Flexible multi-channel microelectrode array device

Abstract

The invention discloses a flexible multi-channel microelectrode array device, and relates to the technical field of electrophysiological sensing detection, and the flexible multi-channel microelectrode array device is technically characterized by comprising a hollow cardiac muscle cell culture chamber, a flexible multi-channel microelectrode array chip and a PCB adapter which are sequentially arranged from top to bottom, the hollow cardiac muscle cell culture chamber is in a hollow circular tube shape, and the flexible multi-channel microelectrode array chip is arranged in the hollow circular tube shape; the radial size of the circular tube is matched with that of the flexible multi-channel microelectrode array chip, the flexible multi-channel microelectrode array chip is composed of low-modulus PDMS and liquid metal, and the PCB adapter is fixed below the chip. By using the insulating elastomer and the liquid metal electrode, the problems of mismatched substrate rigidity, low signal quality, complicated preparation and the like in the traditional technology are solved, and a more accurate and more stable detection tool is provided for research on cardiovascular disease mechanisms.

Description

Technical Field

[0001] The present invention relates to the technical field of electrophysiological sensing detection, and in particular to a soft multi-channel microelectrode array device. Background Art

[0002] Cardiovascular disease (CVD) has become the most common public health hazard in human society, resulting in more than 17 million deaths each year, accounting for approximately 31% of the total global death toll. In order to explore the pathogenesis of CVD for further scientific prevention and treatment, researchers are committed to studying the physiological characteristics of living animals, engineered tissues, and isolated and cultured cardiomyocytes in vitro. The electrocardiogram (ECG) of living animals is non-invasive and highly clinically relevant. However, the ECG signal has low resolution and is easily interfered with by external factors, which is insufficient for accurate exploration of the pathogenesis. On the other hand, isolated and cultured cardiomyocytes in vitro are conducive to high-resolution and high-throughput research on cardiac physiology and are low-cost, ideal in vitro models.

[0003] Patch clamping, voltage-sensitive dyes or voltage-sensitive fluorescent proteins, and microelectrode arrays are currently the most commonly used techniques for measuring cardiomyocyte electrophysiology. Patch clamping is the gold standard for measuring intracellular action potentials. However, its precise positioning imposes a high barrier to entry for users, and its invasive nature hinders long-term, stable recording of signals. Voltage-sensitive dyes or voltage-sensitive fluorescent proteins are alternative tools for achieving high-resolution transmembrane potential recordings, but their performance is limited by phototoxicity, pharmacological side effects, or low expression efficiency of optogenetic reporter genes. With the development of advanced micro- and nanofabrication technologies, microelectrode arrays (MEA) can be fabricated to efficiently record cardiomyocyte electrophysiology in vitro in a noninvasive, long-term, and high-throughput manner. In 1972, Thomas's group first designed a MEA array and successfully detected extracellular electrical signals in cultured chick embryonic cardiomyocytes. They fabricated a 15×2 electrode array by depositing an Au / Ni composite metal layer on a glass substrate and using photoresist as a passivation layer. In recent years, Hu Ning and others have also developed ZnO nanobranched microelectrode arrays on glass substrates to achieve intracellular recordings in primary rat cardiomyocytes.

[0004] However, compared to the human environment in which cardiomyocytes reside—cardiomyocytes are embedded in an extracellular matrix (ECM) characterized by glycosaminoglycans, proteoglycans, collagen, laminarin, and fibronectin—rigid substrates have a much greater Young's modulus than the ECM, which impacts the physiological properties of the cells. Furthermore, information about the physiological properties of cardiomyocytes collected on rigid substrates (such as quartz glass, silicon wafers, and PET) cannot accurately reflect the mechanisms of cardiovascular disease progression. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems and provide a flexible multi-channel microelectrode array device.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] The present invention provides a soft multi-channel microelectrode array device, comprising a hollow myocardial cell culture chamber, a soft multi-channel microelectrode array chip and a PCB adapter arranged in sequence from top to bottom, wherein the soft multi-channel microelectrode array chip is fixed at the center of the PCB adapter.

