Summary of SAW biosensors used to detect Escherichia coli O157 : H7.

	Detection range	Detection time	Temperature	pH	Waveforms	Principle	Advantages	Limitations	References
Ultrahigh-frequency SAW	102 cells per mL	<7 h	30 °C	6.5	Rayleigh wave	Microbial metabolism affects loop capacitance inductance to change the resonant frequency	Simple, high sensitivity, does not require highly skilled technicians, low cost, and real-time bacteria monitoring	Time consuming, frequency dependent	114
Love-wave immunosensor	106 cells per mL	<1 h	37 °C	7.2	Love wave	Antibody–antigen covalent binding, mass-loading effect leading to a resonant frequency shift	Ultrahigh stability, real-time monitoring, low cost, reusable, short detection time	High IL, guiding layer effect	68 and 124
Dual-channel SAW biosensor	105–106 cells per mL	<3 h	25 °C	7.4	Love wave	Mass adsorption effect leading to a frequency difference (Δf) between the test channel and the reference channel	High sensitivity, good response, and short detection time	Influenced by temperature, pressure, competitive non-labeled methods	57, 120 and 125
LGS-SH-SAW	∼106 cells per mL	2–5 h	25 °C	7.4	Shear horizontal wave	Antigen–antibody specific binding changes cause a phase shift	Label-free detection, reduced attenuation, high-temperature stability and flexibility, good antibody bonding	Sensitivity, detection limit	56 and 98
SAW impedance sensor	102–107 cells per mL	7 h	37 °C	7.0	Rayleigh wave and Love wave	Changes in the impedance of the medium produced by bacterial metabolism cause changes in the frequency signal	Simple, real-time bacteria monitoring, can be used by both scientists and unprofessional	Exhibits high attenuation in liquids	108
SH-SAW biosensor	6.54 × 105 CFU mL−1	2 h	30 °C	7.3–7.5	Shear horizontal wave	Antibody adsorption in the waveguide layer causes a resonant frequency shift	High specificity, repeatability, reproducibility, and lower detection time	Loss of energy, orientation of the crystal, corrosion	11, 45 and 124