Self-adaptive hydrogel biomimetic body capable of dynamically adjusting mechanical and frictional characteristics and control method of self-adaptive hydrogel biomimetic body

Abstract

The invention discloses a self-adaptive hydrogel biomimetic body capable of dynamically adjusting mechanical and frictional characteristics and a control method of the self-adaptive hydrogel biomimetic body. A microcavity network capable of being filled with liquid or semi-solid media is built in the simulation body, and an external control module can change the liquid content, viscosity and local pressure of a microcavity in real time by injecting or sucking different types of media (including saline water, glycerin, silicone oil, oil-water mixed liquid, plasma simulation liquid and the like). Therefore, reversible adjustment of mechanical properties such as elastic modulus, compliance, friction coefficient, viscoelasticity and the like of the phantom can be realized in a local or overall range. Compared with an existing fixed simulation body with a single mechanical parameter, the simulation body has the advantages of dynamic adjustment, controllable simulation, multi-area differential simulation, reusability and the like, can be widely applied to performance testing and training teaching of medical instruments such as endoscopes, catheters, stents, puncture needles, surgical robots and the like, and remarkably improves the authenticity and repeatability of a simulation environment.

Description

Technical Field

[0001] This invention relates to the field of medical simulation materials and biomodeling technology, specifically to an adaptive hydrogel biomimetic and its control method that achieves adjustable local or overall mechanical properties and frictional characteristics through internal microcavity structures and external fluid regulation. This biomimetic is suitable for various medical simulation applications, including medical device testing, clinical operation training, preoperative simulation, and multimodal imaging verification. Background Technology

[0002] In recent years, with the rapid development of minimally invasive interventional therapy, robot-assisted surgery, precision medical device development, and medical student skills training, the demand for highly realistic human soft tissue phantoms has been continuously increasing. An ideal medical phantom should closely resemble real human tissue in terms of tissue morphology, elastic modulus, viscoelasticity, coefficient of friction, compliance, and multimodal imaging characteristics. However, currently available commercially available or laboratory-prepared hydrogel phantoms generally have the following limitations: (1) Mechanical properties are fixed and cannot be adjusted Existing hydrogel phantoms mostly use a single material system, and their elastic modulus, hardness, compliance and other properties are fixed after preparation, which cannot simulate the significant differences in tissues under different pathological states (such as edema, inflammation, fibrosis, sclerosis and tumor necrosis).

[0003] (2) The frictional characteristics are uncontrollable, making it difficult to realistically simulate the feel of operating the instrument. There are significant differences in friction between medical devices such as catheters, endoscopes, stent delivery systems, and puncture needles and tissues. However, traditional phantoms, due to their fixed surface water content and material chemical properties, cannot simulate different physiological conditions such as wetness, dryness, mucosal inflammation, or hardening.

[0004] (3) Unable to simulate the differentiated lesion structure in multiple regions Actual human tissues often exhibit spatial heterogeneity, such as central necrosis of tumors with surrounding fibrosis, and the coexistence of local sclerosis and healthy areas in blood vessels. However, existing phantoms have a uniform mechanical distribution, which makes it difficult to meet the needs of device evaluation and training in complex clinical scenarios.

[0005] (4) Lack of dynamic adjustment capability Human tissues exhibit dynamic changes, such as edema worsening or easing over time, tissue tension changing with heart rate, blood flow, and respiration, and fluctuations in local water content. Existing phantoms are all static models and cannot simulate these dynamic behaviors.

[0006] (5) Insufficient clinical reproducibility and parameter controllability Medical device companies and clinical training institutions require a phantom platform with controllable, repeatable, and quantifiable parameters for instrument friction testing, catheter permeability assessment, and puncture mechanics research. However, traditional phantoms, due to their non-adjustable parameters, struggle to meet the needs of quantitative research.

[0007] In summary, existing hydrogel phantoms still have significant shortcomings in realistically simulating human tissues, especially lacking comprehensive simulation capabilities such as regional controllability, reversible adjustment, and adjustable friction, which limits their application value in medical device research and development, teaching and training, and preoperative planning.

[0008] To address the aforementioned technical shortcomings, this invention proposes an adaptive hydrogel phantom with a built-in microcavity control network. By injecting or aspirating different types of liquid or semi-solid media into the microcavities, the phantom's local or overall mechanical properties, friction coefficient, and compliance can be adjusted in real-time, reversibly, and controllably. This allows for the construction of a human tissue phantom system capable of simulating various pathological states and mechanical distributions. This technology overcomes the static limitations of traditional phantoms, providing a novel platform with high fidelity and high parameter controllability for medical device evaluation, clinical skills training, and bionic system research. Summary of the Invention

[0009] Figure 1 shows the macroscopic structure of the adaptive hydrogel phantom of the present invention, wherein the hydrogel body (1) has a microcavity network (2) that can be filled with a medium and is connected to an external control module (3). By injecting or withdrawing liquid through the control module, the local or overall mechanical properties, compliance and friction characteristics of the hydrogel structure can be dynamically adjusted, thereby realizing the simulation of different human tissues or pathological states.

