A subphrenic vagus nerve stimulation system for cancer neuroimmunotherapy and preparation method and application thereof

Abstract

The application belongs to the technical field of biological medicine, and particularly relates to a subphrenic vagus nerve stimulation system for cancer neuroimmunotherapy and a preparation method and application thereof. The system comprises a triboelectric unit and a stimulation electrode. The triboelectric unit comprises a driving module and a triboelectric module. The triboelectric module comprises an encapsulation layer and oppositely arranged first and second triboelectric layers. The triboelectric layers have different triboelectric sequences to generate electric charges under the driving of the driving module. The encapsulation layer is used for encapsulating the triboelectric layers and the stimulation electrode. The encapsulation layer is a self-healing elastomer. The stimulation electrode is electrically connected with the triboelectric module, used for electrically stimulating the vagus nerve, and dynamically adapts to the vagus nerve by using the flexibility. The application solves the technical problems of large volume, wire power supply, non-minimally invasive implantation and non-sensitivity of pancreatic cancer to immunotherapy by wireless power supply, curling and wrapping of the flexible stimulation electrode.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to a subphrenic vagus nerve stimulation system for cancer neuroimmunotherapy, its preparation method, and its application. Background Technology

[0002] Pancreatic cancer is a highly malignant gastrointestinal tumor with an extremely low five-year survival rate. It exhibits high resistance to conventional radiotherapy, chemotherapy, and immune checkpoint inhibitors (such as anti-PD-1 antibodies). This resistance mainly stems from its highly immunosuppressive "cold" tumor microenvironment, characterized by poor infiltration of effector T cells, enrichment of myeloid-derived suppressor cells, and M2 tumor-associated macrophages.

[0003] In recent years, neuroimmunomodulation has emerged as a novel therapeutic strategy. The vagus nerve, as a major parasympathetic pathway, exerts anti-inflammatory and immunomodulatory effects through the release of acetylcholine, which acts on cholinergic receptors on immune cells. Studies have shown that enhancing parasympathetic nerve signals can inhibit the development of pancreatic cancer. However, existing cervical vagus nerve stimulation techniques lack organ specificity and are prone to causing serious side effects such as bradycardia and arrhythmias. The subphrenic vagus nerve, an upstream neural pathway innervating abdominal organs such as the pancreas, is a more promising target. However, due to its close proximity to the esophagus and its periodic deformation with respiration and eating, constructing a long-term stable neural interface adaptable to this dynamic environment is extremely challenging. Furthermore, traditional stimulation systems require implanted batteries or receiving coils, resulting in large sizes that are difficult to achieve with minimally invasive implantation, and pose risks such as wire breakage and infection. Therefore, developing a wirelessly powered, miniaturized, and dynamically adaptable subphrenic vagus nerve stimulation system has significant clinical value. Summary of the Invention

[0004] The purpose of this invention is to provide a subphrenic vagus nerve stimulation system for cancer neuroimmunotherapy, its preparation method and application, so as to achieve wireless power supply and miniaturization, and dynamically adapt to the subphrenic vagus nerve stimulation system.

[0005] To achieve the above objectives, the present invention provides a subphrenic vagus nerve stimulation system for cancer neuroimmunotherapy, comprising: a triboelectric unit and a stimulation electrode; the triboelectric unit includes a driving module and a triboelectric module, the triboelectric module including an encapsulation layer and a first friction layer and a second friction layer disposed opposite to each other; the first friction layer and the second friction layer have different triboelectric sequences to generate charge through contact and separation under the drive of the driving module; the encapsulation layer is used to encapsulate the first friction layer, the second friction layer and the stimulation electrode; the encapsulation layer is a self-healing elastomer, used to fix and close the ends by relying on its self-healing function after curling; The stimulation electrode is electrically connected to the triboelectric module and is used to electrically stimulate the vagus nerve.

[0006] Furthermore, the self-healing elastomer is a thermally reversible crosslinked polyurethane based on oxime-carbamate dynamic covalent bonds. Triethylamine is added to the thermally reversible crosslinked polyurethane. The triethylamine acts as a three-arm hard segment node to adjust the linear regularity of the polymer chain and the degree of hard segment aggregation, thereby balancing the material's mechanical strength, room temperature flowability, and self-healing properties.

[0007] Furthermore, the preparation method of the thermally reversible crosslinked polyurethane based on oxime-carbamate dynamic covalent bonds includes: reacting polytetrahydrofuran and isophorone diisocyanate under the action of a catalyst, then adding dimethylglyoxime and triethylamine to continue the reaction, obtaining a self-healing polyurethane elastomer solution, and then forming a film to obtain a thermally reversible crosslinked polyurethane encapsulation layer based on oxime-carbamate dynamic covalent bonds; the ratio of polytetrahydrofuran, isophorone diisocyanate, dimethylglyoxime and triethylamine is 29 g: (10-20 g): (2.6-4 g): (60-100 μL).

[0008] Furthermore, the stimulation electrode is a flexible electrode used to wrap around the lower esophagus and the outer wall of the gastroesophageal junction; And / or, both the first friction layer and the second friction layer are flexible materials, so that the triboelectric unit can be rolled up to form a Swiss roll structure.

[0009] Furthermore, when both the first friction layer and the second friction layer are conductive materials with different triboelectric sequences, the stimulation electrode includes two electrodes respectively connected to the first friction layer and the second friction layer. When the first friction layer is made of a conductive material and the second friction layer is made of a polymer material, a conductive layer is also attached to the other side of the second friction layer, and the stimulation electrode includes an electrode that is connected to the first friction layer and the conductive layer respectively.

