Nanotechnologies as a Key Issue for Microsensors: Example of wave-based resonant devices for (bio)chemical detection
Résumé
In this talk, we shall first briefly introduce Resonant wave-based microsensing transducers. Among them, the versatile mechanical principle of Surface Acoustic Wave or SAW-based devices for highly sensitive and real time detection have great potential. We shall then touch upon a large spectrum of nano structured materials as sensitive coatings for various chemical or biochemical sensing applications, especially environmental and health related ones.
Nanotechnologies offer a powerful tool for designing innovative advanced materials needed for such sensitive layers, both the material itself by chemists as well as coating and patterning processes by technological multidisciplinary teams. Indeed, good sensing properties imply efficient sensitive layers intimately linked to the transducing platform. This means high specific surface, for increased sensitivity towards target species as well as, most of all, a form of specificity towards interferent compounds. A particular structuration adapted to the size and type of the compounds to be detected, can improve sorption/interaction/diffusion phenomena often leading to necessary compromise between sensitivity and response time. Other properties such as good temperature behaviour or chemical stability, among others, can be of particular importance. A typical approach deals with optimizing a versatile matrix as layer with good mechanical properties on the transducer, and by functionalizing it, before or after deposition, with end-groups dedicated for specific target species.
Among examples, we present materials based on organic, inorganic, hybrid materials, either natural or engineered, typically with micro- to nano-structuration and surface modification. We also discuss an increasing interest for carbon materials such as nanotubes or graphene which could lead to unexpected sensitivities. The integration of sensitive thin-films, microfluidics and other embedded features leads to microsensing platforms customized for the targeted compounds and applications. Development of wireless solutions for micro-energy brings us to perspectives in wireless sensing networks. Nanotechnologies are involved in such overall system integration, too.