The detection of chemical and biological analytes using a monolithic spiral coil acoustic transduction sensor

The monolithic spiral coil acoustic transduction (MSCAT) sensor platform is a novel bulk acoustic wave (BAW) device which is excited by a gold spiral coil antenna photolithographically deposited on one side of an AT-quartz wafer. The MSCAT platform can operate at very high frequencies by efficiently exciting high harmonic transverse shear modes with the application of a high frequency RF signal to the spiral coil. Since one surface of the MSCAT device is bare, this device can be used as a sensing platform upon which one deposits analyte selective chemical or biological films. The bare surface allows the detection of analyte induced mechanical (mass and viscoelasticity) and electrical (conductivity and dielectric constant) property changes in the film. In order to demonstrate the applicability of a MSCAT device as a sensor, the MSCAT platform is coated with biological and chemical films selective to Escherichia coli (E. coli) O157:H7, the E. coli strain most often responsible for serious illnesses in humans, and saxitoxin (STX), the most dangerous neurotoxin associated with shellfish poisoning stemming from red tide, respectively.