[0010] Furthermore, both the flexible electrode and the first friction layer are liquid metal electrodes, preferably composite electrodes formed by embedding a eutectic gallium indium alloy in an elastic fiber membrane; the surface of the flexible electrode is preferably modified with polydopamine and filled with conductive hydrogel. And / or, the second friction layer is a polyurethane layer, and a conductive layer is adhered to the other side of the polyurethane layer.

[0011] Furthermore, the driving module is an ultrasonic driving element, the pulse width of which is 1-5 ms and the sound pressure amplitude of the ultrasonic wave is 80-120 kPa. The triboelectric module generates a short-circuit current of 200-1000 μA under the drive of the ultrasonic driving element.

[0012] The present invention also provides a method for preparing the above-described subphrenic vagus nerve stimulation system for cancer neuroimmunotherapy, comprising: stacking a first friction layer and a second friction layer, distributing stimulation electrodes and electrically connecting them to the first friction layer and the second friction layer, and then attaching an encapsulation layer to the outside of the two friction layers, wherein at least one encapsulation layer is attached to the outside of the stimulation electrode, for encapsulating the stimulation electrode after it is fixed at the vagus nerve.

[0013] Furthermore, the first friction layer and the second friction layer are integrally prepared with the stimulation electrode. Specifically, when the first friction layer and the second friction layer are both conductive materials with different triboelectric sequences, the ends of the first friction layer and the second friction layer are respectively cut to leave the stimulation electrode portion. Then, the first friction layer and the second friction layer are attached together, and the stimulation electrode portion does not overlap. Then, an encapsulation layer is used for encapsulation. When the first friction layer is made of a conductive material and the second friction layer is made of a polymer material, the first friction layer is cut to leave a portion for the stimulation electrode, and the other conductive layer is cut to leave a portion for the stimulation electrode. Then the first friction layer and the second friction layer are bonded together, and the conductive layer is adhered to the other side of the second friction layer, with the stimulation electrode portions not overlapping. Then an encapsulation layer is used for encapsulation. After encapsulation, the part other than the stimulation electrode is curled up, and the curled end is automatically fixed and sealed using the self-healing function of the self-healing elastomer.

[0014] This invention provides an application of the subphrenic vagus nerve stimulation system described in any one of the above claims for cancer neuroimmunotherapy, used to prepare a device for treating pancreatic cancer.

[0015] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: (1) Miniaturized wireless implantation: This invention uses a self-healing polyurethane elastomer based on oxime-carbamate dynamic covalent bonds to encapsulate an ultrasonically driven triboelectric device, and achieves a millimeter-scale miniaturized stimulation system by forming a Swiss roll structure through curling. The curled end is automatically sealed by the self-healing polyurethane elastomer. This design completely avoids implantable batteries, receiving coils and wires, significantly reducing the risk of infection and foreign body reaction.

[0016] (2) This invention employs a self-healing polyurethane elastomer encapsulated with oxime-carbamate dynamic covalent bonds. The oxime-carbamate dynamic covalent bonds can undergo reversible exchange at room temperature and body temperature, endowing the material with self-healing capabilities. The addition of triethylamine cleverly regulates the linear regularity of the polymer chains and the degree of hard segment aggregation, enabling the elastomer to have suitable fluidity and sufficient self-healing properties at body temperature. Thus, it can be rolled into shape at room temperature and naturally fixed in shape by recombination of dynamic bonds, without the need for additional heating or adhesives.

[0017] (3) Wireless Ultrasonic Power Supply: This invention uses transdermal ultrasound as the energy source, which has a large penetration depth and high biosafety. The triboelectric thin-film device can generate an open-circuit voltage of about 12 V and a short-circuit current of 210 μA under low-intensity ultrasound (about 100 kPa), with a power density of 5.8 mW / cm². 2 The stimulation system matches the electrophysiological parameters of nerve tissue. Experiments have shown that this stimulation system can successfully induce compound neural action potentials and muscle contraction.

[0018] (4) Significant anti-pancreatic cancer effect: In a mouse model of KPC orthotopic pancreatic cancer, chronic stimulation of the subphrenic vagus nerve using the miniaturized stimulation system of this invention alone reduced tumor weight by 24.7% and metastatic nodules by 49.5%. The mechanism includes reshaping the tumor neural distribution (parasympathetic ↑, sympathetic ↓) and reversing the immunosuppressive microenvironment (M2→M1 macrophages, increased CD8+ T cell and NK cell infiltration, and reduced MDSCs). When used in combination with anti-PD-1 antibody, the tumor suppression effect was further enhanced (tumor weight reduced by 67.9% and metastatic nodules reduced by 61.8%), successfully transforming "cold" tumors into "hot" tumors.

[0019] (5) Good biocompatibility and long-term stability: The self-healing elastomer has excellent biocompatibility. Its dynamic covalent bonds endow the material with self-repair capabilities, and long-term implantation does not cause local inflammation or fibrosis. Wireless power supply avoids the risks of wire penetration and battery leakage. Animal experiments show that after the stimulation system is implanted, the mice have stable body weight, no pathological changes in major organs, and normal heart rate. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the subdiaphragmatic vagus nerve stimulation system used for neuroimmunotherapy of cancer.

[0021] Figure 2 This is a schematic diagram of a layered structure for a triboelectric module.

