A high-density cell sensor based on an array of oect, method of preparation and system

Abstract

This invention discloses a high-density cell sensor based on an OECT array, its fabrication method, and a system. The high-density cell sensor based on an OECT array includes a substrate, source lines, a semiconductor layer, a drain line, an encapsulation layer, a cell culture chamber, a cell adhesion layer, target cells, cell culture medium, a gate, and external circuit probes. The high-density cell sensor system based on an OECT array includes a driving circuit and a high-density array of OECT cells; wherein the driving circuit includes a power supply module, a control module, a gate driving module, a drain driving module, a source current signal acquisition module, and an analog-to-digital conversion module. The high-density cell sensor based on an OECT array of this invention has advantages such as high precision, small area, low power consumption, flexible driving, high signal-to-noise ratio, and signal amplification. The high-density cell sensor system based on an OECT array proposed in this invention can independently drive each sensor within the array by providing a specified signal.

Description

Technical Field

[0001] This invention belongs to the field of organic electrochemical transistor technology, and more specifically, relates to a high-density cell sensor based on an OECT array, its preparation method, and system. Background Technology

[0002] Organic electrochemical transistors (OECTs) are a rising star in the field of organic electronics, characterized by their simple fabrication, low power consumption, and flexibility. Furthermore, OECTs exhibit excellent biocompatibility, making them ideal for operation inside the human body and enabling their widespread application in implantable devices and other biomedical tools. Even more remarkably, OECTs possess extremely high input sensitivity, granting them the ability to detect weak signals, such as trace electrical signals generated by cells and neurons. This unique characteristic gives OECTs enormous application potential in multiple fields, including biosensing, neuroscience, and artificial skin.

[0003] OECT arrays are miniature arrays composed of numerous organic electrochemical transistors. Each transistor can operate independently or be driven in conjunction with other transistors to perform a predetermined function. Existing OECT arrays have several performance limitations in biological detection applications, primarily: relatively low array integration, which limits their monitoring range and makes it difficult to achieve simultaneous multi-cell detection or broad-based monitoring; the need for complex driving circuits, increasing system complexity and limiting their miniaturization or portable device applications; slow response to cell signals, making it difficult to meet rapid monitoring needs, such as transient cell responses or real-time signal monitoring; and low signal-to-noise ratio, affecting the reliability and accuracy of cell signals and posing challenges when detecting weak signals. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-density cell sensor based on an OECT array, its preparation method, and system.

[0005] This invention proposes a high-density cell sensor based on an OECT array, comprising: a substrate 1, source lines 2, a semiconductor layer 3, a drain line 4, an encapsulation layer 5, a cell culture chamber 6, a cell adhesion layer 7, test cells 8, cell culture medium 9, a gate 10, and external circuit probes 11. The substrate 1 has several parallel rectangular source lines 2, and several uniformly distributed square semiconductor layers 3 are disposed on the source lines 2, the width of the semiconductor layers 3 being greater than the width of the source lines 2. A rectangular drain line 4 is disposed at the center of the semiconductor layers 3, the width of the drain line 4 being less than the width of the semiconductor layers 3. The drain line 4 does not completely cover or obscure the semiconductor portion. Viewed from above, the drain lines 4 and the source lines 2 are perpendicular to each other, with the perpendicular intersection point located at the center of the semiconductor layers. An encapsulation layer 5 is disposed on the substrate, and the encapsulation layer 5 is square-shaped. The shaped aperture exposes the semiconductor layer located at the center of the perpendicular intersection of the drain and source lines; the overlapping areas of the drain and source lines form an array arrangement; a cell culture chamber 6 is disposed above the encapsulation layer 5, exposing the entire area of ​​the drain electrode end and the source electrode end; a cell adhesion layer 7 is disposed inside the cell culture chamber 6, on which test cells 8 are uniformly seeded and cell culture medium 9 is disposed; a gate 10 is disposed above the cell culture medium 9, and the gate 10 is in full contact with the cell culture medium 9; the external circuit probe 11 is connected to the external driving circuit.

