On-chip microenvironment solution switching device

Abstract

The invention provides an on-chip microenvironment solution switching device which comprises a functional shell, driving assemblies and a probe assembly, at least one driving assembly is arranged in the functional shell, and each driving assembly comprises a piezoelectric stack and a first rigid pipe driven by the piezoelectric stack; the first rigid pipe is communicated with the probe assembly through a flexible connecting piece, and a fluid gap with variable volume is formed in the flexible connecting piece; the first rigid pipe is restrained to slide in the axial direction of the first rigid pipe, and the first rigid pipe is driven to move in the axial direction through the telescopic movement of the piezoelectric stack so as to change the volume of the fluid gap, so that the pressure change of the fluid is generated at the outlet of the micro probe; and the functional shell is used for fixedly packaging the driving assembly, the probe assembly and the flexible connecting piece. By adopting a mechanical scheme of combining piezoelectric stack driving and rigid pipeline transmission, millisecond-level high-speed solution switching response is realized.

Description

Technical Field

[0001] This invention relates to the field of microfluidics, specifically to an on-chip microenvironment solution switching device. Background Technology

[0002] In biomedical and biophysical research, rapid switching of liquid environments is crucial for regulating the extracellular microenvironment. By quickly changing the solution, it is possible to apply stimulation to cells while simultaneously detecting it in real time, thereby obtaining the transient response characteristics of cells to external stimuli, which has significant research value.

[0003] However, existing liquid exchange systems still have the following key problems:

[0004] 1. The slow solution switching speed makes it impossible to complete microenvironmental changes on a millisecond timescale, hindering the capture of transient cellular responses to stimuli and failing to meet the application requirements for real-time observation and analysis of rapid response processes. For example, Chalmers University of Technology in Sweden developed a multifunctional microfluidic pipette that applies positive and negative pressure through an external pump to create a flow field at the probe tip, altering the extracellular environment. However, its structure is bulky, and the solution switching time is relatively long, approximately 150 ms, failing to achieve millisecond-level solution switching.

[0005] 2. Large-scale fluid disturbances are easily generated during liquid switching, interfering with the measured cells and detection structures (force sensors, etc.), affecting the stability of solution switching and measurement consistency. The University of Tokyo in Japan developed a microfluidic chip that achieves millisecond-level cell osmotic pressure shock times through liquid-gas-liquid interface transitions. Although this method offers extremely fast solution switching speeds, the high-speed movement of the gas-liquid interface generates severe disturbances, making it impossible to integrate other sensing structures into the chip.

[0006] 3. Existing solution switching systems mostly rely on external pumps, and the probe structure is relatively large, making it difficult to integrate into space-constrained detection environments such as inverted microscopes, thus limiting their practicality and platform compatibility. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an on-chip microenvironment solution switching device. By employing a mechanical scheme that combines piezoelectric stack drive with rigid pipeline transmission, it achieves millisecond-level high-speed solution switching response.

[0008] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0009] An on-chip microenvironment solution switching device includes a functional housing, a driving component, and a probe assembly. The functional housing contains at least one driving component, which includes a piezoelectric stack and a first rigid tube driven by the piezoelectric stack. The first rigid tube is connected to the probe assembly via a flexible connector, which has a variable-volume fluid gap. The first rigid tube is constrained to slide axially. The piezoelectric stack's expansion and contraction drives the first rigid tube to move axially, changing the volume of the fluid gap and thus generating a pressure change at the microprobe outlet. The functional housing is used to securely encapsulate the driving component, the probe assembly, and the flexible connector.

[0010] Furthermore, the probe assembly includes a microprobe and a second rigid tube. One end of the first rigid tube is sealed to one end of the second rigid tube via a flexible connector, forming a closed fluid gap with variable volume between them.

[0011] Furthermore, the functional housing includes a detachably connected upper housing and a lower housing, and the interior of the functional housing is divided into an independent space for placing the drive component by a partition; the independent space is provided with a piezoelectric stack mounting slot for positioning the piezoelectric stack; the independent space is provided with a sliding groove for constraining the first rigid tube.

[0012] Furthermore, the drive assembly also includes a pressure transmission block and a spring. The output end of the piezoelectric stack is in contact with one end of the pressure transmission block, and the first rigid tube is connected to the pressure transmission block. A spring is provided between the pressure transmission block and the wall of the functional housing to provide axial preload to the piezoelectric stack.