[0022] Figure 3To characterize the fabrication, flexibility, and rollability of the SVNS (Spirit Stimulation System). a) The SVNS was fabricated by layer-by-layer assembly of an EGaIn@SBS film, an EGaIn@SBS@PU film, and two layers of self-healing PU elastomer film, followed by modification of the electrode sites with IAAC hydrogel. Scale bar, 5 mm. b) SVNS thickness test photograph. Scale bar, 5 mm. c) The SVNS can be stretched to 100% deformation and exhibits reversible elasticity. Scale bar, 1 cm. d) The SVNS can be rolled up using the self-healing elastomer. Scale bar, 5 mm. e) Pressure distribution under ultrasound after SVNS rollup. f) Quantitative comparison of the open-circuit voltage output at 100 kPa ultrasound before and after SVNS rollup. n = 3.

[0023] Figure 4 Representative photograph of SVNS implantation into the subdiaphragmatic vagus nerve in mice. The implantation procedure mainly includes the following steps: abdominal skin preparation, exposure of the upper esophagus and stomach, implantation of the SVNS electrode, filling the electrode-tissue interface with IAAC hydrogel to establish a stable neural interface, coiling the wireless power supply module, repositioning the abdominal organs, and suturing the muscles and skin layer by layer. Scale bar, 5 mm.

[0024] Figure 5 Photographs showing the state of mice after SVNS implantation into the subdiaphragmatic vagus nerve.

[0025] Figure 6 The following are the wireless transmission performance parameters of the SVNS device: a. Input ultrasound signal (pulse width 2 ms, 100 kPa). b. Input ultrasound signal waveform (500 kHz). c. Output open-circuit voltage waveform. d. Output short-circuit current waveform. e. Relationship between SVNS output short-circuit current and open-circuit voltage and ultrasound driving pressure (n=5). f. Relationship between SVNS output current and voltage and load resistance when the input ultrasound pressure is approximately 100 kPa (n=5). g. Relationship between SVNS output power and load resistance when the input ultrasound pressure is approximately 100 kPa (n=5). h. Comparison of open-circuit voltage output of SVNS under approximately 100 kPa ultrasound input before and after continuous immersion in a simulated physiological environment (1×PBS, 37℃) for 4 weeks. i. Schematic diagram of SVNS implantation in mouse sciatic nerve for ultrasound-driven wireless stimulation, and evaluation of stimulation effect by measuring sciatic nerve potential and gastrocnemius muscle tone. j. Changes in sciatic nerve potential before and after wireless stimulation. k. Separation of sciatic nerve potential waveforms evoked by wireless stimulation, showing stimulation artifacts and evoked compound nerve action potentials. l. Changes in gastrocnemius muscle tone before and after wireless stimulation.

[0026] Figure 7Immune microenvironment and neural remodeling in SVNS electrotherapy for pancreatic cancer. a. Schematic diagram of the antitumor experiment in KPC orthotopic pancreatic cancer-bearing mice implanted with SVNS for chronic SVN stimulation. Two groups were set up: Device-only group and Device+US group. In the Device+US group, SVNS was implanted on day 0, and tumors were inoculated on day 6. From day 9, SVN was stimulated by percutaneous low-intensity pulsed ultrasound for 20 minutes daily for 2 weeks. The Device-only group received the same procedure but without ultrasound stimulation. b, c. Representative photographs (b) and weight comparison (c) of pancreatic cancer tissues in the Device+US group and Device-only group after the antitumor experiment. Scale bar, 5 mm (n=8). d. Comparison of the number of metastatic nodules in the Device+US group and Device-only group after the antitumor experiment (n=8). e. Changes in body weight of mice in the Device+US group and Device-only group over time during the antitumor experiment (n=8). fh Representative immunofluorescence images (f) of vesicular acetylcholine transporter (VAChT) and tyrosine hydroxylase (TH) in pancreatic cancer tissues of the Device+US group and Device-only group after the antitumor experiment, and quantitative comparison of VAChT (g) and TH (h). Scale bar, 100 μm (n=6 fields of view, from 3 mice). ip Comparison of the percentages of macrophages (i), CD80+ macrophages (j), CD86+ macrophages (k), CD206+ macrophages (l), myeloid-derived suppressor cells (m), NK cells (n), activated CD4+ T cells (o), and activated CD8+ T cells (p) in pancreatic cancer tissues of the Device+US group and Device-only group after the antitumor experiment (n=6).

[0027] Figure 8To transform pancreatic cold tumors into an anti-PD-1 responsive state through SVNS neuroimmunomodulation. a. Schematic diagram of the anti-tumor experiment in KPC orthotopic pancreatic cancer-bearing mice undergoing chronic SVN stimulation combined with intraperitoneal injection of anti-PD-1 antibodies after SVNS implantation. Four groups were established: Control group, Anti-PD-1 group, SVNS group, and Anti-PD-1+SVNS group. The Control group received no treatment. The Anti-PD-1 group received intraperitoneal injections of anti-PD-1 antibodies twice weekly after tumor modeling. The SVNS group received SVNS implantation after modeling and underwent 20 minutes of abdominal ultrasound stimulation daily for 2 weeks. The Anti-PD-1+SVNS group received both treatments simultaneously. b, c. Representative photographs (b) and weight comparison (c) of pancreatic cancer tissues from the Control, Anti-PD-1, SVNS, and Anti-PD-1+SVNS groups after the anti-tumor experiment. Scale bar, 1 cm (n=8). d. Comparison of the number of gastrointestinal metastatic nodules in the Control, Anti-PD-1, SVNS, and Anti-PD-1+SVNS groups after the anti-tumor experiment (n=8). e. Changes in body weight over time in the Control, Anti-PD-1, SVNS, and Anti-PD-1+SVNS groups during the anti-tumor experiment (n=8). f. Representative immunohistochemical images of Ki67, TUNEL, granzyme B (GZMB), and forkhead box protein P3 (FOXP3) in pancreatic cancer tissues of the Control, Anti-PD-1, SVNS, and Anti-PD-1+SVNS groups after the anti-tumor experiment. Scale bar, 20 μm. gj. Quantitative comparison of immunohistochemical expression of Ki67 (g), TUNEL (h), GZMB (i), and FOXP3 (j) in pancreatic cancer tissues of the Control, Anti-PD-1, SVNS, and Anti-PD-1+SVNS groups after the anti-tumor experiment (n=6 fields, from 3 mice). Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Please see Figure 1This invention provides a subphrenic vagus nerve stimulation system for cancer neuroimmunotherapy, comprising: a triboelectric unit and a stimulation electrode; the triboelectric unit includes a driving module and a triboelectric module, the triboelectric module including an encapsulation layer and a first friction layer and a second friction layer disposed opposite to each other; the first friction layer and the second friction layer have different triboelectric sequences to generate charge through contact and separation under the drive of the driving module; the encapsulation layer is used to encapsulate the first friction layer, the second friction layer and the stimulation electrode; the encapsulation layer is a self-healing elastomer, used to fix and close the ends by relying on its self-healing function after curling; The stimulation electrode is electrically connected to the triboelectric module and is used to electrically stimulate the vagus nerve.

