Multi-modal real-time evaluation algorithm system for normothermic mechanical perfusion of organs

Abstract

This application relates to the field of biomedical engineering technology and discloses a multimodal real-time assessment algorithm system for organ ambient temperature mechanical perfusion. The system includes a fluid circulation unit, a cross-barrier electrode array unit, and a multimodal control unit. The multimodal control unit executes time-division multiplexing control logic: within the active capture window, the control electrode array generates a dielectrophoretic force pointing towards the biliary tract injury region, driving the engineered organoid to actively target and implant, and simultaneously controlling the fluid circulation unit to enter a residence mode to reduce fluid drag; within the impedance assessment window, the switching circuit acquires the cross-barrier complex impedance signal to calculate the real-time repair index, and restores physiological pulsating flow to screen implantation sites using shear force. This invention solves the problems of low passive diffusion efficiency and unstable implantation of organoids through the synergistic coupling of the flow field and electric field, achieving real-time quantitative monitoring of the biliary barrier repair process.

Description

Technical Field

[0001] This invention relates to the field of biomedical engineering technology, specifically to a multimodal real-time evaluation algorithm system for organ ambient temperature mechanical perfusion. Background Technology

[0002] Liver transplantation is an effective treatment for end-stage liver disease, but the shortage of donor organs and the quality issues of marginal donors have always limited its clinical application. Ischemic biliary tract disease is one of the main causes of graft function loss after liver transplantation, and its pathological feature is necrosis and shedding of bile duct epithelial cells. Normative mechanical perfusion technology provides a platform for the in vitro repair of damaged organs by providing oxygenated blood and nutrients to isolated organs at physiological temperatures. In recent years, the use of engineered bile duct organoids to repair damaged bile duct epithelium has become a research hotspot, but in the actual perfusion repair process, existing methods still face several unresolved technical bottlenecks.

[0003] In terms of cell delivery and colonization, current repair strategies primarily rely on directly injecting suspensions containing organoids into the biliary system, allowing cells to reach the injury site via passive transport through fluid circulation or natural sedimentation due to gravity. However, the hepatobiliary system has a highly complex, multi-level branching structure, and relying solely on passive diffusion results in extremely uneven cell distribution within the lumen. Organoids often accumulate non-specifically in the proximal bile ducts, making it difficult to penetrate deep into the damaged areas of the distal, smaller bile ducts, or to precisely accumulate at specific epithelial defects. This random distribution pattern significantly reduces cell utilization and repair efficiency.

[0004] In terms of fluid dynamics, ambient temperature mechanical perfusion systems require a continuous perfusion flow rate to ensure oxygen supply and metabolic needs of isolated organs. However, continuous fluid flow generates hydrodynamic drag and shear stress on the bile duct wall. In the early stages of organoid colonization, the physical adhesion between cells and the matrix is ​​weak, and normal perfusion flow rates can easily wash away organs that have not yet firmly attached, leading to colonization failure. If perfusion is stopped for an extended period to promote sedimentation, it can cause thermal ischemia injury and microcirculatory congestion in isolated organs. Current technology lacks a dynamic flow field control mechanism that can reconcile the conflict between metabolic oxygen supply requirements and cell mechanical colonization requirements.

[0005] Currently, the assessment of repair effectiveness mainly relies on indirectly judging biliary function by detecting changes in biochemical indicators or glucose and pH levels in bile. These biochemical indicators reflect the metabolic function or damage release of bile duct cells, and their numerical changes have a significant time lag relative to the physical repair of tissue structures. They cannot reflect the formation process of tight junctions between bile duct epithelial cells and the integrity of the physical barrier in real time. Due to the lack of real-time quantitative feedback, operators find it difficult to accurately determine the repair endpoint, which can easily lead to incomplete repair due to insufficient perfusion time, or biliary edema and hydrodynamic damage due to over-perfusion. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a multimodal real-time evaluation algorithm system for organ ambient temperature mechanical perfusion. This system solves the problems of existing organ ambient temperature mechanical perfusion technologies, which lack the means to quantify in real time the colonization efficiency of engineered organoids in the biliary microstructure and the degree of biliary barrier repair, and cannot actively regulate the physical colonization process of organoids in a fluid environment.

[0007] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of the present invention provides a multimodal real-time evaluation algorithm system for organ normothermic mechanical perfusion, the system comprising a fluid circulation unit, a cross-barrier electrode array unit, and a multimodal control unit.

[0008] The fluid circulation unit is equipped with a variable frequency pulsating pump for providing perfusion fluid circulation to the isolated organ and regulating fluid dynamic parameters. The transbarrier electrode array unit includes a vascular-side excitation electrode positioned at the vascular cannulation site of the isolated organ and a bile duct-side sensing electrode inserted retrogradely into the bile duct system of the isolated organ. The vascular-side excitation electrode and the bile duct-side sensing electrode spatially construct a transbarrier electric field loop that penetrates the vessel wall, the Disse gap, and the bile duct epithelium.

[0009] The multimodal control unit is electrically connected to both the fluid circulation unit and the cross-barrier electrode array unit, and executes time-division multiplexing control logic. This time-division multiplexing control logic divides one operating cycle of the system into an active acquisition window and an impedance evaluation window in the time dimension.

[0010] Within the active capture window, the multimodal control unit controls the cross-barrier electrode array unit to generate a high-frequency non-uniform electric field. This high-frequency non-uniform electric field utilizes the distorted electric field distribution characteristics caused by the absence of the epithelial layer in the damaged bile duct region of the ex vivo organ to generate a dielectrophoretic force pointing towards the point of maximum electric field intensity gradient in the physical damage area. This dielectrophoretic force drives the engineered organoid suspended in the perfusion fluid to move directionally towards the physical damage area and aggregate.

[0011] Within the impedance assessment window, the multimodal control unit controls the transbarrier electrode array unit to switch to low-voltage detection mode to acquire the transbarrier complex impedance signal. Based on a series equivalent circuit model, the multimodal control unit extracts the modulus of the transbarrier complex impedance signal at a characteristic frequency. This characteristic frequency is selected as the frequency point where the biological tissue barrier impedance contributes the largest proportion to the total impedance. The multimodal control unit calculates the rate of change of the current modulus relative to the baseline modulus in the unrepaired state as a real-time repair index to quantitatively characterize the integrity of the biliary barrier.

