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Colorimetric Paper-based Detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from Large Volumes of Agricultural Water
Published on: June 9, 2014
Specific and selective biosensor for Salmonella and its detection in the environment
E V Olsen1, S T Pathirana, A M Samoylov
1Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA.
Journal of Microbiological Methods
|March 26, 2003
Summary
This study demonstrates a new biosensor for detecting Salmonella typhymurium in liquid samples. The biosensor uses specific antibodies immobilized on a quartz crystal acoustic wave device for selective and specific bacterial detection.
Area of Science:
- Biosensing
- Microbiology
- Materials Science
Background:
- Accurate detection of Salmonella typhymurium is crucial for food safety and public health.
- Existing detection methods can be time-consuming and lack specificity.
- Development of rapid and selective biosensors is an ongoing area of research.
Purpose of the Study:
- To develop and demonstrate a specific and selective biosensor for Salmonella typhymurium detection.
- To investigate the influence of antibody immobilization methods on biosensor performance.
- To analyze the correlation between bacterial attachment modes and sensor response.
Main Methods:
- Immobilization of polyclonal antibodies (somatic O and flagellar H7) onto a quartz crystal acoustic wave device using the Langmuir-Blodgett method.
- Testing biosensor selectivity and specificity in liquid samples containing Salmonella typhymurium and Escherichia coli O157:H7.
- Utilizing dark-field and electron microscopy to characterize bacterial attachment.
- Analyzing acoustic wave sensor responses in relation to bacterial mass and attachment characteristics.
Main Results:
- The developed biosensor demonstrated high selectivity for Salmonella typhymurium, even in the presence of high concentrations of Escherichia coli O157:H7.
- Specificity was confirmed by the absence of signal when bacteria were pre-incubated with free antibodies.
- Two distinct bacterial attachment modes (rigid via somatic O antibody, flexible via flagellar H7 antibody) were observed.
- Sensor response correlated with bacterial mass for rigid attachment, while it was inversely proportional for flexible attachment, likely due to interfacial viscoelasticity.
Conclusions:
- The Langmuir-Blodgett method enables effective immobilization of antibodies for Salmonella typhymurium detection.
- The type of antibody-bacteria interaction (rigid vs. flexible) significantly influences the acoustic wave sensor's response.
- Both O and H type binding sensors show potential for analytical applications in bacterial detection.