[0030] With this configuration, the present invention achieves wireless power supply through ultrasonic-driven triboelectric generation. The self-healing elastomer encapsulation layer fixes the curled configuration at room temperature or body temperature by relying on its self-healing properties, thus achieving miniaturized wireless implantation.

[0031] Specifically, the self-healing elastomer is a thermally reversibly crosslinked polyurethane based on oxime-carbamate dynamic covalent bonds. Triethylamine is added to this thermally reversibly crosslinked polyurethane to regulate the linear regularity of the polymer chains and the degree of hard segment aggregation, thereby balancing the material's mechanical strength, room temperature flowability, and self-healing properties. The addition of triethylamine gives the material moderate flowability at body temperature to facilitate curling and molding, while avoiding excessive flow, thus allowing it to maintain its shape after curling through the recombination of dynamic bonds.

[0032] Furthermore, the preparation method of the thermally reversible crosslinked polyurethane based on oxime-carbamate dynamic covalent bonds includes: reacting polytetrahydrofuran and isophorone diisocyanate at 60-80℃ for 1-3 h under the action of a catalyst, cooling to room temperature, then adding dimethylglyoxime and triethylamine, and continuing the reaction at 30-50℃ for 10-15 h to obtain a self-healing polyurethane elastomer solution, and then forming a film to obtain a thermally reversible crosslinked polyurethane encapsulation layer based on oxime-carbamate dynamic covalent bonds.

[0033] The ratio of polytetrahydrofuran, isophorone diisocyanate, dimethylglyoxime and triethylamine is 29 g: (10-20 g): (2.6-4 g): (60-100 μL).

[0034] The film formation can include casting followed by hot pressing, specifically: casting a self-healing polyurethane elastomer solution into a polytetrafluoroethylene mold, drying at 80°C for 1 hour to form the film, then drying at 120°C for 6 hours to remove the solvent, to obtain a thick film; finally, hot pressing at 70°C for 60 minutes to obtain a self-healing elastomer film with a thickness of about 50 μm.

[0035] In this system, the dynamic covalent bonds of oxime-carbamate undergo reversible exchange at room temperature and body temperature, endowing the material with self-healing capabilities. Triethylamine, as a regulator of the reversible exchange rate of dynamic bonds, appropriately increases the exchange rate of dynamic bonds, giving the material moderate macroscopic fluidity at body temperature (37°C), facilitating curling operations and interlayer self-adhesion, while preventing excessive flow that could lead to shape instability. Therefore, this elastomer possesses both self-healing capabilities and controllable fluidity at room temperature / body temperature, allowing the integrated device to be curled into a Swiss roll, with interlayer dynamic bonds reorganizing and the curled configuration naturally fixed at body temperature without additional heating.

[0036] Furthermore, the stimulation electrode is a flexible electrode used to wrap around the lower esophagus and the outer wall of the gastroesophageal junction; its flexible structure can dynamically adapt to the periodic deformation of the subdiaphragmatic vagus nerve during breathing and eating.

[0037] Both the first friction layer and the second friction layer are flexible materials, so that the triboelectric generating unit can be rolled up to form a Swiss roll structure to prevent it from breaking.

[0038] Furthermore, when both the first friction layer and the second friction layer are conductive materials with different triboelectric sequences, the stimulation electrode includes two electrodes respectively connected to the first friction layer and the second friction layer. When the first friction layer is made of a conductive material and the second friction layer is made of a polymer material, a conductive layer is also attached to the other side of the second friction layer, and the stimulation electrode includes an electrode that is connected to the first friction layer and the conductive layer respectively.

[0039] like Figure 2 In some specific embodiments, the triboelectric module includes a first self-healing elastomer encapsulation layer, a first liquid metal electrode layer, a polymer friction layer, a second liquid metal electrode layer, and a second self-healing elastomer encapsulation layer stacked sequentially. The polymer friction layer is bonded to the second liquid metal electrode layer but not to the first liquid metal electrode layer, which is used to contact and separate to generate charge. The generated charge is conducted to the stimulation electrode through the first and second liquid metal electrode layers.

[0040] Furthermore, both the flexible electrode and the first friction layer are liquid metal electrodes, preferably composite electrodes formed by embedding a eutectic gallium indium alloy in an elastic fiber membrane; to achieve compliant contact with tissue, the surface of the flexible electrode is preferably modified with polydopamine and filled with conductive hydrogel; the hydrogel can gel in situ to form a conductive adhesion layer, and the hydrogel is a dual-network hydrogel.

