An electrophysiological signal acquisition system

Abstract

The present application provides an electrophysiological signal acquisition system, which includes a microfluidic electrode array chip, a connector, a front-end probe, an acquisition board and a host computer; the microfluidic electrode array chip is configured to use multiple sensing electrodes to respectively capture the electrophysiological signals generated during the migration of sample cells, and lead them out through leads and lead-out probes connected to each sensing electrode; the connector is configured to use multiple spring needles to respectively contact each lead-out probe on the microfluidic electrode array chip, collect the electrophysiological signals led out by each lead-out probe, and send the collected electrophysiological signals to the front-end probe; the front-end probe is configured to amplify, filter, and digitize the collected electrophysiological signals, and send the digitized digital signals to the acquisition board; the acquisition board adds a public timestamp to the digital signals sent by the front-end probe, integrates them, and sends them to the host computer; the host computer can visualize the integrated digital signals and store data.

Description

Technical Field

[0001] The present application relates to the field of information acquisition technology, and in particular to an electrophysiological signal acquisition system. Background Art

[0002] Cell invasion refers to the ability of cells to migrate from one area to another through the extracellular matrix. Cell invasion occurs in both normal and cancerous cells in response to chemical and mechanical stimuli. Prior to migration to a new location, the extracellular matrix is ​​degraded by intracellular proteases. Cell invasion often occurs in processes such as wound repair, angiogenesis, and inflammatory responses, as well as in abnormal tissue infiltration and tumor metastasis.

[0003] Cell invasiveness is typically measured based on two key aspects: the ability of cells to traverse obstacles and their ability to migrate. To validate the hypothesis that the electrical signals generated by cells provide the necessary electric field gradients for directional cell migration, an electrophysiological research platform was developed to analyze the relationship between electrophysiological signals and invasiveness.

[0004] When building electrophysiological research platforms, existing technologies require an interface to integrate the chip into external circuits, as the materials and structure of the chip used to collect electrophysiological signals differ significantly from those of a standard printed circuit board (PCB). This process, known as "packaging" for integrated circuit chips, typically uses gold wire to connect the contact points between the silicon chip and the substrate. However, this method is complex and costly, and it is unable to simultaneously record samples from more locations and obtain a more comprehensive set of electrophysiological signals. Summary of the Invention

[0005] The purpose of this application is to solve at least one of the above-mentioned technical defects, especially the technical defects that the electrophysiological research platform built in the existing technology is complex and costly, and cannot simultaneously record samples from more locations and obtain more comprehensive electrophysiological signals from the samples.

[0006] The present application provides an electrophysiological signal acquisition system, which includes a microfluidic electrode array chip, a connector, a front-end probe, an acquisition board, and a host computer;

[0007] The microfluidic electrode array chip is configured to use a plurality of sensing electrodes to respectively capture the electrophysiological signals generated during the migration of sample cells, and to lead out the electrophysiological signals through leads connected to the respective sensing electrodes and lead-out probes;

[0008] The connector is configured to utilize a plurality of spring pins to contact respective lead-out probe points on the microfluidic electrode array chip, collect electrophysiological signals derived from the respective lead-out probe points, and send the collected electrophysiological signals to the front-stage probe;

[0009] The front-stage probe is configured to amplify, filter, and digitize the collected electrophysiological signals, and send the digitized digital signals to the acquisition board;

[0010] The acquisition board is configured to add a public timestamp to the digital signal sent by the front-stage probe, integrate it and send it to the host computer;

[0011] The host computer is configured to visualize the integrated digital signal and store the data.

[0012] Optionally, the microfluidic electrode array chip includes a glass substrate, a microelectrode array distributed on the surface of the glass substrate, and a microfluidic structure bonded to the surface of the microelectrode array;

[0013] The microelectrode array includes a plurality of sensing electrodes arranged at even intervals, a reference electrode remote from the end of the sensing electrodes, wires connected to each sensing electrode and the reference electrode, and lead probes connected to the ends of each wire, wherein each lead probe is distributed near the corresponding sensing electrode in a shortest path manner;

[0014] The microfluidic structure includes a culture chamber disposed on one side of the first sensing electrode, a migration channel connected to the culture chamber and extending from the first sensing electrode to the reference electrode, and an air pump sealedly connected to the end of the migration channel, wherein the culture chamber is connected to the atmosphere;

[0015] After the culture fluid containing sample cells is placed in the culture chamber, the culture fluid is filled into the migration channel through the air pump, and each sensing electrode captures the electrophysiological signals generated during the migration of the sample cells. The leads and lead-out probes connected to each sensing electrode lead out the captured electrophysiological signals.

