Comparison of surface transverse wave (STW) and shear horizontal acoustic plate mode (SHAPM) devices for biochemical sensors

Surface transverse wave (STW) and shear horizontal acoustic plate mode (SHAPM) geometries have been proposed and demonstrated as potential biochemical sensors. The STW provides simplicity of instrumentation by virtue of its single acoustic mode of operation, while the SHAPM affords ease of packaging since the electronics may be placed on the opposite surface from the liquid solution. First generation device designs using both technologies have previously demonstrated nanogram sensitivity using model biochemical systems such as human IgG/goat anti-human IgG and cytomegalovirus DNA. More recently, second generation devices have been designed and are being tested using bacteria and their toxins. This paper will outline the critical tradeoffs between the two approaches. Initial electrical properties and sensor results are reported