Research On Acoustofludics Mechanism Based On Controllable Micro-bubbles

With the continuous needs of disciplines such as biology,chemistry,physics,scientific research in the field of micro-nano operations has developed rapidly in recent years,from traditional operation to contactless operation,such as micro-nano operation with optical tweezers,micro-nano operation with dielectrophoresis,microinjection,and nuclear transfer.The development of micro-nano operations has brought huge changes to the machinery manufacturing,biomedical,precision processing and other industries.Nowadays,micro-nano manufacturing level has become one of the important indicators to measure a country's science and technology level.However,in the related applications and research of bubble acoustofluidics,bubbles are not well controlled.It largely limits the repeatability and range of applications of this technology.Aiming at this problem,this paper introduced the concept of controllable micro-bubble.The controllable bubble generation and variation are achieved by gas diffusion,due to the hydrophobic and porous characteristic of the PDMS.Design a vision-based bubble size control system,stability of bubble size is guaranteed by detecting the ROI region,setting initial bubble size,analyzing and processing image data,air pressure control strategy and air pressure regulation.Through theoretical analysis and design comparative experiments to explored the effects of bubble vibration at different frequencies,the causes of different types of particle motion trajectories,the magnitude and direction of various forces on particles in the vortex of the sound field,the role of various forces in the particle motion and the reason for the change of particle motion trajectory.Using COMSOL Multiphysics simulation software to simulated the effect of various parameters on particle acoustic microstreaming.The relationship between the particle trajectory and bubble size,particle size and other parameters in acoustic microstreaming is explored by changing the core parameters.The Influence of flow channel structure on particle acoustic microstreaming and particle enrichment is investigated,and particle separation experiments were performed based on acoustofluidics theories,further verifying the correctness of the acoustofluidics theories.The introduction of the controllable microbubble has greatly improved the experimental repeatability,complemented existing theories,broaden the application of bubble acoustofluidics.It is of great significance for the establishment of automated,intelligent and flexible rapid cell sorting system and rapid disease detection system due to controlled micro-bubble's controllability and flexibility.