[0006] This invention proposes a method for fabricating a high-density cell sensor based on an OECT array. The method includes the following steps:

[0007] Step S1: Use isopropyl alcohol to ultrasonically clean the silicon substrate for 15 minutes, and then treat it with ultraviolet ozone for 15 minutes after cleaning.

[0008] Step S2: Sequentially deposit 3nm chromium and 150nm gold as source lines on the cleaned silicon wafer substrate, with a width of 5μm, and place several source lines in parallel.

[0009] Step S3: Perform ultraviolet ozone cleaning treatment on the silicon wafer substrate with evaporated active electrode lines for about 10 minutes;

[0010] Step S4: Spin-coating to prepare a cross-linked semiconductor layer: Control the humidity below 10%, set the spin coater speed to 3000 rpm; turn on the spin coater, spin coat the semiconductor layer for 10 seconds, and uniformly coat the organic semiconductor material onto the silicon wafer surface; Photolithography: Strictly align and tightly adhere the photomask to the silicon wafer coated with the organic semiconductor layer material, use 365nm ultraviolet light to perform photolithography on the semiconductor film at the channel to cross-link it, and wash away the uncross-linked parts to form a semiconductor layer with a length and width of 10μm and a spacing of 10μm in the channel region. The semiconductor layer is distributed in a high-density array.

[0011] Step S5: Fabricate a 150nm gold drain line at the center of the semiconductor layer. The drain line width is 5μm. When viewed from the vertical direction, several drain lines and several source lines are perpendicular to each other, and the perpendicular intersection point is located at the center of the semiconductor layer.

[0012] Step S6: Spin-coating to prepare the encapsulation layer, and using 365nm ultraviolet light for exposure treatment to expose the semiconductor layer located at the center of the perpendicular intersection of the drain line and the source line;

[0013] Step S7: Fabricate a cell culture chamber and fix the cell culture chamber onto the high-density cell sensor of the OECT array using PDMS solution, exposing the drain line electrode end and the source line electrode end;

[0014] Step S8: Preparation of cell adhesion layer: Irradiate the OECT array with ultraviolet light for 30 minutes, and coat the cell culture chamber area of ​​the OECT array sensor with gelatin and fibronectin at 37°C for 1 hour;

[0015] Step S9: Apply to the cell adhesion layer at a rate of 50,000 cells / mm 2 The density of the cells to be tested was determined by planting them.

[0016] Step S10: Add approximately 10 μL of cell culture medium to the cell culture chamber as an electrolyte layer, and connect the gate through the cell culture medium.

[0017] This invention proposes a high-density cell sensor system based on an OECT array, comprising a driving circuit 21 and an OECT array high-density cell sensor 12. The driving circuit 21 includes a power supply module 13, a control module 20, a gate driving module 14, a drain driving module 15, a source current signal acquisition module 18, and an analog-to-digital converter module 19. The source current signal acquisition module 18 includes a current-to-voltage conversion module 16 and a signal amplification module 17. The gate driving module 14 is connected to the gate of the OECT array high-density cell sensor 12. The drain driving module 15 is connected to the drain line ends of the OECT array high-density cell sensor 12 in a one-to-one correspondence. The source current signal acquisition module 18 is connected to the source line ends of the OECT array high-density cell sensor 12 in a one-to-one correspondence. The analog-to-digital converter module 19 is connected to the output terminal of the current signal acquisition module 18 in a one-to-one correspondence.

[0018] The high-density cell sensor based on an OECT array, its preparation method, and the system proposed in this invention have the following beneficial technical effects:

[0019] 1) The key to the high-density cell sensor based on OECT array proposed in this invention is that the size of the sensor is small enough to be closely arranged in the array and to accommodate a large number of sensors in a given area. The small size of the sensor can also get closer to the cell and achieve highly localized measurement.

[0020] 2) The high-density cell sensor based on OECT array proposed in this invention has the advantages of high precision, small area, low power consumption, flexible driving, high signal-to-noise ratio and signal amplification.