[0012] Furthermore, to address the issue of fluid scouring hindering cell colonization, this invention employs a flow-field-electric-field coordinated control strategy. Within the active capture window, the multimodal control unit controls the variable-frequency pulsating pump to enter a resident oscillation mode, reducing the local fluid velocity flowing through the ex vivo organ to a preset threshold. This control strategy reduces the hydrodynamic drag force acting on the engineered organoid, ensuring that the dielectric electrophoretic force acting on the engineered organoid is greater than the sum of its hydrodynamic drag force and effective gravity, thereby achieving physical capture.

[0013] During the impedance assessment time window, the multimodal control unit controls the variable frequency pulsating pump to return to the physiological pulsating mode, using the restored pulsating flow to generate wall shear stress on the bile duct wall. This wall shear stress is used to remove engineered organoids that have not formed a stable physical connection, thereby screening out effective implantation sites and ensuring the authenticity of subsequent impedance assessment results.

[0014] Furthermore, the multimodal control unit operates a closed-loop feedback adjustment algorithm, adaptively adjusting the duty cycle of the active capture window and the voltage amplitude of the high-frequency non-uniform electric field within the working cycle based on the value and rate of change of the real-time repair index. When the real-time repair index is low, the system executes a fast coverage mode, using a high duty cycle and maximum voltage amplitude to accelerate colonization; when the real-time repair index reaches a preset threshold, the system executes a fine trimming mode, linearly reducing the voltage amplitude and gradually decreasing the duty cycle, increasing the time ratio for impedance assessment and fluid shear screening to optimize repair quality.

[0015] Furthermore, the system may also include an optical tracer verification unit, which monitors the concentration difference of fluorescent tracers on the vascular and bile sides and calculates the apparent bile duct permeability coefficient based on the diffusion law. The system executes dual verification logic, determining successful repair only when the real-time repair index increases and the apparent bile duct permeability coefficient decreases, thereby effectively eliminating false positive impedance signals caused by electrode polarization or bubble interference.

[0016] This invention provides a multimodal real-time assessment algorithm system for organ normothermic mechanical perfusion. It has the following beneficial effects: 1. This invention achieves active targeted repair of damaged areas and electrode space reuse. Through time-division multiplexing control logic, dielectric electrophoretic capture and impedance spectroscopy acquisition tasks are alternately performed on the same set of cross-barrier electrode arrays. Utilizing the physical characteristic that the electrical impedance of the bile duct epithelial loss region is lower than that of intact tissue, the system naturally forms a high-intensity electric field gradient at the injury site, thereby generating a dielectric electrophoretic force pointing towards the damaged area. This mechanism enables engineered organoids to overcome random diffusion in fluid environments, preferentially aggregate and colonize towards physically damaged areas, solving the problem of localized repair within tiny bile duct branches without the need for additional navigation equipment, while simplifying the hardware deployment complexity within ex vivo organs.

[0017] 2. This invention resolves the mechanical contradiction between fluid perfusion and cell colonization by establishing a collaborative control model of the flow field and electric field, strictly synchronizing the fluid dynamics state with the electric field sequence. During the capture phase, the fluid residence mode significantly reduces the fluid dynamic drag force, making the weak dielectric electrophoretic force sufficient to dominate the cell's trajectory, thus improving the capture efficiency per cycle. During the evaluation phase, restoring physiological pulsating flow generates wall shear stress, stripping cells that adhere only through non-specific adsorption. This iterative "capture-screening" mechanism effectively prevents ineffective accumulation, ensuring that the final biological barrier possesses mechanical stability capable of withstanding physiological blood flow impacts.

[0018] 3. This invention provides a quantitative, real-time barrier function assessment method. Unlike traditional bile biochemical analysis which suffers from lag, this invention utilizes cross-barrier complex impedance spectroscopy to extract impedance moduli at characteristic frequencies as evaluation indicators. This indicator sensitively reflects the formation process of tight junctions in bile duct epithelial cells and changes in ion permeability, providing millisecond-level real-time feedback on the repair process. Combined with a closed-loop feedback adjustment algorithm, the system can dynamically adjust the dielectric electrophoresis voltage and application time according to the degree of repair, avoiding the risk of luminal narrowing due to over-repair or bile leakage due to under-repair, thus achieving standardized control of the organ repair process. Attached Figure Description

[0019] Figure 1 This is a system architecture diagram of the present invention. Detailed Implementation

[0020] The technical solutions in 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.

[0021] Please see the appendix Figure 1The present invention provides a multimodal real-time evaluation algorithm system for organ normothermic mechanical perfusion, comprising: a fluid circulation unit 100, a cross-barrier electrode array unit 200, a multimodal control unit 300, and an optical tracer verification unit 400.

[0022] The fluid circulation unit 100 is used to construct the physical environment and material transport pathway required for normothermic perfusion of isolated liver. The fluid circulation unit 100 includes a storage tank 110, a variable frequency pulse pump 120, a membrane oxygenator 130, and a constant temperature heat exchanger 140. The storage tank 110 contains perfusion fluid and a suspension of engineered organoids to be implanted.

[0023] The inlet of the variable frequency pulsating pump 120 is connected to the storage tank 110 via a pipeline, and the outlet of the variable frequency pulsating pump 120 is connected to the blood vessel inlet of the isolated organ via a membrane oxygenator 130 and a constant temperature heat exchanger 140. The variable frequency pulsating pump 120 is communicatively connected to the multimodal control unit 300, receiving control signals to switch between constant flow rate mode, physiological pulsation mode, and resident oscillation mode to adjust the hydrodynamic parameters of the fluid flowing through the isolated organ.

[0024] The cross-barrier electrode array unit 200 is used to establish an electrical circuit that penetrates the blood vessel wall, Disse gap, and bile duct epithelial layer inside an isolated organ. The cross-barrier electrode array unit 200 includes a blood vessel-side excitation electrode 210 and a bile duct-side sensing electrode 220.

