Focalization Performance Study of a Novel Bulk Acoustic Wave Device

This work illustrates focalization performances of a silicon-based bulk acoustic wave device applied for the separation of specimens owing to micrometric dimensions. Samples are separated in the microfluidic channel by the presence of an acoustic field, which focalizes particles or cells according to their mechanical properties compared to the surrounded medium ones. Design and fabrication processes are reported, followed by focalization performance tests conducted either with synthetic particles or cells. High focalization performances occurred at different microparticle concentrations. In addition, preliminary tests carried out with HL-60 cells highlighted an optimal separation performance at a high flow rate and when cells are mixed with micro and nanoparticles without affecting device focalization capabilities. These encouraging results showed how this bulk acoustic wave device could be exploited to develop a diagnostic tool for early diagnosis or some specific target therapies by separating different kinds of cells or biomarkers possessing different mechanical properties such as shapes, sizes and densities.

Application of surface acoustic wave to enhance the photocatalytic degradation efficiency of methylene blue

The TiO2 thin film was grown on a [Formula: see text] Y-axis cut, X-axis propagation lithium niobate substrate by radio frequency magnetron sputtering to fabricate a surface acoustic wave device. The sputtering ratios of argon to oxygen at 20% and post-annealing temperature at [Formula: see text]C for 3 h were controlled to improve the photocatalytic activity of TiO2 thin film. The effects of work frequency and input voltage of the surface acoustic wave device on the methylene blue photocatalytic degradation efficiency of the TiO2 thin film were investigated. The TiO2 thin film was vibrated at radio frequency by surface acoustic wave device to increase the scattering and reactive frequency for methylene blue in liquid. The surface acoustic wave device operated at 28.65 MHz work frequency and 0.95 V input voltage revealed the highest photocatalytic degradation efficiency of methylene blue. Compared to the TiO2 thin film combined with and without surface acoustic wave device, the surface acoustic wave device enhanced the TiO2 thin film photocatalytic degradation efficiency to 46%.