Organ-like electrophysiological signal acquisition electrode

Abstract

The invention discloses an organ-like electrophysiological signal acquisition electrode, and relates to the technical field of biomedical engineering and microelectronics crossing, the organ-like electrophysiological signal acquisition electrode comprises a dynamic reconfigurable blade assembly and a high-density distributed electrode system, the dynamic reconfigurable blade assembly is composed of at least eight independent flexible blades, and each blade is of a multi-layer heterostructure; in the body fluid, controllable degradation of the sacrificial material and predetermined deformation of the stress response layer are utilized to automatically surround and fit similar organs with different sizes to form a conformal electric contact interface; the latter is integrated with not less than 120 micro electrode units which are arranged on the inner side and the outer side of the blade in a non-uniform topology mode, and synchronous collection and spatial distribution imaging of all-domain electrophysiological signals of the similar organs are achieved. According to the invention, a dynamic reconfigurable assembly with not less than eight flexible blades is adopted, and 0.3-2.5 mm organs are adapted by virtue of degradation of sacrificial materials and deformation of stress films, so that the 1t pressure is controlled; 5mN; 120 + electrodes are non-uniformly arranged, and a signal module is arranged to synchronously acquire and image in the whole domain; the compatibility of the packaging layer and surface treatment is improved, and the problems of narrow adaptation, easy damage, long-term monitoring failure and the like in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of biomedical engineering and microelectronics interdisciplinary technology, specifically to an organoid electrophysiological signal acquisition electrode. Background Technology

[0002] Organoids, as three-dimensional in vitro models simulating the physiological structure and function of human organs, have demonstrated irreplaceable value in fields such as drug screening, regenerative medicine research, and the analysis of disease pathogenesis. Electrophysiological signals, as core indicators reflecting the functional state of organoid cells, require precise, comprehensive, and non-invasive acquisition, which is a crucial prerequisite for evaluating drug efficacy and diagnosing pathological conditions. Therefore, organoid electrophysiological signal acquisition electrodes have become a research hotspot in related technological fields.

[0003] Currently, organoid electrophysiological signal acquisition mainly relies on traditional microelectrode arrays, flexible thin-film electrodes, and puncture electrodes. Among them, traditional microelectrode arrays mostly use rigid substrate designs. Although they have a certain degree of signal acquisition accuracy, they cannot adapt to the three-dimensional curved morphology of organoids, making it difficult to form tight conformal electrical contacts, resulting in severe signal transmission attenuation. Furthermore, they have extremely poor adaptability to organoids of different sizes (e.g., 0.3 mm to 2.5 mm). Flexible thin-film electrodes, while improving adhesion to some extent, lack autonomous reconfiguration capabilities and require manual adjustment of position. This operation is cumbersome, and improper control of adhesion pressure (usually exceeding 5 mN) can easily cause damage to the surface or internal structure of the organoid, limiting their application in long-term monitoring of living organoids.

[0004] In terms of electrode system design, existing technologies have significant shortcomings: First, the electrode density is low, with most solutions integrating fewer than 50 electrode units and employing a uniform arrangement. This lack of differentiation in design for signal acquisition between functional and non-functional regions of organoids results in a lack of spatial distribution information for the entire electrophysiological signal range, failing to meet the core requirements of "comprehensive acquisition and accurate identification." Second, the electrodes are functionally limited, lacking functional divisions for surface sensing, deep monitoring, and reference calibration. This prevents the simultaneous capture of multi-dimensional signals such as field potential, transmembrane current, and intracellular action potential. Furthermore, the reference electrode potential has poor stability and is susceptible to interference from the body fluid environment, leading to signal reference drift. Third, the biocompatibility and protective properties of the electrode surface are insufficient. The encapsulation layer often uses conventional polymer materials with weak resistance to non-specific protein adsorption. Prolonged immersion in cell culture medium can easily lead to cation and anion permeation, resulting in increased electrode impedance and signal acquisition failure. Simultaneously, the electrode surface lacks effective functional modifications, resulting in poor cell adhesion and further impacting signal transmission efficiency.

[0005] In the signal processing stage, existing acquisition systems mostly rely on external signal processing equipment, which suffers from problems such as large signal transmission delay (usually exceeding 50μs), difficulty in eliminating baseline drift (generally greater than ±10mV), and low action potential classification accuracy (less than 85%), making it impossible to achieve real-time and accurate analysis of electrophysiological signals. In addition, existing electrode systems mostly do not integrate wireless power supply and data transmission units, resulting in complex wiring that is prone to cross-contamination, poor operation convenience, and difficulty in meeting the widespread application requirements of high-throughput drug screening scenarios.

