The AWS technology offers real-time and sensitive monitoring of surface-bound interactions, such as adsorption and desorption processes, characterization of molecular interactions, protein conformational changes, etc.
Our technology is based on the acoustic wave sensing principle. Our acoustic wave system enables an accurate detection of mass and structural changes on the sensor surface because it provides a precise and robust measurement.
Our platforms are versatile, can work combining different types of acoustic wave sensors, including up to 150MHz High Fundamental Frequency Quartz Crystal Microbalance sensors (HFF-QCM), 120 MHz Love Mode-Surface Acoustic Wave sensors (LOVE-SAW), and 5 MHz to 10 MHz Quartz Crystal Microbalance sensors (QCM). Furthermore, our platforms are modular and can be adapted to any requirement or need.
The combination of our acoustic wave devices and the versatility and robustness of the patented characterization methods implemented in our instruments, provides the highest sensitivity and resolution commercially available for acoustic sensing.
Acoustic sensing principle
The acoustic sensing principle is based on the precise detection of changes on the properties of an acoustic (mechanical) wave traveling through the bulk (QCM, HFF-QCM) or the surface (LOVE-SAW) of the acoustic wave sensor.
QCM sensors consist of a thin piece of quartz confined between a pair of metal-based electrodes. An alternating current applied to the quartz crystal induces mechanical oscillations on the quartz due to the piezoelectric effect. A wave is generated and propagated through the sensor and the films attached to it.
The resonance frequency of this wave depends on the oscillating mass of the sensor and its adhering layers. When a thin film is attached to the sensor, the properties of the wave change as well, modifiying the resonance frequency and amplitude. If the film is thin and rigid, the decrease in frequency is proportional to the mass of the film. In this way, the QCM works in the so-called gravimetric regime and the mass of the film can be calculated using the well-known Sauerbrey equation. If the film is not rigid, the measurement of the damped resonance enables the measurement of the viscoelastic changes of the film, allowing the characterization of the QCM working in the non-gravimetric regime.
HFF-QCM sensors allow the researcher to improve the sensitivity and resolution of the measurements by more than two orders of magnitude compared with the QCM. It is based on the same principle of operation as the QCM, but the HFF-QCM piezoelectric substrate is much thinner, so that it can operate at a higher resonant frequency with a higher sensitivity to the changes on its surface. The sensing electrode area is reduced as-well, which allows the reduction of the volume of the sample. A proprietary design ensures the robustness and easiness on handling needed to perform reliable measurements.
LOVE-SAW sensors consists of a thicker quartz piezoelectric substrate with an interdigitated transducer (IDT) on one end of the surface of the substrate, acting as signal input, and a second one, on the other end of the surface substrate, acting as the output. An alternating current applied to the input transducer generates a mechanical wave which propagates along the sensor device, from the input port to the output port. The wave travels confined in a guiding layer of a few microns height at the top part of the surface. When the properties of a film attached to the surface change (due to changes of mass, conformation, analyte binding, etc…), the propagation properties of the acoustic wave travelling along the sensor change as-well. The precise detection of the changes in those properties enables the characterization of mass and structural changes in the vicinity of the sensor surface with high sensitivity and resolution.
Read more about the AWS Technology and the acoustic sensing principles in our Applications and Publications sections.