[0016] Optionally, the connector includes a base, a circuit platform, a quick clamp and a conversion daughter board;

[0017] The base is used to place the microfluidic electrode array chip;

[0018] The circuit platform is arranged above the base, including a PCB mainboard and a plurality of spring pins fixed on the PCB mainboard. After each spring pin contacts each lead-out probe point on the microfluidic electrode array chip, the electrophysiological signal at each lead-out probe point is led out to the PCB board, and the led-out electrophysiological signal is sent to the conversion sub-board through the PCB board;

[0019] The quick clamp is used to control the circuit platform to move up and down, so that each spring pin on the circuit platform can contact or move away from each lead-out probe point on the microfluidic electrode array chip;

[0020] The conversion sub-board is used to transmit the electrophysiological signal sent by the PCB board to the front-stage probe.

[0021] Optionally, the connector further comprises a support structure;

[0022] The supporting structure is used to combine the circuit platform, the conversion sub-board, the base and the quick clamp into a whole.

[0023] Optionally, the PCB main board consists of three PCB boards.

[0024] Optionally, the front-stage probe includes at least a low-noise amplifier, a bandpass filter, a digital-to-analog converter and a standard serial peripheral interface;

[0025] The low noise amplifier is used to amplify the collected electrophysiological signal and then send it to the bandpass filter;

[0026] The bandpass filter is used to filter the amplified electrophysiological signal and then send it to the digital-to-analog converter;

[0027] The digital-to-analog converter is used to convert the filtered electrophysiological signal into a digital signal and then send it to the standard serial peripheral interface;

[0028] The standard serial peripheral interface is used to send the digital signal to the acquisition board.

[0029] Optionally, the number of channels of the front-stage probe is at most 64 channels.

[0030] Optionally, the acquisition board provides four front-stage probe interfaces, and each front-stage probe interface is connected to at most two front-stage probes.

[0031] Optionally, the acquisition board receives digital signals input by all front-stage probes in parallel, adds a common timestamp to each digital signal, and outputs the signals serially to the host computer.

[0032] Optionally, the host computer is used to edit the integrated digital signal in a graphical manner according to experimental requirements, visualize the edited digital signal, and store the edited digital signal.

[0033] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0034] The present application provides an electrophysiological signal acquisition system, which includes a microfluidic electrode array chip, a connector, a front-end probe, an acquisition board and a host computer; wherein the microfluidic electrode array chip is configured to use multiple sensing electrodes to respectively capture the electrophysiological signals generated during the migration of sample cells, and lead them out through leads and lead-out probes connected to each sensing electrode; the connector is configured to use multiple spring needles to respectively contact each lead-out probe on the microfluidic electrode array chip, collect the electrophysiological signals led out by each lead-out probe, and send the collected electrophysiological signals to the front-end probe; the front-end probe is configured to amplify, filter, and digitize the collected electrophysiological signals, and send the digitized digital signals to the acquisition board; the acquisition board is configured to add a common timestamp to the digital signals sent by the front-end probe, integrate them, and send them to the host computer; the host computer is configured to visualize the integrated digital signals and store data. The system uses multiple spring pins on the connector to lead out the electrophysiological signals captured by each sensing electrode on the microfluidic electrode array chip. This not only simplifies the process but also improves the flexibility of the system. In addition, the present application can use multiple sensing electrodes on the microfluidic electrode array chip to collect multiple electrophysiological signals, and add a public timestamp to the digitized multiple electrophysiological signals through the acquisition board. In this way, the host computer can perform personalized editing operations on the digital signals with the public timestamp added according to the user's experimental needs and store the edited digital signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0036] Figure 1 A system architecture diagram of an electrophysiological signal acquisition system provided in an embodiment of the present application;

[0037] Figure 2 A schematic diagram of the structure of a microelectrode array provided in an embodiment of the present application;

[0038] Figure 3 A schematic diagram of the working process of the microfluidic electrode array chip provided in an embodiment of the present application;