[0021] 3) The high-density cell sensor system based on an OECT array proposed in this invention can independently drive each transistor in the array by providing a specified signal. Utilizing structural advantages, it achieves precise driving of specific OECT transistors and readout and monitoring of signals from specific OECT transistors.

[0022] 4) The high-density cell sensor based on an OECT array proposed in this invention provides an effective and reliable detection method, enabling real-time monitoring of cells and their activities with high spatiotemporal resolution. 5) The high-density cell sensor based on an OECT array proposed in this invention can monitor cell activity for extended periods without frequent maintenance, providing a stable and reliable foundation for long-term monitoring.

[0023] 6) The high-density cell sensor based on OECT array proposed in this invention can provide highly personalized measurement and analysis solutions for different types of cells and biological samples. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a cross-sectional view of the high-density cell sensor based on an OECT array proposed in this invention.

[0026] Figure 2 This is a layered structure diagram of the high-density cell sensor based on an OECT array proposed in this invention.

[0027] Figure 3 This invention presents a high-density cell sensor system based on an OECT array.

[0028] Figure 4 It is the output current transfer characteristic curve.

[0029] Figure 5This is a cell state detection curve. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Figure 1 This is a cross-sectional view of the high-density cell sensor based on the OECT array of the present invention. In this embodiment, a vertical OECT based on an organic semiconductor layer is proposed, including: a substrate 1, a source line 2, a semiconductor layer 3, a drain line 4, an encapsulation layer 5, a cell culture chamber 6, a cell adhesion layer 7, a cell to be tested 8, a cell culture medium 9, a gate 10, and an external circuit probe 11.

[0032] Figure 2 This is a layered structure diagram of the high-density cell sensor based on an OECT array according to the present invention, as shown below. Figure 2 As shown, several parallel rectangular source lines 2 are disposed in a substrate 1. Several uniformly distributed square semiconductor layers 3 are disposed on the source lines 2, and the width of the semiconductor layers 3 is greater than the width of the source lines 2. A rectangular drain line 4 is disposed at the center of the semiconductor layers 3, and the width of the drain line 4 is less than the width of the semiconductor layers 3. The drain line 4 does not completely cover or obscure the semiconductor portion. Viewed from above, the drain lines 4 and the source lines 2 are perpendicular to each other, and the perpendicular intersection is located at the center of the semiconductor layers. An encapsulation layer 5 is disposed on the substrate, and the encapsulation layer 5 has square holes that expose the area where the drain lines and source lines are perpendicular to each other. The semiconductor layer at the center of the intersection, when viewed from above, must have an opening size that exposes all or part of the overlapping area of ​​the drain and source lines; the overlapping areas of the drain and source lines are arranged in an array; a cell culture chamber 6 is provided above the encapsulation layer 5, exposing the entire area of ​​the drain and source electrode ends; a cell adhesion layer 7 is provided inside the cell culture chamber 6, on which test cells 8 are uniformly seeded and cell culture medium 9 is provided; a gate 10 is provided above the cell culture medium 9, and the gate 10 is in full contact with the cell culture medium 9; an external circuit probe 11 is connected to an external driving circuit.

[0033] The overlapping regions of the drain line, semiconductor layer, and source line constitute a single OECT sensor, and the size of each single OECT sensor is less than 10 μm × 10 μm, with a sensor density in the array region exceeding 2,500 sensors / mm². 2 During cell signal detection, each cell can be evenly distributed on each individual OECT sensor.

[0034] An external circuit probe 11 is applied to the ends of the source line 2 and the drain line 4; a voltage signal is applied to the gate 10 and the drain line 2. Under the action of the gate voltage and the source-drain voltage between the drain line and the source line, ions in the cell culture medium 9 can penetrate into or precipitate into the interior of the semiconductor layer, thereby realizing the detection of the state of the cells to be tested grown on the surface of the OECT array sensor.

[0035] The substrate is one of glass, silicon wafer, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), or polyurethane (PU).

