Biological micro-nano force testing device

Abstract

The utility model provides a biological micro-nano force testing device which comprises a base, a sample table capable of moving on the surface of the base and a testing frame installed on one side of the base, and a microneedle and a nano displacement table driving the microneedle to be close to / away from the sample table are installed on the testing frame. And a pressure sensor is arranged between the microneedle and the nanometer displacement table. The biological micro-nano force testing device is simple in structure, the high-precision large-stroke nano displacement table is adopted to provide a driving force of cross-scale movement from nanometer to centimeter for the microneedle, and meanwhile, the device has a nano-scale positioning resolution ratio, so that the requirement of testing mechanical property parameters of microneedle instruments for breaking through biological tissues can be met.

Description

Technical Field

[0001] The utility model belongs to the technical field of biomechanical material testing, and particularly relates to a biological micro-nano force testing device. Background Art

[0002] The breakthrough force of a micro-needle piercing the surface of a biological tissue is proportional to the deformation of the biological tissue. The larger the cross-sectional size of the micro-needle, the greater its breakthrough force, the greater the deformation of the biological tissue, and the greater the damage to the biological tissue. Therefore, the design of the micro-needle needs to match the mechanical property parameters of the biological tissue material. A smaller implantation injury requires a smaller cross-section of the micro-needle, but if the cross-section of the micro-needle is too small, its strength may not be sufficient to break through the tissue surface and break during the implantation process. Therefore, testing the mechanical property parameters of biological tissue materials is crucial for designing micro-needles and evaluating the piercing process.

[0003] During the process of a micro-needle piercing a biological tissue such as skin, visceral organs or cerebral cortex, before the tip of the needle breaks through the epidermis of the biological tissue, the surface of the cortex will deform, and the deformation amount is at the mm level, and the breakthrough force is at the μN - mN level. Therefore, for the stress-strain test of the biological tissue during this process, the force test accuracy is required to be at the μN level, and the range reaches dozens to hundreds of mN; the measurement accuracy of the strain is required to be at the level of dozens of nm, and the range reaches mm.

[0004] Currently, commercially available material mechanical property testing instruments, such as compression testing machines or universal force measuring instruments, often have a measurement accuracy at the mN level, which cannot meet the measurement accuracy requirements. For nano-indenters used for micro-nano force testing, their measurement accuracy can reach the nN level, and the stroke test accuracy can reach the nm level, but their stroke is short, only at the μm level, suitable for inorganic materials, and not suitable for flexible materials with large displacement strokes, such as biological tissue materials. Content of the Utility Model

[0005] The purpose of the utility model is to provide a biological micro-nano force testing device, which can at least solve some defects existing in the prior art.

[0006] To achieve the above purpose, the utility model adopts the following technical scheme:

[0007] A biological micro-nano force testing device includes a base, a sample stage movable on the surface of the base, and a test frame installed on one side of the base. A micro-needle and a nano-displacement stage for driving the micro-needle to approach / away from the sample stage are installed on the test frame, and a pressure sensor is arranged between the micro-needle and the nano-displacement stage.

[0008] Further, an axial angle adjustment stage for driving the micro-needle to rotate around the X-axis on the end face of the test frame close to the sample stage is installed on the test frame.

[0009] Furthermore, the axial angle adjustment stage includes a fixing plate for fixedly mounting the nano-displacement stage, a turntable for driving the fixing plate to rotate, and a driving motor for driving the turntable to rotate; the driving motor is fixedly mounted on one side of the test stand close to the sample stage, and the fixing plate is fixedly connected to the outer peripheral edge of the turntable.

[0010] Furthermore, a micro-needle fixing fixture for clamping the micro-needle is provided on the pressure sensor.

[0011] Furthermore, the micro-needle fixing fixture is detachably connected to the pressure sensor through a fastener.

[0012] Furthermore, the control precision of the nano-displacement stage is 0 - 50 nm, and the stroke is 0 - 50 mm; the measurement resolution of the pressure sensor is 0 - 50 μN, and the range is 0 - 500 mN.

