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  and since then has been extensively used for various purposes  like pulmonary drug delivery , preparation of fine powders , combustion of liquid fuels , ultrasonic spray pyrolysis  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 .
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.
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