A love-wave sensor for direct detection of biofunctionalized nanoparticles

In this work, we have designed and manufactured Love wave sensors equipped with a liquid cell for the detection of bio-functionalized nano-particules in water. Measurements using these devices are based on the determination of velocity and propagation loss changes of a guided acoustic shear wave generated by Inter-Digital Transducers (IDTs) patterned on a (YXlt)/36deg/90deg cut of quartz and passivated by a silica overlay. The so-called Love mode acoustic wave sensors are known to be compatible with operation in liquid medium but requires and adapted fluidic packaging. The SU-8-based liquid cell is patterned atop the SiO₂ guiding layer. We then describe the use of these sensors for the time resolved identification of the presence of nanoparticles in suspension. Silane surface chemistry for non-selective detection of most bio-functionalized nanoparticles health hazards is demonstrated by analyzing the gravimetric signal associated with the binding of avidin-functionalized gold nanoparticles.