Microfluidic electrically interconnected neural network chip system

Abstract

The application discloses a microfluidic electrically interconnected neural network chip system, which is used for realizing programmable electrically interconnected neural networks with different functional partitions.The system of the application is composed of an electrically interconnected control circuit, a microelectrode array and a microfluidic structure.The electrically interconnected control circuit controls the internal connection of a commercial CMOS switch array by using a single-chip microcomputer or an FPGA, and a signal input line of the commercial CMOS switch array is connected with a microelectrode site, so that the communication or disconnection between different detection sites is controlled;the microfluidic structure realizes the neuron partition function and physically isolates the neurons in different partitions; and the microelectrode array is used for detecting and stimulating neurons and is also a control object of the CMOS switch array.The chip controls the mutual connection of the microelectrode sites in different neuron partitions by using a circuit, is used for exploring the information interaction ability of the physically separated neuron groups through metal wires, and provides a new idea for regulating and constructing neuron networks.

Description

Technical Field

[0001] This disclosure relates to fields such as electronic information, biosensors, micro-nano manufacturing technology and bioelectronics, and specifically to a microfluidic electrically interconnected neural network chip system. Background Technology

[0002] The brain is the most complex structure known to humankind. Although scientists worldwide are striving to decipher its working mechanisms, a definitive answer remains elusive. Studying the brain allows for a clearer understanding of ourselves and significantly advances fields such as medicine, artificial intelligence, and philosophy. One crucial direction is the in vitro cultivation of neural networks. By observing the formation, characteristics, and functions of different neural networks outside the body, we can further understand the brain's working mechanisms. Currently, there are two main methods for regulating and constructing neural networks in vitro: one uses microfluidic structures to restrict neuronal movement and synaptic growth, but this method has the drawback that once formed, the neural network is difficult to alter; the other method uses stimulation to change the neural network, but this method has the disadvantage of being difficult to predict the direction of change after stimulation. Summary of the Invention

[0003] The microfluidic electro-interconnected neural network chip system proposed in this invention aims to regulate and construct neural networks by changing the connection state of microelectrodes in different neuronal partitions through CMOS switch control circuits. It can flexibly and controllably change the neural network, providing a new approach for in vitro research on neural networks.

[0004] The purpose of this invention is to provide a microfluidic electro-interconnected neural network chip system for realizing circuit regulation and constructing neural networks. This system acquires neuronal signals and regulates neuronal activity through a microelectrode array; it constructs physically separated neuronal partitions 7 using a PDMS; and it uses a main control chip 12 to control the internal connections of a CMOS switch array 11 to interconnect or disconnect the microelectrodes 2 within different physically separated neuronal partitions 7. Neurons within different neuronal partitions 7 interact with each other through the interconnected microelectrodes 2. The interconnection relationship between different neuronal partitions 7 is changed through an electro-interconnection circuit, thereby regulating and constructing different neural networks. Each neuronal partition 7 contains multiple microelectrodes 2, one of which is used for electro-interconnection, while the others are used for electrophysiological detection or electrical stimulation. The microelectrodes 2 used for electro-interconnection can also be controlled by a suitable electro-interconnection circuit for electrophysiological detection or electrical stimulation.

[0005] To achieve this objective, the present invention adopts the following technical solution: A microfluidic electrically interconnected neural network chip system, the system comprising a microelectrode array, a microfluidic structure, and an electrically interconnected control circuit; The microelectrode array includes: an insulating substrate, microelectrodes, counter electrodes, connecting wires, contact points, and an insulating layer; it is used to collect nerve signals or transmit electrical stimulation. Microfluidic structures include: neuronal partitions and cell culture loops; used to culture neurons and construct physically separated neuronal partitions; The electrical interconnection control circuit includes: a spring-loaded needle, a latch, a CMOS switch array, a main control chip, and a pin header. The electrical interconnection control circuit connects the spring-loaded needle to the contact points of the microelectrode array, and the latch provides the necessary pressure for contact. The points at the tip of the spring-loaded needle requiring electrical interconnection control are connected to the signal input of the CMOS switch array. The signal output of the CMOS switch array is connected to the pin header. Points at the tip of the spring-loaded needle that do not require electrical interconnection control are directly connected to the pin header. The pin header is connected to the electrophysiological detection system. The main control chip is connected to the control circuit of the CMOS switch array. The main control chip controls the internal connections of the CMOS switch array, controlling the interconnection of microelectrodes within different neuronal regions. It selectively provides a pathway for information exchange between neurons in different neuronal regions by transmitting electrical signals via metal wires, thereby achieving the purpose of regulating or constructing a neuronal network in the form of a circuit.

