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Updated: Jun 28, 2026
Foodborne Pathogen Screening Using Magneto-fluorescent Nanosensor: Rapid Detection of E. Coli O157:H7
Published on: September 17, 2017
Sequential detection of Salmonella typhimurium and Bacillus anthracis spores using magnetoelastic biosensors
S Huang1, H Yang, R S Lakshmanan
1Materials Engineering, Auburn University, Auburn, AL 36849, USA. huangsh@auburn.edu
Abstract:
Multiple phage-based magnetoelastic (ME) biosensors were simultaneously monitored for the detection of different biological pathogens that were sequentially introduced to the measurement system. The biosensors were formed by immobilizing phage and 1mg/ml BSA (blocking agent) onto the magnetoelastic resonator's surface. The detection system included a reference sensor as a control, an E2 phage-coated sensor specific to S. typhimurium, and a JRB7 phage-coated sensor specific to B. anthracis spores. The sensors were free standing during the test, being held in place by a magnetic field. Upon sequential exposure to single pathogenic solutions, only the biosensor coated with the corresponding specific phage responded. As the cells/spores were captured by the specific phage-coated sensor, the mass of the sensor increased, resulting in a decrease in the sensor's resonance frequency. Additionally, non-specific binding was effectively eliminated by BSA blocking and was verified by the reference sensor, which showed no frequency shift. Scanning electron microscopy was used to visually verify the interaction of each biosensor with its target analyte. The results demonstrate that multiple magnetoelastic sensors may be simultaneously monitored to detect specifically targeted pathogenic species with good selectivity. This research is the first stage of an ongoing effort to simultaneously detect the presence of multiple pathogens in a complex analyte.
Insights
This study developed phage-based magnetoelastic (ME) biosensors for simultaneous pathogen detection. The novel biosensors accurately identified specific bacteria and spores with high selectivity, paving the way for multi-pathogen diagnostics.
Area of Science:
- Biosensing and Nanotechnology
- Microbiology and Immunology
- Materials Science
Background:
- Magnetoelastic (ME) biosensors offer a label-free detection method.
- Phage display technology enables specific pathogen recognition.
- Simultaneous detection of multiple pathogens remains a challenge.
Purpose of the Study:
- To develop and evaluate multiple phage-based ME biosensors for simultaneous detection of different pathogens.
- To assess the specificity and selectivity of the developed biosensors.
- To establish a foundation for a multi-pathogen detection system.
Main Methods:
- Immobilization of specific phages (E2 for S. typhimurium, JRB7 for B. anthracis) and BSA onto ME resonators.
- Sequential introduction of target pathogens to a system with multiple, individually monitored sensors.
- Measurement of resonance frequency shifts in response to analyte binding.
- Scanning electron microscopy for visual verification of analyte-biosensor interaction.
Main Results:
- Each phage-coated sensor specifically responded to its cognate pathogen, indicated by a decrease in resonance frequency.
- BSA blocking effectively prevented non-specific binding, confirmed by a stable reference sensor.
- Simultaneous monitoring of multiple sensors demonstrated selective detection of S. typhimurium and B. anthracis spores.
Conclusions:
- Multiple phage-based ME biosensors can be simultaneously monitored for selective detection of specific pathogenic species.
- BSA blocking is crucial for eliminating non-specific binding in ME biosensor systems.
- This work represents a significant first step towards a multiplexed pathogen detection platform.