[0036] The electrode width of the source and drain lines ranges from 1 to 10 μm, and the spacing between parallel source or drain lines is 1 to 10 μm. The source and drain lines are made of electrochemically stable conductive materials, specifically one or more of gold, chromium, platinum, carbon nanotubes, or graphene.

[0037] The gate is made of a conductive material that is either electrochemically active or non-electrochemically active, specifically one of gold, silver, poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, carbon nanotubes, graphene, or graphyne.

[0038] The semiconductor layer has a thickness of 10–200 nm and a width of 1–15 μm, and is constructed using a composite semiconductor material that simultaneously conducts ions and electrons.

[0039] The encapsulation layer is made of an electrochemically stable insulating material, specifically one of Parylene-C, cellulose, SU-8, polystyrene, PDMS, and SEBS.

[0040] The cell adhesion layer is made of biocompatible and adhesive chemical materials, specifically one or more of gelatin, fibronectin, polyvinyl alcohol and cellulose.

[0041] The cells to be tested are cells with electrophysiological activity, specifically one of neuronal cells, cardiomyocytes, and skeletal muscle cells.

[0042] The cell culture medium used is a buffer system with a variety of amino acids and vitamins, specifically dmem high glucose medium.

[0043] The cell culture chamber has a three-dimensional structure with specific dimensions of less than 10mm×10mm×10mm, and is made of polydimethylsiloxane (PDMS), which is suitable for accommodating cell growth and attachment.

[0044] This invention proposes a high-density cell sensor using an OECT array. The key to this is the vertical structure of the sensor, which effectively reduces energy consumption and heat generation during the detection process, enabling high-precision cell measurement and more accurate data acquisition. The monitoring area of ​​a single sensor in the array is less than 10μm × 10μm, the spacing between adjacent sensors is less than 10μm, and the integration density is higher than 2500 sensors / mm². 2 A single cell can be monitored by multiple sensors simultaneously. The size is small enough to allow for close arrangement in an array, accommodating a large number of sensors within a given area. The small sensor size also allows for better proximity to the cell and enables highly localized measurements. This invention proposes a high-density cell sensor for OECT arrays, ensuring that each individual OECT sensor has a short semiconductor layer of micrometers or less, while further improving the temporal and spatial resolution of the OECT array in cell detection.

[0045] The high-density cell sensor based on OECT array of the present invention has the advantages of high precision, small area, low power consumption, flexible driving, high signal-to-noise ratio and signal amplification.

[0046] This invention also proposes a method for fabricating a high-density cell sensor based on an OECT array, which will be described in detail below:

[0047] First, the materials were selected. In this embodiment, a silicon wafer was used as the substrate; the electrode width of the source and drain lines was set to 5 μm, and chromium and gold were used; silver was used as the gate; the thickness of the semiconductor layer was set to 50 nm, and poly[thiophene-bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)-2,2'-bithiophene] was used; cellulose was used as the encapsulation layer; gelatin and fibronectin were used as the cell adhesion layer; polydimethylsiloxane (PDMS), which is suitable for cell growth and adhesion, was used as the cell culture chamber; and mouse cardiomyocytes were used as the test cells.

[0048] The fabrication method of a high-density cell sensor based on an OECT array specifically includes the following steps:

[0049] Step S1: Use isopropyl alcohol to ultrasonically clean the silicon substrate for 15 minutes, and then treat it with ultraviolet ozone for 15 minutes after cleaning.

[0050] Step S2: Sequentially deposit 3nm chromium and 150nm gold as source lines on the cleaned silicon wafer substrate, with a width of 5μm, and place several source lines in parallel.

[0051] Step S3: Perform ultraviolet ozone cleaning treatment on the silicon wafer substrate with evaporated active electrode lines for about 10 minutes;

[0052] Step S4: Spin-coating to prepare a cross-linked semiconductor layer: Control the humidity below 10% and set the spin coater speed to 3000 rpm. Turn on the spin coater and spin-coat the semiconductor layer for 10 seconds to uniformly coat the organic semiconductor material onto the silicon wafer surface; Photolithography: Strictly align and tightly adhere the photomask to the silicon wafer coated with the organic semiconductor layer material. Use 365nm ultraviolet light to perform photolithography on the semiconductor film at the channel to cross-link it, and wash away the uncross-linked parts to form a semiconductor layer with a length and width of 10μm and a spacing of 10μm in the channel region. The semiconductor layer is distributed in a high-density array.