[0006] In summary, existing organoid electrophysiological signal acquisition electrodes have significant shortcomings in terms of structural adaptability, non-invasive fitting, signal acquisition integrity, long-term stability, and ease of operation, which severely restrict the industrial application of organoid technology in related fields. Therefore, it is urgent to develop an organoid electrophysiological signal acquisition electrode with self-adaptation capability, high biocompatibility, and precise global acquisition and real-time signal processing functions to solve the bottleneck problems faced by existing technologies. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an organoid electrophysiological signal acquisition electrode. This invention uses a dynamically reconfigurable component with no less than eight flexible blades to adapt to 0.3-2.5mm organoids through sacrificial material degradation and stress membrane deformation, with controlled pressure <5mN; 120+ electrodes are non-uniformly arranged in three categories, and equipped with a signal module to achieve synchronous acquisition and imaging across the entire domain; the encapsulation layer and surface treatment improve compatibility and solve problems such as narrow adaptation, easy damage, and long-term monitoring failure in existing technologies.

[0008] To address the aforementioned technical problems, this invention provides the following technical solution: an organoid electrophysiological signal acquisition electrode, mainly composed of a dynamically reconfigurable leaf assembly, a high-density distributed electrode system, an integrated signal processing module, and a wireless power supply and data transmission unit. The various components work together to achieve accurate signal acquisition. Specific technical details have been verified as feasible through multiple experiments, as described below: The dynamically reconfigurable blade assembly consists of 8 to 12 independent flexible blades. Experiments have shown that 8 blades are sufficient to meet the requirements for full coverage of the organoid surface, while a number exceeding 12 significantly increases assembly complexity. Each blade employs a multi-layered heterogeneous structure design, which was determined through three layer sequence adjustments to simultaneously achieve flexibility, conductivity, and biocompatibility. The specific structure of each layer from top to bottom is as follows: Flexible material substrate: It is prepared by mixing polydimethylsiloxane (PDMS) and silica nanoparticles at a mass ratio of 9:1. This ratio was determined after 5 component adjustments. It can ensure that the substrate has a Young's modulus of 0.1MPa to 1MPa to meet the flexibility requirements, while avoiding excessive deformation of the single PDMS material. The substrate thickness is controlled between 10μm and 30μm. The actual measurement shows that the blade can bend 1000 times without breaking when the thickness is 20μm. In the preparation process, it can be formed by casting and curing at 80℃ for 2 hours. Sacrifice triggering medium: Two types are available: magnesium-zinc binary alloy or temperature-sensitive gelatin-sodium alginate blend hydrogel. The magnesium-zinc binary alloy is prepared at an atomic ratio of 7:3 and can be completely dissolved in standard cell culture medium within 5 to 20 minutes. In actual testing, the dissolution rate was the most stable and there was no residue at 10 minutes. The gelatin-sodium alginate hydrogel is mixed at a mass ratio of 6:4 and requires incubation at 37°C to trigger degradation. It can be completely dissolved within 15 minutes. The thickness of both media is controlled between 5 μm and 10 μm. Too thick a medium will prolong the degradation time, while too thin a medium is prone to premature breakage. Stress-modulated film: Liquid crystal elastomers with shape memory effect or double-crosslinked polyvinyl alcohol hydrogels are selected. The phase transition temperature of the liquid crystal elastomer is controlled between 36℃ and 38℃, and the shrinkage strain can reach 55% at 37℃, which can adapt to the conventional culture temperature of human organoids. The polyvinyl alcohol hydrogel has a volume change rate of 300% in the pH range of 6.5 to 7.5, and the deformation is more uniform when attached to organoids. The film thickness is 8μm to 10μm, and it can be formed by spin coating followed by UV curing for 30 seconds. Insulating support skeleton: Nanoporous polyimide or photocurable SU-8 epoxy resin polymer is used. The preparation of nanoporous polyimide requires polyamic acid as a precursor, with 5% by mass of lithium tert-butoxide added as a pore-forming agent. After casting, imidization is carried out in a stepwise temperature program of 100℃ / 1 hour, 200℃ / 1 hour, and 300℃ / 2 hours. Finally, it is dried by supercritical carbon dioxide. The measured porosity of polyimide prepared by this process is 60% to 80%. The best balance between insulation and flexibility is achieved at 70% porosity. The dielectric constant is ≤3.0 (the measured value is 2.8 at 1kHz), and the breakdown electric field strength is ≥200 volts / micrometer. Internal wiring network: A conductive mesh is formed using gold and silver core-shell nanowires, requiring a sheet resistance of less than 10 ohms / cube (signal transmission loss is less than 3% when measured at 8 ohms / cube) and an elongation at break greater than 150% to avoid wire breakage during folding. Three fabrication methods can be selected: First, a silver nanowire suspension with polyvinyl alcohol as a template is directly written onto an insulating support skeleton using microfluidic inkjet printing technology, followed by annealing at 150℃ in an argon atmosphere for 30 minutes; second, a circuit pattern is generated on the polyimide surface using femtosecond laser-induced graphene technology, with a minimum linewidth of 5μm; third, a gold-indium tin oxide stack is magnetron sputtered onto a pre-stretched 300% thermoplastic polyurethane film, and a meandering structure is formed after releasing the prestress to improve flexibility. Encapsulation protective layer: It is prepared by vapor deposition process using fluorinated polymers (such as fluorinated ethylene propylene copolymer), with the thickness controlled between 1μm and 5μm. At a thickness of 3μm, it can achieve the function of resisting non-specific protein adsorption without affecting the overall flexibility of the leaf. After being immersed in cell culture medium for 72 hours, the surface protein adsorption amount of this protective layer is less than 5nm, and it can effectively prevent the penetration of anions and cations. Surface contact electrode array: Using iridium oxide semiconductor or nitrogen-doped diamond thin film, it is processed into a micron-scale columnar structure by reactive ion etching process. The diameter of a single electrode is 15μm, and the tolerance is controlled within ±2μm to ensure a moderate contact area with the organoid surface. The impedance amplitude at 1000 Hz frequency is ≤100 kΩ (the signal sensitivity is best when measured at 80 kΩ). During the processing, burrs must be avoided at the electrode edges to prevent damage to the organoid surface cells.

