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Published on: December 14, 2020
A Real-Time Thermal Sensor System for Quantifying the Inhibitory Effect of Antimicrobial Peptides on Bacterial
Tobias Wieland1, Julia Assmann2,3, Astrid Bethe2
1Department of Microsystems Engineering (IMTEK)-Laboratory of Sensors, University of Freiburg, 79110 Freiburg, Germany.
Abstract:
The increasing rate of antimicrobial resistance (AMR) in pathogenic bacteria is a global threat to human and veterinary medicine. Beyond antibiotics, antimicrobial peptides (AMPs) might be an alternative to inhibit the growth of bacteria, including AMR pathogens, on different surfaces. Biofilm formation, which starts out as bacterial adhesion, poses additional challenges for antibiotics targeting bacterial cells. The objective of this study was to establish a real-time method for the monitoring of the inhibition of (a) bacterial adhesion to a defined substrate and (b) biofilm formation by AMPs using an innovative thermal sensor. We provide evidence that the thermal sensor enables continuous monitoring of the effect of two potent AMPs, protamine and OH-CATH-30, on surface colonization of bovine mastitis-associated Escherichia (E.) coli and Staphylococcus (S.) aureus. The bacteria were grown under static conditions on the surface of the sensor membrane, on which temperature oscillations generated by a heater structure were detected by an amorphous germanium thermistor. Bacterial adhesion, which was confirmed by white light interferometry, caused a detectable amplitude change and phase shift. To our knowledge, the thermal measurement system has never been used to assess the effect of AMPs on bacterial adhesion in real time before. The system could be used to screen and evaluate bacterial adhesion inhibition of both known and novel AMPs.
Insights
A novel thermal sensor monitors antimicrobial peptides
Area of Science:
- Microbiology
- Biotechnology
- Materials Science
Background:
- Antimicrobial resistance (AMR) is a global health threat.
- Antimicrobial peptides (AMPs) show potential against AMR pathogens.
- Bacterial adhesion and biofilm formation complicate treatments.
Purpose of the Study:
- Develop a real-time method to monitor AMP inhibition of bacterial adhesion and biofilm formation.
- Utilize an innovative thermal sensor for continuous assessment.
- Evaluate AMP efficacy on surfaces against common mastitis pathogens.
Main Methods:
- Employed a thermal sensor with a heater and thermistor.
- Detected temperature oscillations to monitor bacterial adhesion.
- Confirmed adhesion using white light interferometry.
- Tested protamine and OH-CATH-30 against *E. coli* and *S. aureus*.
Main Results:
- The thermal sensor successfully monitored bacterial adhesion in real time.
- Bacterial adhesion caused detectable changes in amplitude and phase shift.
- Demonstrated continuous monitoring of AMP effects on surface colonization.
- Showcased the system's potential for screening AMPs.
Conclusions:
- A novel thermal sensor system enables real-time monitoring of AMPs' effect on bacterial adhesion.
- This method offers a new approach for evaluating AMP efficacy against surface-bound bacteria.
- The system can be used for screening known and novel AMPs for anti-adhesion properties.