[0013] Furthermore, a horizontal displacement stage is mounted on the base, and the horizontal displacement stage includes an X-direction displacement adjustment slide and a Y-direction displacement adjustment slide for driving the sample stage to move along the X-axis and Y-axis respectively.

[0014] Furthermore, the X-direction displacement adjustment slide includes a first slide, a first slide rail, and a first differential head. The first slide rail is arranged on the base along the X-axis direction. The bottom of the first slide is slidably connected to the first slide rail, and a return spring is provided between the first slide and the first slide rail. A first connecting block is provided on the side of the first slide parallel to the X-axis direction. The first differential head is arranged on the side of the first slide where the first connecting block is provided, and the movable end of the first differential head abuts against the first connecting block; the Y-direction displacement adjustment slide includes a second slide, a second slide rail, and a second differential head. The second slide rail is fixedly connected to the upper surface of the first slide. The bottom of the second slide is slidably connected to the second slide rail, and a return spring is provided between the second slide and the second slide rail. A second connecting block is provided on the side of the second slide parallel to the Y-axis direction. The second differential head is fixedly connected to the first slide, and the movable end of the second differential head abuts against the second connecting block.

[0015] Furthermore, a swing angle adjustment slide is mounted on the horizontal displacement stage, and the sample stage is arranged on the swing angle adjustment slide.

[0016] Further, the swing angle adjustment slide table includes a slide table base, a third slide rail, a third slide table, and a third differential head. The upper surface of the slide table base is an arc-shaped concave surface. The third slide table is slidably connected to the slide table base through the third slide rail, and a return spring is provided between the third slide table and the slide table base. The bottom surface of the third slide table is matched with the arc-shaped concave surface of the slide table base. A connecting shaft arranged along the Y-axis direction is penetrated through the third slide table. The third differential head is fixedly connected to one side of the slide table base, and the movable end of the third differential head abuts against one side of the connecting shaft.

[0017] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0018] The biological micro-nano force testing device provided by the present utility model has a simple structure. It uses a high-precision large-stroke nano-displacement stage to provide a driving force for the micron-scale needle to perform cross-scale movement from nano-scale to centimeter-scale, and at the same time has a nano-scale positioning resolution, so as to meet the requirements for testing the mechanical performance parameters of micron-scale needle-like instruments to break through biological tissues.

[0019] The following will further elaborate on the present utility model in detail with reference to the accompanying drawings. Description of the Drawings

[0020] Figure 1 is the first perspective view of the biological micro-nano force testing device of the present utility model;

[0021] Figure 2 is the second perspective view of the biological micro-nano force testing device of the present utility model;

[0022] Figure 3 is the side view of the biological micro-nano force testing device of the present utility model.

[0023] Description of the reference numerals: 1, base; 2, sample stage; 3, test frame; 4, drive motor; 5, turntable; 6, fixing plate; 7, nano-displacement stage; 8, pressure sensor; 9, micro-needle fixing jig; 10, micro-needle; 11, swing angle adjustment slide table; 12, horizontal displacement stage; 13, first differential head; 14, first slide table; 15, second slide table; 16, second differential head; 17, slide table base; 18, third differential head; 19, third slide table; 20, connecting shaft. Detailed Embodiments

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0025] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0026] In the description of the present utility model, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a contact connection, or an integral connection; for those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0027] The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features; in the description of the present utility model, unless otherwise stated, the meaning of "a plurality" is two or more.

[0028] As Figure 1 , Figure 2 and Figure 3 shown, this embodiment provides a biological micro-nano force testing device, including a base 1, a sample stage 2 that can move on the surface of the base 1, and a test frame 3 installed on one side of the base 1. A micro-needle 10 and a nano-displacement stage 7 for driving the micro-needle 10 to approach / separate from the sample stage 2 are installed on the test frame 3. A pressure sensor 8 is provided between the micro-needle 10 and the nano-displacement stage 7. In this embodiment, the sample to be tested is fixed on the sample stage 2, and the sample stage 2 is moved so that the sample to be tested on the sample stage 2 is located at the micro-needle 10 of the test frame 3. The micro-needle 10 is driven by the nano-displacement stage 7 to pierce the sample to be tested. At the same time, the tip of the micro-needle 10 contacts the sample to be tested and is subjected to resistance. The magnitude of this force can be measured by the pressure sensor 8, and at the same time, the displacement magnitude of the tip of the micro-needle 10 piercing the sample to be tested and the test value of the pressure sensor are recorded, so that the stress-strain relationship of the micro-needle 10 piercing the sample to be tested can be obtained.