[0039] Figure 4 A circuit design diagram of the PCB motherboard provided in the embodiment of the present application;

[0040] Figure 5 A circuit design diagram of the conversion sub-board provided in an embodiment of the present application;

[0041] Figure 6 Schematic diagram of the electrode impedance distribution and baseline noise distribution results of each electrode of the microfluidic electrode array chip provided in the embodiment of the present application. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0043] In one embodiment, Figure 1 As shown, Figure 1 This is a system architecture diagram of an electrophysiological signal acquisition system provided in an embodiment of the present application; the present application provides an electrophysiological signal acquisition system, which includes a microfluidic electrode array chip, a connector, a front-end probe, an acquisition board and a host computer.

[0044] The microfluidic electrode array chip is configured to use a plurality of sensing electrodes to respectively capture the electrophysiological signals generated during the migration of sample cells, and lead them out through leads connected to the respective sensing electrodes and lead-out probes.

[0045] The connector is configured to utilize a plurality of spring pins to contact respective lead-out probe points on the microfluidic electrode array chip, collect electrophysiological signals derived from the respective lead-out probe points, and send the collected electrophysiological signals to the front-stage probe.

[0046] The front-stage probe is configured to amplify, filter, and digitize the collected electrophysiological signals, and send the digitized digital signals to the acquisition board.

[0047] The acquisition board is configured to add a public timestamp to the digital signal sent by the front-stage probe, integrate the digital signal, and send the digital signal to the host computer.

[0048] The host computer is configured to visualize the integrated digital signal and store the data.

[0049] In this embodiment, the electrophysiological signal acquisition system is a tool for acquiring, amplifying, filtering, digitizing multi-channel micro signals, and storing and visualizing these data. Figure 1As shown, the electrophysiological signal acquisition system of the present application may include a microfluidic electrode array chip, a connector, a front-end probe, an acquisition board and a host computer; after the microfluidic electrode array chip acquires multi-channel electrophysiological signals, it is sent to the front-end probe through the connector, and the front-end probe processes the multi-channel analog signals and outputs digital signals. The acquisition board adds a public timestamp to the digital signals sent by the front-end probe, integrates them and sends them to the host computer, and then the signals are visualized and stored in the host computer software.

[0050] Specifically, the microfluidic electrode array chip of the present application is configured to use multiple sensing electrodes to capture the electrophysiological signals generated during the migration of sample cells, and lead them out through leads and lead-out probes connected to each sensing electrode, so as to collect the electrophysiological signals led out by each lead-out probe through spring needles in the connector that contact each lead-out probe, and send the collected electrophysiological signals to the front-end probe. The front-end probe can amplify, filter, and digitize the collected electrophysiological signals, and send the digitized digital signals to the acquisition board. After the acquisition board adds a public timestamp to the digital signals sent by the front-end probe, it integrates and sends them to the host computer so that the host computer can visualize the integrated digital signals and store the data.

[0051] Among them, the microfluidic electrode array chip of the present application is provided with a plurality of sensing electrodes, and the number of sensing electrodes can be determined according to the number of acquisition channels of the front-stage probe. For example, when the amplifier module in the front-stage probe is 32 channels, the number of sensing electrodes can also be set to 32; when the amplifier module in the front-stage probe is 64 channels, the number of sensing electrodes can also be set to 64, and so on. When the number of sensing electrodes is greater, the more information can be obtained, but accordingly, the number of channels of the required back-end processing circuit is also increased accordingly, thereby increasing the cost. Therefore, when setting, the number of sensing electrodes can be set according to the balance point between cost and amount of information, and there is no restriction here.

[0052] Furthermore, in order to simplify the process and improve the flexibility of the system, the present application can also set spring pins on the connector with the same number as the sensing electrodes, and when collecting electrophysiological signals, the spring pins are brought into contact with the lead-out probes corresponding to each sensing electrode to collect the electrophysiological signals led out by each lead-out probe. At the non-collection time, the spring pins can be disconnected from each lead-out probe, so that the microfluidic electrode array chip can be placed back into the incubator. This not only facilitates the collection of electrophysiological signals, but also prevents the microfluidic electrode array chip from being exposed to the external environment for a long time, thereby causing abnormal detection results.