[0053] Step S5: Fabricate a 150nm gold drain line at the center of the semiconductor layer. The drain line width is 5μm. When viewed from the vertical direction, several drain lines and several source lines are perpendicular to each other, and the perpendicular intersection point is located at the center of the semiconductor layer.

[0054] Step S6: Spin-coating to prepare the encapsulation layer, and using 365nm ultraviolet light for exposure treatment to expose the semiconductor layer located at the center of the perpendicular intersection of the drain line and the source line;

[0055] Step S7: Fabricate a cell culture chamber and fix the cell culture chamber onto the OECT array high-density cell sensor using PDMS solution, exposing the drain line electrode end and the source line electrode end;

[0056] Step S8: Preparation of cell adhesion layer: Irradiate the OECT array with ultraviolet light for 30 minutes, and coat the cell culture chamber area of ​​the OECT array sensor with gelatin and fibronectin at 37°C for 1 hour;

[0057] Step S9: Apply to the cell adhesion layer at a rate of 50,000 cells / mm 2 The density of the cells to be tested was determined by planting them.

[0058] Step S10: Add approximately 10 μL of cell culture medium to the cell culture chamber as an electrolyte layer, and connect the gate through the cell culture medium;

[0059] After fabricating the high-density cell sensor based on the OECT array, the following steps are also included to facilitate testing:

[0060] Step S11: Apply external circuit electrodes to the ends of the source and drain lines.

[0061] When preparing the drain line at the top, this invention can effectively avoid contact between the drain line and the source line, thereby preventing short circuits in the sensor signal. The preparation method of the high-density cell sensor based on the OECT array of this invention is compatible with large-scale solution preparation methods, which can effectively reduce preparation energy consumption and preparation cost.

[0062] In this embodiment, the source line, drain line, and gate are prepared using one of the following methods: vapor deposition, magnetron sputtering, spraying, inkjet printing, aerosol printing, or screen printing. The semiconductor layer, encapsulation layer, and electrolyte layer are prepared using one of the following methods: spin coating, screen printing, inkjet printing, 3D printing, aerosol printing, electrofluid printing, or blade coating.

[0063] This invention also proposes a high-density cell sensor system based on an OECT array, such as... Figure 3 As shown, the high-density cell sensor system based on the OECT array includes a driving circuit 21 and an OECT array of high-density cell sensors 12; wherein, the driving circuit 21 includes a power supply module 13, a control module 20, a gate driving module 14, a drain driving module 15, a source current signal acquisition module 18, and an analog-to-digital conversion module 19; wherein, the source current signal acquisition module 18 includes a current-to-voltage conversion module 16 and a signal amplification module 17.

[0064] The gate driving module 14 is connected to the gate of the OECT array high-density cell sensor 12; the control module 20 controls the digital-to-analog converter (DAC) to apply a DC bias voltage, and its communication interface is SPI with a resolution of 16 bits; that is, the LSB is 2.5*10^6 / 2^16=38.15uV, the settling time is 4.5us, and the linearity is ±4LSB, which is ±0.152mV, which can meet the testing requirements.

[0065] The drain driving module 15 is connected one-to-one with the drain line ends of the high-density cell sensor 12 of the OECT array; the control module 20 controls the CMOS analog multiplexer to select one of the multiple drain lines in the high-density cell sensor 12 of the OECT array, and controls the digital-to-analog converter (DAC) to apply a DC bias voltage; wherein the CMOS analog multiplexer switches the common input D to 32 outputs (S1-S32) according to the address determined by the 5 binary address lines A0, A1, A2, A3 and A4, its on-resistance is 4Ω, its on-resistance flatness is 0.5Ω, and its switching time can reach 30ns, that is, the switching frequency can reach 33MHz, which can meet the testing requirements.