[0041] In some specific embodiments, the composite electrode is formed by embedding a eutectic gallium indium alloy (EGaIn) into a styrene-butadiene-styrene block copolymer (SBS) electrospun fiber membrane.

[0042] The second friction layer is a polyurethane layer, and a conductive layer is adhered to the other side of the polyurethane layer.

[0043] Furthermore, the driving module is an ultrasonic driving element, the pulse width of which is 1-5 ms and the sound pressure amplitude of the ultrasonic wave is 80-120 kPa. The triboelectric module generates a short-circuit current of 200-1000 μA under the drive of the ultrasonic driving element.

[0044] The present invention also provides a method for preparing the above-described subphrenic vagus nerve stimulation system for cancer neuroimmunotherapy, comprising: stacking a first friction layer and a second friction layer, distributing stimulation electrodes and electrically connecting them to the first friction layer and the second friction layer, and then attaching an encapsulation layer to the outside of the two friction layers, wherein at least one encapsulation layer is attached to the outside of the stimulation electrode, for encapsulating the stimulation electrode after it is fixed at the vagus nerve.

[0045] Furthermore, the first friction layer and the second friction layer are integrally prepared with the stimulation electrode. Specifically, when the first friction layer and the second friction layer are both conductive materials with different triboelectric sequences, the ends of the first friction layer and the second friction layer are respectively cut to leave the stimulation electrode portion. Then, the first friction layer and the second friction layer are attached together, and the stimulation electrode portion does not overlap. Then, an encapsulation layer is used for encapsulation. When the first friction layer is made of a conductive material and the second friction layer is made of a polymer material, the first friction layer is cut to leave a portion for the stimulation electrode, and the other conductive layer is cut to leave a portion for the stimulation electrode. Then the first friction layer and the second friction layer are bonded together, and the conductive layer is adhered to the other side of the second friction layer, with the stimulation electrode portions not overlapping. Then an encapsulation layer is used for encapsulation. After encapsulation, the part other than the stimulation electrode is curled up, and the curled end is automatically fixed and sealed using the self-healing function of the self-healing elastomer.

[0046] In some specific embodiments, the preparation method specifically includes: (1) Preparation of self-healing elastomer film: Polytetrahydrofuran was vacuum dried and reacted with isophorone diisocyanate and the catalyst dibutyltin dilaurate at 70°C. Then, dimethylglyoxime and triethylamine were added and the reaction was continued at 40°C to obtain a self-healing polyurethane elastomer solution. The solution was cast into a film, dried, and hot-pressed to obtain a self-healing elastomer film. (2) Preparation of triboelectric thin film device: A liquid metal electrode layer and a polymer friction layer are stacked sequentially between two self-healing elastomer films and encapsulated to form an ultrasonically driven triboelectric thin film device; (3) Integrated flexible electrode: The flexible electrode is electrically connected to the triboelectric thin film device to form an integrated device; (4) Miniaturized roll-up: The integrated device is rolled up into a Swiss roll structure at room temperature. The self-healing elastomer is used to make dynamic bonds between the rolled layers recombine in a body temperature environment, thereby fixing the rolled-up configuration and obtaining a miniaturized stimulation system.

[0047] In step (4), after curling, the self-healing elastomer is placed in a 37°C environment to allow the layers to recombine and bond through dynamic bonds, thus permanently fixing the curled configuration.

[0048] The stimulation system described above is used to prepare drugs or devices for treating pancreatic cancer, wherein the treatment of pancreatic cancer includes one or more of the following effects: inhibiting the growth of pancreatic cancer in situ; reducing peritoneal or mesenteric metastasis of pancreatic cancer; remodeling the tumor neural microenvironment, increasing parasympathetic nerve density, and decreasing sympathetic nerve density; reprogramming tumor-associated macrophages from M2 to M1 type; increasing the infiltration and activation of CD8+ T cells, CD4+ T cells, and natural killer cells; reducing the proportion of myeloid-derived suppressor cells; and enhancing the efficacy of anti-PD-1 immunotherapy.

[0049] Specifically, the stimulation system is used in combination with an immune checkpoint inhibitor; preferably, the immune checkpoint inhibitor is an anti-PD-1 antibody.

[0050] Example 1: Preparation of self-healing elastomers and construction of miniaturized stimulation systems In this embodiment, a self-healing polyurethane elastomer film was first prepared based on the dynamic covalent bonds of oxime-carbamate, and then a miniaturized subdiaphragmatic vagus nerve stimulation system was constructed.

[0051] (1) Synthesis and film formation of self-healing polyurethane elastomers: a. Place 29 g of polytetrahydrofuran (PTMEG, Mn=1000) in a three-necked flask, dry it under vacuum at 100°C with stirring for 1 hour, then cool it to 70°C and store it under nitrogen protection.

[0052] b. Dissolve 13.54 g of isophorone diisocyanate (IPDI) and 0.10 g of dibutyltin dilaurate (DBTDL) in 10 mL of N,N-dimethylacetamide (DMAc) to obtain a mixed solution.

[0053] c. Add the mixed solution dropwise to the above-mentioned dried PTMEG and stir the mixture at 70°C for 2 hours.

[0054] d. After the reaction is complete and cooled to room temperature, 3.366 g of dimethylglyoxime (DMG) and 80 μL of triethylamine (TEA) are added, and the reaction is continued to be stirred at 40 °C for 12 hours. Triethylamine is used to regulate the reversible exchange rate of the oxime-carbamate dynamic bonds, ensuring that the final elastomer has moderate macroscopic fluidity at body temperature (facilitating curling operations and interlayer self-adhesion) while maintaining self-healing ability.

