KR20000073367A - Microelectrode Array For Cultured Neural Network - Google Patents

Abstract

PURPOSE: An electrode substrate of cultivating a nerve net is provided to simultaneously observe or stimulate several hundreds of nerve cells by forming an electrode array of the desired number and pattern on a substrate and cultivating a nerve circuit net on the semiconductor substrate. CONSTITUTION: A nerve cell is put on a second insulation layer(24). A conductor layer(23) stimulates the nerve cell or forms a connection unit for connecting an electrode unit with an outside circuit. First and second insulation layers(22,24) prevent ions or water from permeating into a substrate in a cultivation atmosphere on the substrate. A nitride film efficiently prevents ion permeation. An oxidation film has a small amount of pinhole so that the nitride film is prevented from being oxidized in the cultivation atmosphere.

Description

Neural network culture electrode substrate {Microelectrode Array For Cultured Neural Network}

The present invention relates to a neural network culture electrode substrate capable of stimulating a neural network and recording a signal of the neural circuit membrane after culturing neural cells in neuroscience or physiology to form a neural network.

In order to understand basic mechanisms and network functions such as learning, cognition, and memory, it is very effective to study brain slices and cultured neuronal networks. In the study of cultured neural networks, we understand neural networks by constructing relatively simple synaptic neural networks in a controlled culture environment to find out the interactions and input / output relationships between nerves. At this time, the activity of nerves is mainly caused by the generation of electric potential and the transfer of electric potential, so that the nerve cells are electrically stimulated and the cell membrane potential is recorded to understand the nerve activity.

Conventionally, after culturing brain slices or neural networks, a method of stimulating nerve cells or measuring membrane potential by inserting electrodes into neural cell membranes forming a neural network was used.

However, the method of inserting electrodes after culturing the neural network is only two or three cells which can be accessed simultaneously, so that each neural cell obtained in several experiments can be used to analyze the neural network. It should be inferred from the correlation of their time-averaged responses. Not only is this a very laborious task, it is difficult to maintain consistent experimental conditions due to environmental changes in the network during the time difference between experiments. In addition, there is a problem that can cause damage to the cell in the process of inserting the electrode into the cell membrane.

The present invention is to solve the problems of the prior art as described above, an object of the present invention is to form a predetermined number of electrodes array of the desired number and the desired pattern on the substrate using a semiconductor processing technology, and on the pre-formed semiconductor substrate The present invention provides a neural network culture electrode substrate capable of culturing neural networks and observing or stimulating tens to hundreds of neural cells simultaneously.

The present invention also provides a neural network culture electrode substrate capable of integrating a circuit capable of generating or processing a signal from a nerve cell cultured on a substrate and a signal for stimulating the nerve cell.

The present invention also provides a neural network culture electrode substrate to facilitate observing nerve cells cultured on the substrate with a back microscope.

1 is a schematic view for explaining the culture of nerve cells using the neural network culture electrode substrate according to the present invention,

2 is a block diagram of a neural network culture electrode substrate according to a first embodiment of the present invention;

3 is a block diagram of a neural network culture electrode substrate according to a second embodiment of the present invention;

Figure 4 is a block diagram of a neural network culture electrode substrate according to a third embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: substrate 20: electrode

30: connection portion 40: container

21: substrate 22: first insulating layer

23 conductor layer 24 second insulating layer

Hereinafter, the neural network culture electrode substrate according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 is a schematic diagram for explaining the culture of nerve cells using the neural network culture electrode substrate according to the present invention.

As shown in FIG. 1, in the neural network culture electrode substrate according to the present invention, electrodes 20 and a connection part 30 for connecting the electrodes with an external circuit are formed on the substrate 10 by a semiconductor processing technique. The container 40 for cell culture is attached to the electrode portion on the electrode substrate with a biocompatible adhesive and cultured nerve cells such as brain slices. Compared to the conventional method of culturing nerve cells and plugging electrodes connected to an external circuit therein, in the present invention, in the semiconductor manufacturing process, dozens or hundreds of electrodes are pre-formed on a substrate, and then the nerve cells are formed thereon. In this way, the cultured nerve cells are stimulated with preformed electrodes.

Hereinafter, embodiments of the neural network culture electrode substrates according to the present invention will be described.

Figure 2 is a block diagram of a neural network culture electrode substrate according to a first embodiment of the present invention.

As shown in the figure, the neural network culture electrode substrate according to the present invention includes a substrate 21 and a first insulating layer 22 formed on the substrate 21, which are support members of the substrate, and the first insulating layer 22. And a second insulating layer 24 which insulates between the electrodes of the conductor layer 23 formed on the top of the plurality of electrodes and the electrodes of the conductor layer 23 and insulates the cultured nerve cells.

The nerve cells are placed on the second insulating layer 24, and the conductor layer 23 externally separates the electrodes and the electrode part which serves to stimulate or receive signals from the nerve cells placed on the second insulating layer 24. Form a connection for connecting with the circuit of.

