Stefan Cular1, Venkat R. Bhethanabotla1, Darren W. Branch2, and Joel A. Strom1. (1) Department of Chemical Engineering, University of South Florida, 4202 East Fowler Ave., ENB 118, Tampa, FL 33620, (2) Biosensors and Nanomaterials Department, Sandia National Laboratories, Albuquerque, NM 87185
We present the development and application of a hexagonal surface acoustic wave (SAW) biosensor for Interleukin-6 at levels required for physiological relevance. Interleukin-6 is a proinflammatory cytokine involved in the body's pathophysiologic response to injury due to various causes, e.g. trauma, burns, sepsis, and disease. We have optimized the sensor configuration to provide a substantially improved response in comparison with traditional SAW sensors. The hexagonal SAW biosensor was fabricated in 36° YX LiTaO3 to generate shear horizontal (SH) waves using the high electro-mechanical conversion efficiency of this substrate material. The biosensors were coated with an optimally thick polystyrene waveguide enabling Love-wave generation. The generated Love-waves were shown to improve sensitivity 40-fold. Results from the human Interleukin-6 analyte biosensor will be presented. The biosensor was fabricated using an anti-human Interleukin-6 biosensor film physically adsorbed to the polystyrene waveguide. The resulting data were collected using a homebuilt sensor circuit connected to a multimeter and personal computer for data acquisition, and were verified using fluorescent microscopy.