Stomach sampling device based on obdurability biocompatible hydrogel film

Abstract

The invention belongs to the technical field of medical apparatus and instruments, and discloses a stomach sampling device based on a obdurability biocompatible hydrogel film, which comprises an expandable sampling cap and an in vitro traction device, the sampling cap is a closed cavity formed by a high-toughness hydrogel film, and water-absorbing particles and a magnetic control capsule are packaged in the hydrogel film; the in-vitro traction device comprises a traction line and an external oral fixing card, one end of the traction line is fixed inside the sampling cap in an embedding, knotting or anchoring manner, and the other end of the traction line is connected with the external oral fixing card. The whole process does not need intubation anesthesia, physiological pain and psychological fear of a patient are greatly reduced, the surface of the expanded hydrogel sphere is smooth and soft, the discomfort of the expanded hydrogel sphere passing through the esophagus during recovery is far lower than that of traditional gastric sponge, the compliance of the patient is remarkably improved, and the magnetic control capsule and an external magnetic control system are combined. Due to the real-time visualization and active navigation functions, the sampling accuracy and the cell acquisition rate are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more specifically, to a gastric sampling device based on a tough, biocompatible hydrogel membrane. Background Technology

[0002] The diagnosis of gastric diseases largely depends on the acquisition and analysis of gastric mucosal tissue or cell samples. Currently, the most mainstream sampling technique in clinical practice is gastric mucosal biopsy via gastroscopy, which involves using biopsy forceps to extract tissue samples from the patient's stomach under direct visualization. While this method can obtain complete tissue structure information, it is a typical invasive examination. The procedure not only causes mechanical damage to the gastric mucosa but may also lead to complications such as bleeding and infection. Furthermore, gastroscopy also causes significant psychological stress and physical discomfort for patients, resulting in low patient compliance during routine screenings and population surveys.

[0003] To reduce invasiveness, several novel gastric sampling techniques have emerged in recent years, such as swallowable sponge-like sampling devices with traction wires. Once swallowed, the sponge structure expands in the gastric juices, collecting cells from the gastric mucosa through adsorption and scraping, which are then retrieved orally via the traction wire. This method reduces reliance on endoscopy and anesthesia, offering greater convenience and scalability. However, these methods still have several significant drawbacks in practical applications: 1. Insufficient performance of sampling materials: Materials such as sponges have limited mechanical strength and are prone to breakage during traction and recovery, resulting in sample loss or device residue; 2. Poor biocompatibility: The material may trigger a local inflammatory response in the gastric mucosa, which may not only affect patient safety but also interfere with the accuracy of subsequent cytological tests; 3. Insufficient sampling and recovery accuracy: The amount of sample attached is limited and there is a risk of cell loss during the recovery process, which affects the reliability of the detection; 4. Lack of stable fixing structure: Relying on the traction line for recovery, but the traction line is prone to slippage, breakage or tangling, which seriously reduces the safety and success rate of operation.

[0004] In the field of materials science, hydrogels are highly hydrophilic polymer materials with a three-dimensional network structure that can swell in water and retain a large amount of water without dissolving. They possess good flexibility, excellent biocompatibility, and tunable physicochemical properties, thus finding wide application in wound dressings, drug delivery systems, tissue engineering scaffolds, and medical device coatings. Existing technology has developed an ingestible hydrogel device that encapsulates water-absorbing particles through a tough hydrogel membrane. This device rapidly expands into a large, robust, soft sphere in gastric juice, achieving long-term gastric retention. Upon ingestion of a calcium solution, it contracts and is safely expelled from the gastrointestinal tract.

[0005] However, the device has obvious limitations: its function is too singular, mainly used for passive monitoring, lacking active intervention capabilities (such as sampling and targeted drug delivery), and its recovery usually depends on the contraction caused by drinking calcium solution and excretion with feces, which is an uncontrollable process and is not suitable for cytological examinations that require active and rapid sample recovery. Furthermore, its long-term biosafety and the complexity of its preparation process are also issues that need to be considered in practical applications.

[0006] Therefore, there is an urgent need in this field for a novel gastric sampling device that can integrate visual diagnosis with precise sampling and achieve safe, reliable, and controllable recovery. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a gastric sampling device based on a tough biocompatible hydrogel membrane. This device can achieve gastric cell sampling without anesthesia and with minimal trauma, and achieves real-time visualization and targeted positioning through the integration of a magnetically controlled capsule, which significantly improves the accuracy and success rate of sampling.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A gastric sampling device based on a tough, biocompatible hydrogel membrane, including an expandable sampling cap and an external traction device. The sampling cap consists of a sealed cavity formed by a strong and resilient hydrogel membrane. The hydrogel membrane encapsulates water-absorbing particles and a magnetically controlled capsule. The magnetically controlled capsule integrates a camera, a wireless transmission module, an illumination source, and a power supply module. The camera captures real-time images of the gastric environment and transmits them to an external receiving device, enabling observation and recording of the sampling location. The magnetically controlled capsule can cooperate with an external magnetically controlled device to actively move and precisely position the sampling cap within the gastric cavity using magnetic field force. This allows the entire sampling cap to actively approach a specific area of ​​the stomach wall for targeted sampling, significantly improving the accuracy and effectiveness of the sampling.

