The Research Of Acoustic Streaming Effect And Rotary Motor Based On Lamb Wave Resonator Array

The manipulation of micro particles and fluid is an important task in many biological and chemical researches and applications such as cell detection and tissue engineering.Recent advances in microfluidics and lab-on-a-chip have made many portable biosensors and diagnostic devices applied for biomedicine and healthcare.This work applies the acoustic streaming based on Lamb wave resonator(LWR)array to manipulate particles and biomolecules in the open fluid field.Besides,the novel LWR arrays are designed to drive a non-contact rotary motor.The silicon-based LWR has great potential to be integrated into lab-on-a-chip devices.The principle and numerical study of the acoustic streaming effect of LWRs is clarified,and a ring array composed of 8 LWRs is presented and fabricated.The FEA model is consulted that a main vortex can be formed at the center of the array with the largest velocity.The experiments explore the relationship between the linear speed of micro-particles with the increasing input power when the paricle size and liquid viscosity is varied,obtaining the maximum speed of 62 mm/s with the power of 0.1 W.The speed of particle is basically independent of particle size and dominated by Stokes drag force.A slightly higher viscosity of liquid can improve the effectiveness of particle enrichment.Furthermore,the HeLa cells and neural stem cells are manipulated,and the photosensitive polymer PEGDA is introduced as a scaffold for tissue engineering,which verifies the feasibility of the device in cell manipulation and micro-structure assembly.In order to overcome the effect of secondary vortices excited by the normal LWR array and ensure the stability of the on-chip application,a flow field with the single main vortex is obtained by changing the acoustic boundary conditions of the resonator.LWR is optimized into a novel structure with gratings on one side,preventing the propagation of acoustic waves to the liquid from both sides simultaneously.Several novel LWRs are formed into a large ring array,which is placed perpendicular to the fluid coupling layer and the rotor with a hollow structure.The rotary motor can achieve the maximum speed of 270 rpm with the input power of 3W.The relationship between the angular velocity and the input power in the cases of different rotor diameters,rotor structures,the arrangement of array,and the thickness of liquid coupling layer are established.The novel design has guiding significance for constructing a microfluidic platform with a complex acoustic straming field and provides an additional insight for nano/micro-actuation technology.