[0029] Among them, the nano-displacement stage 7 adopts a high-precision large-stroke sliding stage with a control accuracy of 0 - 50 nm and a stroke of 0 - 50 mm, which can drive the microneedle 10 to perform cross-scale motion from nanometers to centimeters. At the same time, it has a nanometer-level positioning resolution. This nano-displacement stage 7 is based on piezoelectric inertial stick-slip technology, equipped with a specific piezoelectric ceramic actuator, and uses an optical encoder to provide large-range and nanometer-resolution position feedback at high frequencies, meeting the measurement requirements of large displacement and high precision in the process of biomaterial force measurement. The pressure sensor 8 adopts a precision force sensor based on the piezoresistive atomic force sensing principle, with a measurement resolution of 0 - 50 μN and a range of 0 - 500 mN, so as to achieve the measurement accuracy of the tiny force for piercing biomaterials.

[0030] Specifically, in this embodiment, the microneedle 10 is placed above the sample stage 2. The microneedle 10 is installed on the pressure sensor 8, and the pressure sensor 8 is fixed on the nano-displacement stage 7. The nano-displacement stage 7 drives the microneedle 10 to move in the vertical direction to pierce the sample to be tested on the sample stage 2.

[0031] Furthermore, a microneedle fixing fixture 9 for clamping the microneedle 10 is provided on the pressure sensor 8. The microneedle 10 can be removed from the microneedle fixing fixture 9, which is convenient for microneedle replacement. Optionally, the microneedle fixing fixture 9 is detachably connected to the pressure sensor 8 through a fastener. The fastener can be selected but not limited to screws, bolts, etc., which are used to quickly fix the microneedle fixing fixture 9 and prevent the microneedle fixing fixture 9 from being unstable during use.

[0032] In order to enable the microneedle 10 to pierce the sample to be tested at different angles, preferably, an axial angle adjustment stage is installed on the test frame 3. The axial angle adjustment stage drives the microneedle 10 to rotate around the X axis on the end face of the test frame 3 close to the sample stage 2, so as to adjust the piercing angle of the microneedle 10 when piercing the sample to be tested and meet the test requirements for piercing at different angles.

[0033] Specifically, the axial angle adjustment stage includes a fixing plate 6 for fixedly installing the nano-displacement stage 7, a turntable 5 for driving the fixing plate 6 to rotate, and a driving motor 4 for driving the turntable 5 to rotate; the driving motor 4 is fixedly installed on one side of the test frame 3 close to the sample stage 2, the fixing plate 6 is fixedly connected to the outer peripheral edge of the turntable 5, and the driving motor 4 drives the turntable 5 to rotate, thereby driving the fixing plate 6 to rotate, and further driving the nano-displacement stage 7, the pressure sensor 8 and the microneedle as a whole to rotate, so as to achieve the purpose of adjusting the microneedle 10 to the target piercing angle.

[0034] For a specific implementation of the movement of the sample stage 2 on the base 1, a horizontal displacement stage 12 is installed on the base 1. The horizontal displacement stage 12 includes an X-direction displacement adjustment slide and a Y-direction displacement adjustment slide. The sample stage 2 can be driven to move along the X-axis and Y-axis respectively through the X-direction displacement adjustment slide and the Y-direction displacement adjustment slide, so that the pre-designed piercing position of the sample to be measured on the sample stage 2 corresponds to the position of the microneedle 10.