[0009] The regulatory mechanism of leaf autonomous folding is a key step in avoiding mechanical damage to organoids. After two iterations of the regulatory scheme, the following mechanism was determined, and experimental results showed that the instantaneous pressure on the organoid surface can be stably controlled between 3mN and 5mN: Nonlinear stiffness micro torsion hinge: A micro torsion hinge is installed at the root of each blade. The restoring torque and the rotation angle are related by the function M=k1θ+k3θ³, where k1 and k3 are coefficients. The coefficients need to be calibrated by finite element simulation (using ANSYS software) and live organoid creep experiment. For example, for the adaptation scenario of myocardial organoid, k1=0.02N・m / rad and k3=0.005N・m / rad³ are determined by calibration. This parameter can effectively avoid overshoot during the folding process. Gap feedback sensor: An infrared photoelectric pair or a piezoresistive strain sensor is installed between adjacent blades. The infrared photoelectric pair has a detection accuracy of up to 0.01mm. The sensor is connected to a closed-loop control system (using an STM32 microcontroller) to monitor the change in blade gap in real time. When the gap is less than 0.1mm, the control system automatically reduces the folding speed from the initial 0.3mm / s to 0.1mm / s to ensure the tightness of the wrapping between the blade and the organoid. Bézier curve folding trajectory: A Bézier curve is generated using MATLAB software as the folding trajectory of the blade. The trajectory parameters are input into the control system. The actual measurement shows that this trajectory can stabilize the blade bending radius between 0.1 mm and 2 mm, which can be adapted to organoids of different sizes, while avoiding the problem of local pressure concentration caused by zigzag folding.

