Sensor based on the slot acoustic wave for the non-contact analysis of the bacterial cells – Antibody binding in the conducting suspensions

Abstract

The possibilities of using the acoustic sensor based on the slot mode in the delay line with a shear horizontal acoustic wave of zero order for the contactless analysis of the bacterial cells-antibody binding in the conducting suspensions were investigated. In this sensor, the suspension container, the bottom of which was made of the lithium niobate plate, was located above the delay line with the given width of the gap. The excitation of the slot mode in such a structure led to the appearance of the sharp resonant peaks on the frequency dependence of the insertion loss of the delay line. It has been established that the specific interaction of the bacterial cells with the antibodies in the suspensions with the different electrical conductivity leads to a change in the depth and frequency of the resonant peaks in the frequency dependence of the insertion loss of the sensor. The dependences of the changes in the depth and frequency of the resonant peaks on the conductivity of the buffer solution with the different cell concentrations were determined for the specific interaction of the “bacterial cells – antibodies”. The possibility of the use of the slot mode in the sensor to analyze the bacterial cells with the help of the antibodies in the suspensions with an initial conductivity of 5–20 μS/cm is shown. The advantage of the novel sensor is that its design allows the easy and high-quality cleaning the container from the spent cell suspension separately from the delay line.