[0055] e. After the reaction is complete, add 60 mL of DMAc to dilute and obtain a self-healing polyurethane elastomer solution with a solid content of about 30%.

[0056] f. The solution is cast into a polytetrafluoroethylene mold, dried at 80°C for 1 hour to form the film, and then thoroughly dried at 120°C for 6 hours to remove the solvent, resulting in a thick film.

[0057] g. The above-mentioned thick film is hot-pressed at 70°C for 60 minutes to obtain a self-healing elastomer film with a thickness of approximately 50 μm. This film has self-healing capabilities at room temperature and body temperature. Simultaneously, due to the regulation of triethylamine, the film exhibits moderate viscoelastic flow at 37°C, allowing it to bend and curl under slight external force and self-adhere, fixing its shape without additional heating.

[0058] (2) Fabrication of flexible liquid metal electrodes: a. Dissolve 12.5 wt% of styrene-butadiene-styrene block copolymer (SBS) in 1,2-dichloroethane and stir magnetically overnight at 60°C to obtain a transparent viscous solution.

[0059] b. SBS fiber membranes were prepared on a rotating cylindrical collector using electrospinning at voltages of 13 kV and -3 kV, a feed rate of 0.3 mm / min, and a receiving distance of 15 cm.

[0060] c. Eutectic gallium indium alloy (EGaIn) is dropped onto the surface of SBS fiber membrane, repeatedly rolled with PTFE rollers, and then subjected to 6 cycles of 200% strain stretching to fully embed EGaIn into the fiber network to obtain LM electrode.

[0061] (3) Construction of triboelectric thin film devices: a. The LM electrode was cut into a "hammer" shape using a blade: the power module portion was 3.5 mm × 12 mm, and the stimulation electrode portion was 1.3 mm × 7 mm. The stimulation electrode portion of the LM electrode was immersed in a Tris-HCl buffer solution (pH = 8.5) containing 1 wt% dopamine hydrochloride and reacted at room temperature for 6 hours to obtain the LM@PDA electrode, which enhances subsequent compliance and adhesion to tissues.

[0062] b. Completely cover and adhere the power module portion of the LM@PDA electrode with commercial polyurethane (PU) tape (20 μm thick) to form a PU friction layer.

[0063] c. Take two self-healing elastomer films prepared in step (1), with dimensions of 23 mm × 5 mm (top layer) and 12 mm × 5 mm (bottom layer), respectively.

[0064] d. Align and overlap the power module portion of the PU side of the LM@PDA electrode and the PU friction layer to form two triboelectric power generation structures that can contact and separate. Then, place them between two self-healing elastomer films and thermo-press them at 70°C and 2 MPa pressure to form an integrated triboelectric thin film device. Figure 3 As shown in Figure a, this triboelectric generator has a thickness of only about 240 μm and exhibits good tensile properties, recovering its original shape after being stretched 100%. Figure 3 As shown in b and c.

[0065] (4) Miniaturized curling and shaping: a. Keep the flexible stimulation electrode portion of the integrated device flat, and tightly roll the power module portion into a Swiss roll structure (about 3 turns) along its length at room temperature.

[0066] b. Place the curled device in a 37°C constant temperature oven for 2 hours to allow the dynamic covalent bonds between the self-healing elastomer layers to recombine, bonding the layers together through self-healing, thereby permanently fixing the curled configuration. Figure 3 Medium d. No heating or pressurization is required; shaping is achieved solely through body temperature. Furthermore, performance output decreases by less than 10% after curling. Figure 3 China and Figure 1 (f)

[0067] c. The final miniaturized stimulation system has a power module with a diameter of approximately 1.5 mm and a length of approximately 3 mm, and a flexible electrode section with a straight length of approximately 7 mm.

[0068] (5) Characterization of wireless output capability: The constructed stimulation system was placed in a simulated physiological environment (1×PBS, 37℃), and pulsed ultrasound was applied via a coupling medium using an ultrasound probe with a center frequency of 500 kHz. The ultrasound parameters were set to a pressure of approximately 100 kPa, each pulse containing 1000 sine waves (corresponding to a 2 ms pulse width), and a pulse interval of 1 second. Figure 6 (ad). Under the above driving conditions, the open-circuit voltage generated by the stimulation system is approximately 12 V, and the short-circuit current is approximately 210 μA. Output performance increases with increasing ultrasonic pressure. Figure 6(e). Measured under different load resistances, the maximum output power density, approximately 5.8 mW / cm², is reached at a load resistance of approximately 20 kΩ. 2 ( Figure 6 (f and g). Long-term stability tests showed that after immersion in a simulated physiological environment for 4 weeks, the open-circuit voltage output decreased by less than 10%. Figure 6 (h).

[0069] (6) Characterization of neural activation capacity: The neural activation capability of the stimulation system was verified using a mouse sciatic nerve model. The stimulation system (i.e., the triboelectric thin-film device) prepared in Example 1 was implanted around the sciatic nerve in mice, and percutaneous ultrasound stimulation (100 kPa, 2 ms pulse width, 1 second interval) was applied. Sciatic nerve potentials and gastrocnemius muscle tone were simultaneously recorded using an electrophysiological recording system. After ultrasound stimulation, stimulation artifacts and evoked compound action potentials (CNAPs) were clearly recorded, confirming that the electrical pulse signal was successfully transmitted to the nerve fiber. Figure 6 (i, j, and k). Simultaneously, the gastrocnemius muscle exhibited visible rhythmic twitching, and the muscle tone recording showed a corresponding 1Hz pulse pattern, consistent with the ultrasound stimulation frequency, indicating that neural activation successfully triggered a physiological response in the effector. Figure 6 (l).