[0010] Functional optimization of key structures: The core structure is functionally optimized to meet the needs of different experimental scenarios, thereby solving specific problems in practical applications. Degradation Modulation of Sacrifice-Triggered Media: Three intervention methods were designed to adapt to different experimental needs. The first is a rapid degradation scenario, in which 5 mmol / L of disodium ethylenediaminetetraacetate (EDTA-2Na) is added to the cell culture medium, which can shorten the degradation time to 5 minutes. The second is a site-specific degradation scenario, in which the area of ​​the sacrificial layer carrying carbon nanospheres is irradiated with a near-infrared laser with a wavelength of 808 nm, and the local temperature is raised to 40 °C to accelerate degradation. The third is a precise control scenario, in which the local temperature of the sacrificial layer is raised to 45 °C to 50 °C within a millisecond timescale by a micro-film heating resistor integrated on the leaf, so as to achieve thermal ablation and removal without affecting the surrounding tissue. Intelligent response of stress-regulated films: The response mode is selected according to the experimental environment. In the case of constant temperature culture (37℃), the temperature-sensitive liquid crystal elastomer is selected, which can achieve deformation without additional stimulation; in the case of pH fluctuation environment (such as the pH of tumor organoid culture medium of 6.5 to 7.2), the pH-sensitive dual network hydrogel is selected, which triggers volume deformation through pH change; in the case of precise in vitro control, the photocrosslinked shape memory polymer is selected, which can recover the preset shape within 10 seconds after being irradiated by ultraviolet light. Functionalization of surface contact electrode arrays: Signal stability and biocompatibility are improved through three methods. First, when it is necessary to reduce electrode impedance, a PEDOT:PSS conductive polymer layer is deposited on the electrode surface using an electropolymerization process, which can further reduce impedance by 20%. Second, when it is necessary to enhance signal capture capability, a vertically oriented boron nitride nanosheet array is grown on the electrode working interface through plasma-enhanced chemical vapor deposition, increasing the contact area between the electrode and the cell. Third, when it is necessary to promote cell adhesion, RGD peptides are fixed on the electrode tip region using microcontact printing technology, which can improve the adhesion between organoids and electrodes by 30%.

[0011] A high-density distributed electrode system integrates no fewer than 120 microelectrode units; the actual design uses 192 electrodes to meet the requirements of full-domain acquisition. The electrodes adopt a non-uniform topological arrangement, with denser arrangement in organoid functional regions (such as the contractile region of cardiac organoids and the neuron-rich region of brain organoids) at a spacing of 50 μm; and sparse arrangement in non-functional regions at a spacing of 100 μm. The electrodes are divided into three categories according to function, and the measured results show that the three types of electrodes working together can cover 98% of the signal acquisition requirements. Surface sensing electrodes: Located on the innermost side of the leaf, directly in contact with the organoid surface, mainly used to collect field potential (amplitude 5mV to 20mV) and transmembrane current, with a response time of less than 10 microseconds for a single electrode; Deep monitoring electrode: buried in the middle layer of the leaf, 5μm away from the surface, it captures intracellular action potentials (amplitude 1mV to 5mV) based on the principle of capacitive coupling, without the need for direct cell puncture, thus avoiding damage to organoids; Reference electrode: Distributed on the outer edge of the blade, with a silver chloride functional layer on the surface, it is used to provide a stable potential reference with potential fluctuation of less than 1mV to ensure the accuracy of signal acquisition.

[0012] The integrated signal processing and transmission unit includes an integrated signal processing module fabricated using CMOS technology with a chip size of 2mm × 2mm to meet the miniaturization requirements of the electrodes. The module comprises four core units: an adaptive bias correction circuit with a correction range of ±10mV, which can effectively eliminate signal baseline drift; a 16Kb on-chip data buffer that can temporarily store the acquired signals within 10 minutes to avoid data loss; a real-time action potential classification processor based on a convolutional neural network with a classification accuracy of over 95%, which can quickly distinguish different types of electrophysiological signals; and a 100Hz to 1MHz impedance spectrum scanning unit that scans every 5 minutes to monitor the contact status between the electrodes and the organoids in real time. Wireless power supply and data transmission unit: Adopting Bluetooth 5.0 protocol, the transmission rate can reach 1Mbps, which can meet the needs of real-time signal transmission; the power supply is 10mW, which does not require an external power source. It is powered by a micro lithium battery (capacity 100mAh, voltage 3.7V), and the battery life is more than 48 hours.

[0013] Compared with existing technologies, this organoid electrophysiological signal acquisition electrode has the following advantages: I. This invention utilizes a dynamically reconfigurable component consisting of no fewer than eight independent flexible blades. By taking advantage of the controllable degradation characteristics of sacrificial materials in a body fluid environment within 5-20 minutes, combined with a linear contraction strain of no less than 50% generated by a stress-controlled film, it can automatically surround and conform to organoids with dimensions ranging from 0.3 to 2.5 mm, forming a gapless conformal electrical contact interface. Simultaneously, by setting a nonlinear stiffness micro-torsional hinge with a recovery torque coefficient calibrated through finite element simulation and live organoid creep experiments at the root of the blades, and installing infrared photoelectric pairs or piezoresistive strain sensors between adjacent blades for real-time gap monitoring, combined with the folding trajectory generated by Bezier curves, the instantaneous maximum pressure on the organoid surface can be strictly controlled below 5 mN, solving the problems of narrow applicability and easy damage to organoids in existing technologies.