[0025] The vascular-side excitation electrode 210 is disposed at the distal end of the portal vein cannula and hepatic artery cannula connected to the isolated organ in the fluid circulation unit 100. The portal vein cannula and hepatic artery cannula are made of insulating polymer material, or have an insulating coating on their inner walls. The vascular-side excitation electrode 210 is made of a biocompatible conductive material in a ring structure and is attached and fixed to the inner wall of the portal vein cannula and hepatic artery cannula, so that the vascular-side excitation electrode 210 maintains direct electrical contact with the perfusion fluid flowing into the isolated organ, while being electrically isolated from external metal tubing.

[0026] The biliary-side sensing electrode 220 is constructed in the form of a flexible microfilament catheter. The biliary-side sensing electrode 220 is inserted retrogradely through the common bile duct of an isolated organ and extends into the intrahepatic bile duct branching network. The biliary-side sensing electrode 220 and the vascular-side excitation electrode 210 form an electric field channel that crosses the biological tissue barrier in spatial position.

[0027] The multimodal control unit 300 is electrically connected to the fluid circulation unit 100 and the cross-barrier electrode array unit 200, respectively. The multimodal control unit 300 includes an arbitrary waveform generator 310, a time-division multiplexing switch module 320, a signal acquisition module 330, and a central processing module 340.

[0028] The arbitrary waveform generator 310 is used to generate multi-frequency sinusoidal AC scanning signals and high-voltage non-uniform electric field excitation signals. The time-division multiplexing switch module 320 is connected in series between the arbitrary waveform generator 310 and the cross-barrier electrode array unit 200. The time-division multiplexing switch module 320 is used to periodically switch the circuit connection state according to a preset timing sequence.

[0029] The signal acquisition module 330 is connected to the bile duct-side sensing electrode 220. The signal acquisition module 330 is used to acquire the electrical response signal modulated by the biological tissue barrier. The central processing module 340 receives the data from the signal acquisition module 330 and sends feedback control commands to the variable frequency pulsating pump 120 and the arbitrary waveform generator 310 according to the calculation results.

[0030] An optical tracer verification unit 400 is disposed in the perfusion fluid inlet line and the bile outflow line of the fluid circulation unit 100. The optical tracer verification unit 400 includes a first fluorescence probe 410 and a second fluorescence probe 420. The first fluorescence probe 410 monitors the fluorescence intensity in the perfusion fluid on the vascular side, and the second fluorescence probe 420 monitors the fluorescence intensity in the outflowing bile. The first fluorescence probe 410 and the second fluorescence probe 420 detect the concentration data of a specific molecular weight fluorescent tracer in the fluid in real time and transmit the concentration data to the central processing module 340 of the multimodal control unit 300.

[0031] This invention provides a multimodal real-time assessment and control method for organ normothermic mechanical perfusion based on the aforementioned hardware system. The multimodal real-time assessment and control method for organ normothermic mechanical perfusion mainly includes the following steps: S100: Initialization and Baseline Acquisition Steps. The portal vein and hepatic artery of the isolated liver are connected to the cannula of the fluid circulation unit 100, and the biliary side sensing electrode 220 of the transbarrier electrode array unit 200 is retrogradely inserted into the intrahepatic biliary system via the common bile duct. The multimodal control unit 300 starts the variable frequency pulsating pump 120 to maintain basal physiological perfusion. The multimodal control unit 300 applies a multi-frequency scanning signal through the transbarrier electrode array unit 200, measures and records the initial transbarrier complex impedance value of the isolated organ in the state without organoid injection, and stores the initial transbarrier complex impedance value as baseline data.

[0032] S200: Injection and Tracing Start-up Step. A suspension containing engineered hepatobiliary organoids is injected into the perfusion circuit through the reservoir 110 or the injection port located downstream of the variable frequency pulse pump 120. Simultaneously with the injection operation, an inert fluorescent tracer of a specific molecular weight is added to the fluid circulation unit 100. The first fluorescence probe 410 and the second fluorescence probe 420 of the optical tracer verification unit 400 are then activated to monitor real-time fluorescence intensity data in the vascular perfusion fluid and bile effluent, respectively, and transmit the real-time fluorescence intensity data to the multimodal control unit 300.

[0033] S300: Time-division multiplexing cyclic control step. The multi-modal control unit 300 executes time-division multiplexing logic, and the control system alternates between the active acquisition state and the impedance assessment state for a preset period.

[0034] S310: In active capture mode, the multimodal control unit 300 sends a first control command to the fluid circulation unit 100, controlling the variable frequency pulsating pump 120 to switch to a resident oscillation mode. **In resident oscillation mode, the variable frequency pulsating pump 120 reduces its rotational speed to a stagnant or slightly oscillating state, causing the fluid velocity flowing through the excised organ to decrease below a preset low shear force threshold.** In conjunction with the reduced flow velocity, the multimodal control unit 300 controls the cross-barrier electrode array unit 200 to generate a high-frequency non-uniform electric field. Utilizing the dielectric electrophoretic force generated by the electric field distortion in the damaged bile duct region, the suspended engineered hepatobiliary organoids are driven to move directionally towards and attach to the physically damaged area of ​​the bile duct wall.

[0035] S320: In impedance assessment mode, the multimodal control unit 300 sends a second control command to the fluid circulation unit 100, controlling the variable frequency pulsating pump 120 to resume the pulsating flow mode and continue for a preset time, using fluid flushing force to remove loosely attached engineered hepatobiliary organoids. In conjunction with flow rate recovery, the multimodal control unit 300 switches the cross-barrier electrode array unit 200 to low-pressure measurement mode, acquires the current cross-barrier complex impedance signal, and calculates the real-time repair index based on baseline data.

[0036] S400: Dual-modal determination and steady-state maintenance steps. The central processing module 340 of the multimodal control unit 300 monitors the real-time repair index trend and the apparent bile duct permeability coefficient change rate fed back by the optical tracer verification unit 400 in real time. When the calculated real-time repair index exceeds the preset target threshold and the apparent bile duct permeability coefficient shows a continuous downward trend, the multimodal control unit 300 determines that the colonization repair is complete. At this time, the multimodal control unit 300 terminates the time-division multiplexing cycle, stops outputting the high-frequency non-uniform electric field, and controls the fluid circulation unit 100 to enter a steady-state perfusion mode with constant physiological parameters.

