Towards optimised wireless Love wave biosensor with high sensitivity

A Love wave biosensor, which is composed of a one-port surface acoustic wave reflective delay line on a piezoelectric substrate, a thin overlayer (waveguide layer) on top of the substrate, and a sensitive film that responds only to a specific cell, was optimally designed on a 41° YX LiNbO₃ substrate and then fabricated according to the extracted design parameters. Based on multilayer theory, polymethylmethacrylate waveguide thickness was optimised. For derivation of the coupling of mode parameters, the periodic using the periodic finite-element method/boundary element method modelling was utilised. Optimal interdigital transducers and reflectors´ features were determined to realise high-quality reflection peaks. The experimentally measured reflection coefficient S₁₁ showed good agreement with simulated results. The evaluated sensitivity was 11.5 deg/ g/ml in terms of anti-DNP immunoglobulin G absorption.