[0014] II. The high-density distributed electrode system of this invention integrates no fewer than 120 microelectrode units, arranged in a non-uniform topology, with a spacing of 50 μm between electrodes in the organoid functional region and 100 μm between electrodes in the non-functional region. It is clearly divided into three types of electrodes: surface sensing electrodes directly contact the organoid to collect field potentials and transmembrane currents, with a response time of less than 10 μs; deep monitoring electrodes are embedded in the middle layer of the leaf, capturing intracellular action potentials through capacitive coupling, eliminating the need for organoid puncture; and reference electrodes are distributed on the outer periphery of the leaf, covered with a silver chloride functional layer, with potential fluctuations controlled within 1 mV to ensure stable signal acquisition. Furthermore, it is coupled with an integrated signal processing module including an adaptive bias correction circuit and a convolutional neural network real-time action potential classification processor. The adaptive bias correction circuit can eliminate ±10 mV baseline drift, and the classification processor has an accuracy exceeding 95%, enabling synchronous acquisition of electrophysiological signals across the entire organoid domain with a signal synchronization delay of less than 10 μs. Simultaneously, it completes spatial distribution imaging of the signal, meeting the requirements for comprehensive signal acquisition and accurate feature identification during drug screening.

[0015] Third, this invention prepares a 1-5 μm thick encapsulation and protective layer through a fluorinated polymer vapor deposition process, which can control the non-specific adsorption of surface proteins to below 5 nm, while effectively preventing the penetration of anions and cations. By performing functionalization treatments such as electropolymer deposition of conductive polymer layers, growth of vertically oriented boron nitride nanosheet arrays, or immobilization of RGD peptides on the electrode surface, biocompatibility is further improved, and the practical problems of easy failure and complex operation of existing technologies in long-term monitoring are completely solved.

[0016] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0018] Figure 1 A flowchart illustrating the dynamic reconfigurable leaf-based autonomous attachment of organoid electrophysiological signal acquisition electrodes to organoids. Figure 2 Flowchart of high-density distributed electrode signal acquisition and processing for organoid electrophysiological signal acquisition electrodes; Figure 3 A flowchart illustrating the degradation regulation of the sacrificial triggering medium for organoid electrophysiological signal acquisition electrodes. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0020] Example 1: Electrode for acquiring electrophysiological signals of myocardial organoids based on magnesium-zinc binary alloy sacrificial layers Flexible blade preparation: For the flexible material substrate, PDMS and silica nanoparticles were mixed at a mass ratio of 9:1 and degassed for 20 minutes under a vacuum of -0.095MPa to avoid residual bubbles. Then, the mixture was cast into a film with a thickness of 20μm and cured in an 80℃ oven for 2 hours. After curing, the film was cut into 1mm×5mm blade substrates.

[0021] Sacrifice triggering medium: A magnesium-zinc alloy with an atomic ratio of 7:3 is used. It is deposited on the surface of a flexible substrate by magnetron sputtering. The sputtering power is set to 100W, the time is 5 minutes, and the film thickness is controlled to be 5μm. During the process, the sputtering rate needs to be controlled at 1μm / min to avoid film peeling.

[0022] Stress-controlled film: A temperature-sensitive liquid crystal elastomer with a phase change temperature of 37℃ was selected and coated onto the surface of the sacrificial layer by spin coating at a speed of 3000 rpm for 30 seconds, with a thickness of 8 μm. It was then cured with ultraviolet light at a wavelength of 365 nm and a power of 10 mW / cm² for 30 seconds.

[0023] Insulating support skeleton: Polyamic acid is used as a precursor, and 5% by mass of lithium tert-butoxide pore-forming agent is added. The film thickness is controlled at 12μm by casting. The polyimide is imidized by step temperature increase program of 100℃ / 1 hour, 200℃ / 1 hour, and 300℃ / 2 hours. Finally, it is dried by supercritical carbon dioxide under 10MPa pressure and 40℃ temperature. The measured porosity of the polyimide is 70% and the dielectric constant is 2.8.

[0024] Internal wiring network: A silver nanowire suspension with a concentration of 5 mg / mL was prepared and directly written onto the surface of the insulating support skeleton using microfluidic inkjet printing technology. The inkjet nozzle diameter was 50 μm and the flow rate was 1 μL / min. After completion, it was placed in an argon atmosphere furnace at 150℃ for annealing for 30 minutes. The measured sheet resistance was 8 ohms / block and the elongation at break was 160%.

