Over the past three years, Arora investigated bubbles originating from high intensity pressure pulses in the Physics of Fluids research group led by Detlef Lohse. These so-called cavitation bubbles can have devastating effects on the propellers of ships when they collapse. However, there are several biomedical applications for the controlled formation and collapse of cavitation. Arora studied the mechanism of cavitation with these applications in mind.
`My thesis actually consists of three parts,' says Arora. `First, I studied controlled formation of cavitation bubbles. A high pressure pulse causes bubbles to form on the surface of very small particles in liquid. Particles are driven forward by taking energy from expanding bubbles'.
The second part of Arora's thesis is dedicated to lithotripsy, a treatment in which kidney stones are fragmented by a pressure pulse outside the body. It is thought that clusters of cavitation bubbles on the surface of the kidney stones helps to fragment them. Arora investigated the dynamics of cavitation in this therapy. He also studied the interaction of cavitation bubbles with cells: `A collapsing bubble momentarily opens the cell membrane, allowing an entrance for drugs or genes that would normally be unable to cross.'
Because Arora used his time so efficiently as a PhD candidate, there is time and money for him to conduct further research into cavitation in Twente. `The next six months I will be working as a post-doc on controlled bubble formation on biodegradable micro-particles, which has applications in drug delivery,' says Arora. `After that I will probably look for another post-doc position, but eventually I will return to India. More avenues open up there for people with prior experience abroad.'
