Research On The Three-dimensional Cell Forming System Actuated By Ultrasonic Acoustic Pressure Potential Micro-well Array

The establishment of a biologically active three-dimensional multi-cell system in vitro is the prerequisite and key link for cell 3D printing.The three-dimensional multi-cell system achieves the purpose of tissue regeneration and organ repair through culture and reproduction,which is of great significance to the development of life sciences and biomedicine.Aiming at the problems of cell density,inter-cell communication,scaffold degradation rate,printability and biocompatibility caused by the use of biological scaffolds or supports for existing cell 3D printing,this paper proposed a method for non-contact manipulation of cells based on ultrasonic array acoustic pressure micropotential wells to construct a three-dimensional cell system.The main research was the manipulation method of the array acoustic pressure micro-potential well cells,and the formation of the threedimensional system of scaffold-free cells has been realized by introducing the pulse micro-transport technology of the cells.Firstly,the construction method of the array acoustic pressure potential well and the research on the dynamics of particle manipulation in the potential well were carried out.A multi-physics coupling model of pressure acoustics and particle tracing was established,and the method of constructing acoustic pressure micro-potential well by double traveling wave coupling in the resonant cavity and the movement characteristics of particles under the action of acoustic radiation force were studied.The results show that the use of a dual-axis sound source in the pentagonal resonant cavity can construct a differential planar array acoustic pressure potential well,which has higher flexibility and achieves accurate trapping of particles in the differential array acoustic pressure potential well.In the simulation,under the 1Mhz acoustic source,two particle arrangement lines with a spacing of 0.79 mm and 1.27 mm can be formed.The corresponding line widths were 0.11 mm and 0.19 mm.At 2MHz,the spacing became 0.39 mm,0.64 mm,and the width became 0.55 mm,0.95 mm.Secondly,the research on pulsed micro-transport method for scaffold-free cell 3D printing was carried out.In this paper,pulsed gas was used to shear the fluid column to form micro-droplets to realize the pulsed micro-transport of cell suspension.The sandwich micro-fluid nozzle was designed and manufactured,the micro-transport system was built,and the pulse pneumatic micro-transport experiment was studied.The experimental results show that when the liquid pressure increases(5-40KPa),the droplet size shows a decelerating and increasing trend accordingly(0.748mm-1.462mm),and when the control parameters(input air pressure,hydraulic pressure)are(40KPa,10KPa),(45KPa,10KPa)and(50KPa,15KPa),the coefficient of variation of the micro-transport droplet size was kept below 5% to achieve stable delivery.Finally,the experimental research on the formation of the three-dimensional system of the array acoustic pressure micro-potential well manipulating cells was carried out.In a pentagonal resonant cavity,an array acoustic potential well was constructed through the coupling of a dual-axis sound source,and the arrangement of particles under the control of the acoustic potential well was investigated.The experimental results show that the particles could form a stable line arrangement the by using acoustic potential well control.When the acoustic source was 1MHz,two particle arrangements with line spacing of 0.8mm and 1.29 mm can be formed,and the corresponding line widths are 0.2mm and 0.32 mm,respectively.When the acoustic source was increased to 2MHz,the line spacing was 0.4mm,0.63 mm,and the line width was 0.11 mm,0.16 mm.The arrangement of the cells under the control of the double-layer array acoustic potential well has been studied.In the experiment,two layers of particle arrays with a cross angle of about 72° were formed.The line spacing of each layer was 0.4mm and the line width was 0.2mm.On this basis,by superimposing a multilayer acoustic field,a scaffold-free cell three-dimensional system shaping method based on array acoustic pressure micro-potential well manipulation can be realized,which provides the possibility for the realization of acoustically controlled scaffold-free cell 3D printing.