[0010] Figure 2 is a schematic diagram of the mechanical test of the adaptive hydrogel phantom of the present invention. In the figure, the test sphere 3, driven by the loading device 4, applies a pressure force vertically to the surface layer 6 of the phantom to detect the local deformation performance of the phantom under different internal microcavity states (e.g., regions 6a, 6b, and 6c). The dragged object 5 is used to evaluate the frictional behavior. Different regions can generate differentiated mechanical and frictional responses through the injection of different internal media. Even if there are no visible micropores on the hydrogel surface, the present invention can still achieve reversible changes in the lubricity and friction coefficient of the phantom surface through mechanisms such as internal microcavity pressure regulation, liquid infiltration, the semi-permeability of the material itself, and the formation of a lubricating film, thereby realizing dynamic control of the frictional response. Detailed Implementation Example 1: Adaptive hydrogel phantom with a uniform microcavity network

[0011] This embodiment constructs a basic hydrogel phantom with uniform mechanical control capability.

[0012] (1) Preparation of main materials: A 10 wt% PVA hydrogel solution was used to form a uniform elastic matrix by two freeze-thaw cycles (freezing at -20 ℃ for 10 h and thawing at room temperature for 4 h), with an initial elastic modulus of approximately 10 kPa.

[0013] (2) Constructing a microcavity network: Soluble PVA fibers are used as sacrificial templates to uniformly embed fibers with a diameter of 0.5–1.5 mm into hydrogels. After gelation, the fibers are dissolved in warm water to form microcavity channels.

[0014] (3) Control module connection: The microcavity has interfaces at both ends for connection to an external injection pump.

[0015] (4) Adjustment process: Different concentrations of NaCl solution are injected into the microcavity using a syringe pump: – 0.9% physiological saline → Coefficient of friction 0.08, modulus remains stable – 3% hypertonic saline solution → modulus increases to 15–20 kPa – Pure water → Simulates soft tissue edema This embodiment achieves dual control of mechanical and frictional properties in a uniform region. Example 2: High-fluid-content phantom for simulating edematous tissue

[0016] This embodiment is used to simulate soft tissues with high water content, such as inflammation and edema.

[0017] (1) Main materials: It uses a 7 wt% PVA + 1 wt% gelatin composite hydrogel, which gives it higher water content and softness.

[0018] (2) Microcavity structure: Using 3D printing to form a "honeycomb" microcavity network with pore sizes of 1–3 mm can significantly improve regional compliance.

[0019] (3) Filling medium: Injecting a large amount of pure water into the microcavity rapidly increases the local tissue fluid content, thereby adjusting the elastic modulus to 30–40 kPa, which is close to the physiological state of moderately edematous tissue.

[0020] (4) Friction adjustment: Injecting a small amount of glycerin into the microcavity can cause a small amount of moisture to seep out from the surface of the phantom, increasing surface wettability and reducing the coefficient of friction to about 0.03.

[0021] This embodiment can simulate the operating environment of gastrointestinal or respiratory tract inflammation or intraoperative soft tissue edema. Example 3: High-viscosity modulated phantoms for simulating fibrotic or hardened tissues

[0022] This embodiment is used to simulate hardened blood vessels, fibrotic areas of tumors, or proliferating tissue.

[0023] (1) Main hydrogel: A high-strength matrix is ​​formed by cross-linking CaCO3 with a 12 wt% PVA + 2 wt% sodium alginate composite system and an initial modulus of approximately 80–100 kPa.

[0024] (2) Microcavity structure: Internally, "longitudinal parallel" microcavities with a diameter of 0.4–1 mm are constructed to achieve localized hardening.

[0025] (3) Injection of high-viscosity media: Injecting high-viscosity silicone oil (5000–15000 cSt) into the microcavity increases the local modulus to 200–400 kPa, which can simulate atherosclerotic arteries or peripheral fibrosis zones of tumors.

[0026] (4) Friction control: By adding a hydrophobic oil phase to the microcavity, the surface friction coefficient was increased to 0.12–0.18, which was used to simulate the real situation of increased friction between hardened blood vessels and catheters.

[0027] This embodiment is suitable for stent delivery testing, hardened vascular catheter permeability testing, etc. Example 4: Composite adaptive phantom with different mechanical distributions in multiple regions

[0028] This embodiment is used to simulate typical heterogeneous structures, such as central tumor necrosis and surrounding sclerotic zones.

