Electromagnetic Excitation of Acoustic Biosensors

One of the problems associated with the acoustic biosensor format, is the isolation of the electrical connections, from the liquid test sample. In this paper, we describe our search for an electromagnetic coupling solution, how we modified it for acoustic biosensors, and some of the physical characteristics that we did not anticipate: We began by reviewing the formal descriptions of electromagnetically induced acoustic produced by solid-state physicists of the 1960s, to help understand electronic properties. Over the past decade, our group has modified this electromagnetic geometry to increase signal levels, operating frequency and resolution. Our focus was to prepare a simple non-contact acoustic device that could emulate the functionality of traditional surface acoustic wave and quartz crystal microbalance sensors. The result was a simple non-contact acoustic device with high signal performance, and low cost. It also supported superior bandwidth, so interfacial acoustic spectroscopy could be performed, and enhanced coherence obtained for broken chips of quartz. We conclude that non-contact approaches increase the value of acoustic biosensors.