[0035] Specifically, the X-direction displacement adjustment slide includes a first slide 14, a first slide rail, and a first differential head 13. The first slide rail is arranged on the base 1 along the X-axis direction. The bottom of the first slide 14 is slidably connected to the first slide rail, and a return spring is provided between the first slide 14 and the first slide rail. A first connection block is provided on the side of the first slide 14 parallel to the X-axis direction. The first differential head 13 is arranged on the side of the first slide 14 where the first connection block is provided, and the movable end of the first differential head 13 abuts against the first connection block. When it is necessary to adjust the displacement of the sample stage 2 in the X-axis direction, rotate the knob of the first differential head 13. The ejector rod of the first differential head 13 pushes the first connection block on the first slide 14, thereby pushing the first slide 14 to move along the X-axis direction on the first slide rail. When the knob of the first differential head 13 is rotated in the reverse direction, the pushing action of the first differential head 13 on the first connection block is cancelled, and the first slide 14 can be reset under the action of the return spring, thereby realizing the position adjustment of the sample stage 2 in the X-axis direction.

[0036] The structure of the Y-direction displacement adjustment slide is basically the same as that of the X-direction displacement adjustment slide. The Y-direction displacement adjustment slide includes a second slide 15, a second slide rail, and a second differential head 16. The second slide rail is fixedly connected to the upper surface of the first slide 15. The bottom of the second slide 15 is slidably connected to the second slide rail, and a return spring is provided between the second slide 15 and the second slide rail. A second connection block is provided on the side of the second slide 15 parallel to the Y-axis direction. The second differential head 16 is fixedly connected to the first slide 14, and the movable end of the second differential head 16 abuts against the second connection block. When it is necessary to adjust the displacement of the sample stage 2 in the Y-axis direction, rotate the knob of the second differential head 16. The ejector rod of the second differential head 16 pushes the second connection block on the second slide 15, thereby pushing the second slide 15 to move along the Y-axis direction on the second slide rail. When the knob of the second differential head 16 is rotated in the reverse direction, the pushing action of the second differential head 16 on the second connection block is cancelled, and the second slide 15 can be reset under the action of the return spring, thereby realizing the position adjustment of the sample stage 2 in the Y-axis direction.

[0037] Further, a swing angle adjustment slide table 11 is installed on the horizontal displacement table 12, and the sample table 2 is arranged on the swing angle adjustment slide table 11. The swing angle of the sample table 2 (i.e., pitching adjustment) is adjusted by the swing angle adjustment slide table 11, and its swing direction is to swing in a vertical plane perpendicular to the turntable 5 of the test stand 3, so as to cooperate with the axial angle adjustment table to adjust the piercing angle of the micro needle 10, further expanding the adjustment of the piercing angle of the micro needle 10 to the sample to be tested.

[0038] Specifically, the swing angle adjustment slide table 11 includes a slide table base 17, a third slide rail, a third slide table 19 and a third differential head 18. The upper surface of the slide table base 17 is an arc-shaped concave surface. The third slide table 19 is slidably connected to the slide table base 17 through the third slide rail, and a return spring is arranged between the third slide table 19 and the slide table base 17. The bottom surface of the third slide table 19 is matched with the arc-shaped concave surface of the slide table base 17. A connecting shaft 20 arranged along the Y-axis direction penetrates through the third slide table 19. The third differential head 18 is fixedly connected to one side of the slide table base 17, and the movable end of the third differential head 18 abuts against one side of the connecting shaft 20. When it is necessary to adjust the swing angle of the sample table 2 (i.e., pitching adjustment), rotate the knob of the third differential head 18. The ejector rod of the third differential head 18 pushes against the connecting shaft 20 on the third slide table 19 to move, thereby driving the third slide table 19 to move on the arc-shaped concave surface of the slide table base 17, and further realizing the swing of the third slide table 19 to drive the sample table 2. When the knob of the third differential head 18 is rotated in the reverse direction, the pushing action of the third differential head 18 on the connecting shaft 20 is cancelled, and the third slide table 19 can be reset under the action of the return spring, so as to realize the adjustment of the pitching angle of the sample table 2.