[0053] In the above embodiment, the system includes a microfluidic electrode array chip, a connector, a front-end probe, an acquisition board and a host computer; wherein the microfluidic electrode array chip is configured to use multiple sensing electrodes to respectively capture the electrophysiological signals generated during the migration of sample cells, and lead them out through leads and lead-out probes connected to each sensing electrode; the connector is configured to use multiple spring needles to respectively contact each lead-out probe on the microfluidic electrode array chip, collect the electrophysiological signals led out by each lead-out probe, and send the collected electrophysiological signals to the front-end probe; the front-end probe is configured to amplify, filter, and digitize the collected electrophysiological signals, and send the digitized digital signals to the acquisition board; the acquisition board is configured to add a common timestamp to the digital signals sent by the front-end probe, integrate them and send them to the host computer; the host computer is configured to visualize the integrated digital signals and store data. The system uses multiple spring pins on the connector to lead out the electrophysiological signals captured by each sensing electrode on the microfluidic electrode array chip. This not only simplifies the process but also improves the flexibility of the system. In addition, the present application can use multiple sensing electrodes on the microfluidic electrode array chip to collect multiple electrophysiological signals, and add a public timestamp to the digitized multiple electrophysiological signals through the acquisition board. In this way, the host computer can perform personalized editing operations on the digital signals with the public timestamp added according to the user's experimental needs and store the edited digital signals.

[0054] In one embodiment, the microfluidic electrode array chip includes a glass substrate, a microelectrode array distributed on the surface of the glass substrate, and a microfluidic structure bonded to the surface of the microelectrode array.

[0055] The microelectrode array includes a plurality of sensing electrodes arranged at uniform intervals, a reference electrode away from the end sensing electrodes, wires connected to each sensing electrode and the reference electrode, and lead probes connected to the ends of each wire, wherein each lead probe is distributed near the corresponding sensing electrode in a shortest path manner.

[0056] The microfluidic structure includes a culture chamber arranged on one side of a first sensing electrode, a migration channel connected to the culture chamber and extending from the first sensing electrode to the reference electrode, and an air pump sealed to the end of the migration channel. The culture chamber is connected to the atmosphere.

[0057] After the culture fluid containing sample cells is placed in the culture chamber, the culture fluid is filled into the migration channel through the air pump, and each sensing electrode captures the electrophysiological signals generated during the migration of the sample cells. The leads and lead-out probes connected to each sensing electrode lead out the captured electrophysiological signals.

[0058] In the present embodiment, in order to non-destructively collect the electrophysiological signals of sample cells, the present application can use microelectrode arrays and microfluidic technology to construct a microfluidic electrode array chip, and the microfluidic electrode array chip is a passive microelectrode array, which usually uses glass as a substrate, so as to facilitate the observation of cells during culture. In addition, the microelectrode array technology can also monitor the spatiotemporal distribution of electrophysiological signals of cell clusters in a long-term and low-noise manner without interfering with the movement of sample cells. Therefore, the microfluidic electrode array chip of the present application has the advantages of flexible design and processing and non-invasive cells. Microfluidic technology has the characteristics of accurately controlling the patterned growth of cells, thereby providing a powerful tool for cell migration experiments. After combining the two, the present application can obtain a microfluidic electrode array chip that can monitor the spatiotemporal distribution of electrophysiological signals of cell clusters in a long-term and low-noise manner without interfering with the movement of sample cells, and can also accurately control the patterned growth of cells in the process.

[0059] Specifically, the microfluidic electrode array chip of the present application may include a glass substrate, a microelectrode array distributed on the surface of the glass substrate, and a microfluidic structure bonded to the surface of the microelectrode array; wherein, Figure 2 As shown, Figure 2 A schematic diagram of the structure of a microelectrode array provided in an embodiment of the present application; Figure 2 The microelectrode array of the present application may include a plurality of evenly spaced sensing electrodes, a reference electrode remote from the distal sensing electrodes, wires connected to each sensing electrode and reference electrode, and lead probes connected to the distal ends of each wire. Each lead probe is distributed near the corresponding sensing electrode in a shortest path manner, which facilitates wiring and avoids circuit redundancy. Furthermore, the present application connects the reference electrode to ground and places it as far away from the wires and sensing electrodes as possible, thereby increasing the impedance between the reference electrode and the sensing electrode and improving the insulation of the wires from ground.