[0037] The cross-barrier electrode array unit 200 provided by the present invention is used to construct an electric field environment that can penetrate the biological membrane barrier of isolated organs. The cross-barrier electrode array unit 200 includes a blood vessel-side excitation electrode 210 and a bile duct-side sensing electrode 220.

[0038] The vascular-side excitation electrode 210 is an embedded ring-shaped conductive structure. The vascular-side excitation electrode 210 is fixedly installed on the inner wall of the outlet end of the portal vein cannula and hepatic artery cannula connected to the isolated organ in the fluid circulation unit 100. The substrate material of the vascular-side excitation electrode 210 is selected from biocompatible platinum-iridium alloy or gold-plated copper to reduce the electrochemical polarization resistance at the interface between the vascular-side excitation electrode 210 and the perfusion fluid.

[0039] To ensure that the electric field excitation signal is conducted only through biological tissue and not short-circuited through external tubing, the cannula housing the vascular excitation electrode 210 is made of medical-grade polyurethane or polytetrafluoroethylene insulating polymer material. The inner surface of the vascular excitation electrode 210 is in direct contact with the perfusion fluid flowing through the cannula, while the outer surface of the vascular excitation electrode 210 is tightly bonded to the cannula, forming an insulating and sealed structure. The vascular excitation electrode 210 is led out through a coaxial shielded wire embedded in the cannula wall and connected to the time-division multiplexing switch module 320 of the multimodal control unit 300.

[0040] The biliary tract-side sensing electrode 220 is a microcatheter electrode with flexible and shape memory properties. The biliary tract-side sensing electrode 220 is composed of a highly elastic nickel-titanium alloy core wire and an insulating sheath layer covering the nickel-titanium alloy core wire. The tip of the biliary tract-side sensing electrode 220 has a predetermined length of exposed conductive area, the surface of which has been nanoporousized to increase the effective specific surface area.

[0041] The outer diameter of the bile duct-side sensing electrode 220 is smaller than the inner diameter of the common bile duct of the isolated organ, allowing it to be inserted retrogradely through the common bile duct and penetrate deep into the common hepatic duct or the bifurcation of the left and right hepatic ducts. The length of the exposed conductive area along the axial direction of the bile duct-side sensing electrode 220 is configured to match the depth of the region from the porta hepatis to the liver parenchyma of the isolated organ, ensuring that the exposed conductive area is located at the center of the bile duct branching network of the isolated organ. The tail end of the bile duct-side sensing electrode 220 is led out through a fluid-sealed connector and connected to the signal acquisition module 330 of the multimodal control unit 300.

[0042] The vascular-side excitation electrode 210 and the bile duct-side sensing electrode 220 spatially constitute a near-coaxial electrode field distribution structure surrounding the isolated organ parenchyma. When the multimodal control unit 300 applies an excitation voltage, the current path originates from the vascular-side excitation electrode 210, is conducted via the intravascular perfusion fluid, penetrates the vascular endothelial cell layer, the Disse gap, and the bile duct epithelial cell layer to enter the bile duct lumen, and finally converges at the bile duct-side sensing electrode 220. The electrical characteristics of the aforementioned current path characterize the integrity of the physical barrier between the vascular endothelium and the bile duct epithelium.

[0043] The multimodal control unit 300 provided by the present invention realizes the switching and execution of electric field intervention and impedance monitoring functions of isolated organs through timing control at the hardware circuit level. The multimodal control unit 300 mainly includes an arbitrary waveform generator 310, a time-division multiplexing switch module 320, a signal acquisition module 330, and a central processing module 340.

[0044] The arbitrary waveform generator 310 includes a direct digital frequency synthesizer (DDS) and a programmable gain power amplifier. The arbitrary waveform generator 310 generates and outputs two electrical signals with different characteristics: a high-voltage non-uniform electric field excitation signal for dielectric electrophoresis capture, and a low-voltage multi-frequency scanning signal for impedance measurement. The high-voltage non-uniform electric field excitation signal has an amplitude range of 10V to 200V and a frequency range of 100kHz to 10MHz. The low-voltage multi-frequency scanning signal has an amplitude of 10mV to 100mV and a frequency coverage of a wide bandwidth from 10Hz to 1MHz. The output of the arbitrary waveform generator 310 is connected to the input port of the time-division multiplexing switch module 320, and simultaneously outputs a synchronous reference clock signal to the signal acquisition module 330.

[0045] The time-division multiplexing switch module 320 is composed of a high-speed solid-state relay array or a high-voltage metal-oxide-semiconductor field-effect transistor (MOSFET) switch group. The time-division multiplexing switch module 320 is connected in series between the cross-barrier electrode array unit 200 and the signal acquisition module 330 to construct a switching path between the high-voltage drive circuit and the low-voltage detection circuit.

[0046] In dielectric electrophoresis capture mode, the time-division multiplexing switch module 320 switches the biliary side sensing electrode 220 of the cross-barrier electrode array unit 200 to the system reference ground or the high-voltage return terminal, while simultaneously disconnecting the biliary side sensing electrode 220 from the signal acquisition module 330. This forms a closed high-voltage electric field loop between the vascular side excitation electrode 210 and the biliary side sensing electrode 220, protecting the downstream detection circuit. In impedance measurement mode, the time-division multiplexing switch module 320 switches the biliary side sensing electrode 220 to the signal input terminal of the signal acquisition module 330.

[0047] The signal acquisition module 330 includes a transimpedance amplifier (TIA) and a digital lock-in amplifier. The TIA converts the weak penetration current signal collected by the biliary side sensing electrode 220 into a voltage signal. The digital lock-in amplifier uses the synchronous reference clock signal output by the arbitrary waveform generator 310 as the demodulation reference to perform quadrature demodulation on the converted voltage signal, extracting the in-phase voltage component (real part) and the quadrature voltage component (imaginary part). The signal acquisition module 330 is used to suppress incoherent noise interference and extract effective electrochemical impedance spectroscopy data reflecting the physical barrier characteristics between blood vessels and bile ducts.

