential two-step sandwich assay, and pre-incubation one-step sandwich assay were evaluated. All three assay formats detect well even at a low level of contamination (0.9 log cfu/g). The SPR assay showed a high specificity for the detection of S. Typhimurium in the presence of other commensal bacteria in the romaine lettuce samples. The results also suggested that further purification of flagellin from the sample preparation using immunomagnetic separation did not improve the detection sensitivity of the SPR assay. The functional protocol developed in this study can be readily used for the detection of S. Typhimurium in leafy vegetables with high sensitivity and specificity.

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Magnetic Nanoparticles Enhanced Surface Plasmon Resonance Biosensor for Rapid Detection of Salmonella Typhimurium in Romaine Lettuce

Sensors ◽

10.3390/s22020475 ◽

2022 ◽

Vol 22 (2) ◽

pp. 475

Author(s):

Devendra Bhandari ◽

Fur-Chi Chen ◽

Roger C. Bridgman

Keyword(s):

Surface Plasmon Resonance ◽

Magnetic Nanoparticles ◽

Salmonella Typhimurium ◽

Surface Plasmon ◽

Plasmon Resonance ◽

Rapid Detection ◽

Sensor Surface ◽

Sandwich Assay ◽

Romaine Lettuce ◽

One Step

Salmonella is one of the major foodborne pathogens responsible for many cases of illnesses, hospitalizations and deaths worldwide. Although different methods are available to timely detect Salmonella in foods, surface plasmon resonance (SPR) has the benefit of real-time detection with a high sensitivity and specificity. The purpose of this study was to develop an SPR method in conjunction with magnetic nanoparticles (MNPs) for the rapid detection of Salmonella Typhimurium. The assay utilizes a pair of well-characterized, flagellin-specific monoclonal antibodies; one is immobilized on the sensor surface and the other is coupled to the MNPs. Samples of romaine lettuce contaminated with Salmonella Typhimurium were washed with deionized water, and bacterial cells were captured on a filter membrane by vacuum filtration. SPR assays were compared in three different formats—direct assay, sequential two-step sandwich assay, and preincubation one-step sandwich assay. The interaction of flagellin and MNPs with the antibody-immobilized sensor surface were analyzed. SPR signals from a sequential two-step sandwich assay and preincubation one-step sandwich assay were 7.5 times and 14.0 times higher than the direct assay. The detection limits of the assay were 4.7 log cfu/mL in the buffer and 5.2 log cfu/g in romaine lettuce samples.

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Handbook of Surface Plasmon Resonance

10.1039/9781788010283 ◽

2017 ◽

Cited By ~ 46

Keyword(s):

Surface Plasmon Resonance ◽

Surface Plasmon ◽

Plasmon Resonance

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Comparison of sensitivity of the refractometric methods of frustrated total internal reflection and surface plasmon resonance

Izmeritel`naya Tekhnika ◽

10.32446/0369-1025it.2020-2-44-49 ◽

2020 ◽

pp. 44-49

Author(s):

I. N. Pavlov

Keyword(s):

Surface Plasmon Resonance ◽

Surface Plasmon ◽

Plasmon Resonance ◽

Total Internal Reflection ◽

Resonance Method ◽

Internal Reflection ◽

Optical Methods ◽

Thin Boundary Layer ◽

Experimental Conditions ◽

Frustrated Total Internal Reflection

Two optical methods, namely surface plasmon resonance imaging and frustrated total internal reflection, are described in the paper in terms of comparing their sensitivity to change of refractive index of a thin boundary layer of an investigated medium. It is shown that, despite the fact that the theoretically calculated sensitivity is higher for the frustrated total internal reflection method, and the fact that usually in practice the surface plasmon resonance method, on the contrary, is considered more sensitive, under the same experimental conditions both methods show a similar result.

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