[0060] Furthermore, if Figure 3 As shown, Figure 3 Schematic diagram of the working process of the microfluidic electrode array chip provided in the embodiment of the present application; wherein, Figure 3 a- Figure 3 c is the working principle diagram of the microfluidic electrode array chip. Figure 3As shown in a-3c, the microfluidic structure of the present application is bonded to the surface of the microelectrode array and includes a culture chamber arranged on one side of the first sensing electrode, a migration channel connected to the culture chamber and extending from the first sensing electrode to the reference electrode, and an air pump sealed to the end of the migration channel, wherein the culture chamber is connected to the atmosphere, allowing a pipette to directly load cells and culture medium from above. The air pump can change the air pressure in the migration channel. The air pump of the present application is preferably a syringe. When using a syringe as an air pump, the cells and culture medium are first loaded into the culture chamber, and then the syringe is squeezed so that the liquid medium cannot enter the migration channel under the action of air pressure, and the cell monolayer is only established in the culture chamber; then, the syringe is evacuated to allow the culture medium in the culture chamber to enter the migration channel. After the cells migrate into the migration channel, microelectrodes are embedded in the substrate to which they are attached, so that the electrophysiological signals of the cell migration can be recorded.

[0061] Figure 3 d is the design diagram of the fence-shaped microelectrode array; Figure 3 In d, the dark blue part is the glass substrate, the yellow part is the sensing electrode, and the light blue part is the microfluidic structure. During the migration of cells, the electrophysiological signals generated during the migration process can be recorded through the sensing electrodes at the bottom. After collecting the signals, they can be used to study the cell migration characteristics.

[0062] Figure 3 e is a schematic diagram of the process of collecting electrical signals of migrating cells; Figure 2 As can be seen, the present invention arranges multiple sensing electrodes evenly spaced on a glass substrate, enabling long-term, low-noise monitoring of the spatiotemporal distribution of electrophysiological signals from cell clusters without interfering with sample cell movement. Furthermore, the present invention places the reference electrode away from the distal sensing electrode, which not only increases the impedance between the reference and sensing electrodes but also improves the insulation of the wire from ground.

[0063] In one embodiment, the connector may include a base, a circuit platform, a quick clamp, and a conversion daughter board.

[0064] The base is used for placing the microfluidic electrode array chip.

[0065] The circuit platform is arranged above the base, including a PCB mainboard and a plurality of spring pins fixed on the PCB mainboard. After each spring pin contacts each lead-out probe point on the microfluidic electrode array chip, the electrophysiological signal at each lead-out probe point is led out to the PCB board, and the led-out electrophysiological signal is sent to the conversion sub-board through the PCB board.

[0066] The quick clamp is used to control the circuit platform to move up and down, so that each spring pin on the circuit platform can contact or move away from each lead-out probe point on the microfluidic electrode array chip.

[0067] The conversion sub-board is used to transmit the electrophysiological signal sent by the PCB board to the front-stage probe.

[0068] In this embodiment, the connector is configured to use multiple spring pins to contact each lead-out probe point on the microfluidic electrode array chip, collect electrophysiological signals from each lead-out probe point, and send the collected electrophysiological signals to the front-end probe.

[0069] To elaborate, the connector of the present application may include a base, a circuit platform, a quick clamp and a conversion sub-board, wherein the base can place a microfluidic electrode array chip, the circuit platform is located above the base, and the circuit platform is provided with a PCB main board and a plurality of spring pins fixed on the PCB main board, and the quick clamp can control the circuit platform to rise and fall, so that when collecting electrophysiological signals, the lever and hinge on the quick clamp can be used to control the circuit platform to perform vertical displacement, so that each spring pin on the circuit platform contacts each lead-out probe point on the microfluidic electrode array chip respectively, and the electrophysiological signals at each lead-out probe point are led out to the PCB board, and the led-out electrophysiological signals are sent to the conversion sub-board through the PCB board. The conversion sub-board can transmit the electrophysiological signals sent by the PCB board to the front-end probe, so that the front-end probe can amplify, filter and digitize the collected electrophysiological signals, and send the digitized digital signals to the acquisition board.