[0013] Furthermore, the drive assembly also includes a connecting pipe, with one end of the first rigid pipe fixedly connected to one end of the connecting pipe; the other end of the connecting pipe extends to the liquid inlet of the functional housing for connecting to an external fluid drive device.

[0014] Furthermore, the microprobe has a constricted flow channel and a cylindrical flow channel connected thereto, and the second rigid tube is connected to the cylindrical flow channel.

[0015] Furthermore, the microprobe is conical, and the tip surface area of ​​the microprobe is 100 square micrometers to 100 square millimeters.

[0016] Furthermore, the functional housing contains two drive components, which are symmetrically arranged within the functional housing; the two drive components are respectively connected to the probe assembly through flexible connectors.

[0017] Furthermore, it also includes a control unit for applying opposite-phase driving voltages to the piezoelectric stacks of the two driving components to drive the first rigid tubes of the two driving components to move axially in different directions, thereby achieving solution switching.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. The on-chip microenvironment solution switching device of this invention achieves millisecond-level high-speed solution switching response through a mechanical scheme combining piezoelectric stack drive and rigid tubing transmission. The piezoelectric stack, as the driving source, possesses microsecond-level expansion and contraction response capabilities. This invention further combines the piezoelectric stack with a first rigid tube, a second rigid tube, and flexible connectors to construct a power transmission chain with extremely low energy dissipation. This design minimizes the absorption or dissipation of driving energy by flexible components during transmission, enabling the minute displacement of the piezoelectric stack to be efficiently and almost instantaneously converted into volume changes in the fluid gap, thereby driving high-speed fluid movement. Experiments show that this device can achieve complete solution exchange on the order of 10 milliseconds, significantly faster than the response time of many cell biological processes (such as osmotic pressure shock responses), providing a crucial technical foundation for capturing transient physiological behaviors of cells.

[0020] 2. The on-chip microenvironment solution switching device of this invention achieves extremely low fluid disturbance and high-precision flow control during the switching process by constructing a sealed fluid gap between the first and second rigid tubes using a flexible connector, and cooperating with precisely constrained axial sliding. This variable-volume fluid gap constitutes a micro "fluid pump chamber" with precisely adjustable volume. When the first rigid tube moves axially under piezoelectric drive, the volume of the fluid gap changes precisely, generating a direct and stable pressure drive on the fluid within the chamber. This driving method avoids the pressure fluctuations and pulsations caused by the long pipelines and large inertia of traditional external pumps, and also eliminates the severe disturbances that may be caused by the movement of the gas-liquid interface. The fluid flow is smooth and orderly, forming a stable laminar or thin-film flow below the microprobe, thereby minimizing the hydrodynamic interference to the surrounding microenvironment and potentially integrated sensitive sensing elements (such as microforce sensors) while applying precise solution stimulation to the cells, ensuring the reliability and consistency of experimental data.

[0021] 3. The on-chip microenvironment solution switching device of this invention effectively balances structural stability, ease of use, and platform compatibility through its integrated functional housing and detachable modular drive and probe components. The functional housing not only provides robust support and protection, but its internal partitions, grooves, and piezoelectric stack mounting slots provide precise positioning and guidance for the drive and probe components, ensuring that all moving parts move along the designed axis and avoiding energy loss and sealing failure caused by misalignment. Simultaneously, the spring preload design ensures tight contact between the piezoelectric stack and the pressure transmission block interface for power transmission, and facilitates the replacement of vulnerable components such as the piezoelectric stack, improving the maintainability and service life of the device. Furthermore, the device's compact overall structure allows for convenient connection to a 3D robotic arm via the interface on the housing, enabling precise positioning above the stage of an inverted microscope, solving the problem of traditional systems being bulky and difficult to integrate into optical inspection platforms.