[0070] Example 2: Miniaturized stimulation system as a standalone treatment for pancreatic cancer This embodiment verifies the therapeutic effect of using the aforementioned miniaturized stimulation system alone on pancreatic cancer.

[0071] (1) Animal model establishment: KPC (KrasG12D, Trp53R172H) mouse pancreatic cancer cells were injected into the pancreatic head of C57BL / 6 mice to establish an orthotopic pancreatic cancer model.

[0072] (2) Grouping and Treatment: Mice were randomly divided into two groups: a control group (Device-only) and a stimulation group (Device+US). Both groups underwent implantation of the stimulation system (i.e., the triboelectric thin-film device) prepared in Example 1 into the subdiaphragmatic vagus nerve site, as described in Example 1. The implantation process is as follows: Figure 4 and 5 As shown. The control group did not receive ultrasound stimulation; the stimulation group received percutaneous ultrasound (100 kPa, 2 ms pulse width, 1 second interval, for 20 minutes) to drive the stimulation system daily starting on the 3rd day after surgery, for 2 weeks.

[0073] (3) Experimental results: a. Inhibiting tumor growth and metastasis: such as Figure 7As shown in the figure, compared with the control group, the in situ tumor weight of the stimulation group was significantly reduced by 24.7%, and the number of mesenteric metastatic nodules was significantly reduced by 49.5%, indicating that stimulation alone can effectively inhibit the progression of pancreatic cancer.

[0074] b. Safety: The body weight of both groups of mice remained stable during the experiment. Figure 7 (e) There was no significant difference.

[0075] c. Remodeling the tumor neural microenvironment: Immunofluorescence staining ( Figure 7 The results showed that the expression of the parasympathetic marker VAChT in the tumor of the stimulation group was significantly higher than that of the control group, while the expression of the sympathetic marker TH was significantly lower, indicating that the stimulation successfully remodeled the neural innervation balance of the tumor.

[0076] d. Reversing the immunosuppressive microenvironment: flow cytometry analysis ( Figure 7 The study (in 1-IP) showed that, compared with the control group, the proportion of M1 macrophages (CD80+, CD86+) was significantly increased and the proportion of M2 macrophages (CD206+) was significantly decreased in the stimulation group; the proportions of NK cells, CD4+ and CD8+ T cells and their activated subsets (CD69+) were all significantly increased; and the proportion of myeloid-derived suppressor cells (MDSCs) was significantly decreased. This indicates that the tumor microenvironment has shifted from a "cold" state to a "hot" state of immune activation.

[0077] Example 3: Verification Experiment of Subphrenic Vagus Nerve Resection This application case verifies the therapeutic effect of combining the stimulation system with anti-PD-1 immunotherapy.

[0078] (1) Animal model establishment: Same as in Example 2.

[0079] (2) Grouping and Treatment: Mice were randomly divided into four groups (n=8 per group): Control group, SVNS group, Anti-PD-1 group, and Combined group (Anti-PD-1 + SVNS). The control group underwent only sham surgery without implantation of the SVNS system and received no treatment. The SVNS group received the SVNS system implanted as described in Example 1, and received daily ultrasound stimulation (parameters as in Example 2) starting on the 3rd day after surgery for 2 weeks. The Anti-PD-1 group did not receive the SVNS system implanted, but received intraperitoneal injection of anti-PD-1 antibody (5 mg / kg, twice a week for 2 weeks) starting on the 3rd day after modeling. The Combined group received SVNS implantation, ultrasound stimulation, and anti-PD-1 antibody injection simultaneously (administration regimen as above).

[0080] (3) Experimental results: a. Inhibiting tumor growth and metastasis: such as Figure 8As shown in the diagram, both the stimulation system group and the anti-PD-1 monotherapy group showed certain anti-tumor effects compared with the control group, but the combination group showed the most significant effect. Compared with the anti-PD-1 monotherapy group, the combination group had a 67.9% reduction in tumor weight and a 61.8% reduction in metastatic nodules.

[0081] b. Safety evaluation: The body weight of mice in all treatment groups remained stable ( Figure 8 (e).

[0082] c. Enhancing anti-PD-1 efficacy: Immunohistochemical analysis ( Figure 8 The results showed that the combined group had the lowest expression of the tumor proliferation marker Ki67, the highest expression of the apoptosis marker TUNEL and the cytotoxic T cell activity marker GZMB, and the lowest expression of the immunosuppressive regulatory T cell marker Foxp3. This indicates that the stimulation system successfully overcame the resistance of pancreatic cancer to anti-PD-1 therapy.

[0083] In summary, after implantation, the stimulation system of this invention features flexible electrodes that wrap around the lower esophagus and the outer wall of the gastroesophageal junction, forming compliant contact with the tissue through in-situ gelled conductive hydrogel. This invention provides long-term, stable, chronic stimulation of the subphrenic vagus nerve via this miniaturized stimulation system, significantly inhibiting pancreatic cancer growth and metastasis, reshaping the tumor immune microenvironment, and transforming "cold" tumors into "hot" tumors sensitive to PD-1 immunotherapy, thus offering a novel wireless, minimally invasive neuromodulation approach for pancreatic cancer treatment.