[0025] Encapsulation protective layer: Fluorinated ethylene propylene copolymer is deposited on the surface of the wiring network by vapor deposition process at a deposition temperature of 80℃ and a pressure of 0.1MPa, with a controlled thickness of 3μm. Tests show that after the protective layer is immersed in the culture medium for 72 hours, the surface protein adsorption thickness is only 3nm.

[0026] Surface contact electrode array: Iridium oxide semiconductor is processed into a micron pillar structure with a diameter of 15μm by reactive ion etching process with an etching power of 50W and a time of 10 minutes. Then, a PEDOT:PSS layer is deposited by electropolymerization process with an electropolymerization voltage of 0.8V and a time of 5 minutes. The measured impedance at 1000Hz is 75 kΩ.

[0027] Folding control component assembly: Torque hinge installation: A miniature torsion hinge made of titanium alloy with a thickness of 10μm was attached to the root of each blade. Finite element simulation was performed using ANSYS software, and creep experiments were conducted using myocardial organoids as samples. The applied force ranged from 0.1mN to 1mN, and the joint calibration of the restoring torque function coefficients was k1=0.02N・m / rad and k3=0.005N・m / rad³.

[0028] Sensor and control system connection: GP2Y0A21YK infrared photodiodes are installed between adjacent blades and connected to a closed-loop control system composed of an STM32F103 microcontroller. The gap threshold is set to 0.1mm. When the gap is detected to be less than 0.1mm, the microcontroller outputs a signal to reduce the speed of the folding motor from 0.3mm / s to 0.1mm / s.

[0029] Folding trajectory input: Bézier curves are generated using MATLAB software, with control points at (0,0), (0.5,1), and (1,0.5). The trajectory parameters are then imported into the control system. The measured radius of curvature of the blade is stable at 1 mm, which is suitable for myocardial organoids with a diameter of 1 mm.

[0030] High-density electrode system integration: Electrode arrangement and connection: 12 surface sensing electrodes with a spacing of 50μm and 8 deep monitoring electrodes with a spacing of 50μm are set on the inner working surface of each blade. 4 reference electrodes with a spacing of 100μm are set on the outer edge, for a total of 192 electrodes. The electrodes are connected to the internal wiring network using an ultrasonic bonding process with a power of 5W and a time of 1 second. Tensile testing shows that the connection strength exceeds 0.5N, ensuring no risk of detachment.

[0031] Signal processing and transmission unit integration: Signal processing module soldering: A 2mm×2mm CMOS signal processing chip is bonded to the internal wiring network using a gold wire bonding process with a gold wire diameter of 25μm. The chip is then encapsulated in an electrode base made of PDMS material to ensure protection performance. The electrode base is 1mm thick.

[0032] Wireless unit integration: The nRF52832 Bluetooth 5.0 module is electrically connected to the signal processing module. A 100mAh, 3.7V micro lithium battery is used as the power supply module. Tests show that the wireless transmission rate is 1Mbps and the battery life exceeds 48 hours.

[0033] Performance testing: Using a 1mm diameter cardiac organoid as the test sample, the test results are as follows: Adaptability test: When the electrode was placed in the cell culture medium containing organoids, the magnesium-zinc alloy sacrificial layer completely dissolved within 10 minutes, the leaf automatically folded and adhered to the organoid, and microscopic observation showed that the contact gap was 0.03 mm, and the morphology of the organoid remained unchanged.

[0034] Signal acquisition test: Field potential signals of myocardial organoids were acquired, with an amplitude range of 8mV to 15mV, a signal-to-noise ratio of 35dB, a global signal synchronization delay of 8μs, and spatial distribution imaging that clearly showed the signal intensity differences in the organoid contraction area.

[0035] Stability test: After 72 hours of continuous data collection, the electrode impedance increased from 75 kΩ to 78 kΩ, with a drift amplitude of 4%; under an inverted microscope, the organoid survival rate was 96%, and the contraction frequency remained stable at 60 times / minute, with no abnormal changes.

[0036] Mechanical damage test: The folding process was monitored in real time using an FSH0100 pressure sensor. The maximum pressure on the organoid surface was 3.5 mN, and no cell rupture or morphological abnormalities were observed.

[0037] Example 2: Electrode for acquiring electrophysiological signals from tumor organoids based on a thermosensitive hydrogel sacrificial layer Differences in core structure fabrication: To address the culture characteristics of tumor organoids, the core structure was adjusted as follows: Sacrifice triggering medium: A temperature-sensitive gelatin-sodium alginate blend hydrogel with a mass ratio of 6:4 was used, with 2% calcium chloride added as a crosslinking agent. The coating thickness was 10 μm, and it was completely dissolved in cell culture medium at 37℃ within 15 minutes to avoid the influence of zinc ions on tumor cell activity.

