Development of Microparticle Manipulation Using Piezoelectric Acoustic Transducers

Acoustic tweezers capable of manipulate micro-particles are proposed. Recently, micro-particlemanipulation in liquid draws lots of interests in many biomedical applications. For example, opticaltweezers using laser beam has been explored to trap small particles such as macromolecules and cells.However, it usually requires expensive optical components and lasers. Compared to optical tweezers,acoustic tweezers were found to be more practical in the opaque medium. In this proposal, acoustic tweezerscontrolled by piezoelectric acoustic transducer array will be used to trap micro-particles. The proposedacoustic tweezers are built on piezoelectric film with top and bottom electrodes. The electrodes will bepatterned into annular rings to form acoustic Fresnel lens, so that the acoustic waves generated by theseannular zones could form constructive interferences at the focal point. The acoustic wave can be focusedinto tens of microns or even smaller by different excitation frequencies. By adequately arranging thelocations of several acoustics transducers, the acoustic trapping can be formed on the minimum energyregions. The acoustic trapping force would be affected by several parameters, such as acoustic wavefrequency, distance, particle size and acoustic medium. Various FEM simulations and experiments will beperformed to optimize the trapping force on a micro-particle or a red blood cell.