[0022] 4. The on-chip microenvironment solution switching device of this invention significantly improves the spatial resolution and application adaptability of solution switching by optimizing the geometry of the microprobe, particularly its sub-millimeter to centimeter-level tip face size and internal constricted flow channel. The tiny size of the microprobe tip allows it to approach the target area on the chip surface very closely, achieving highly localized solution exchange and effectively avoiding the influence on non-observation areas and the obstruction of the microscopic imaging optical path. The transition of the internal flow channel from cylindrical to constricted helps the fluid to accelerate and focus smoothly, further defining and stabilizing the morphology of the outlet flow field. The "straight" and "folded" options provided by the rigid tube of the probe assembly allow users to flexibly choose according to the height of the actual microscope workspace and the requirements of the optical path, enhancing the adaptability of the device to different experimental scenarios.

[0023] 5. The on-chip microenvironment solution switching device of this invention achieves flexible and precise control over the solution switching range and mode by employing a control strategy of symmetrically arranging dual (or multiple) drive components and applying voltages with opposite phases. This "push-suction" coordinated working mode can rapidly form a localized closed flow field (confined flow field) below the microprobe, where the solution to be switched is efficiently injected and extracted from the target area, with a clear switching boundary. By adjusting the amplitude ratio of the two drive voltages, the hydrodynamic balance between injection and extraction can be actively controlled, thereby fine-tuning the local flow field morphology and the size of the solution replacement area to meet the different stimulation range requirements of different cell or tissue samples. The extended design of multiple drive components further enables the rapid, sequential, or selective switching of various solutions, greatly expanding the experimental capabilities of the device. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional diagram of the on-chip microenvironment solution switching device described in this invention.

[0026] Figure 2 This is a three-dimensional diagram of the switching device with two drive components according to the present invention.

[0027] Figure 3 for Figure 2 The main view.

[0028] Figure 4 This is a 3D view of the lower shell.

[0029] Figure 5 This is a schematic diagram of a flexible connector connection.

[0030] Figure 6 This is a three-dimensional diagram of the microprobe described in this invention.

[0031] Figure 7 This is an internal cross-sectional view of the microprobe described in this invention.

[0032] Figure 8 This is a diagram showing the positional relationship between the switching device and the planar plate described in this invention.

[0033] Figure 9 This is a schematic diagram illustrating the solution switching principle of the switching device described in this invention.

[0034] Figure 10 This is a graph showing the relationship between grayscale value changes and solution switching time during solution switching.

[0035] Figure 11 This is a graph showing the relationship between cell size and solution switching time during solution switching.

[0036] Figure 12 Switch photos for the solution.

[0037] Figure 13 This is an extended schematic diagram of multiple driver components.

[0038] Figure 14 A 3D diagram of an on-chip microenvironment solution switching device for a four-drive component.

[0039] In the picture:

[0040] 100-Functional housing; 101-Outlet; 102-Inlet; 103-Baffle; 104-Lower housing; 105-Upper housing; 106-Piezoelectric stack mounting slot; 107-Slide groove; 200-Drive assembly; 201-Piezoelectric stack; 202-Pressure transmission block; 203-First rigid tube; 204-Connecting tube; 205-Spring; 300-Probe assembly; 310-Micro probe; 311-Cylindrical flow channel; 312-Contraction flow channel; 320-Second rigid tube; 400-Flexible connector. Detailed Implementation

[0041] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0042] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0043] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] like Figure 1As shown, the on-chip microenvironment solution switching device of the present invention includes a functional housing 100, a driving component 200, and a probe component 300. The functional housing 100 contains at least one driving component 200, which includes a piezoelectric stack 201 and a first rigid tube 203 driven by the piezoelectric stack 201. The first rigid tube 203 is connected to the probe component 300 via a flexible connector 400, which has a fluid gap with variable volume. The first rigid tube 203 is constrained to slide along its axial direction. The piezoelectric stack 201's extension and retraction movement drives the first rigid tube 203 to move axially, changing the volume of the fluid gap and thus generating a pressure change at the outlet of the microprobe 310. The functional housing 100 is used to fix and encapsulate the driving component 200, the probe component 300, and the flexible connector 400. The present invention achieves millisecond-level high-speed solution switching response by employing a mechanical scheme combining piezoelectric stack driving and rigid tubing transmission. As a driving source, the piezoelectric stack itself has a microsecond-level scaling response capability.