[0070] Schematically, as Figure 4 、 5 As shown, Figure 4 This is a circuit design diagram of the PCB motherboard provided in the embodiment of the present application. Figure 5 The circuit design diagram of the conversion sub-board provided in the embodiment of the present application; Figure 4 It can be seen that the present application designs a circuit pattern on the PCB motherboard that is the same as the microelectrode array on the microfluidic electrode array chip, and connects it to each lead-out probe point on the microfluidic electrode array chip through a spring needle, thereby collecting the electrophysiological signals led out by each lead-out probe point. Figure 5The conversion daughter board in the circuit is used to send the collected electrophysiological signals to the front-end probe. The conversion daughter board can convert the 2.54mm standard connector output by the PCB main board into an omnetics connector that is adapted to the input of the front-end probe. It is understandable that the omnetics connector is expensive, and there is a high probability that the omnetics connector components will be lost during the development and optimization of the PCB main board. In contrast, the present application installs the omnetics connector on a conversion daughter board that does not require optimization, and the output port of the PCB main board only needs to use a low-cost 2.54mm standard connector, which greatly reduces the development, testing and optimization costs of the PCB main board.

[0071] In one embodiment, the connector may further include a support structure.

[0072] The supporting structure is used to combine the circuit platform, the conversion sub-board, the base and the quick clamp into a whole.

[0073] In this embodiment, the support structure combines the circuit platform, base, and quick-release clamp into a stable whole. During use, the quick-release clamp is first rotated to raise the circuit platform; then the chip is placed in the base slot in the correct orientation; finally, the quick-release clamp is restored, pressing the spring pins on the circuit platform downward and tightly contacting the chip's peripheral contact points to collect electrophysiological signals from the chip.

[0074] In one embodiment, the PCB mainboard is composed of three PCB boards, which can achieve modular design of functions and improve development flexibility. It is understandable that this application separates the PCB mainboard and the front-end probe, and improves the convenience of testing and optimizing the module functions by sacrificing system integration, thereby effectively improving development flexibility.

[0075] In one embodiment, the front-stage probe includes at least a low-noise amplifier, a bandpass filter, a digital-to-analog converter, and a standard serial peripheral interface, and the number of channels of the front-stage probe is at most 64 channels.

[0076] The low noise amplifier is used to amplify the collected electrophysiological signal and then send it to the bandpass filter.

[0077] The bandpass filter is used to filter the amplified electrophysiological signal and then send it to the digital-to-analog converter.

[0078] The digital-to-analog converter is used to convert the filtered electrophysiological signal into a digital signal and then send the digital signal to the standard serial peripheral interface.

[0079] The standard serial peripheral interface is used to send the digital signal to the acquisition board.

[0080] In this embodiment, since the front-stage probe of the present application is configured to amplify, filter, and digitize the collected electrophysiological signals, and send the digitized digital signals to the acquisition board, the front-stage probe of the present application may at least include a low-noise amplifier, a bandpass filter, a digital-to-analog converter, and a standard serial peripheral interface. In this way, the collected electrophysiological signals can be amplified by the low-noise amplifier, the amplified electrophysiological signals can be filtered by the bandpass filter, the filtered electrophysiological signals can be converted into digital signals by the digital-to-analog converter, and then sent to the standard serial peripheral interface, and the digital signals can be sent to the acquisition board via the standard serial peripheral interface.

[0081] It is understandable that the role of the pre-stage probe in this application is to amplify, filter, and digitize the input analog signal. Since the original signal is weak (amplitude less than 1 mV), it is easily submerged in noise, so the pre-stage probe is a key link in determining the signal-to-noise ratio. The pre-stage probe of this application can be developed based on the RHD-2000 series chip of Intan Technologies. It encapsulates up to 64 channels of signal processing circuits in an area of ​​less than 70 mm2, including a low-noise amplifier, a programmable bandpass filter, a 16-bit digital-to-analog converter, and a standard serial peripheral interface (Serial Peripheral Interface, SPI). The key parameters are shown in Table 1:

[0082]

[0083] Table 1 Key parameters of the front-end probe

[0084] The present application can realize the relevant functions of the front-stage probe by designing the above-mentioned key parameters, thereby obtaining a digital signal of better quality.