[0038] Stress-regulating film: Acrylamide-sodium alginate dual-network hydrogel with a thickness of 10 μm is selected. The volume change rate reaches 300% in tumor organoid culture medium with pH values ​​of 6.8 to 7.2, ensuring close adhesion to the organoid surface.

[0039] Internal wiring network: Femtosecond laser-induced graphene technology is used to generate circuit patterns on the surface of polyimide. The laser wavelength is 1064nm, the power is 1W, the scanning speed is 100mm / s, and the minimum line width is 5μm, which is suitable for signal acquisition needs of small-sized areas of tumor organoids.

[0040] Surface contact electrode array: Vertically oriented boron nitride nanosheets are grown at the electrode working interface using plasma-enhanced chemical vapor deposition (PECVD) with a plasma power of 100W for 15 minutes, which increases the contact area between the electrode and tumor cells and improves the intracellular signal capture rate.

[0041] Performance testing: Using lung cancer organoids with a diameter of 0.8 mm as test samples, the test results are as follows: Adaptability: After folding, the leaf fits tightly against a 0.8 mm diameter lung cancer organoid with a contact gap of 0.04 mm, and no mechanical damage is observed under a microscope.

[0042] Signal acquisition: Intracellular action potential signals of lung cancer organoids were successfully captured, with an amplitude range of 2mV to 4mV and a signal-to-noise ratio of 32dB. Spatial distribution imaging can clearly locate the proliferation area of ​​tumor organoids.

[0043] Stability: After 96 hours of continuous data collection, the electrode impedance drift was 3.8%, and the organoid survival rate was 95%, meeting the monitoring requirements for long-term drug testing.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An organoid electrophysiological signal acquisition electrode, characterized in that, The electrode includes a dynamically reconfigurable blade assembly and a high-density distributed electrode system; The dynamically reconfigurable blade assembly consists of multiple independent flexible blades, with a total number of no less than eight blades. Each blade is a multi-layered heterogeneous structure. In a body fluid environment, through the controllable degradation of the sacrificial material and the predetermined deformation of the stress response layer, it automatically surrounds and conforms to the outer surface of three-dimensional organoids of different sizes to form a conformal electrical contact interface. The high-density distributed electrode system integrates no less than 120 microelectrode units, which are arranged in a non-uniform topological manner on the inner working surface and the outer bearing surface of each leaf, enabling synchronous acquisition and spatial distribution imaging of the organoid's global electrophysiological signals.

2. The organoid electrophysiological signal acquisition electrode according to claim 1, characterized in that, The multi-layered heterogeneous structure of each flexible blade in the dynamically reconfigurable blade assembly, from top to bottom, includes: Flexible material substrate: The flexible substrate is formed by composite filling of polydimethylsiloxane polymer and silica nanoparticles, with a thickness of 10 micrometers to 30 micrometers and a Young's modulus of 0.1 MPa to 1 MPa. Sacrifice triggering medium: a magnesium-zinc binary alloy or a hydrogel of temperature-sensitive gelatin and sodium alginate, which completely dissolves within five to twenty minutes in a standard cell culture medium environment; Stress-controlled film: It is composed of liquid crystal elastomer material with shape memory effect or double cross-linked polyvinyl alcohol hydrogel. After the sacrificial layer medium is completely dissolved, it generates a linear contraction strain of not less than 50%, which drives the blade to achieve controllable bending deformation with a curvature radius of 0.1 mm to 2 mm. Insulating support frame: Made of nanoporous polyimide material or light-cured SU-8 epoxy resin polymer, with a dielectric constant of not more than 3.0 and a breakdown electric field strength of not less than 200 volts per micrometer; Internal wiring network: a conductive mesh formed by electrospinning of gold and silver core-shell nanowires, with a sheet resistance of less than 10 ohms per square and an elongation at break of more than 150%. Encapsulation and protective layer: It is a dense film formed by vapor deposition of fluorinated polymer, with a thickness of one to five micrometers, which has the ability to resist non-specific adsorption of proteins and prevent the penetration of anions and cations; Surface contact electrode array: a micron-scale columnar structure processed by reactive ion etching of iridium oxide semiconductor or nitrogen-doped diamond film. The diameter of a single electrode is 15 micrometers with a tolerance of ±2 micrometers, and the impedance amplitude does not exceed 100 kiloohms at a frequency of 1 kilohertz.

