Researchers in Australia have demonstrated a SAW device for releasing monodisperse aerosols and particles to suit various drug-delivery routes. In particular, the group from Monash University has used its 20 MHz SAW design to generate insulin aerosols for pulmonary delivery and solid protein nanoparticles for transdermal and gastrointenstinal pathways.

The chip features an interdigital transducer consisting of 25 pairs of 400 nm electrodes that are sputter-coated on to a piezoelectric lithium niobate substrate. To generate a series of surface acoustic waves, the operator simply applies a sinusoidal electrical signal across the electrodes. The waves disrupt liquid placed on top of the chip to produce a fine mist of micron-sized material.

By allowing the atomized droplets to evaporate in-flight, the team has successfully formed nanoparticles in the 50–100 nm range.

The group's vision is to develop simple-to-operate, portable devices that can be carried around by patients to provide treatment on demand. In addition, by arranging the chips in parallel, the technology may also turn out to be a useful way of producing correctly sized material in bulk.

Back in the lab, the team is now looking to simplify its apparatus. "We need better prototypes, ones that are programmable and easy for an average person to use," James Friend, who co-directs Monash University's micro and nanophysics research laboratory with Leslie Yeo, told

Mar Alvarez, James Friend and Leslie Yeo presented their work in Nanotechnology.