A driving device for detecting the mechanical and electrical properties of cells

Abstract

The present invention relates to a driving device for detecting the mechanical and electrical properties of cells. The structure of this driving device mainly includes a piezoelectric stack, a bridge-type flexible hinge mechanism, a parallel hinge mechanism, a lead screw guide rail, a stepping motor, a linear displacement sensor, a force sensor, a ceramic needle, an electrode one, an electrode two, a cell container, an XY-axis displacement platform, positioning holes, a metal base one, a metal base two, a metal connecting plate one, a metal connecting plate two, a pre-tightening wedge one, a pre-tightening wedge two, screws, and pre-tightening screws. When the driving device works, under the excitation of a driving electric field signal, the piezoelectric stack is driven, causing the bridge-type flexible hinge mechanism to elongate. Through the parallel flexible hinge mechanism, the ceramic needle is driven to move downward. The advantages of the present invention are that the driving device not only has a simple structure and an integrated control system, but also can detect the mechanical and electrical properties of cells.

Description

Technical Field

[0001] The present invention relates to the fields of precision and ultra-precision machining, and micro-electromechanical systems engineering research, and particularly relates to a driving device for detecting the mechanical and electrical properties of cells. Background Art

[0002] With the development of science and technology, micro / nano-level precision driving technology is a key technology in research fields such as precision and ultra-precision machining and measurement, micro-electromechanical systems, aerospace, and biomedicine. Each type of driver has its own advantages. Piezoelectric drivers have characteristics such as simple structure, convenient control, high resolution, and precise positioning, and have shown good application effects and bright prospects especially in the projects of micro-electromechanical systems, micro / nano indentation, and biological cell manipulation.

[0003] Most of the existing devices for detecting cell characteristics only have one detection effect, that is, they only detect the mechanical properties of cells or only detect the electrical properties of cells, without combining the two. Currently, atomic force microscopy, micropipette aspiration technology, optical tweezers technology, microfluidics technology, etc. are usually used to detect the mechanical properties of cells; patch clamp, electrochemical impedance analysis method, rotating electric field technology, etc. are usually used to detect the electrical properties of cells. These technologies have deficiencies such as complex structure, difficult operation, and too high research costs. Therefore, it is necessary to design a driving device that simultaneously has the functions of detecting the mechanical and electrical properties of cells, solve the barriers existing in the prior art, and reduce the research costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a driving device for detecting the mechanical and electrical properties of cells, which solves the above-mentioned existing problems. The present invention has a simple and compact structure and has the function of simultaneously detecting the mechanical and electrical properties of cells.

[0005] The present invention performs linear motion through two driving units. The output of a larger displacement is realized by a lead screw guide rail, and the output of a small displacement is realized by the deformation of a piezoelectric stack and two flexure hinge mechanisms to achieve downward linear motion. The present invention uses a combination of a force sensor and a ceramic needle to detect the mechanical properties of cells. In order to observe the small displacement of the actual downward movement of the driving device, a linear displacement sensor is used to obtain a micron-level displacement. At the same time, the electrical properties of cells are detected by a resistance impedance analyzer through the connection of electrodes.

[0006] The above object of the present invention is achieved by the following technical solutions:

[0007] A driving device for detecting the mechanical and electrical properties of cells mainly includes a piezoelectric stack (5), a bridge-type flexible hinge mechanism (4), a parallel hinge mechanism (6), a lead screw guide rail (2), a stepping motor (1), a linear displacement sensor (20), a force sensor (8), a ceramic needle (16), an electrode one (9), an electrode two (10), a cell container (11), an XY-axis displacement platform (14), a positioning hole (15), a metal base one (13), a metal base two (12), a metal connecting plate one (3), a metal connecting plate two (7), a pre-tightening wedge one (17), a pre-tightening wedge two (18), a pre-tightening screw (19), and a screw (21). The driving device realizes micron-level precise linear driving. The lead screw guide rail (2) is fixed on the metal base one (13). The driver body includes a bridge-type flexible hinge mechanism (4) and a parallel hinge mechanism (6), which are fixed on the metal connecting plate one (3) by screws. The metal connecting plate one (3) is fixed on the lead screw guide rail (2) by a screw (21). The force sensor (8) and the ceramic needle (16) are fixed under the driver body through the metal connecting plate two (7). The cell container (11) is placed above the XY-axis displacement platform (14) and adjusted to a suitable position through the XY-axis displacement platform (14). The pre-tightening wedge one (17) and the pre-tightening wedge two (18) are pre-tightened by the pre-tightening screw (19) and fixed on the metal base one (13) by screws. The linear displacement sensor (20) is installed in the pre-tightening wedge one (17). The metal base one (13) and the metal base two (12) play the role of supporting and installing and fixing other parts. The force sensor (8) is connected to the ceramic needle (16). The ceramic needle (16) is prepared from zirconia, alumina, and silicon carbide materials. An electrode one (9) is attached to the ceramic needle (16). An electrode two (10) is attached to the bottom of the cell container (11). The electrode one (9) is connected to an impedance analyzer with the electrode two (10). During the downward linear movement of the driving device, the ceramic needle (16) presses down into the cell container (11) to detect the mechanical and electrical properties of the cells;