[0084] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A subdiaphragmatic vagus nerve stimulation system for cancer neuroimmunotherapy, characterized in that, include: A triboelectric generating unit and a stimulation electrode; the triboelectric generating unit includes a driving module and a triboelectric generating module, the triboelectric generating module includes an encapsulation layer and a first friction layer and a second friction layer disposed opposite to each other; the first friction layer and the second friction layer have different triboelectric sequence positions, so as to generate charge by contacting and separating under the drive of the driving module; The encapsulation layer is used to encapsulate the first friction layer, the second friction layer, and the stimulation electrode; the encapsulation layer is a self-healing elastomer, which is used to fix and close the end by relying on its self-healing function after being rolled up. The stimulation electrode is electrically connected to the triboelectric module and is used to electrically stimulate the vagus nerve.

2. The subdiaphragmatic vagus nerve stimulation system for cancer neuroimmunotherapy according to claim 1, characterized in that, The self-healing elastomer is a thermally reversible crosslinked polyurethane based on oxime-carbamate dynamic covalent bonds. Triethylamine is added to the thermally reversible crosslinked polyurethane. The triethylamine serves as a three-arm hard segment node to adjust the linear regularity of the polymer chain and the degree of hard segment aggregation.

3. The subdiaphragmatic vagus nerve stimulation system for cancer neuroimmunotherapy according to claim 2, characterized in that, The method for preparing the thermally reversible crosslinked polyurethane based on oxime-carbamate dynamic covalent bonds includes: reacting polytetrahydrofuran and isophorone diisocyanate under the action of a catalyst, then adding dimethylglyoxime and triethylamine to continue the reaction, to obtain a self-healing polyurethane elastomer solution, and then forming a film to obtain a thermally reversible crosslinked polyurethane encapsulation layer based on oxime-carbamate dynamic covalent bonds; The ratio of polytetrahydrofuran, isophorone diisocyanate, dimethylglyoxime and triethylamine is 29 g: (10-20 g): (2.6-4 g): (60-100 μL).

4. The subdiaphragmatic vagus nerve stimulation system for cancer neuroimmunotherapy according to any one of claims 1-3, characterized in that, The stimulation electrode is a flexible electrode used to wrap around the outer wall of the lower esophagus and the gastroesophageal junction, and its flexibility is used to achieve dynamic adaptation of the subphrenic vagus nerve. And / or, both the first friction layer and the second friction layer are flexible materials, so that the triboelectric generating unit can be rolled up to form a Swiss roll structure.

5. The subdiaphragmatic vagus nerve stimulation system for cancer neuroimmunotherapy according to any one of claims 1-3, characterized in that, When both the first friction layer and the second friction layer are conductive materials with different triboelectric sequences, the stimulation electrode includes two electrodes that are respectively connected to the first friction layer and the second friction layer. When the first friction layer is made of a conductive material and the second friction layer is made of a polymer material, a conductive layer is also attached to the other side of the second friction layer, and the stimulation electrode includes an electrode that is connected to the first friction layer and the conductive layer respectively.

6. The subdiaphragmatic vagus nerve stimulation system for cancer neuroimmunotherapy according to claim 4, characterized in that, Both the flexible electrode and the first friction layer are liquid metal electrodes, preferably composite electrodes formed by embedding a eutectic gallium indium alloy in an elastic fiber membrane; the surface of the flexible electrode is preferably modified with polydopamine and filled with conductive hydrogel. And / or, the second friction layer is a polyurethane layer, and a conductive layer is adhered to the other side of the polyurethane layer.

7. The subdiaphragmatic vagus nerve stimulation system for cancer neuroimmunotherapy according to any one of claims 1-6, characterized in that, The driving module is an ultrasonic driving element, the pulse width of which is 1-5 ms and the sound pressure amplitude of the ultrasonic wave is 80-120 kPa. The triboelectric module generates a short-circuit current of 200-1000 μA under the drive of the ultrasonic driving element.

8. A method for preparing a subdiaphragmatic vagus nerve stimulation system for cancer neuroimmunotherapy as described in any one of claims 1-7, characterized in that, include: The first friction layer and the second friction layer are stacked, and the stimulation electrode is electrically connected to the first friction layer and the second friction layer. Then, the encapsulation layer is attached to the outside of the two friction layers, and at least one encapsulation layer is attached to the outside of the stimulation electrode, so that the stimulation electrode can also be encapsulated after it is fixed at the vagus nerve.

9. The method for preparing the subdiaphragmatic vagus nerve stimulation system for cancer neuroimmunotherapy according to claim 8, characterized in that, The first friction layer and the second friction layer are integrated with the stimulation electrode. Specifically, when the first friction layer and the second friction layer are both conductive materials with different triboelectric sequences, the ends of the first friction layer and the second friction layer are respectively cut to leave the stimulation electrode portion. Then, the first friction layer and the second friction layer are attached together, and the stimulation electrode portion does not overlap. Then, an encapsulation layer is used for encapsulation. When the first friction layer is made of a conductive material and the second friction layer is made of a polymer material, the first friction layer is cut to leave a portion for the stimulation electrode, and the other conductive layer is cut to leave a portion for the stimulation electrode. Then the first friction layer and the second friction layer are bonded together, and the conductive layer is adhered to the other side of the second friction layer, with the stimulation electrode portions not overlapping. Then an encapsulation layer is used for encapsulation. After encapsulation, the part other than the stimulation electrode is curled up, and the curled end is automatically fixed and sealed using the self-healing function of the self-healing elastomer.

10. The application of the subdiaphragmatic vagus nerve stimulation system according to any one of claims 1-7 for cancer neuroimmunotherapy, characterized in that, Devices used to prepare for the treatment of pancreatic cancer.

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