UC Irvine

Nanobubbles (NBs) have been studied for more than 20 years. One of the two types of NB, the bulk NB, with its extraordinary physical, chemical and biological properties, drew a lot of attention among researchers. However, the fundamental mechanisms of NB generation, stability, longevity and ability to bind nanoparticles are far behind the development of its applications in the industry.We started from studying the generation of NBs with an alternating magnetic field, and studied NB clustering effects with different kinds of nanoparticles that include CaCO3 and nanoscale Polystyrene beads. Furthermore, we tested NB’s effects on the \textit{ex vivo} dissolution of human atherosclerosis plaque. More recently, the NB-nanoparticle clustering mechanism was studied based on established DLVO theories and experimental data. The technologies employed for characterizing NBs, nanoparticles and clusters include Nanoparticle Tracking Analysis (NTA), Dynamic Light Scattering (DLS) with zeta potential measurement and Transmission Electron Microscopy (TEM). Intravascular Optical Coherence Tomography (IVOCT) and Micro Computed Tomography (Micro-CT) were used to characterize the volume of plaque in coronary/periphery arteries and aortic valve tissue, respectively. \par It turns out that Bulk NBs are able to attract not only cations or nanoparticles with dipoles, but also hydrophobic nanoparticles that are nearly electroneutral considering hydrophobic attraction. It provided more insight in the interaction between nano-objects at the nanoscale. The research on the \textit{ex vivo} dissolution of human plaque based on NB clustering also promotes the idea of developing NB treatment methods for atherosclerosis, the most lethal chronic disease.