Device and method for measuring overall bulk modulus of cells based on ultrasonic standing wave sound field

Abstract

The invention discloses a device and method for measuring the overall bulk modulus of cells based on an ultrasonic standing wave sound field. The measurement method comprises the following steps: according to Y-direction initial positions of each cell at the force start time of the standing wave sound field, calculating an ideal motion trajectory curve by using a Y-direction motion control equation of the cells in combination with field intensity parameters of the standing wave sound field, fitting the actual motion trajectory curve of the cells with the ideal motion trajectory curve of the cells through a least square method, and calculating the overall bulk modulus of the cells by combining the field intensity parameters of the standing wave sound field; due to the fact that a micro-fluidic channel chip is adopted, the cells are subjected to non-contact force motion by combining the ultrasonic standing wave sound field generated in a micro-flow channel of the piezoelectric ceramic, and the overall bulk modulus of the cells is obtained through conversion by measuring the motion trajectory of the cells, such that the problems that the local deformation amount is large and the measurement is inaccurate due to the contact type measurement method are effectively avoided, contact damage to the cells is also avoided, the activity of the cells is effectively ensured, continuous measurement is realized, and the detection flux is relatively high.

Description

technical field [0001] The present invention relates to the field of devices and methods for measuring the overall elastic modulus of cells, in particular to a device and method for measuring the overall elastic modulus of cells based on an ultrasonic standing wave sound field. Background technique [0002] As the basic mechanical properties of cells, cell (bulk) elastic modulus is an important physical quantity that characterizes the characteristics of cells; in this paper, cell elastic modulus refers to the bulk modulus of cells, also known as cell bulk modulus ( modulus of volume elasticity) or cell volume modulus. [0003] Specifically, it is known that cells in P 0 The volume under pressure is V 0 , if the pressure change is dP (that is, the final state pressure minus the initial state pressure P 0 , dP can be positive or negative), that is, to exert an overall pressure on the cell, and the pressure change is called the volume stress dP , the volume change is dV...

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Problems solved by technology

[0005] 1) Measurement method based on atomic force microscope (AFM): use the atomic force microscope to measure the force-distance curve of the interaction between the microsphere on the needle tip and the cell, and then calculate the cell by fitting the model (commonly used, such as the Hertz model). elastic modulus; however, the AFM measurement method is only suitable for measuring adherent cells, and cannot directly measure suspended cells; at the same time, the microspheres on the needle tip can only interact with a part of the cell area, so what is measured is the local area of ​​the cell. mechanical properties, and only one cell can be measured at a time, and the detection throughput is low; and, because the cells are attached to the substrate, there will also be situations where the microspheres on the needle tip interact with the substrate, and the depth of intrusion It will also directly affect the measurement results; in addition, the AFM measurement method has cumbersome steps and expensive instruments

[0006] 2) The measurement method based on the micropipette: use negative pressure to enter the cell to be tested into the pipette, and calculate the elastic modulus of the cell by studying the local deformation of the cell in contact with the tube wall (cell membrane); however, the pipette wall of the micropipette measurement method must In contact with the cells, the cells need to be deformed sufficiently, and the deformation of some areas of the cells may exceed the range of its elastic deformation; and the micropipette measurement method is also the local deformation of the cell membrane, which cannot reflect the overall elastic modulus of the cells. amount; and, the negative pressure environment used in the micropipette measurement method is also likely to cause cell damage; in addition, the detection throughput of the micropipette measurement method is also low

[0007] Therefore, the existing technology still needs to be improved and developed

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