[0008] The detected mechanical properties include elastic modulus, Poisson's ratio, shear modulus, and degree of deformation. The detected electrical properties include impedance, hysteresis frequency, conductivity, dielectric constant, and cell membrane specific capacitance.

[0009] The displacement of the driving device is divided into two steps. First, the piezoelectric stack (5), the bridge-type flexible hinge mechanism (4), the parallel hinge mechanism (6), the metal connecting plate one (3), the metal connecting plate two (7), the force sensor (8), and the ceramic needle (16) are driven by the lead screw guide rail (2) to move downward. Second, the piezoelectric stack (5) is arranged in the bridge-type flexible hinge mechanism (4). The piezoelectric stack (5) is driven, and the bridge-type flexible hinge mechanism (4) elongates, thereby driving the parallel hinge mechanism (6) to elongate and move downward in a straight line;

[0010] The displacement detection mechanism of the driving device is realized by the linear displacement sensor (20). By detecting the minute displacement of the driving device, the displacement data of the driving device can be obtained. The mechanical detection of cells by the driving device uses a force sensor (8). The XY-axis displacement platform (14) realizes the positioning of the cell container (11) in two directions, the X-axis and the Y-axis.

[0011] The bridge-type flexible hinge mechanism (4) and the parallel hinge mechanism (6) can be made of high-strength aluminum alloy. Connected by two flexible hinges, they have good stiffness output characteristics, can output relatively large loads, and their size structure is more compact.

[0012] The pre-tightening wedge block one (17) and the pre-tightening wedge block two (18) fix the linear displacement sensor (20) on the metal connecting plate two (7) to achieve a wedging connection. The initial pre-tightening force of the linear displacement sensor (20) is adjusted by the pre-tightening wedge block one (17), the pre-tightening wedge block two (18), and the pre-tightening screw (19). The pre-tightening wedge block one (17) and the pre-tightening wedge block two (18) can be made of plastic material.

[0013] The piezoelectric stack (5) is arranged in the bridge-type flexible hinge mechanism (4). Driving the piezoelectric stack (5) causes the bridge-type flexible hinge mechanism (4) to elongate. At the same time, the parallel hinge mechanism (6) below also elongates to play a guiding role, enabling the driving body to perform linear precision motion without deformation.

[0014] The main advantages of the present invention are as follows: Two driving units are adopted to achieve rough measurement and precise measurement of displacement. The first displacement of the driving body is obtained through the lead screw guide rail. Then, under the drive of the piezoelectric stack, the second displacement of the driving body is obtained through the linear displacement sensor. The sum of the two displacements is the total displacement of the entire driving device. A force sensor is used to obtain the mechanical properties of cells, and an impedance analyzer is used to obtain the electrical properties of cells. The structure of the present invention is simple, the method is novel, the driving reliability is high, the investment is small, and the benefit is high. It is applicable to important scientific engineering fields such as precision and ultra-precision machining, micro-electromechanical systems, modern medicine and biological genetic engineering, and biotechnology. Brief Description of the Drawings

[0015] Figure 1 is the overall structural schematic diagram of the present invention;

[0016] Figure 2 is the left view schematic diagram of the present invention;

[0017] Figure 3 is the partial cross-sectional view of the electrical property measurement of the present invention;

[0018] Figure 4 is the schematic diagram of the driving body of the present invention;

[0019] Figure 5 It is a schematic diagram of the motion process of the driver body of the present invention;

[0020] Figure 6 It is a force-displacement diagram. Specific embodiments

[0021] The following further describes the detailed content and specific embodiments of the present invention in conjunction with the accompanying drawings.