[0045] Example 1

[0046] like Figure 2 and Figure 3 As shown, Embodiment 1 is an on-chip microenvironment solution switching device with two driving components. The functional housing 100 contains two driving components 200, as follows: Figure 3 As shown, the functional housing 100 includes a detachably connected upper housing 105 and a lower housing 104. The interior of the functional housing 100 is divided into two independent spaces for placing the drive assembly 200 by a partition 103. Each independent space is provided with a piezoelectric stack mounting slot 106 for positioning the piezoelectric stack 201. A spring 205 is pre-installed in the piezoelectric stack mounting slot 106 to provide axial preload to the piezoelectric stack 201. Each independent space is provided with a sliding groove 107 for constraining the first rigid tube 203. The upper housing 105 and the lower housing 104 are fastened together by screws at the four corners.

[0047] The two drive components 200 have the same structure. Each drive component 200 includes a piezoelectric stack 201, a first rigid tube 203 driven by the piezoelectric stack 201, a pressure transmission block 202, and a spring 205. The piezoelectric stack 201 is a ceramic element that generates micron-level precision expansion and contraction under an applied voltage. The piezoelectric stack 201 is installed and positioned in the piezoelectric stack mounting slot 106.

[0048] The output end (i.e., the telescopic end) of the piezoelectric stack 201 contacts one end of the pressure transmission block 202, and the first rigid tube 203 is connected to the pressure transmission block 202. In this embodiment, the pressure transmission block 202 has a through hole, through which the first rigid tube 203 passes and is firmly bonded with high-strength epoxy resin. Thus, the movement of the pressure transmission block 202 directly drives the synchronous movement of the first rigid tube 203. A spring 205 is provided between the pressure transmission block 202 and the wall of the functional housing 100 to provide axial preload to the piezoelectric stack 201. The preload of the spring 205 ensures that the contact surface between the output end of the piezoelectric stack 201 and the pressure transmission block 202 is always tightly fitted without gaps, allowing any minute displacement of the piezoelectric stack to be transmitted to the pressure transmission block 202 without loss. Furthermore, when the piezoelectric stack 201 needs to be replaced after prolonged use, simply pressing the spring 205 releases the preload, allowing the old component to be easily removed and replaced with a new one, making maintenance extremely convenient. The other end of the first rigid tube 203 is fixedly connected to one end of the connecting tube 204; the other end of the connecting tube 204 extends to the liquid inlet 102 of the functional housing 100, and is used to connect to an external fluid driving device, which is generally the tubing of a micro syringe or injection pump. The connecting tube 204 is made of PEEK or Teflon material, and the other end of the connecting tube 204 can slide freely within a small range at the liquid inlet 102.

[0049] like Figure 8 As shown, the probe assembly 300 of this invention acts directly on the chip. For example... Figure 6 and Figure 7 As shown, the probe assembly 300 includes a microprobe 310 and a second rigid tube 320. One end of the first rigid tube 203 is sealed to one end of the second rigid tube 320 via a flexible connector 400, forming a closed, variable-volume fluid gap between them. The microprobe 310 can be manufactured using photopolymerization 3D printing technology. The microprobe 310 has two flow channels, each of which is connected to a drive assembly 200 via the second rigid tube 320. Each flow channel includes a converging flow channel 312 and a cylindrical flow channel 311 connected thereto. The second rigid tube 320 is connected to the cylindrical flow channel 311. The converging flow channel 312 helps the fluid accelerate smoothly before the outlet, forming a more concentrated flow stream. The outer contour of the microprobe 310 is tapered, and the tip surface area of ​​the microprobe 310 is 100 square micrometers to 100 square millimeters. If the end face is rectangular, the end face area is the area of ​​the rectangle; if the end face is circular, the end face area is the area of ​​the circle. In this embodiment, the tip surface area is as small as 100 square micrometers, which allows it to be very close to the cell without physical collision, and also minimizes the obstruction of the microscope objective's light path.

[0050] like Figure 5As shown, the flexible connector 400 is a silicone tube. One end of the first rigid tube 203 is sealed to one end of the second rigid tube 320 through the flexible connector 400, forming a closed, variable-volume fluid gap between them. The end face of the first rigid tube 203 does not contact the end face of the second rigid tube 320, but a tiny gap, such as tens to hundreds of micrometers, is maintained between them. This gap is surrounded by the tube wall of the flexible connector 400, forming a closed, variable-volume microfluidic chamber.

