ABSTRACT
Acoustic waves have been extensively investigated and have had a practical significance in many different contexts. Seismology was one of the first areas where they were utilized and the substantial seismological literature, extending back to the nineteenth century, established many of the fundamental properties of acoustics. A second, but equally important application was the introduction of acoustic waves into the electronics field in the 1920s and the subsequent fabrication of components such as resonators, filters and delay lines. Today, the utilization of acoustic waves in signal processing has become commonplace and recent advances in transduction technology enable the manufacture of devices covering the frequency range from about 10KHz to a few GHz. Following developments in the electronics field, the first attempt to utilize acoustic devices in analytical chemistry was made in the mid1960s. This work involved the utilization of a bulk acoustic wave device as a sensitive mass-sensor for gas chromatography. Since then, acoustic sensors have been developed to detect not only gas molecules in the ppm and ppb range, but also submonolayers of proteins deposited on the device surface in presence of liquid. Today, despite considerable advances in the development of new acoustic sensors, their application in biological analysis is still limited compared to optical and electrochemical devices. However, current research in the area strongly suggests that acoustic wave devices can become competitive sensors and many indications exist that their use will expand significantly in the future.