[0085] Furthermore, an electrode impedance measurement module can be provided in the front-end probe of the present application. The electrode resistance measurement module can directly detect the resistance value from the sensing electrode to the lead-out probe point on the microfluidic electrode array chip. Since the circuit cross-sectional area on the chip is small and the impedance is large, it has a great impact on the signal acquisition quality. Therefore, it is necessary to verify that the electrical part of the chip is well conductive. Among them, the baseline noise measurement is to detect the potential change of the cell-free electrode in the culture fluid environment, so as to obtain the background noise of the system and verify whether the detection limit of the system meets the acquisition requirements of the electrophysiological signal.

[0086] Schematically, as Figure 6 As shown, Figure 6 Schematic diagram of the electrode impedance distribution and baseline noise distribution of each electrode of the microfluidic electrode array chip provided in an embodiment of the present application; Figure 6Figure a shows the resistance of each sensing electrode. The green area represents the kernel density of the electrode resistance, the black line represents the region between the upper and lower extremes of the resistance (data outside the extreme range are considered outliers), and the black dot represents the median electrode resistance. With the exception of a few electrodes with resistances near 60 kΩ, the remaining electrodes exhibit a Gaussian distribution, with an average value of approximately 12 kΩ and a standard deviation of approximately 10 kΩ. According to the resistance law, the theoretical resistance of the electrodes and wires on the chip at room temperature is approximately 150Ω to 200Ω. The significant discrepancy between the measured results and the theoretical values ​​may be due to uneven metal sputtering, resulting in some traces being thinner than designed, or due to manual testing and the small size of the electrodes, which may have resulted in poor contact between the test leads and the electrodes. Although the measured values ​​are greater than the theoretical resistance, they still meet the requirements for acquiring electrophysiological signals and demonstrate electrical continuity across the traces on the chip.

[0087] Figure 6 Figure b shows the baseline noise potential of the electrodes in a cell-free culture medium (pH = 7.2-7.4). The blue area represents the kernel density of the baseline noise potential values ​​for each electrode over a 10-second period, and the black dots represent the average potential values. The noise in each channel follows a Gaussian distribution, consistent with the inherent noise characteristics of the system, indicating that the baseline noise originates primarily from within the system, with minimal external interference. The maximum and minimum baseline noise voltages during the test were 4.91 μV and -4.65 μV, respectively. While the amplitudes of most extracellular electrophysiological signals are greater than 10 μV, the detection limit of the system meets the experimental requirements.

[0088] In one embodiment, the acquisition board provides four front-stage probe interfaces, and each front-stage probe interface is connected to at most two front-stage probes.

[0089] In this embodiment, the acquisition board can provide four front-end probe interfaces, each of which can be connected to up to two front-end probes. In this way, an acquisition board can connect to up to 8 64-channel front-end probes and simultaneously collect 512 channels of electrical signals, thereby effectively improving signal acquisition efficiency.

[0090] In one embodiment, the acquisition board receives digital signals input by all front-stage probes in parallel, adds a common timestamp to each digital signal, and outputs the signals serially to the host computer.

[0091] In this embodiment, the acquisition board can be driven by the Opal Kelly XEM-6310 Field Programmable Gate Array (FPGA) module. Of course, it can also be driven by other modules. The specific selection can be made according to the actual situation and is not limited here. The main purpose of the acquisition board in this application is to synchronize the data input by all front-end probes and serialize the parallel input data and transmit it to the host computer through a USB 3.0 interface. In addition, the acquisition board of this application can also be connected to peripheral devices through the I / O board. The auxiliary input of the peripheral device (such as electrical stimulation of the sample) is recorded synchronously with the electrical signal, so as to improve the utilization rate of the acquisition board and increase the diversity of the collected signals.

[0092] In one embodiment, the host computer is used to edit the integrated digital signal in a graphical manner according to experimental requirements, visually display the edited digital signal, and store the edited digital signal.

[0093] In this embodiment, the host computer software supporting the acquisition system can be used to visualize and store data, and provide closed-loop feedback in response to events detected by the data stream. Inspired by digital music production software, this software can configure the signal processing chain in a modular manner. Users can graphically edit the required data stream according to experimental requirements, maximizing experimental flexibility and simplifying the process of experimental modification. In addition, the GUI is completely open source, allowing any user to develop and share modular plug-ins written in C++, which is also conducive to the development of signal processing chains for glioma electrical signals.

[0094] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0095] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referenced to each other.