[0009] The external traction device includes a traction wire and an extraoral fixation card. One end of the traction wire is fixed inside the sampling cap by embedding, knotting or anchoring, and the other end is connected to the extraoral fixation card. The sampling cap absorbs water and swells in the gastric juice after being swallowed. Its outer surface comes into contact with the gastric mucosa and adheres to exfoliated cells. Then, it is pulled out of the body through the esophagus by the traction line to complete the non-invasive gastric mucosal cell sampling.

[0010] Its working process is as follows: Before being swallowed, the device is in a dry and compressed state. After entering the stomach, gastric juice permeates into the cavity through the hydrogel membrane and is absorbed by the water-absorbing particles. The water-absorbing particles rapidly swell, generating a huge expansion force, driving the sampling cap from a compressed state to an expanded state. After expansion, the diameter of the sampling cap increases significantly, and the outer surface becomes soft and adhesive, allowing it to make extensive contact with the gastric mucosa and adhere to exfoliated cells.

[0011] Simultaneously, the internal camera and illumination source of the magnetically controlled capsule activate, capturing images of the stomach cavity. These images are then wirelessly transmitted to an external receiving device, allowing doctors to monitor the stomach in real time. If sampling of a specific area is required, an external magnetically controlled device can generate a magnetic field to attract or repel the capsule, driving the entire sampling cap to move within the stomach cavity and locate the target stomach wall region, achieving targeted sampling. After sampling, the sampling cap can be completely pulled out of the body via the esophagus using an external traction wire, thus obtaining a gastric mucosal cell sample.

[0012] Preferably, the sampling cap, in its dry, unexpanded state, is a slender cylinder or olive shape with a diameter of 2-8 mm and a length of 5-40 mm, a shape that facilitates swallowing. When expanded, the sampling cap becomes an approximate sphere or ellipsoid with a diameter of 10-60 mm. This size ensures sufficient and gentle contact with the stomach wall while guaranteeing easy retrieval.

[0013] Preferably, the traction suture is made of a material selected from polyester, nylon, silk, or bioabsorbable suture, and has good biocompatibility and tensile strength.

[0014] Preferably, the length of the traction wire embedded in the sampling cap is 5-60 mm, and the diameter of the traction wire is 0.5-3 mm, for example, 1.5 mm. The total length of the traction wire is 5-60 cm, for example, 40, 45, or 50 cm. Sufficient embedment length ensures the reliability of traction and prevents it from falling off during traction.

[0015] Preferably, the hydrogel membrane is made of one or more composite materials selected from polyvinyl alcohol (PVA), gelatin methacryloyl (GelMA), alginate, chitosan, or polylactic-co-glycolic acid copolymer (PLGA) that have undergone physical or chemical cross-linking. These materials have good biocompatibility, strong mechanical properties, and controllable degradation characteristics.

[0016] Preferably, the thickness of the hydrogel film is 0.05-0.5 mm, the tensile breaking strength is not less than 1 MPa, and the elongation at break is not less than 200%. These mechanical properties ensure that the sampling cap will not easily break during expansion and traction, thus guaranteeing the success rate and safety of sampling.

[0017] Preferably, the absorbent particles are made of materials including but not limited to sodium polyacrylate, sodium carboxymethyl cellulose, gelatin particles, chitosan derivatives, etc. The absorbent particles have a particle size of 50-500 micrometers. These materials are all mature medical-grade polymers with good water absorption and swelling properties and biocompatibility. They are widely used in oral delivery systems and biomedical materials, and can be used alone or in combination in gastric sampling devices.

[0018] Preferably, the surface of the hydrogel membrane is provided with a plurality of water-permeable pores, the pore diameter of which is 10-500 micrometers and the pore density is 1-10 pores / cm². The water-permeable pores can significantly accelerate the permeation of gastric juice, shorten the expansion start time of the sampling cap, and control the expansion rate.

[0019] Preferably, the diameter of the water-absorbing particles is larger than the pore size of the water-permeable pores on the surface of the hydrogel membrane.

[0020] Preferably, the camera is a high-definition pinhole camera.

[0021] Preferably, the shell portion of the magnetically controlled capsule is bonded and fixed to the inner wall of the hydrogel membrane with a biocompatible adhesive to prevent the magnetically controlled capsule from rolling or shifting inside the sampling cap.

[0022] Compared with the prior art, the advantages of this invention are: I. High patient comfort: The entire process does not require intubation anesthesia, which greatly reduces the patient's physical pain and psychological fear. The surface of the expanded hydrogel spheres is smooth and soft, and the discomfort when passing through the esophagus during retrieval is far less than that of traditional gastric sponges, which significantly improves patient compliance.

[0023] II. Precise and controllable sampling: Combining the magnetically controlled capsule with an external magnetic control system, real-time visualization and active navigation functions allow doctors to "see" and "control" the sampling cap to move to the target area for targeted sampling, greatly improving the accuracy of sampling and cell acquisition rate, and avoiding blind sampling.

