Ultrasonic atomisation and the Faraday instability - a route for drug nanoparticle synthesis: Experiments, modelling and simulations


The phenomenon of ultrasonic atomisation was first reported by Wood and Loomis nearly a century ago in 1927 [1] and since then has been extensively used for various purposes [2] like pulmonary drug delivery [3], preparation of fine powders [4], combustion of liquid fuels [5], ultrasonic spray pyrolysis [6] to name only a few. In this method of atomisation, mechanical energy transmitted from a rapidly vibrating piezoelectric crystal (in the ultrasonic regime) to a liquid layer in contact with it, causes large capillary waves to develop at the surface of the liquid. These waves eject droplets whose size scale with the driving frequency, surface tension and the viscosity of the liquid. Typically in the kilohertz frequency range, the droplet sizes are in tens of microns. The mechanisms responsible for the formation of these droplets are thought to be a combination of formation of cavitation bubbles at very high frequencies together with the Faraday wave instability, particularly at lower frequencies [7].

In recent years ultrasonic atomisation has been utilised as a promising technique for drug nanoparticle synthesis and microencapsulation [8, 9]. This project aims to develop a method using Faraday wave atomisation in combination with an aerosol reactor method for soft nanoparticle synthesis. Evaporative self-assembly in droplets containing drugs and encapsulating biomolecules will be studied to control nanoparticle properties for controlled drug release. The basic experimental setup exists and the student is expected to refine it. There will be opportunity for extensive experimentation with various drug and solvent combinations. Analytical modelling and simulations will be necessary at later stages. We may also explore inhalation based drug delivery using ultrasonic aerosolisation.


1. Wood, Robert Williams, and Alfred L. Loomis. "XXXVIII. The physical and biological effects of high-frequency sound-waves of great intensity." The London, Edinburgh, and Dublin philosophical magazine and journal of science 4.22 (1927): 417-436.

2. Gaete-Garretón, L., et al. "Ultrasonic atomization of distilled water." The Journal of the Acoustical Society of America 144.1 (2018):  222-227.

3. Groneberg, D. A., et al. "Fundamentals of pulmonary drug delivery." Respiratory medicine 97.4 (2003): 382-387.

4. S. Wisutmethangoon, T. Plookphol, and P. Sungkhaphaitoon, “Production of SAC305 powder by ultrasonic atomization,” Powder Technol. 209, 105–111 (2011).

5. Non-polluting combustion engine having ultrasonic fuel atomizer in place of carburetor, U.S. Patent No. 3,860,173 (1975).

6. Mwakikunga, Bonex W. "Progress in ultrasonic spray pyrolysis for > condensed matter sciences developed from ultrasonic nebulization theories since michael faraday." Critical reviews in solid state and materials sciences 39.1 (2014): 46-80.

7. Rajan, Raghavachari, and Aniruddha B. Pandit. "Correlations to predict droplet size in ultrasonic atomisation." Ultrasonics 39.4 (2001): 235-255.

8. Dalmoro, Annalisa, Matteo d’Amore, and Anna Angela Barba. "Droplet size prediction in the production of drug delivery microsystems by ultrasonic atomization." Translational Medicine@ UniSa 7 (2013): 6

9. Gao, Bing, et al. "A novel preparation method for drug nanocrystals and characterization by ultrasonic spray-assisted electrostatic adsorption." International Journal of Nanomedicine 8 (2013): 3927