[0008] The cardiomyocyte culture chamber is a hollow, cylindrical tube whose radial dimensions are compatible with the flexible multi-channel microelectrode array chip. It is fixed to the center of the flexible multi-channel microelectrode array chip, with the latter's surface serving as the bottom of the hollow chamber. Cardiomyocytes are seeded into the chamber and cell culture medium is added through the exposed upper bottom surface.

[0009] The soft multi-channel microelectrode array chip is composed of low-modulus PDMS and liquid metal. The former serves as a soft substrate, with a modulus close to that of human tissue and much smaller than that of materials such as quartz glass, silicon wafers, and PET. The latter serves as the electrode material. Using 3D printing technology, several electrode sites are printed in a dot matrix at the center of the substrate, and several electrode leads are evenly formed along the circumference. Each electrode lead is insulated from each other. 3D printing is then used again to cover all areas except the sensing sites and the tail electrode leads with the insulating low-modulus PDMS.

[0010] The upper surface of the PCB adapter has several lead channels, the number of which is consistent with the number of electrode leads and is connected one by one to the electrode leads on the soft multi-channel microelectrode array chip through conductive silver paste; the other end of the lead channel is connected to the pin header welded on the edge.

[0011] The present invention also provides a method for preparing a flexible multi-channel microelectrode array device chip, comprising the following steps:

[0012] Step S1: taking a silane prepolymer and a curing agent, mixing them in proportion and adding them to the PDMS prepolymer to mix evenly, removing bubbles under vacuum, and then spin-coating on a glass substrate and heating and curing to obtain a low modulus PDMS film;

[0013] Step S2: using the low modulus PDMS film in step S1 as a substrate, constructing a gallium-based liquid metal microelectrode array on the surface of the substrate using 3D printing technology;

[0014] Step S3: Following the operation of step S1, take the same mixing ratio as in step S1, remove bubbles under vacuum, and then print the PDMS prepolymer on all areas except the sensing area and the tail electrode lead using 3D printing technology, and heat and cure.

[0015] Compared with the existing technology, the beneficial effects of this solution are: the present invention uses insulating elastomers and liquid metal electrodes to solve the problems of substrate rigidity mismatch, low signal quality, and complex preparation in traditional technologies, providing a more accurate and stable detection tool for the study of cardiovascular disease mechanisms. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 2 is a schematic diagram of a flexible multi-channel microelectrode array device according to an embodiment of the present invention;

[0017] Figure 2 The mechanical properties of the PDMS films prepared in different proportions in the embodiments of the present invention;

[0018] Figure 3 In the embodiment of the present invention.

[0019] Figure: 1. Hollow cardiomyocyte culture chamber; 2. Flexible multi-channel microelectrode array chip; 3. PCB adapter. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described in detail below in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0021] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0022] Example:

[0023] A method for preparing a flexible multi-channel microelectrode array chip comprises the following steps:

[0024] (1) Mixing silane prepolymer and curing agent in proportion or adding a certain amount of surfactant to PDMS prepolymer and mixing them evenly, removing bubbles under vacuum, then spin coating on a glass substrate and heating to cure to obtain a low modulus PDMS film;

[0025] (2) using the film described in (1) as a substrate, and constructing a gallium-based liquid metal microelectrode array on the surface of the substrate using 3D printing technology;

[0026] (3) Obtain the same PDMS prepolymer as in (1), print the PDMS prepolymer on all areas except the sensing area and the tail electrode lead using 3D printing technology, and heat and cure;

[0027] At this point, according to the above three steps, the gallium-based liquid metal microelectrode array is encapsulated between two layers of PDMS layers with the same modulus, and the soft multi-channel microelectrode array chip is prepared;

[0028] The present invention adjusts the modulus of the PDMS film by adjusting the ratio of silane prepolymer to curing agent or by adding a surfactant, thereby achieving a soft environment similar to the extracellular matrix. This is more conducive to the growth of myocardial cells compared to traditional quartz glass and silicon wafer substrate materials. As the ratio of silane prepolymer to curing agent increases, the Young's modulus of the PDMS film decreases, because a small amount of curing agent content leads to a lower cross-linking density. Similarly, adding a small amount of surfactant to the PDMS prepolymer causes the surfactant to wrap around the surface of the curing agent, reducing the contact between the curing agent and the silane prepolymer, thereby also leading to a decrease in the cross-linking density during the curing process, and thus causing a decrease in the Young's modulus of the PDMS film. In addition, due to the decrease in modulus, the surface viscosity of the cured PDMS film increases, which is conducive to the printing of liquid metal on the surface of the PDMS film.