[0066] The source current signal acquisition module 18 is connected one-to-one with the source line ends of the high-density cell sensor 12 of the OECT array; by using a two-stage operational amplifier built with a precision operational amplifier, it acquires the current signals I output from multiple source lines in the OECT array. SThe signal is fed into the current-to-voltage conversion module 16 to be converted into an analog voltage signal, and then sent to the signal amplification module 17 to obtain an analog voltage signal that can be used by the analog-to-digital conversion module 19. The first-stage operational amplifier is a transconductance amplifier, and the second-stage operational amplifier is a voltage non-inverting amplifier; the precision operational amplifier has an input bias current of 0.2pA, an input offset voltage of 5μV, and an output current of 50mA, which can meet the testing requirements.

[0067] The analog-to-digital converter module 19 is connected to the output terminals of the current signal acquisition module 18 in a one-to-one correspondence. The analog-to-digital converter module 19 is used to acquire the voltage output by the current signal acquisition module 18 after processing. The analog-to-digital converter communication interface is SPI, with a sampling rate of 250kHz and a resolution of 24 bits. When the voltage signal is acquired at 250kHz, the setup time is 20µs. That is, when the sampling is performed by switching channels, the highest sampling frequency is 50kHz. At this time, the noise-free bit depth is 17.2 bits, that is, the LSB is 2.5*10^6 / 2^17.2=16.60µV, which can meet the test requirements.

[0068] The driving circuit can interact with all sensors in the OECT array. This interaction is defined as achieving gating control and readout operations for any single OECT sensor by defining combinations of rows and columns. Specifically, a constant gate voltage and a gating drain voltage are applied to drive a single OECT sensor, and a readable voltage signal is obtained through source current acquisition and transconductance amplification. The external circuit has the ability to configure logic code, allowing flexible setting and adjustment of row and column combinations according to different detection requirements to achieve gating control and readout of specific OECTs, thus achieving the effect of OECT array signal acquisition.

[0069] This invention employs an organic semiconductor layer. Under the action of the gate voltage, ions in the electrolyte layer are incorporated into or deposited into the semiconductor, effectively controlling the carrier concentration in the semiconductor and changing the conductivity of the semiconductor.

[0070] This invention tests the high-density cell sensor of the prepared OECT array using two methods.

[0071] Method 1 uses the source table to test the high-density cell sensor of the prepared OECT array. The test conditions are as follows:

[0072] At a constant drain voltage (V d Under the condition of -0.1V, a forward scan of the gate-source voltage from 0.2V to -0.5V was performed to capture the transfer characteristics of a single OECT output current, and the transfer characteristic curves were plotted, as shown below. Figure 4As shown in the figure, the high-density cell sensor of the OECT array exhibits excellent current modulation performance under these test conditions. The source current can be adjusted from the order of 10... -7 A to 10 -3 The current between A and B is controllable, while the gate current is kept at a low level (<10). -6 A).

[0073] Method two involves using the driving circuit proposed in this invention to test the high-density cell sensor of the prepared OECT array, under the following test conditions:

[0074] Under constant drain voltage (Vd = -0.1V) and gate voltage (Vg = -0.2V), the source output voltage curve of a single OECT is captured, as shown below. Figure 5 As shown in the figure, the high-density cell sensor of the OECT array exhibits excellent cell state monitoring performance under these test conditions. The source voltage can be controllably amplified from 0mV to ±2V.

[0075] Meanwhile, under the conditions of constant drain voltage (Vd = -0.1V) and gate voltage (Vg = -0.2V), to obtain the OECT array signal, it is only necessary to set the gate voltage to a constant value and use the microcontroller to control the CMOS analog multiplexer to select one of the multiple drain lines in the OECT array. Then, each sensor in the array can be driven independently by the control signal and the gating signal to obtain the sampling value of the entire OECT.

[0076] As can be seen from the two testing methods described above, the high-density cell sensor based on OECT array proposed in this invention has the advantages of high precision, flexible test drive, low power consumption, and high signal-to-noise ratio.