[0006] The present invention has the following beneficial technical effects: This invention utilizes microfluidic technology to construct independent neuronal partitions in vitro. By controlling neurons within different independent neuronal partitions via metal wires using a CMOS switching chip, neural information exchange is achieved, altering the original neuronal network structure and constructing a new one. Combined with a microelectrode array and an electrophysiological detection system, changes in the neuronal network can be monitored in real time. This method is simple to control, altering the connections of the neuronal network by controlling the on / off state of the CMOS switching array; it causes no damage to neurons and can be flexibly applied to various stages of in vitro neuronal culture; the neuronal network structures constructed by combining and configuring the connections of different independent neuronal partitions are rich and controllable; the microelectrode array has 256 microelectrode sites with both detection and stimulation functions, significantly increasing the number of detection channels compared to the currently commercially available 60-channel in vitro microelectrode arrays. Attached Figure Description

[0007] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which: Figure 1 A schematic diagram of the structure of a microfluidic electrically interconnected neural network chip system according to an embodiment of the present disclosure is shown.

[0008] Figure 2 The diagram illustrates the structure of a first part of a microelectrode array and a second part of a microfluidic portion of a microfluidic interconnected neural network chip system according to an embodiment of the present disclosure.

[0009] Figure 3 The schematic diagram illustrates the CMOS switch array in the third part of the electrical interconnection control circuit of a microfluidic electrical interconnection neural network chip system according to an embodiment of the present disclosure.

[0010] In the diagram: 1. Insulating substrate; 2. Microelectrode; 3. Counter electrode; 4. Connecting wire; 5. Contact point; 6. Insulating layer; 7. Neuron partition; 8. Cell culture ring; 9. Spring needle; 10. Clip; 11. CMOS switch array; 12. Main control chip; 13. Needle row. Detailed Implementation

[0011] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0012] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0013] like Figures 1-2 As shown, a microfluidic electrical interconnection neural network chip system of the present invention includes three parts: a first part microelectrode array, a second part microfluidic structure, and a third part electrical interconnection control circuit.

[0014] The first part, the microelectrode array, includes: an insulating substrate 1, microelectrodes 2, counter electrodes 3, connecting wires 4, contact points 5, and an insulating layer 6. There are 256 microelectrodes 2, which are used to collect nerve signals or transmit electrical stimulation.

[0015] The second part of the microfluidic structure includes: neuronal partitions 7 and cell culture loops 8. Sixty-four physically isolated neuronal partitions 7 were constructed using PDMS, with four microelectrodes 2 distributed within each neuronal partition 7. This part was used to culture neurons and construct the physically separated neuronal partitions 7.

[0016] The third part, the electrical interconnection control circuit, includes: a spring pin 9, a latch 10, a CMOS switch array 11, a main control chip 12, and a pin header 13. This part controls the internal connections of the CMOS switch array 11 through the main control chip 12, controlling the on / off state of the microelectrodes 2 in different neuronal partitions 7. It selectively provides a pathway for information interaction for neurons in different neuronal partitions 7 in the form of electrical signals transmitted through metal wires, thereby achieving the purpose of circuit regulation or constructing a neuronal network.

