Ultrasound For The Preparation And Manipulation Of Lipid Vesicles

BackgroundSpherical lipid vesicles(lipid vesicles)are microspheres composed of lipid bilayers,which can be used as a multifunctional carrier to deliver drugs or other macromolecules into humans or animals,or as a model to simulate cell membranes..Lipid vesicles prepared in a high-ion concentration solution environment can provide a physiological environment closest to cells,and are used in cell models,gene transfer vectors and bioreactors.Due to the inhibition of high ion concentration on lipid membrane swelling and lamella separation,it is currently difficult to prepare high-quality and high-yield lipid vesicles in a high-ion concentration solution environment.The manipulation of lipid vesicles has great application value in the fields of biology and chemistry.The manipulation of lipid vesicles can be used to capture and collect lipid vesicles in fluids and sort lipid vesicles of different particle sizes to obtain monodisperse.Lipid vesicles can also manipulate vesicle fusion to study the process of biomembrane fusion,but the existing lipid vesicle manipulation technology is limited by lipid materials and manipulation systems.purposeUse ultrasound to prepare lipid vesicles in a high-ion concentration solution;use ultrasonic drag force to pull out cylindrical lipid vesicles from lipid membranes remotely and controllably;use acoustic radiation force and secondary lipid vesicles Acoustic radiation force captures lipid vesicles in the fluid space.In order to further control the controllability and efficiency of lipid vesicles with high ultrasound,a microstructure array chip combined with body acoustic waves is used to capture lipid vesicles in the fluid space.Method1.Use the finite element method to establish a physical model of lipid vesicle formation in the sound field,and conduct experimental verification;2.Establish and verify the theoretical dynamic model of cylindrical lipid vesicles prepared by ultrasonic drag force;3.Using bulk acoustic wave combined with microstructure array chip,using microfluidic trap array to capture lipid vesicles in the three-dimensional fluid space.Result1.Based on the acoustic flow theory,the physical model model of lipid vesicles in the sound field is established by the finite element method,and the simulation results of the sound flow inside the lipid vesicles are obtained,and the formation mechanism of the lipid vesicles in the sound field is revealed.Using 830 KHz piezoelectric ceramics as the sound source,lipid vesicles were successfully prepared in 0.65% Na Cl solution;a planar piezoelectric ultrasonic transducer was used to prepare cylindrical lipids with ultrasonic drag force generated in a remotely controllable manner Vesicles,in order to clearly explain the formation mechanism,a theoretical kinetic model of the formation of cylindrical lipid vesicles is established.Experimental results show that cylindrical lipid vesicles can be quickly and effectively prepared by ultrasound in deionized water.The stretching speed of cylindrical lipid vesicles can reach 33 ?m/s,and the formed cylindrical lipid vesicles have a diameter of about 500 nm.Uniform pipe diameter,length can reach millimeter level.2.Using acoustic radiation force and secondary acoustic radiation force to capture lipid vesicles in the fluid,but the controllability is insufficient,so an improved method is proposed to use a bulk acoustic wave microfluidic trap array to capture lipid vesicles in a three-dimensional fluid space In the method,two types of microarrays of cylindrical and round holes were prepared,and the finite element method was used for simulation calculation.In the simulation,polystyrene particles were used to simulate the movement of lipid vesicles in the flow field.The experimental results show that the bulk acoustic wave microfluidic trap can quickly and efficiently capture lipid vesicles in the three-dimensional fluid space.Both the cylindrical bulk acoustic wave microfluidic trap and the round-hole bulk acoustic wave microfluidic trap can capture the three-dimensional space in tens of seconds.The trapping efficiency of the cylindrical bulk acoustic microfluidic trap is higher than that of the round-hole bulk acoustic microfluidic trap.ConclusionThe preparation efficiency of using ultrasonic volume force to prepare lipid vesicles in high ion concentration solution is similar to that of electroforming;this paper reports a method of preparing cylindrical lipid vesicles using ultrasonic drag force in theory and experiment The preparation speed is ten times faster than existing methods,providing a remote-controllable and efficient technology for the preparation of cylindrical lipid vesicles;a bulk acoustic wave microfluidic trap array is proposed to capture lipid vesicles in a three-dimensional fluid space This method breaks through the space limitation of the surface acoustic wave microfluidic trap and improves the controllability and efficiency of capturing lipid vesicles.