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Sensor for ampicillin based on a microwave electrodynamic resonator
O I Guliy1, B D Zaitsev2, A V Smirnov3
1Institute of Biochemistry and Physiology of Plants and Microorganisms, RAS, 13 Prospekt Entuziastov, Saratov 410049, Russia.
Biosensors & Bioelectronics
|February 8, 2019
Summary
A novel biosensor utilizing a waveguide resonator and immobilized Escherichia coli K-12 cells detects ampicillin in aqueous solutions. This biological sensor demonstrates high sensitivity and stability for antibiotic detection.
Area of Science:
- Biosensor Technology
- Electromagnetics
- Biotechnology
Background:
- Development of sensitive and stable biosensors is crucial for detecting antibiotics in aqueous solutions.
- Existing detection methods may lack the required sensitivity or stability for real-time monitoring.
- Escherichia coli K-12 immobilization on porous polystyrene films offers a promising platform for biological sensing.
Purpose of the Study:
- To develop and characterize a novel biosensor for detecting β-lactam antibiotics, using ampicillin as a model.
- To evaluate the performance of a waveguide resonator-based biosensor functionalized with immobilized Escherichia coli K-12.
- To determine the optimal conditions for film modification and cell immobilization for enhanced biosensor performance.
Main Methods:
- Fabrication of a rectangular waveguide resonator (8 GHz) with a lithium niobate plate and porous polystyrene film.
- Immobilization of Escherichia coli K-12 cells onto the modified polystyrene film via centrifugation and plasma treatment.
- Measurement of the reflection coefficient (S11) using a coaxial-waveguide adapter and S parameter meter.
- Analysis of changes in S11 and resonance frequency upon introduction of ampicillin solutions.
Main Results:
- The biosensor exhibited a significant change in reflection coefficient (S11) from -10.15 dB to -15.09 dB with ampicillin concentrations of 4-50 μg/ml.
- Resonance frequency shift was minimal (8.06-8.068 GHz), indicating sensor stability.
- Immobilized cells maintained activity for 4 months at 4°C, and the limit of detection for ampicillin was determined to be 4 μg/ml.
Conclusions:
- The developed waveguide resonator biosensor shows significant promise for the detection of β-lactam antibiotics like ampicillin in aqueous solutions.
- The biosensor design, incorporating immobilized E. coli K-12 on a plasma-modified polystyrene film, offers a sensitive and stable detection platform.
- Further optimization of the immobilization process and film modification can potentially enhance the biosensor's performance for broader antibiotic detection applications.
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