[0048] The central processing module 340 employs a field-programmable gate array (FPGA) or a high-performance microcontroller. The central processing module 340 is connected to the bus interfaces of the arbitrary waveform generator 310, the time-division multiplexing switch module 320, and the signal acquisition module 330, respectively. The central processing module 340 sends timing trigger pulses to the time-division multiplexing switch module 320 to control loop switching. The central processing module 340 receives the in-phase and quadrature voltage components from the signal acquisition module 330 and calculates the magnitude and phase angle of the trans-barrier complex impedance according to Ohm's law.

[0049] This invention analyzes the frequency response data collected by the cross-barrier electrode array unit 200 based on a series equivalent circuit model to quantify the integrity of the biliary barrier inside an isolated organ.

[0050] Total complex impedance of series equivalent circuit model The ohmic resistance of the infusion fluid Electrode interface polarization impedance and biological tissue barrier impedance It is connected in series. Among them... ω is the angular frequency of the excitation signal.

[0051] Ohmic resistance of the infusion fluid The ionic conductivity of the perfusion fluid and the geometric distance between the vascular-side excitation electrode 210 and the biliary-side sensing electrode 220 depend on the temperature of the perfusion fluid under the isothermal environment of ambient temperature mechanical perfusion. It maintains a constant value and dominates the impedance spectrum in the high-frequency range. Electrode interface polarization impedance Due to the double-layer capacitance effect on the electrode surface, it exhibits high impedance characteristics in the low-frequency range.

[0052] Biological tissue barrier resistance Reflecting the ion permeability of the bile duct epithelium and tight junctions, its influence on the total complex impedance in the mid-frequency range of 10kHz to 100kHz. The contribution of this method is most significant. In the physical model of this invention, the bile duct wall of the isolated organ is equivalent to the leakage conductivity from the damaged area. With the electrical conductance of intact epithelial cells The parallel conductive dielectric is formed.

[0053] The effective coverage rate of engineered liver and gallbladder organoids in the injury area is set to be... At this point, the equivalent barrier conductivity of the bile duct wall... Expressed as: With engineered liver and gallbladder organoids implanted and sealed in the damaged area under the action of dielectrophoresis, the effective coverage rate is high. Increased, leading to equivalent barrier conductivity Decrease. Based on the inverse relationship between impedance and conductance, the impedance of biological tissue barriers... The modulus value increases accordingly.

[0054] The multimodal control unit 300 calculates the real-time repair index based on the above physical model. $ is calculated using the following formula: In the formula, At the current time, at the characteristic frequency The total complex impedance modulus measured below; The baseline impedance magnitude value in the unrepaired state obtained in step S100; This is a preset target impedance threshold representing a fully repaired state. Characteristic frequency. Selected as biological tissue barrier impedance The frequency point corresponding to the peak phase angle. Real-time repair index. Used for feedback adjustment of the fluid dynamic parameters of the variable frequency pulsating pump 120.

[0055] This invention is based on a dielectric electrophoresis active targeting mechanical model, which utilizes the difference in dielectric properties between engineered liver and gallbladder organoids and perfusion fluid to establish an active targeted delivery mechanism for physically damaged areas.

[0056] The multimodal control unit 300 controls the cross-barrier electrode array unit 200 to generate a high-frequency non-uniform electric field. In the physically damaged area of ​​the isolated organ, due to the absence of the bile duct epithelial cell layer, the electrical impedance of the physically damaged area is lower than that of the surrounding intact epithelial tissue, causing current lines to accumulate in the physically damaged area, forming a high-intensity electric field gradient region. The engineered hepatobiliary organoid suspended in the perfusion fluid generates an induced dipole moment in the high-frequency non-uniform electric field and is subjected to a time-averaged dielectric electrophoretic force pointing towards the region of maximum electric field intensity.

[0057] The central processing module 340 calculates the time-averaged dielectric electrophoretic force acting on engineered liver and gallbladder organs based on the principles of dielectric physics. The calculation formula is as follows: In the formula, The average radius of engineered liver and gallbladder organoids; Represents the absolute dielectric constant of the perfusion fluid; The squared gradient of the root mean square value of the electric field intensity represents the degree of non-uniformity of the electric field caused by structural and tissue damage to the cross-barrier electrode array unit 200. Represents the real part of the Clausius-Mosotti factor.

[0058] Clausius-Mosotti factor The Clausius-Mosotti factor determines the direction of the time-averaged dielectric electrophoretic force. This depends on the relative relationship between the complex permittivity of the engineered hepatobiliary organoid and the complex permittivity of the perfusion fluid. The frequency of the high-voltage non-uniform electric field excitation signal output by the arbitrary waveform generator 310 is set to such that... The frequency band generates a positive dielectric electrophoretic force, driving engineered liver and gallbladder organoids to move towards the area of ​​physical damage with the highest electric field strength.

[0059] During fluid circulation, engineered hepatobiliary organoids are simultaneously subjected to hydrodynamic drag forces generated by the flow of perfusion fluid. Hydrodynamic drag force Obeying Stokes' Law: In the formula, Represents the dynamic viscosity of the injection fluid; The local fluid velocity represents the location of engineered liver and gallbladder organoids.

[0060] To ensure that engineered liver and gallbladder organoids can be implanted in the physically damaged area, the multimodal control unit 300 adjusts the rotational speed of the variable frequency pulsating pump 120 and the output voltage of the arbitrary waveform generator 310 to satisfy the following mechanical competitive equilibrium conditions in the physically damaged area: In the formula, This represents the settling force acting on engineered hepatobiliary organs, which is the resultant force of gravity and buoyancy. When the mechanical competitive equilibrium condition is met, the time-averaged dielectric electrophoretic force dominates the motion trajectory of the engineered hepatobiliary organs, achieving anchoring of the physically damaged areas of the bile duct wall. The multimodal control unit 300 provided by the present invention adopts a time-division multiplexing strategy to alternately perform dielectric electrophoresis capture and impedance spectrum acquisition tasks on a single physical channel.

