High Frequency Acoustic STW Biosensor

A Surface Transverse Wave (STW) acoustic biosensor for monitoring chemical interactions in aqueous solution has been developed. The STW acoustic biosensor was utilized to monitor antigen-antibody and ligand-receptor interactions, and to follow sorption kinetics of organic chemicals dissolved in aqueous solution. The STW delay-line sensor has been designed to control the oscillation frequency of an rf oscillator at ~ 80 MHz. SiO₂ and poly[methylmethacrylate] (PMMA) served as wave guiding layers for the STW devices. The acoustic devices were placed in a thermostatic (25 °C) stainless steel flow-cell, and frequency has been followed with time. The applicability of the STW device in three model systems will be presented and discussed: The immunosensor model was based on the interaction between rabbit IgG and goat anti rabbit IgG peroxidase conjugate. The receptor-ligand interaction model was studied by use of a matrix bound procainamide and a soluble butyrilcholinesterase (BuChE). A special methacrylic-procainamide polymer (PPA) was designed and synthesized as an anchor for the BuChE molecule. Chemical sorption of organic solvents in aqueous phase was studied by poly[nbutylmethacrylate] (PBMA) coated STW sensors with SiO₂ as a wave guiding layer. Sorption kinetics were analyzed by a simulation method to derive the chemical diffusion and partition coefficients.