Research On Manipulating Tiny Particles Based On Acoustic Tweezers

Acoustic tweezer for manipulation,which is a kind of new technology boom,has shown great potential in fields such as medical science,biology and material science for its low level of hazards,wide range of material adaptation,and avoidance of contamination,contact and damage.Today,with successful application in multiple realms including cell manipulation,particle agglomeration,molecular filtration,drug delivery etc.,acoustic tweezer has become a hot spot in acoustical research.Forces exerted on tiny particles mentioned in this paper and manipulation of these particles are based on the problems of transporting targeted medicine inside human body,which is a problem of manipulating radially diffracted particles.This paper started with the derivation of formulas,analyzing the feature of force exerted on particles when immerse in different fluidic media.Under the guidance of formula,specializing the problem of acoustic tweezer,we put forward the idea of manipulating particles by establishing an acoustic radiation force trap through focusing sound pressure.The method was verified in the simulation software.Finally,the experiment of manipulation was set up based in the back of theory and simulation.The contents of research are as follows:(1)The expression of acoustic radiation force exerted by acoustic field on particles has been derived.Features of acoustic radiation force exerted on single-layered particles and double-layered particles have been figured out when the parameters of particles or the surrounding medium changes.(2)The principle of manipulation supported by phased-array acoustic tweezer in standing wave has been elaborated.Stability of particles’ movement has been studied by the using FEM(Finite Element Method)simulating software to see the moving status in the vertical and horizontal scale.In addition,detailed analysis of in-plane moving stability for micro beads manipulated by acoustic tweezer with 32 elements(the distribution of transducers is 4×4 in each plane respectively)was given.(3)Independently established a system for driving phased-array acoustic tweezers in standing wave field.Experiments was done to validate the results of simulation.Besides,comparisons of step lengths were made between theory and experiments.The reason for differences were analyzed.This paper discussed the properties of acoustic tweezer based on acoustic principles.The research plays a significant role in putting acoustic tweezers into practice for military usage,medical research and material studies.