[0061] The multimodal control unit 300 will complete a full work cycle. Divided into two non-overlapping independent time periods: active capture window and impedance evaluation time window Work cycle To actively capture the window With impedance assessment time window The sum of all. Work cycle. The duration is set to 100 milliseconds to 1000 milliseconds to match the mechanical response characteristics of the variable frequency pulsating pump 120.

[0062] Active capture window During this period, the central processing module 340 of the multimodal control unit 300 sends a high-voltage mode control command to the time-division multiplexing switch module 320. The time-division multiplexing switch module 320 performs a circuit switching action, connecting the biliary side sensing electrode 220 of the cross-barrier electrode array unit 200 to the system reference ground, and simultaneously physically disconnecting the biliary side sensing electrode 220 from the signal acquisition module 330.

[0063] After the circuit switching is confirmed, the central processing module 340 triggers the arbitrary waveform generator 310 to output a high-voltage non-uniform electric field excitation signal. At this time, the cross-barrier electrode array unit 200 establishes a dielectric electrophoretic force field inside the isolated organ, driving the engineered liver and gallbladder organoids to converge towards the physically damaged area. During this stage, the signal acquisition module 330 is in an isolated protection state and does not acquire data.

[0064] Impedance evaluation time window During this period, the central processing module 340 of the multimodal control unit 300 first terminates the high-voltage output of the arbitrary waveform generator 310 and sends a measurement mode control command to the time-division multiplexing switch module 320. The time-division multiplexing switch module 320 switches the biliary side sensing electrode 220 of the cross-barrier electrode array unit 200 to the input terminal of the signal acquisition module 330.

[0065] Subsequently, the central processing module 340 triggers the arbitrary waveform generator 310 to output a low-voltage multi-frequency scanning signal. The signal acquisition module 330 then performs impedance evaluation within the specified time window. The system internally acquires the cross-barrier current response and demodulates the real and imaginary voltage components. The central processing module 340 utilizes an impedance evaluation time window. The data within the calculation unit is used to determine the current cross-barrier complex impedance value and the real-time repair index.

[0066] The multimodal control unit 300 during the active capture window With impedance assessment time window The switching node incorporates a dead time. The length of the dead time is set from 10 microseconds to 500 microseconds. During the dead time, the arbitrary waveform generator 310 stops all signal outputs, and the time-division multiplexing switch module 320 remains fully open to prevent induced electromotive force or residual high voltage during circuit switching from damaging the signal acquisition module 330.

[0067] The multimodal control unit 300 dynamically adjusts the active capture window based on changes in the real-time repair index. During the work cycle The percentage in, i.e., duty cycle During the initial infusion phase, the multimodal control unit 300 is set to a high duty cycle. To maximize the duration of dielectric electrophoretic force application; as the real-time repair index increases, the multimodal control unit 300 gradually reduces the duty cycle in preset steps. Increase the impedance assessment time window The length improves the time resolution of monitoring. The multimodal control unit 300 provided by the present invention generates control signals to drive the variable frequency pulsating pump 120 based on a fluid dynamics control model, and constructs an unsteady flow field matching the dielectrophoretic capture timing within the blood vessels and biliary network of the isolated organ.

[0068] The central processing module 340 of the multimodal control unit 300 constructs a perfusion flow function that dynamically varies with time. Injection flow function Maintain synchronization with time-division multiplexing sequential logic, and inject flow functions. Cycle and work cycle Maintain consistency. Injection flow function. It includes two flow stages: a low-velocity residence stage and a high-velocity shear stage.

[0069] Active capture window During this period, the central processing module 340 controls the variable frequency pulsating pump 120 to enter a low-flow-rate residence phase. The output flow rate of the variable frequency pulsating pump 120 is reduced to a preset residence flow rate threshold. Dwelling flow threshold The retention flow threshold is set as the non-zero minimum value that can maintain the basal filling pressure of the vascular bed in an isolated organ. It is 5% to 10% of the steady-state injection flow rate.

[0070] The multimodal control unit 300 reduces the rotational speed of the variable frequency pulsating pump 120 to decrease the hydrodynamic drag force acting on the engineered hepatobiliary organoids. The central processing module 340 maps macroscopic flow rate to microscopic flow velocity based on the flow tube model, ensuring that the following flow control conditions are met during the low-velocity residence phase: In the formula, Represents the effective cross-sectional area of ​​the fluid channel; This is the velocity distribution correction factor. This characterizes the ratio of the maximum flow velocity to the average flow velocity at the center of the pipe under laminar flow conditions. When flow control conditions are met, suspended engineered hepatobiliary organoids can overcome hydrodynamic drag forces and move along the electric field gradient direction under the action of dielectric electrophoresis force.

[0071] Impedance evaluation time window During this period, the central processing module 340 controls the variable frequency pulsating pump 120 to enter the high-flow-rate shearing phase. The output flow rate of the variable frequency pulsating pump 120 is restored to the physiological pulsating flow rate. Wall shear stress is generated on the fluid channel wall. .

[0072] Wall shear stress Mechanical screening is applied to the already attached engineered liver and gallbladder organoids. For tubular fluid channels, wall shear stress... The calculation is as follows: In the formula, The average hydraulic radius represents the target fluid channel. Engineered hepatobiliary organoids that adhere solely to the surface of physically damaged areas through non-specific physical adsorption lack the support of tight junction proteins and cannot withstand wall shear stress. The impact caused the organs to be detached; engineered liver and gallbladder organoids that had been embedded in the physically damaged area and physically anchored by dielectric electrophoresis were preserved.

[0073] The multimodal control unit 300 achieves iterative implantation of engineered hepatobiliary organoids by cyclically switching between a low-flow-rate residence phase and a high-flow-rate shearing phase. The central processing module 340 monitors the real-time repair index after the high-flow-rate shearing phase ends, and determines that implantation is effective only when the real-time repair index continues to rise. The multimodal control unit 300 provided by this invention runs a closed-loop feedback adjustment algorithm based on the real-time repair index. and its first derivative Adaptive adjustment of dielectric electrophoresis voltage amplitude and work cycle Timing parameters.

[0074] The central processing module 340 of the multimodal control unit 300 sets two threshold criteria: a fast acquisition threshold. and fine repair threshold ,in Based on the real-time repair index With fast capture threshold and fine repair threshold The comparison results show that the central processing module 340 executes three different control modes: fast overwrite mode, fine trimming mode, and steady-state consolidation mode.