[0051] Assembly process: The assembled probe assembly 300 and drive assembly 200 are placed into the lower housing 104. The body of the first rigid tube 203 will be inserted into the sliding groove 107 of the lower housing 104. The corresponding position on the inner side of the upper housing 105 also has a sliding groove. After the upper and lower housings are closed and tightened, the sliding groove 107 hugs the first rigid tube 203 from all sides, restricting the first rigid tube 203 to slide back and forth along its axis, without any lateral swing or rotation. This constraint is crucial to ensuring the linearity and transmission efficiency of the drive action. At the same time, the middle section of the second rigid tube 320 of the probe assembly 300 is held and fixed by the liquid outlet 101 at the front end of the housing, ensuring the stability of the microprobe 310 position. The threaded hole reserved at the rear end of the housing 100 can be used to install the connecting rod, thereby fixing the entire device to a high-precision three-dimensional electric displacement stage.

[0052] Work process:

[0053] Pre-positioning: Fix the microfluidic chip or culture dish containing cultured cells onto the microscope stage. Move the target cells to the center of the field of view by moving the microscope platform. Then, control the three-dimensional displacement stage to lower the on-chip microenvironment solution switching device described in this invention, so that the tip of the microprobe 310 slowly approaches the liquid surface where the cells are located, until it is about a height of several micrometers to tens of micrometers from the liquid surface. After recording this precise three-dimensional coordinate, lift the probe.

[0054] Tubing infusion: The new solution to be switched, such as a buffer solution containing a certain stimulating factor, is slowly infused through a syringe pump connected to the connecting tube 204 of one side of the drive component, expelling all air bubbles from the tubing, flexible connector gaps, and microprobe channels until the solution slowly flows out from the microprobe tip. Similarly, the old solution or waste liquid channel to be replaced is connected to the connecting tube of the other side of the drive component.

[0055] Switching Execution: The control stage moves the device back to the predetermined position. A fast-rise step voltage signal is applied to both piezoelectric stacks 201 through a voltage control circuit, and the two signals are out of phase. For example, the left piezoelectric stack extends while the right piezoelectric stack contracts. The extension of the left piezoelectric stack pushes the corresponding pressure transmitting block and the first rigid tube forward, compressing the fluid gap within its corresponding flexible connector, generating positive pressure on the fluid inside the cavity, and pushing the new solution out of the left microprobe outlet. At the same time, the right piezoelectric stack contracts, and under the action of the spring, its pressure transmitting block and the first rigid tube move backward, widening its fluid gap, generating negative pressure, and drawing the old solution around the cells into the right microprobe outlet, such as... Figure 12 As shown, this push and pull rapidly creates a localized fluid displacement field in a very small area below the tip of the microprobe, completing the complete replacement of the solution surrounding the cell within milliseconds.

[0056] Withdrawal and Observation: After the solution is switched, the device can be lifted again to avoid prolonged contact with and interference with the cells. The entire process can be observed and recorded in real time using a microscope and a high-speed camera to capture the instantaneous response of cells to sudden changes in the external environment.

[0057] In this embodiment, the switching solution connected to the left-side drive component 200 contains Rhodamine B. The extracellular solution changes from a high-osmotic concentration solution (clear) to a low-osmotic concentration solution mixed with Rhodamine B. The external environment changes from bright to dark, and the grayscale value decreases. The change in grayscale value during solution switching is related to the solution switching time as follows: Figure 10 As shown, the grayscale value decreases and reaches a stable value within 10ms; the cell response during the transition from a hypertonic solution to a hypotonic solution in the extracellular environment is as follows: Figure 11 As shown, the cell size expands to a stable size within 10 ms; both the grayscale value and the cell size indicate that the liquid switching speed reaches the millisecond level.

[0058] Example 2

[0059] The on-chip microenvironment solution switching device of the present invention is not limited to two driving components. Embodiment 2, based on Embodiment 1, has multiple sets of driving components. Figure 13 An expansion scheme for multiple drive components is illustrated schematically. Example 2 is as follows. Figure 14 As shown, the device includes a four-drive assembly, which can be understood as stacking and integrating two dual-drive devices as in Example 1 vertically, sharing a central microprobe 310. This allows for the integration of more independent flow channels within the microprobe, enabling the on-demand, rapid sequential switching or mixing of three or four solutions, which is crucial for experiments requiring complex stimulus sequences.