[0017] The insulating substrate 1 is made of soda-lime glass; the microelectrode 2, counter electrode 3, connecting wire 4 and contact point 5 are made of platinum metal with excellent biocompatibility and good conductivity; the counter electrode 3 and the microelectrode 2 are both extended through the connecting wire 4 and connected to the contact point 5 on the periphery of the insulating substrate 1; the surface of all connecting wires 4 is covered with an insulating layer 6; preferably, the insulating layer 6 is made of silicon dioxide and silicon nitride.

[0018] The microfluidic structure is constructed with 64 independent regions using polydimethylsiloxane (PDMS) as 64 neuron partitions 7, and an outer cell culture ring 8 is used to contain the nutrients required for neuronal growth.

[0019] The electrical interconnection control circuit contacts the contact point 5 of the microelectrode array via the spring needle 9, and provides the required pressure for the spring needle 9 to contact via the latch 10. The point at the end of the spring needle 9 requiring electrical interconnection control is connected to the signal input of the CMOS switch array 11; the signal output of the CMOS switch array 11 is connected to the needle array 13; the point at the end of the spring needle 9 not requiring electrical interconnection control is directly connected to the needle array 13; the needle array 13 is connected to the electrophysiological detection system; the main control chip 12 is connected to the control circuit of the CMOS switch array 11; the main control chip 12 is a microcontroller or FPGA; for example... Figure 3 As shown, the CMOS switch array 11 uses 16 The AD75019 commercial chip with a 16-bit specification can achieve arbitrary signal input and arbitrary signal output connection by changing the internal CMOS switch array 11, thereby realizing the interconnection between arbitrary signal inputs. To achieve arbitrary electrical interconnection of 64 zones, five AD75019 chips are used as CMOS switch array 11 chips. The first four AD75019 chips realize arbitrary electrical interconnection of 16 zones respectively, and the fifth AD75019 chip realizes arbitrary electrical interconnection between the first four AD75019 chips and the CMOS switch array 11 chip.

[0020] The first part of the microelectrode array and the second part of the cell culture ring 8 structure are bonded together using PDMS as an adhesive material; the first part of the microelectrode array and the second part of the neuronal partition 7 structure are bonded together using van der Waals forces generated by the evaporation of alcohol between the layers. Specific Implementation Example 1: PDL (poly-L-lysine), which promotes neuronal adhesion and growth, is coated onto the microelectrode array in the first part of this invention. Alcohol is sprayed onto the surface of the microelectrode array in the first part of this invention and the surface of the neuronal partition 7 structure of the microfluidic structure in the second part of this invention. Under a microscope, tweezers are used to align the neuronal partition 7 structure and the microelectrode array, and alignment is completed after the alcohol evaporates. Liquid PDMS is then used as an adhesive to align and attach the microelectrode array in the first part to the cell culture loop 8 structure in the second part, and attachment is completed after the PDMS cures.

[0022] The original program is burned into the microcontroller to control the internal connections of the CMOS switch array 11, providing interconnection for building a specific neural network.

[0023] Primary cortical excitatory neurons were isolated from ICR rat embryos at 15-18 days of gestation and then seeded into neuronal compartment 7 of the microfluidic structure in Part II of this invention. After culturing the neurons in a CO2 incubator for 2-3 weeks, the neuronal network began to mature.

[0024] The neural network was detected and analyzed using a 128-channel electrophysiological testing instrument from Blackrock Corporation in the United States.

[0025] A new program is burned into the microcontroller, and then the neural network is detected using a 128-channel electrophysiological detection instrument from Blackrock Corporation in the United States. The changes in the neural network are observed, and the newly formed neural network is analyzed. Specific Implementation Example 2: PDL (poly-L-lysine), which promotes neuronal adhesion and growth, is coated onto the microelectrode array in the first part of this invention. Alcohol is sprayed onto the surface of the microelectrode array in the first part of this invention and the surface of the neuronal partition 7 structure of the microfluidic structure in the second part of this invention. Under a microscope, tweezers are used to align the neuronal partition 7 structure and the microelectrode array, and alignment is completed after the alcohol evaporates. Liquid PDMS is then used as an adhesive to align and attach the microelectrode array in the first part to the cell culture loop 8 structure in the second part, and attachment is completed after the PDMS cures.