[0075] When the real-time repair index Less than the fast capture threshold At this time, the central processing module 340 determines that the excised organ is in a state of large-area damage and unrepaired condition, and executes the fast coverage mode. In the fast coverage mode, the central processing module 340 controls the amplitude of the high-voltage non-uniform electric field excitation signal output by the arbitrary waveform generator 310 to be maintained at the maximum voltage allowed by the system. Meanwhile, the central processing module 340 will actively capture the time window. duty cycle A high duty cycle range of 70% to 90% was set to improve the directional movement speed of engineered liver and gallbladder organoids toward the area of ​​physical damage.

[0076] When the real-time repair index Greater than or equal to the fast capture threshold And less than the fine repair threshold At this point, the central processing module 340 determines that the excised organ has entered the initial coverage state and switches to the fine trimming mode. In the fine trimming mode, the central processing module 340 controls the amplitude of the high-voltage non-uniform electric field excitation signal to follow the real-time repair index. The value decreases linearly with a negative correlation as the value increases. Meanwhile, the central processing module 340 gradually reduces the active capture window with a preset step size. duty cycle This correspondingly increases the proportion of time that the variable frequency pulsating pump 120 is in the high-flow-rate shearing phase. (Reducing the duty cycle) The procedure utilizes fluid dynamics and shear force to remove loosely bonded engineered liver and gallbladder organoids, and then screens out implantation sites that have formed strong connections.

[0077] When the real-time repair index Greater than the fine repair threshold And real-time repair index first derivative When the value falls below a preset stable minimum, the central processing module 340 determines that the colonization repair is complete and enters a steady-state consolidation mode. In this mode, the central processing module 340 stops the high-voltage output of the arbitrary waveform generator 310. The central processing module 340 controls the variable frequency pulsating pump 120 to return to physiological pulsating perfusion mode and continuously monitors the transbarrier complex impedance value. If the monitored transbarrier complex impedance value decreases by more than a preset backoff threshold (e.g., 5%) compared to the steady-state peak value, the central processing module 340 switches back to the fine-tuning mode for remedial repair.

[0078] The optical tracer verification unit 400 provided by this invention is based on the physical barrier function verification principle independent of the electrochemical detection pathway. By monitoring the permeation dynamics of substances with specific molecular weights at the blood vessel-bile duct interface, it eliminates the interference of electrode polarization or contact artifacts on the impedance assessment results.

[0079] The optical tracer verification unit 400 uses a bio-inert macromolecular polymer as the fluorescent tracer, specifically FITC-Dextran. The molecular weight of the fluorescent tracer is set to be greater than the pore size limit of the tight junctions of bile duct epithelial cells, ensuring that the fluorescent tracer can only passively diffuse and leak through tissue defects caused by physical damage.

[0080] In the injection and tracer initiation step S200, the first fluorescence probe 410 monitors the fluorescence intensity of the perfusion fluid at the vascular side inlet of the fluid circulation unit 100 in real time. The data monitored by the first fluorescence probe 410 is marked as the vascular side tracer concentration by the central processing module 340. Simultaneously, the second fluorescence probe 420 monitors the fluorescence intensity of the effluent in the bile outflow line in real time, and the data monitored by the second fluorescence probe 420 is marked by the central processing module 340 as the bile-side tracer leakage concentration. .

[0081] The central processing module 340 of the multimodal control unit 300 calculates the apparent bile duct permeability coefficient, which characterizes the physical barrier integrity of the bile duct wall, based on Fick's first diffusion law. Under quasi-steady-state perfusion conditions, the apparent bile duct permeability coefficient The calculation formula is as follows: In the formula, The effective luminal volume representing the biliary system of an isolated organ; This represents the effective diffusion area between the vascular network and the biliary network. and These are constants estimated in advance based on the weight or volume of the ex vivo organ; This represents the rate of change in the concentration of the tracer leaked on the bile side.

[0082] The central processing module 340 executes a dual-verification strategy. The central processing module 340 sets a penetration coefficient attenuation threshold. Only when the real-time repair index is reached. Greater than the fine repair threshold And the apparent bile duct permeability coefficient It exhibits a monotonically decreasing trend and the value is below the permeability decay threshold. At that time, the central processing module 340 outputs a final determination signal indicating successful repair.

[0083] If the real-time repair index It shows a high impedance value, but the apparent bile duct permeability coefficient If the impedance remains high or shows an upward trend, the central processing module 340 determines that the current high impedance value is a false positive signal, which originates from adsorption or bubble blockage on the electrode surface. At this time, the central processing module 340 triggers an alarm command and controls the time-division multiplexing switch module 320 to execute the electrode self-cleaning sequence or prompt for manual inspection.

[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multimodal real-time evaluation algorithm system for normothermic mechanical perfusion of organs, characterized in that, include: The fluid circulation unit is configured to provide perfusion fluid circulation to the isolated organ, including a variable frequency pulsating pump capable of adjusting the flow rate and waveform; The cross-barrier electrode array unit includes a vascular excitation electrode disposed at the vascular cannulation site of an isolated organ and a bile duct sensing electrode inserted retrogradely into the bile duct system of the isolated organ. The vascular excitation electrode and the bile duct sensing electrode spatially construct a cross-barrier electric field loop that penetrates the vascular wall and the bile duct epithelial layer. A multimodal control unit is electrically connected to both the fluid circulation unit and the cross-barrier electrode array unit. The multimodal control unit is configured to execute time-division multiplexing control logic, dividing the working cycle into an active acquisition window and an impedance assessment window. Within the active acquisition window, the multimodal control unit controls the cross-barrier electrode array unit to generate a high-frequency non-uniform electric field, utilizing the dielectric electrophoretic force generated by the electric field distortion in the damaged bile duct region to drive the engineered organoid in the perfusion fluid towards the physically damaged area. Within the impedance assessment window, the multimodal control unit controls the cross-barrier electrode array unit to acquire cross-barrier complex impedance signals and calculates a real-time repair index characterizing the integrity of the biliary barrier based on the cross-barrier complex impedance signals.