3. The organoid electrophysiological signal acquisition electrode according to claim 1, characterized in that, The autonomous folding process of the dynamically reconfigurable blade assembly is regulated by the following physical constraints and feedback mechanisms: Each blade has a micro torsion hinge with nonlinear stiffness at its root. Its restoring torque is related to the rotation angle by a function containing first-order and third-order terms. The function coefficients are calibrated by a combination of finite element simulation and live organoid creep experiments. Infrared photoelectric pairs or piezoresistive strain sensors are installed between adjacent blades to monitor the gap and feed back to the closed-loop control system, dynamically adjusting the blade folding speed and final position to achieve optimal wrapping tightness. The blade folding trajectory is generated by a Bezier curve interpolation algorithm to ensure that the instantaneous maximum pressure on the organoid surface is less than five millinewtons throughout the process.

4. The organoid electrophysiological signal acquisition electrode according to claim 2, characterized in that, The degradation process of the sacrificial triggering medium can be modulated by any of the following methods: Adding a specific concentration of disodium ethylenediaminetetraacetate chelating agent or calcium ion compound to the cell culture medium alters the local chemical environment; Local photothermal decomposition was induced by irradiating the sacrificial layer region carrying carbon nanospheres with a near-infrared laser with a wavelength of 808 nanometers. By integrating micro-thin film heating resistors on each blade, the local temperature of the sacrificial layer is raised to 45 to 50 degrees Celsius within a millisecond timescale, achieving thermal ablation removal.

5. The organoid electrophysiological signal acquisition electrode according to claim 2, characterized in that, The material of the stress-modulated thin film can exhibit any of the following smart response modes: Thermosensitive liquid crystal elastomers have a phase transition temperature of 36 to 38 degrees Celsius. After being heated, they undergo controllable shrinkage along the molecular orientation direction. pH-sensitive dual-network hydrogels exhibit a volume change rate of 300% within a pH range of 6.5 to 7.

5. Photocrosslinked shape memory polymers can recover their permanent shape after being exposed to ultraviolet radiation.

6. The organoid electrophysiological signal acquisition electrode according to claim 2, characterized in that, The conductive mesh of the internal wiring network is fabricated using any of the following processes: Silver nanowire suspension with polyvinyl alcohol as template was directly written onto an insulating support skeleton using microfluidic inkjet printing technology, and then annealed at 150 degrees Celsius in an inert atmosphere for 30 minutes. Femtosecond laser-induced graphene technology was used to generate circuit patterns on the surface of polyimide, with a minimum linewidth of five micrometers; A gold-indium tin oxide (ITO) stack is magnetron sputtered onto a pre-stretched 300% thermoplastic polyurethane film to release prestress and form a meandering structure.

7. The organoid electrophysiological signal acquisition electrode according to claim 2, characterized in that, The micron-pillar structure of the surface contact electrode array undergoes any of the following surface functionalization treatments: A PEDOT:PSS conductive polymer layer is electropolymerized and deposited on the electrode surface; Vertically oriented boron nitride nanosheet arrays were grown at the electrode working interface by plasma-enhanced chemical vapor deposition. The RGD peptide was immobilized on the electrode tip region using microcontact printing.

8. The organoid electrophysiological signal acquisition electrode according to claim 2, characterized in that, The nanoporous polyimide material used in the insulating support framework is prepared by the following process: Using polyamic acid as a precursor solution, lithium tert-butoxide is incorporated as a pore-forming agent, and the mixture is cast into a film. The film is then imidized by stepwise heating and dried with supercritical carbon dioxide. The resulting material has a porosity of 60% to 80%, a pore size distribution of 10 to 100 nanometers, and a coefficient of thermal expansion of approximately 3 parts per million per Kelvin.

9. The organoid electrophysiological signal acquisition electrode according to claim 1, characterized in that, The microelectrodes in the high-density distributed electrode system are classified into three categories according to their functions: Surface sensing electrode: Located on the innermost side of the leaf, it directly contacts the organoid to collect field potential and transmembrane current; Deep monitoring electrode: buried in the middle layer of the leaf, it captures intracellular action potentials based on capacitive coupling; Reference electrode: distributed on the outer edge of the blade, with a silver chloride functional layer on the surface.

10. The organoid electrophysiological signal acquisition electrode according to claim 1, characterized in that, The electrode also includes an integrated signal processing module and a wireless power supply and data transmission unit; The integrated signal processing module includes an adaptive bias correction circuit, an on-chip data buffer, a real-time action potential classification processor, and an impedance spectrum scanning unit.

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