[0039] The test process of the biological micro-nano force test device of the present utility model is as follows: 1) Install the micro needle 10 on the micro needle fixing fixture 9; 2) Fix the sample to be tested on the sample table 2 and adjust it to a suitable position through the horizontal displacement table 12; 3) Adjust the micro needle 10 to the target piercing angle through the axial angle adjustment table; 4) Control the nano displacement table 7 to drive the pressure sensor 8 to move downward as a whole; 5) The tip of the micro needle 10 contacts the sample and is subjected to resistance, and the pressure sensor 8 measures the magnitude of the resistance; 6) The test software simultaneously records the downward displacement magnitude of the tip of the micro needle 10 and the test value of the pressure sensor 8.

[0040] The above examples are only illustrative examples of the present utility model and do not constitute a limitation on the protection scope of the present utility model. Any design identical or similar to the present utility model falls within the protection scope of the present invention.

Claims

1. A biological micro-nano force testing device, characterized in that: It includes a base, a sample stage movable on the surface of the base, and a test stand installed on one side of the base. A microneedle and a nano-displacement stage for driving the microneedle to approach / retreat from the sample stage are installed on the test stand. A pressure sensor is provided between the microneedle and the nano-displacement stage, and a microneedle fixing fixture for clamping the microneedle is arranged on the pressure sensor.

2. The biological micro-nano force testing device according to claim 1, wherein: An axial angle adjustment stage for driving the microneedle to rotate around the X-axis on the end face of the test stand close to the sample stage is installed on the test stand.

3. The bio-micro-nano force testing device according to claim 2, wherein: The axial angle adjustment stage includes a fixing plate for fixedly installing the nano-displacement stage, a turntable for driving the fixing plate to rotate, and a driving motor for driving the turntable to rotate; the driving motor is fixedly installed on the side of the test stand close to the sample stage, and the fixing plate is fixedly connected to the outer peripheral edge of the turntable.

4. The biomicro-nano force testing device according to claim 1, characterized in that: The microneedle fixing fixture is detachably connected to the pressure sensor through a fastener.

5. The biomicro-nano force testing device according to claim 1, wherein: The control precision of the nano-displacement stage is 0 - 50 nm, and the stroke is 0 - 50 mm; the measurement resolution of the pressure sensor is 0 - 50 μN, and the range is 0 - 500 mN.

6. The bio-micro-nano force testing device according to claim 1, characterized in that: A horizontal displacement stage is installed on the base, and the horizontal displacement stage includes an X-direction displacement adjustment slide and a Y-direction displacement adjustment slide for driving the sample stage to move along the X-axis and Y-axis respectively.

7. The bio-micro-nano force testing device according to claim 6, characterized in that: The X-direction displacement adjustment slide includes a first slide, a first slide rail, and a first differential head. The first slide rail extends along the X-axis direction on the base. The bottom of the first slide is slidably connected to the first slide rail, and a return spring is provided between the first slide and the first slide rail. A first connection block is provided on the side of the first slide parallel to the X-axis direction. The first differential head is arranged on the side of the first slide where the first connection block is provided, and the movable end of the first differential head abuts against the first connection block. The Y-direction displacement adjustment slide includes a second slide, a second slide rail, and a second differential head. The second slide rail is fixedly connected to the upper surface of the first slide. The bottom of the second slide is slidably connected to the second slide rail, and a return spring is provided between the second slide and the second slide rail. A second connection block is provided on the side of the second slide parallel to the Y-axis direction. The second differential head is fixedly connected to the first slide, and the movable end of the second differential head abuts against the second connection block.

8. The bio-micro-nano force testing device according to claim 6, wherein: A swing angle adjustment slide is installed on the horizontal displacement stage, and the sample stage is arranged on the swing angle adjustment slide.

9. The bio-micro / nano force testing device according to claim 8, characterized in that: The swing angle adjustment slide includes a slide base, a third slide rail, a third slide, and a third differential head. The upper surface of the slide base is an arc-shaped concave surface. The third slide is slidably connected to the slide base through the third slide rail, and a return spring is provided between the third slide and the slide base. The bottom surface of the third slide is matched with the arc-shaped concave surface of the slide base. A connecting shaft arranged along the Y-axis direction is penetrated through the third slide. The third differential head is fixedly connected to one side of the slide base, and the movable end of the third differential head abuts against one side of the connecting shaft.

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