[0077] The high-density cell sensor system based on an OECT array proposed in this invention has the following advantages: 1) It achieves high spatial resolution cell monitoring and recording while maintaining cell bioactivity, avoiding adverse effects on cells, and ensuring uniform capture and efficient recording of cell signals; 2) It can simultaneously capture and analyze the electrical signals of multiple cells at the micrometer scale, thus enabling fine observation and analysis of cell activity, achieving spatial resolution and real-time monitoring capabilities at the cellular and subcellular levels; 3) By gating and adjusting the drain voltage, it can effectively drive sensors at specified locations, achieving specific adjustment of OECT sensor performance; 4) It has extremely high degrees of freedom, allowing for the detection / monitoring of cell clusters of different sizes by adjusting the array size; 5) The driving circuit can independently drive each sensor in the array by providing a specified signal; 6) Utilizing structural advantages, it achieves precise driving of specified OECT sensors and reading and monitoring of specified OECT signals; 7) The system can adapt to different types and sizes of cell samples, and the test logic can be adjusted and optimized for various experimental and application needs; 8) The system is stable and can maintain a high level of performance and accuracy during long-term monitoring.

[0078] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A high-density cell sensor based on an OECT array, characterized in that, The system includes a substrate (1), source lines (2), semiconductor layers (3), drain lines (4), encapsulation layers (5), cell culture chambers (6), cell adhesion layers (7), cells to be tested (8), cell culture medium (9), gate (10), and external circuit probes (11). The substrate (1) contains several parallel rectangular source lines (2), and several uniformly distributed square semiconductor layers (3) are disposed on the source lines (2). The width of the semiconductor layers (3) is greater than the width of the source lines (2). A rectangular drain line (4) is disposed at the center of the semiconductor layers (3). The width of the drain line (4) is less than the width of the semiconductor layers (3). The drain line (4) does not completely cover or obscure the semiconductor portion. When viewed from above, the drain lines (4) and the source lines (2) are perpendicular to each other, and the perpendicular intersection point is located at the semiconductor... In the center of the substrate, the overlapping areas of the drain line (4), semiconductor layer (3), and source line (2) constitute a single OECT sensor; an encapsulation layer (5) is provided on the substrate, and the encapsulation layer (5) has a square hole to expose the semiconductor layer located at the center of the perpendicular intersection of the drain line and the source line; the overlapping areas of the drain line and the source line constitute an array arrangement; a cell culture chamber (6) is provided above the encapsulation layer (5), exposing the entire area of ​​the drain line electrode end and the source line electrode end; a cell adhesion layer (7) is provided in the cell culture chamber (6), and the cells to be tested (8) are uniformly seeded on the cell adhesion layer (7) and a cell culture medium (9) is provided; a gate (10) is provided above the cell culture medium (9), and the gate (10) is in full contact with the cell culture medium (9); an external circuit probe (11) is connected to an external driving circuit.

2. The high-density cell sensor based on an OECT array according to claim 1, characterized in that, Each individual OECT sensor element is less than 10 μm × 10 μm in size, and the sensor density in the array area is higher than 4,400 elements / mm². 2 .

3. The high-density cell sensor based on an OECT array according to claim 1, characterized in that, The substrate is one of glass, silicon wafer, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), or polyurethane (PU).

4. The high-density cell sensor based on an OECT array according to claim 1, characterized in that, The electrode width of the source and drain lines ranges from 1 to 10 μm, and the spacing between parallel source or drain lines is 1 to 10 μm; the source and drain lines are selected from one or more of gold, chromium, platinum, carbon nanotubes or graphene.

5. The high-density cell sensor based on an OECT array according to claim 1, characterized in that, The gate is selected from one of the following: gold, silver, poly(3,4-ethylenedioxythiophene), polystyrene sulfonate, carbon nanotubes, graphene, and graphyne.

6. The high-density cell sensor based on an OECT array according to claim 1, characterized in that, The encapsulation layer is made of an electrochemically stable insulating material, specifically one of Parylene-C, cellulose, SU-8, polystyrene, PDMS, and SEBS.