[0029] In this embodiment, the modulus of the PDMS film is adjusted by adjusting the ratio of silane prepolymer to curing agent.

[0030] PDMS films with different ratios of silane prepolymer to curing agent (15:1, 20:1, 30:1) were prepared experimentally. Mechanical stretching machine tests showed that the PDMS film prepared at a ratio of 30:1 had a modulus similar to that of the heart (~60 kPa, see for detailed data). Figure 2 ), which provides a growth environment similar to that of the human body for the cultivation of cardiomyocytes.

[0031] Impedance is one of the parameters that characterize the characteristics of electronic devices. Here, we use an electrochemical workstation to test a multi-channel microelectrode array device. Figure 3 The 3D-printed gallium-based liquid metal microelectrode array has low impedance, thanks to the high conductivity of liquid metal. Low impedance can reduce signal attenuation and distortion during transmission, thereby improving signal quality and accuracy.

[0032] The above specific embodiments are merely explanations of the present invention and are not limitations of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the embodiments as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A flexible multi-channel microelectrode array device, characterized in that: It includes a hollow cardiomyocyte culture chamber, a flexible multi-channel microelectrode array chip, and a PCB adapter arranged from top to bottom: The hollow myocardial cell culture chamber is in the shape of a hollow circular tube, and the radial dimensions of the circular tube are adapted to the flexible multi-channel microelectrode array chip. The hollow myocardial cell culture chamber is fixed at the center of the flexible multi-channel microelectrode array chip, and the surface of the latter serves as the bottom surface of the hollow cavity. Myocardial cells are seeded into the hollow cavity through the exposed upper bottom surface, and cell culture medium is added. The soft multi-channel microelectrode array chip is composed of low-modulus PDMS and liquid metal. The low-modulus PDMS serves as a soft substrate. The Young's modulus of the soft substrate is close to that of the extracellular matrix (60±10kPa) by adjusting the ratio of silane prepolymer to curing agent or adding a surfactant. The liquid metal serves as electrodes. The electrodes include a dot matrix electrode site located at the center of the substrate and electrode leads evenly distributed around the circumference. The electrodes are formed using 3D printing technology and covered with an insulating PDMS layer to encapsulate the non-sensing area and the lead ends. The PCB adapter is fixed under the chip, and a conductive channel matching the number of electrode leads is provided on the upper surface. The conductive channels are connected to the electrode leads through conductive silver paste, and pins are welded at the ends of the channels to output electrical signals.

2. The flexible multi-channel microelectrode array device according to claim 1, wherein: The Young's modulus of the low modulus PDMS is preferably 60 kPa, and is prepared by mixing a silane prepolymer and a curing agent in a mass ratio of 30:

1.

3. The flexible multi-channel microelectrode array device according to claim 1, wherein: The liquid metal is gallium or a gallium alloy.

4. A method for preparing a flexible multi-channel microelectrode array device chip, characterized in that: The following steps are involved: Step S1: taking a silane prepolymer and a curing agent, mixing them in proportion and adding them to the PDMS prepolymer to mix evenly, removing bubbles under vacuum, and then spin-coating on a glass substrate and heating and curing to obtain a low modulus PDMS film; Step S2: using the low modulus PDMS film prepared in step S1 as a substrate, constructing a gallium-based liquid metal microelectrode array on the surface of the substrate using 3D printing technology; Step S3: Following the operation of step S1, take the same mixing ratio as in step S1, remove bubbles under vacuum, and then print the PDMS prepolymer on all areas except the sensing area and the tail electrode lead using 3D printing technology, and heat and cure.

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