2. The multi-modal real-time assessment algorithm system for normothermic mechanical perfusion of organs according to claim 1, characterized in that, The vascular side excitation electrode is a ring-shaped conductive structure embedded in the inner wall of the insulating cannula, used to establish electrical contact with the perfusion fluid flowing into the blood vessel. The biliary side sensing electrode is a flexible microcatheter containing an insulating sheath layer and an exposed conductive area, the axial length of which is configured to cover the biliary branch network of the excised organ. The current path of the high-frequency non-uniform electric field is configured to originate from the vascular-side excitation electrode, penetrate the vascular endothelial cell layer, the Disse gap, and the bile duct epithelial cell layer, and converge to the bile duct-side sensing electrode.

3. The multi-modal real-time assessment algorithm system for normothermic mechanical perfusion of an organ according to claim 1, wherein, The multimodal control unit includes an arbitrary waveform generator, a time-division multiplexing switch module, and a signal acquisition module; The time-division multiplexing switch module is configured to: during the active acquisition time window, switch the biliary side sensing electrode to the system reference ground and disconnect it from the signal acquisition module to form a high-voltage circuit for generating the dielectric electrophoretic force. During the impedance assessment time window, the biliary side sensing electrode is switched to the input terminal of the signal acquisition module to form a low-voltage detection loop for measuring the cross-barrier complex impedance signal. The multimodal control unit is also configured to insert a dead time of a preset length at the switching node between the active acquisition window and the impedance evaluation window, and to cut off all signal outputs and circuit connections during the dead time.

4. The multimodal real-time evaluation algorithm system for organ normothermic mechanical perfusion according to claim 1, characterized in that, The multimodal control unit is also configured to perform flow field-electric field coordinated control: within the active capture window, the variable frequency pulsating pump is controlled to enter a dwell oscillation mode to reduce the local fluid velocity flowing through the ex vivo organ to a preset threshold, so that the dielectric electrophoretic force acting on the engineered organ is greater than the hydrodynamic drag force. During the impedance assessment time window, the variable frequency pulsating pump is controlled to enter the physiological pulsation mode, and the pulsating flow is restored to generate wall shear stress on the bile duct wall. The wall shear stress is then used to remove engineered organoids that have not formed a stable connection.

5. The multimodal real-time evaluation algorithm system for organ normothermic mechanical perfusion according to claim 4, characterized in that, The multimodal control unit is configured to adjust the flow rate of the variable frequency pulsating pump based on a fluid dynamics control model; The fluid dynamics control model specifies that, under the dwell oscillation mode, the output flow rate of the variable frequency pulsating pump is reduced to 5% to 10% of the steady-state infusion flow rate to meet the mechanical competition equilibrium condition dominated by dielectric electrophoresis force. In the physiological pulsation mode, the output flow rate of the variable frequency pulsating pump is restored to a physiological flow rate level capable of generating screening wall shear stress.

6. The multimodal real-time evaluation algorithm system for organ normothermic mechanical perfusion according to claim 1, characterized in that, The multimodal control unit is configured to calculate the real-time repair index based on a series equivalent circuit model; The series equivalent circuit model includes the ohmic resistance of the perfusion fluid, the polarization impedance of the electrode interface, and the biological tissue barrier impedance. The multimodal control unit extracts the magnitude of the cross-barrier complex impedance signal at a characteristic frequency, and defines the rate of change of the current magnitude relative to the baseline magnitude in the unrepaired state as the real-time repair index. The characteristic frequency is selected as the frequency point where the contribution of the biological tissue barrier impedance to the total impedance is the largest.

7. The multimodal real-time assessment algorithm system for organ normothermic mechanical perfusion according to claim 1, characterized in that, The multimodal control unit is configured to run a closed-loop feedback adjustment algorithm to adaptively adjust the duty cycle of the active capture window in the working cycle according to the real-time repair index and its rate of change. When the real-time repair index is less than the preset fast capture threshold, the fast coverage mode is executed, the duty cycle is set to a high value and the high-frequency non-uniform electric field with the largest amplitude is output. When the real-time repair index is greater than the fast capture threshold and less than the preset fine repair threshold, the fine trimming mode is executed, controlling the amplitude of the high-frequency non-uniform electric field to decrease linearly with the increase of the real-time repair index, and gradually reducing the duty cycle to increase the duration of the impedance evaluation window.

8. The multimodal real-time assessment algorithm system for organ normothermic mechanical perfusion according to claim 1, characterized in that, The system also includes an optical tracer verification unit, which includes a first fluorescence probe for monitoring the fluorescence intensity of the perfusion fluid on the blood vessel side and a second fluorescence probe for monitoring the fluorescence intensity of the bile effluent. The multimodal control unit is configured to receive data from the first fluorescence probe and the second fluorescence probe, and to calculate the apparent bile duct permeability coefficient based on Fick's diffusion law.

9. The multimodal real-time assessment algorithm system for organ normothermic mechanical perfusion according to claim 8, characterized in that, The multimodal control unit is configured to execute dual verification judgment logic: only when the real-time repair index is greater than the preset fine repair threshold, and the apparent bile duct permeability coefficient shows a monotonically decreasing trend and is lower than the preset permeability coefficient decay threshold, is it determined that the colonization repair is completed and the time-division multiplexing control logic is terminated. If the real-time repair index is greater than the fine repair threshold and the apparent bile duct permeability coefficient does not show a decreasing trend, the cross-barrier complex impedance signal is determined to be a false positive signal and an electrode maintenance command is triggered.

10. The multimodal real-time evaluation algorithm system for organ normothermic mechanical perfusion according to claim 4, characterized in that, The frequency of the high-frequency non-uniform electric field is configured such that the real part of the Clausius-Mosotti factor of the engineered organoid relative to the perfusion fluid is greater than zero, thereby generating a positive dielectrophoretic force pointing towards the region of maximum electric field intensity gradient. The multimodal control unit adjusts the voltage amplitude of the high-frequency non-uniform electric field so that the positive dielectric electrophoretic force generated in the physical damage area overcomes the effective gravity and hydrodynamic drag force on the engineered organoid.

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