The first insulating layer 22 and the second insulating layer 24 should prevent ions or moisture from penetrating into the substrate in a culture environment on the substrate. For this purpose, it is preferable to use a triple insulating film of an oxide film / nitride film / oxide film. The nitride film is effective in preventing ion penetration, and the oxide film is effective in preventing the nitride film from being oxidized in a culture environment because of less pinholes.

By using silicon as a substrate of the neural network culture electrode substrate according to the present invention, and using a semiconductor manufacturing process, necessary circuits such as an amplifier, a multiplexer, and a remote transceiver circuit can be integrated in the substrate.

On the other hand, in the biological experiment, the rear microscope is observed by shooting light on the bottom surface of the object placed on the object, in order to use the rear microscope using the substrate of a transparent material, the first insulating layer 22 Since the oxide film or the nitride film is transparent, the electrode of the conductor layer 23 can be observed by using a thin film of gold or ITO (Induim Tin Oxide) with a rear microscope. In the case of using glass as a substrate made of a transparent material, circuits cannot be integrated in the substrate, so that external circuits are used through the connecting portion, or a circuit formed in silicon is flipped onto a transparent substrate on which electrodes are formed. It can also be used by electrically connecting by coupling.

Figure 3 is a block diagram of a neural network culture electrode substrate according to a second embodiment of the present invention.

The embodiment shown in Figure 3 is for close contact between the cells and the cells cultured on the substrate. When measuring signals or stimulating cells outside the cell membrane of nerve cells, leakage currents must be prevented to increase cell selectivity. In order to prevent leakage current, close contact between the cell and the electrode is required. To this end, in the second embodiment of the present invention, a hole penetrating the substrate 21, the first insulating layer 22, and the conductor layer 23 is formed. In such a structure, when the pressure of the rear surface of the substrate 21 is lowered by using a vacuum pump or the like, the cells placed on the electrodes of the conductor layer 23 adhere to the electrodes by the suction effect from the rear surface of the substrate 21. .

Figure 4 is a block diagram of a neural network culture electrode substrate according to a third embodiment of the present invention.

In the third embodiment, the substrate is easily observed with a rear microscope without using a transparent material. If the substrate is made of a transparent material, a material such as glass should be used. In this case, however, it has already been described that the characteristic of integrating a circuit in the substrate cannot be utilized.

On the other hand, since the subject observed by the rear microscope is the electrode region on which the cell is placed, removing the portion from the rear of the substrate allows the rear microscope to be observed without using the substrate as a transparent material.

As shown in FIG. 4, a part of the rear surface of the substrate 21 may be etched and removed, and a transparent material may be used for the electrodes of the first insulating layer 22 and the conductor layer 23. In this case, since the substrate 21 may be made of a material such as silicon, a circuit may be integrated in the substrate.

As described above, the neural network culture electrode substrate according to the present invention first forms an electrode on a substrate by a semiconductor process, and then cultivates the nerve cells thereon, thereby stimulating the nerve cell through the first electrode or receiving a signal from the nerve cell. It is characterized by what can be obtained. In particular, it proposes a structure in which necessary circuits are integrated in the substrate or the rear microscope can be easily viewed. Since the neural network culture electrode substrate according to the present invention can form tens to hundreds of electrodes, the neural network culture electrode substrate is effective in analyzing signals recorded and stimulated in multiple channels in a study of neural networks performed in vitro.

Claims (6)

As a neural network culture electrode substrate manufactured by a semiconductor process, The substrate and the first insulating layer formed on the substrate, the substrate supporting the substrate, the conductor layer formed on the first insulating layer and constituting a plurality of electrodes and the nerve cells are insulated and cultured between the electrodes of the conductor layer Neural network culture electrode substrate comprising a second insulating layer for insulating between. The neural network culture electrode substrate according to claim 1, wherein circuits necessary for stimulation and observation analysis of nerve cells are integrated in the substrate using a semiconductor process. The neural network culture electrode substrate of claim 1, wherein the substrate is made of a transparent material, and the plurality of electrodes of the conductor layer is made of a thin film of gold or a transparent material. The method of claim 1, wherein a hole penetrating through the substrate, the first insulating layer, and the conductor layer is formed so that the cells placed on the electrode of the conductor layer are brought into close contact with the electrode by the suction effect from the rear surface of the substrate. Neural network culture electrode substrate, characterized in that. The neural network culture electrode substrate according to claim 2, wherein a part of the rear surface of the substrate corresponding to the electrode portion in which the cells are placed is removed from the substrate. 4. The neural network electrode culture substrate of claim 3, wherein the neural network electrode culture substrate is electrically connected to a semiconductor substrate in which a circuit is integrated in a transparent substrate on which electrodes are formed by flip chip bonding.