Love wave devices for physico-chemical and biological microsensors
Résumé
Surface Acoustic Wave or SAW-based devices are spreadly studied for highly sensitive and real-time chemical or biochemical sensing applications. In particular, Love waves or shear horizontal waves guided in a thin surface film, are of particular interest for liquid samples. This overview is based on a basic structure and introduces its versatility through a large spectrum of applications investigated in IMS Bordeaux Labs. Fabricated with the collaboration of the national technological network (RTB) of LAAS-CNRS in Toulouse, the devices were then functionalized with various innovative materials developed with specialized chemists and biologists, e.g. functionalized polymeric matrices for organophosphorus compounds, antibodies after nanostructured modification of the surface for multipurpose biological detection of virus, bacteria or toxins, or structured thin-film materials emphasized for their high effective surface among other advantages, such as mesoporous materials (vapors), molecularly imprinted polymers (cancer biomarkers), or, soon, carbonated materials which could lead to unexpected sensitivities. Due to their generic sensing mechanism, these devices can be useful also to detect and monitor overall parameter, such as toxicity of heavy metals as shown with a bio-inspired microsensor based on microfluidic chip / bacteria / titania / Love wave hybrid structure.
Responses of bare and functionalized devices are used to investigate the interaction mechanisms involved between the mechanical wave propagation and the adjacent medium, and to estimate dynamically some effective visco-elastic parameters of the material at the near interface: vapor, thin-film or complex fluid.