[0096] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electrophysiological signal acquisition system, characterized in that: The system includes a microfluidic electrode array chip, a connector, a front-end probe, a collection board and a host computer; The microfluidic electrode array chip is configured to use a plurality of sensing electrodes to respectively capture the electrophysiological signals generated during the migration of sample cells, and to lead out the electrophysiological signals through leads connected to the respective sensing electrodes and lead-out probes; The connector is configured to utilize a plurality of spring pins to contact respective lead-out probe points on the microfluidic electrode array chip, collect electrophysiological signals derived from the respective lead-out probe points, and send the collected electrophysiological signals to the front-stage probe; The front-stage probe is configured to amplify, filter, and digitize the collected electrophysiological signals, and send the digitized digital signals to the acquisition board; The acquisition board is configured to add a public timestamp to the digital signal sent by the front-stage probe, integrate it and send it to the host computer; The host computer is configured to visualize the integrated digital signal and store the data; The microfluidic electrode array chip includes a glass substrate, a microelectrode array distributed on the surface of the glass substrate, and a microfluidic structure bonded to the surface of the microelectrode array; The microelectrode array includes a plurality of sensing electrodes arranged at even intervals, a reference electrode remote from the end of the sensing electrodes, wires connected to each sensing electrode and the reference electrode, and lead probes connected to the ends of each wire, wherein each lead probe is distributed near the corresponding sensing electrode in a shortest path manner; The microfluidic structure includes a culture chamber disposed on one side of the first sensing electrode, a migration channel connected to the culture chamber and extending from the first sensing electrode to the reference electrode, and an air pump sealedly connected to the end of the migration channel, wherein the culture chamber is connected to the atmosphere; After the culture fluid containing sample cells is placed in the culture chamber, the culture fluid is filled into the migration channel through the air pump, and each sensing electrode captures the electrophysiological signals generated during the migration of the sample cells. The leads and lead-out probes connected to each sensing electrode lead out the captured electrophysiological signals.

2. The electrophysiological signal acquisition system according to claim 1, characterized in that: The connector includes a base, a circuit platform, a quick clamp and a conversion sub-board; The base is used to place the microfluidic electrode array chip; The circuit platform is arranged above the base, including a PCB mainboard and a plurality of spring pins fixed to the PCB mainboard. After each spring pin contacts each lead-out probe point on the microfluidic electrode array chip, the electrophysiological signal at each lead-out probe point is led out to the PCB mainboard, and the electrophysiological signal is sent to the conversion sub-board through the PCB mainboard. The quick clamp is used to control the circuit platform to move up and down, so that each spring pin on the circuit platform can contact or move away from each lead-out probe point on the microfluidic electrode array chip; The conversion sub-board is used to transmit the electrophysiological signal sent by the PCB main board to the front-stage probe.

3. The electrophysiological signal acquisition system according to claim 2, characterized in that: The connector further includes a support structure; The supporting structure is used to combine the circuit platform, the conversion sub-board, the base and the quick clamp into a whole.

4. The electrophysiological signal acquisition system according to claim 3, characterized in that: The PCB main board is composed of three PCB boards.

5. The electrophysiological signal acquisition system according to claim 1, characterized in that: The front-stage probe at least includes a low-noise amplifier, a bandpass filter, a digital-to-analog converter and a standard serial peripheral interface; The low noise amplifier is used to amplify the collected electrophysiological signal and then send it to the bandpass filter; The bandpass filter is used to filter the amplified electrophysiological signal and then send it to the digital-to-analog converter; The digital-to-analog converter is used to convert the filtered electrophysiological signal into a digital signal and then send it to the standard serial peripheral interface; The standard serial peripheral interface is used to send the digital signal to the acquisition board.

6. The electrophysiological signal acquisition system according to claim 1, characterized in that: The number of channels of the front-stage probe is at most 64 channels.

7. The electrophysiological signal acquisition system according to claim 1, characterized in that: The acquisition board provides four front-stage probe interfaces, and each front-stage probe interface is connected to at most two front-stage probes.

8. The electrophysiological signal acquisition system according to claim 1, characterized in that: The acquisition board receives the digital signals input by all the front-stage probes in parallel, adds a common time stamp to each digital signal, and outputs the signals serially to the host computer.

9. The electrophysiological signal acquisition system according to claim 1, characterized in that: The host computer is used to edit the integrated digital signal in a graphical manner according to experimental requirements, visually display the edited digital signal, and store the edited digital signal.

Images