Surface Modifications of Love Acoustic Waves Sensors for Chemical and Biological Detection

The surface functionalization of guided-SH-SAW (Shear Horizontal-Surface Acoustic Wave) transducers was carried out to prepare layers for heavy metals chelation and antibodies recognition. For the preparation of the chemical sensors, a thiourea molecule acting as a chelating agent for heavy metals was grafted on the top-layer of the transducer. This covalent immobilization was obtained by amide bonds through primary amine groups immobilized on the device by the chemisorption of the 3-aminopropyltriethoxysilane (APTES). The thiourea modified transducer was inserted in a microfluidic analysis system to test its sensitivity for cadmium ions in liquid media. In the aim to develop bio-chemical sensors based on antigen/antibody recognition, a functionalization way based on SAMs of semicarbazide functions leading to α-oxo-semicarbazone bonds with antigenic peptides is described. The real-time immobilization of the peptide on the surface was observed for the first time and the antibody recognition was successfully monitored. Based on these results, the gravimetric determination by guided-SH-SAW transducers functionalized by the semicarbazide/α-oxo-aldehyde chemistry is a promising complementary route for antibodies analysis.