[0027] The original program is burned into the microcontroller to control the internal connections of the CMOS switch array 11, providing interconnection for building a specific neural network.

[0028] With density / mL of undifferentiated PC12 cells were seeded and cultured in fresh F-12K medium, providing a suitable environment and growth factors for cell growth. Nerve growth factor was used to promote cell differentiation, and the cells were cultured for six days to obtain a neuronal network with a certain degree of maturity.

[0029] The neural network was detected and analyzed using a 128-channel electrophysiological testing instrument from Blackrock Corporation in the United States.

[0030] The STG4002 electrostimulator from Multi Channel Systems was used to electrically stimulate a single neuronal region 7. The neuronal network was then detected and analyzed using a 128-channel electrophysiological monitoring instrument from Blackrock Corporation to observe the effect of electrical stimulation on this specific neuronal network.

[0031] The above embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A microfluidic electrically interconnected neural network chip system, characterized in that, The system includes a microelectrode array, a microfluidic structure, and an electrical interconnect control circuit; The microelectrode array includes: an insulating substrate (1), microelectrodes (2), counter electrodes (3), connecting wires (4), contact points (5), and an insulating layer (6); used to collect nerve signals or transmit electrical stimulation. The microfluidic structure includes: neuronal partitions (7) and cell culture loops (8); used to culture neurons and construct physically separated neuronal partitions (7); The electrical interconnection control circuit includes: a spring needle (9), a latch (10), a CMOS switch array (11), a main control chip (12), and a pin array (13); the electrical interconnection control circuit contacts the contact point (5) of the microelectrode array through the spring needle (9), and provides the pressure required for the spring needle (9) to contact through the latch (10). The point at the end of the spring needle (9) that needs to be electrically interconnected is connected to the signal input of the CMOS switch array (11); the signal output of the CMOS switch array (11) is connected to the pin array (13); the point at the end of the spring needle (9) that does not need to be electrically interconnected is directly connected to the pin array (13); the pin array (13) is connected to the electrophysiological detection system; the main control chip (12) is connected to the control circuit of the CMOS switch array (11); the internal connection of the CMOS switch array (11) is controlled by the main control chip (12), and the interconnection of microelectrodes (2) in different neuronal partitions (7) is controlled. The circuit selectively provides a way for neurons in different neuronal partitions (7) to interact with each other in the form of transmitting electrical signals through metal wires, thereby achieving the purpose of regulating or constructing a neuronal network in the form of a circuit. The signal input lines of the CMOS switch array (11) are connected to the microelectrode array via metal wires. The main control chip (12) controls the internal connection of the CMOS switch array (11) to interconnect the arbitrarily connected microelectrodes (2) via metal wires. Neurons in different neuronal regions (7) interact with each other through interconnected microelectrodes (2). The interconnection of microelectrodes (2) is controlled by the main control chip (12) and CMOS switch array (11) to artificially regulate or construct neuronal networks. The microelectrode array is connected to the CMOS switch array (11) control circuit and electrophysiological detection system by means of contact with spring needles (9).

2. The microfluidic electrically interconnected neural network chip system according to claim 1, characterized in that, Sixty-four or more physically separated neuronal partitions were constructed using polydimethylsiloxane PDMS (7), with multiple microelectrodes in each partition (2).

3. The microfluidic electrically interconnected neural network chip system according to claim 1, characterized in that: A microcontroller or FPGA is used as the main control chip (12) to control the internal connection of the CMOS switch array (11).

4. The microfluidic electrically interconnected neural network chip system according to claim 1, characterized in that: The spring pin (9) is provided with the pressure required for contact by using a snap-fit ​​(10) to lock.

Images