7. The high-density cell sensor based on an OECT array according to claim 1, characterized in that, The cell adhesion layer is selected from one or more of gelatin, fibronectin, polyvinyl alcohol and cellulose; the test cells are selected from one of neuronal cells, cardiomyocytes and skeletal muscle cells.

8. A method for fabricating a high-density cell sensor based on an OECT array, characterized in that, Includes the following steps: Step S1: Use isopropanol to ultrasonically clean the silicon wafer substrate for 15 minutes, and then treat it with ultraviolet ozone for 15 minutes after cleaning. Step S2: Sequentially deposit 3nm chromium and 150nm gold as source lines on the cleaned silicon wafer substrate, with a width of 5μm, and place several source lines in parallel. Step S3: Perform ultraviolet ozone cleaning treatment on the silicon wafer substrate with evaporated active electrode lines for about 10 minutes; Step S4: Spin-coating to prepare a cross-linked semiconductor layer: Control the humidity below 10%, set the spin coater speed to 3000 rpm; turn on the spin coater, spin coat the semiconductor layer for 10 seconds, and uniformly coat the organic semiconductor material onto the silicon wafer surface; Photolithography: Strictly align and tightly adhere the photomask to the silicon wafer coated with the organic semiconductor layer material, use 365nm ultraviolet light to perform photolithography on the semiconductor film at the channel to cross-link it, and wash away the uncross-linked parts to form a semiconductor layer with a length and width of 10μm and a spacing of 10μm in the channel region. The semiconductor layer is distributed in a high-density array. Step S5: Fabricate a 150nm gold drain line at the center of the semiconductor layer. The drain line width is 5μm. When viewed from the vertical direction, several drain lines and several source lines are perpendicular to each other, and the perpendicular intersection point is located at the center of the semiconductor layer. Step S6: Spin-coating to prepare the encapsulation layer, and using 365nm ultraviolet light for exposure treatment to expose the semiconductor layer located at the center of the perpendicular intersection of the drain line and the source line; Step S7: Fabricate a cell culture chamber and fix the cell culture chamber onto the high-density cell sensor of the OECT array using PDMS solution, exposing the drain line electrode end and the source line electrode end; Step S8: Preparation of cell adhesion layer: Irradiate the OECT array with ultraviolet light for 30 minutes, and coat the cell culture chamber area of ​​the OECT array sensor with gelatin and fibronectin at 37°C for 1 hour; Step S9: Apply to the cell adhesion layer at a rate of 50,000 cells / mm 2 The density of the cells to be tested was determined by planting them. Step S10: Add approximately 10 μL of cell culture medium to the cell culture chamber as an electrolyte layer, and connect the gate through the cell culture medium.

9. The method for fabricating a high-density cell sensor based on an OECT array according to claim 8, characterized in that, The source line, drain line, and gate are prepared by one of the following methods: vapor deposition, magnetron sputtering, spraying, inkjet printing, aerosol printing, and screen printing; the semiconductor layer, encapsulation layer, and electrolyte layer are prepared by one of the following methods: spin coating, screen printing, inkjet printing, 3D printing, aerosol printing, electrofluid printing, or scraping coating.

10. A high-density cell sensor system based on an OECT array, comprising a driving circuit (21) and the high-density cell sensor (12) based on an OECT array as described in claim 1; wherein, The driving circuit (21) includes a power supply module (13), a control module (20), a gate driving module (14), a drain driving module (15), a source current signal acquisition module (18), and an analog-to-digital conversion module (19); wherein, the source current signal acquisition module (18) includes a current-to-voltage conversion module (16) and a signal amplification module (17); the gate driving module (14) is connected to the gate of the high-density cell sensor (12) based on the OECT array; the drain driving module (15) is connected to the drain line end of the high-density cell sensor (12) based on the OECT array; the source current signal acquisition module (18) is connected to the source line end of the high-density cell sensor (12) based on the OECT array; the analog-to-digital conversion module (19) is connected to the output terminal of the source current signal acquisition module (18).

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