[0029] (1) Constructing a multi-region structure: A dual-mold structure is adopted to form a partitioned hydrogel structure with a central area and a surrounding area.

[0030] (2) Central region (simulated necrotic zone): Fill with soft PVA gel (8 wt%) with an initial modulus of about 8 kPa; inject a small amount of physiological saline into the microcavity to further soften it to 5–8 kPa.

[0031] (3) Surrounding area (simulated fibrous hard ring): Fill with PVA / sodium alginate gel (12% / 2%), inject high-viscosity silicone oil into microcavities to achieve a modulus of 150–300 kPa.

[0032] (4) Friction adjustment: The microcavity medium is controlled separately in different regions, so that the friction coefficient of the central part is 0.10–0.15 and the friction coefficient of the periphery is 0.15–0.3.

[0033] This phantom is ideally suited as a testing platform for puncture training and evaluation of interventional tumor devices. Example 5: Intelligent phantom system with real-time adjustable mechanical parameters

[0034] This embodiment integrates sensors into the phantom to achieve closed-loop control.

[0035] (1) Main body phantom: The uniform microcavity structure of Example 1 is adopted.

[0036] (2) Integrated sensor: A flexible pressure sensor or fiber Bragg (FBG) sensor is embedded in a certain area inside the phantom to monitor local deformation and pressure changes.

[0037] (3) Control system: The sensor measures the local hardness and friction response of the phantom in real time and feeds the data back to the micro-electrically controlled pump.

[0038] (4) Dynamic adjustment: The pump automatically injects or pumps media into the microcavity, allowing the phantom to switch automatically according to different needs: – “Soft tissue model”: Modulus 5–20 kPa – “Muscle Tissue Pattern”: Modulus 30–60 kPa – “Hardened tissue pattern”: Modulus 100–300 kPa (5) Adaptable scenarios: It is used for high-precision applications such as force control algorithm training in robotic surgery, catheter push resistance simulation, and puncture simulation.

[0039] This embodiment demonstrates the scalability and intelligent development direction of the present invention.

Claims

1. An adaptive hydrogel biomimetic with dynamically adjustable mechanical and tribological properties, characterized in that: The phantom body has a microcavity network that can be filled with liquid or semi-solid media inside; the external control module is connected to the microcavity network and can change the local liquid content, viscosity or pressure by injecting or aspirating media to achieve dynamic adjustment of the local or overall mechanical properties and / or frictional properties of the phantom body.

2. The phantom according to claim 1, characterized in that: The microcavity network has a mesh-like, honeycomb-like, branched, spiral, or combination thereof structure, and is located in the inner layer, surface layer, or between multiple layers of the phantom.

3. The phantom according to claim 1, characterized in that: The media used for conditioning include saline, glycerol, silicone oil, oil-water mixtures, plasma simulation solutions, physiological buffer solutions, or combinations thereof.

4. The phantom according to claim 1, characterized in that: The phantom material includes PVA hydrogel, sodium alginate gel, PEG gel, gelatin, chitosan, or composites thereof.

5. The phantom according to claim 1, characterized in that: By adjusting the volume fraction and lubrication level of the medium within the microcavity, the elastic modulus can be varied within the range of 5–1000 kPa, and the coefficient of friction can be adjusted within the range of 0.01–0.

3.

6. The phantom according to claim 1, characterized in that: The microcavity network has reversible deformation capability and includes multiple independently controlled microcavity partitions for regional differential regulation.

7. An adaptive phantom body control system, characterized in that: It includes the phantom, microfluidic control module and sensor module as described in any one of claims 1–6; the sensor module is used to monitor pressure, hardness, friction or displacement and feed it back to the control module to realize closed-loop adjustment of mechanical or frictional properties.

8. The system according to claim 7, characterized in that: The sensor module includes pressure sensors, strain sensors, force sensors, or fiber Bragg grating sensors; the control module can preset biomimetic modes such as healthy tissue, edema, fibrosis, sclerosis, or tumor-like tissue.

9. A method for preparing an adaptive hydrogel phantom, characterized in that: This includes constructing the main hydrogel structure; forming a microcavity network within the main body using molds, sacrificial templates, 3D printing, or microfluidic methods; setting external interfaces to connect control modules; and injecting different media into the microcavities to obtain the target mechanical or tribological properties.

10. A method for using the phantom as described in claim 1, characterized in that: High-viscosity media are injected into specific microcavity regions to simulate hardened or fibrotic tissue, while low-viscosity liquids are injected into other regions to simulate normal or edematous tissue, thereby obtaining a multi-regional mechanical gradient structure.

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