[0022] Referring to Figures 1 to 5 As shown, a driving device for detecting the mechanical and electrical properties of cells mainly includes a piezoelectric stack (5), a bridge-type flexible hinge mechanism (4), a parallel hinge mechanism (6), a lead screw guide (2), a stepping motor (1), a linear displacement sensor (20), a force sensor (8), a ceramic needle (16), an electrode one (9), an electrode two (10), a cell container (11), an XY-axis displacement platform (14), a positioning hole (15), a metal base one (13), a metal base two (12), a metal connecting plate one (3), a metal connecting plate two (7), a pre-tightening wedge one (17), a pre-tightening wedge two (18), a pre-tightening screw (19), and a screw (21). The driving device realizes micron-level precision linear driving. The lead screw guide (2) is installed on the metal base one (13); the driver body includes a piezoelectric stack (5), a bridge-type flexible hinge (4), and a parallel flexible hinge (6) which are installed on the metal connecting plate one (3) by screws; the metal connecting plate one (3) is fixed on the lead screw guide (2) by screws (21); the linear displacement sensor (20) is connected and fixed to the metal connecting plate two (7) and the metal base one (13) respectively through the pre-tightening wedge one (17) and the pre-tightening wedge two (18) by screws, and the positioning and adjustable function of the linear displacement sensor (20) can be realized through the screws; the force sensor (8) and the ceramic needle (16) are connected to the driver body through the metal connecting plate two (7).

[0023] The driving device utilizes the piezoelectric effect and the flexible hinge mechanism to realize the micron-level linear displacement motion of the driver body. The bridge-type flexible hinge mechanism (4) and the parallel hinge mechanism (6) included in the driver body have good stiffness output performance, stable and efficient motion. The piezoelectric stack (5) is installed in the bridge-type flexible hinge mechanism (4). When the piezoelectric stack (5) is driven, the bridge-type flexible hinge mechanism (4) deforms and extends downward, and the parallel hinge mechanism (6) connected to the bridge-type flexible hinge mechanism (4) extends simultaneously. The parallel hinge mechanism (6) plays a guiding role in the driver body and can enable the driver to move in a straight line without deviating from the track.

[0024] The initial pre-tightening force of the linear displacement sensor (20) is provided by the cooperation of the first pre-tightening wedge block (17) and the pre-tightening screw (19). The second pre-tightening wedge block (18) is installed and fixed to the first metal base (13) by screws. The linear displacement sensor (20) is simultaneously fixed to the second metal connecting plate (7). The position of the second pre-tightening wedge block (18) is adjusted through the positioning hole (15) in the first metal base (13).

[0025] The force sensor (8) cooperates with the ceramic needle (16). During the linear movement of the driver body, when it contacts the cell, it can return the force signal for transmission and display in the upper computer, achieving the purpose of real-time monitoring.

[0026] An electrode I (9) is attached to the ceramic needle (16), and an electrode II (10) is attached to the cell container. During the downward movement of the ceramic needle (16), the electrode I (9) and the electrode II (10) are connected to an impedance analyzer to measure the electrical characteristics of the cell.

[0027] The mechanical properties include elastic modulus, Poisson's ratio, shear modulus, and degree of deformation. The electrical properties include impedance, hysteresis frequency, conductivity, dielectric constant, and cell membrane specific capacitance.

[0028] See Figures 1 to 6 As shown, the specific working process of the present invention is as follows:

[0029] The present invention realizes linear displacement through two driving units. The first driving unit is realized by the lead screw guide rail (2). The stepping motor (1) is controlled by the controller, and the lead screw guide rail (2) makes an appropriate displacement to achieve a large linear displacement. The second driving unit is realized by the driver body, which includes a piezoelectric stack (5), a bridge-type flexible hinge mechanism (4), and a parallel hinge mechanism (6). The piezoelectric stack (5) is placed in the bridge-type flexible hinge mechanism (4). When the piezoelectric stack (5) is driven, the bridge-type flexible hinge mechanism (4) elongates and moves downward, and the parallel hinge mechanism (6) below also elongates to play a guiding role, so that the movement trajectory of the driver body can remain unchanged. While the driver body makes a linear displacement downward, the linear displacement sensor (20) on the left side of the driving device detects the minute displacement of the driver body. The linear displacement sensor (20) is fixed between the positioning hole (15) of the first metal base (13) and the second metal connecting plate (7) by the first pre-tightening wedge block (17) and the second pre-tightening wedge block (19) through screws, realizing the function of detecting minute displacement, and at the same time, the displacement data can be detected in real time through the upper computer. The combination of the force sensor (8) and the ceramic needle (16) connected to the lower part of the driver body can detect the mechanical properties of the cell through the force sensor (8) during the process of the ceramic needle (16) contacting the cell until the cell is flattened, obtaining a force-displacement diagram. See the appendix Figure 6; Connect to an impedance analyzer through electrode one (9) and electrode two (10) to detect the corresponding electrical characteristics of the cells.

[0030] A driving device for detecting the mechanical and electrical characteristics of cells according to the present invention uses two driving units, a linear displacement sensor, and a force sensor as the main detection devices, and detects the electrical characteristics through an impedance analyzer. The driving device has the characteristics of simple and compact structure, stable and reliable driving, integrated functions, and real-time data display, and can effectively detect the mechanical and electrical characteristics of cells and reflect the state of the cells.

Claims

1. A driving device for detecting the mechanical and electrical properties of cells, mainly including a piezoelectric stack (5), a bridge-type flexible hinge mechanism (4), a parallel hinge mechanism (6), a lead screw guide rail (2), a stepping motor (1), a linear displacement sensor (20), a force sensor (8), a ceramic needle (16), an electrode one (9), an electrode two (10), a cell container (11), an XY-axis displacement platform (14), a positioning hole (15), a metal base one (13), a metal base two (12), a metal connecting plate one (3), a metal connecting plate two (7), a pre-tightening wedge one (17), a pre-tightening wedge two (18), a pre-tightening screw (19), a screw (21). The lead screw guide rail (2) is fixed on the metal base one (13). The driver body includes a bridge-type flexible hinge mechanism (4) and a parallel hinge mechanism (6), and is fixed on the metal connecting plate one (3) by screws. The metal connecting plate one (3) is fixed on the lead screw guide rail (2) by screws (21). The cell container (11) is placed above the XY-axis displacement platform (14) and adjusted to a suitable position through the XY-axis displacement platform (14). The pre-tightening wedge one (17) and the pre-tightening wedge two (18) are pre-tightened by the pre-tightening screw (19) and fixed on the metal base one (13) by screws. The linear displacement sensor (20) is installed in the pre-tightening wedge one (17). The metal base one (13) and the metal base two (12) play the role of supporting and installing and fixing other parts. It is characterized in that: The force sensor (8) and the ceramic needle (16) are fixed under the driver body through the metal connecting plate II (7). An electrode I (9) is attached to the ceramic needle (16), and an electrode II (10) is attached to the bottom of the cell container (11). The electrode I (9) and the electrode II (10) are connected to an impedance analyzer. During the downward linear motion of the driving device, the ceramic needle (16) presses down into the cell container (11) to detect the mechanical and electrical properties of the cells.

2. The driving device for detecting the mechanical and electrical properties of cells according to claim 1, wherein The detected mechanical properties include elastic modulus, Poisson's ratio, shear modulus, and degree of deformation, and the detected electrical properties include impedance, hysteresis frequency, conductivity, dielectric constant, and cell membrane specific capacitance.

3. The driving device for detecting the mechanical and electrical properties of cells according to claim 1, characterized in that The displacement of the driving device is divided into two steps: First, the lead screw guide (2) drives the piezoelectric stack (5), the bridge-type flexible hinge mechanism (4), the parallel hinge mechanism (6), the metal connecting plate I (3), the metal connecting plate II (7), the force sensor (8), and the ceramic needle (16) to move downward. Second, the piezoelectric stack (5) is arranged in the bridge-type flexible hinge mechanism (4), and the piezoelectric stack (5) is driven, causing the bridge-type flexible hinge mechanism (4) to elongate, thereby driving the parallel hinge mechanism (6) to elongate and move downward in a straight line.

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