[0060] Furthermore, in Embodiment 2, the second rigid tube 320 is a straight tube, providing the most direct flow path and theoretically minimizing liquid resistance, which is beneficial for achieving the fastest switching speed. However, in the application of inverted microscopes, the objective lens is very close to the sample from below, and the space above (i.e., the working distance) is often very limited. A straight rigid tube and the drive housing above it may collide with the microscope's condenser or other components. Therefore, the second rigid tube 320 of this invention can be a folded (or bent) type. The second rigid tube 320 has an obtuse angle bend greater than 90 degrees near the microprobe, allowing the functional housing 100 to be "offset" to the side, thereby freeing up vertical space above the objective lens and ensuring sufficient illumination and imaging quality. Users can flexibly choose to use a straight or folded probe according to the space constraints of their experimental platform, demonstrating the device's good platform adaptability.

[0061] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0062] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. An on-chip microenvironment solution switching device, characterized in that, The device includes a functional housing (100), a drive assembly (200), and a probe assembly (300). The functional housing (100) contains at least one drive assembly (200), which includes a piezoelectric stack (201) and a first rigid tube (203) driven by the piezoelectric stack (201). The first rigid tube (203) is connected to the probe assembly (300) via a flexible connector (400), which has a fluid gap with variable volume. The first rigid tube (203) is constrained to slide along its axial direction. The first rigid tube (203) is driven to move axially by the telescoping motion of the piezoelectric stack (201) to change the volume of the fluid gap, thereby generating a pressure change of the fluid at the outlet of the microprobe (310). The functional housing (100) is used to fix and encapsulate the drive assembly (200), the probe assembly (300), and the flexible connector (400).

2. The on-chip microenvironment solution switching device according to claim 1, characterized in that, The probe assembly (300) includes a microprobe (310) and a second rigid tube (320). One end of the first rigid tube (203) is sealed to one end of the second rigid tube (320) through a flexible connector (400), forming a closed fluid gap with variable volume between them.

3. The on-chip microenvironment solution switching device according to claim 1, characterized in that, The functional housing (100) includes a detachably connected upper housing (105) and a lower housing (104). The interior of the functional housing (100) is divided by a partition (103) to create an independent space for placing the drive assembly (200). The independent space is provided with a piezoelectric stack mounting groove (106) for positioning the piezoelectric stack (201). The independent space is also provided with a groove (107) for constraining the first rigid tube (203).

4. The on-chip microenvironment solution switching device according to claim 1, characterized in that, The drive assembly (200) also includes a pressure transmission block (202) and a spring (205). The output end of the piezoelectric stack (201) is in contact with one end of the pressure transmission block (202). The first rigid tube (203) is connected to the pressure transmission block (202). A spring (205) is provided between the pressure transmission block (202) and the wall of the functional housing (100) to provide axial preload to the piezoelectric stack (201).

5. The on-chip microenvironment solution switching device according to claim 1 or 4, characterized in that, The drive assembly (200) also includes a connecting pipe (204), the other end of the first rigid pipe (203) being fixedly connected to one end of the connecting pipe (204); the other end of the connecting pipe (204) extends to the liquid inlet (102) of the functional housing (100) for connecting to an external fluid drive device.

6. The on-chip microenvironment solution switching device according to claim 2, characterized in that, The microprobe (310) has a constricted flow channel (312) and a cylindrical flow channel (311) connected thereto, and the second rigid tube (320) is connected to the cylindrical flow channel (311).

7. The on-chip microenvironment solution switching device according to claim 6, characterized in that, The microprobe (310) is conical, and the tip surface area of ​​the microprobe (310) is 100 square micrometers to 100 square millimeters.

8. The on-chip microenvironment solution switching device according to claim 1, characterized in that, The functional housing (100) has two drive components (200) arranged symmetrically inside the functional housing (100); the two drive components (200) are respectively connected to the probe assembly (300) through flexible connectors (400).

9. The on-chip microenvironment solution switching device according to claim 8, characterized in that, It also includes a control unit for applying opposite-phase driving voltages to the piezoelectric stacks (201) of the two drive components (200) to drive the first rigid tubes (203) of the two drive components (200) to move axially in different directions, thereby achieving solution switching.

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