[0024] Third, high sample quality: The soft hydrogel surface can make gentle, large-area contact with the gastric mucosa, effectively adhering to exfoliated cells, while avoiding mechanical damage to cells by biopsy forceps or sponges, which is beneficial for subsequent cytological and molecular biological analysis.

[0025] IV. High integration: It innovatively integrates the three major functions of sampling, visualization and magnetic navigation into a micro device, forming a complete "observation-positioning-sampling" closed-loop system.

[0026] V. Safety and Reliability: The use of a high-strength and tough hydrogel membrane ensures that the device will not rupture during expansion in the stomach and retrieval via the esophagus. Physical retrieval via a traction line is an active, controllable, and rapid process, avoiding the uncertainties and long cycles of existing technologies that rely on chemical contraction and excretion with feces.

[0027] VI. Ultimate Safety and Self-Guiding Capability: During the recovery process, the soft hydrogel spheres act as pioneers, adapting to the shape of the esophagus and effectively avoiding the risk of obstruction. The pulling force is evenly distributed by the hydrogel membrane, preventing the rigid capsule from directly compressing the esophageal wall and fundamentally eliminating mechanical damage. Simultaneously, the device naturally forms a streamlined shape under traction, with the hydrogel spheres leading the way and the capsule following stably behind, significantly reducing operational difficulty and achieving smooth recovery without the need for precise control. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the expanded sampling cap of the present invention; Figure 3 This is a schematic diagram of the system structure of the magnetically controlled capsule of the present invention.

[0029] Explanation of the labels in the diagram: 1. Magnetic control capsule; 11. Camera; 12. Wireless transmission module; 13. Light source; 14. Power supply module; 2. Sampling cap; 21. Hydrogel membrane; 211. Water-permeable pores; 22. Water-absorbing particles; 3. Traction wire; 4. External fixation card. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] Example 1: Basic Rapid Sampling Type See Figure 1 , 2 This embodiment presents a basic gastric sampling device. The device includes an expandable sampling cap 2 and an external traction device.

[0032] The sampling cap 2 is a sealed cavity formed by a tough hydrogel membrane 21. In this embodiment, the hydrogel membrane 21 is made of chemically cross-linked polyvinyl alcohol (PVA) material with a thickness of 0.1 mm, a tensile breaking strength of 2.5 MPa, and an elongation at break of 350%. The membrane surface does not have water-permeable pores 211, and mainly relies on the material's own permeability to absorb water.

[0033] The hydrogel membrane 21 encapsulates water-absorbing particles 22 and a magnetically controlled capsule 1. The water-absorbing particles 22 are medical-grade sodium polyacrylate with a particle size of 100-200 micrometers. The magnetically controlled capsule 1 integrates a high-definition pinhole camera 11, a wireless transmission module 12, an LED lighting source 13, and a button battery power supply module 14. Figure 3 As shown.

[0034] The external traction device includes a traction wire 3 and an extraoral fixation card 4. One end of the traction wire 3 is firmly fixed inside the sampling cap 2 by embedding it with a biocompatible adhesive, and the fixation point is located between the tail end of the magnetically controlled capsule 1 and the inner wall of the hydrogel membrane 21, ensuring that the traction force acts directly on the rigid body of the magnetically controlled capsule 1. The other end is connected to the extraoral fixation card 4. In this embodiment, the traction wire 3 is a nylon wire with a diameter of 1.5 mm, and the length embedded in the sampling cap 2 is 20 mm, with a total length of 40 cm. The sampling cap 2 in this embodiment expands rapidly, has high strength, can effectively collect cells, and has reliable retrieval.

[0035] The method for preparing the gastric sampling device of the present invention is as follows: First, fold and heat-press the hydrogel membrane 21 into a pocket shape, fill it with water-absorbing particles 22 and the magnetically controlled capsule 1, insert and attach the traction wire 3, and finally seal it, rolling it into a pill-sized form for easy swallowing. During the insertion of the traction wire 3, ensure it is securely encased inside the sampling cap 2, and simultaneously ensure the camera window of the magnetically controlled capsule 1 is not obstructed. The hydrogel membrane 21 should adhere tightly to the capsule shell to ensure stability.

[0036] The method of using the gastric sampling device of the present invention is as follows: The patient swallows the sampling cap 2, containing the magnetically controlled capsule 1, with water, placing it into the stomach. The end with the external fixation card 4 remains outside the body; either the medical staff or the patient holds the card, or the distal end of the thin thread can be attached to the user's cheek using medical tape. Gastric fluid slowly permeates into the cavity through the hydrogel membrane 21 and is absorbed by the absorbent particles 22. The sampling cap 2 is a cylindrical shape with a diameter of 5 mm and a length of 20 mm in its dry state (e.g., ...). Figure 1 (As shown) or an olive shape, expanded into an approximate sphere with a diameter of about 35 mm (such as) Figure 2 (As shown).

[0037] During this process, the magnetically controlled capsule 1 and the illumination source 13 activate, capturing images of the stomach cavity and transmitting them wirelessly to an external receiving device via the wireless transmission module 12. By observing the real-time images, the doctor can manipulate the magnetically controlled capsule 1 using the external magnetic control device, causing the entire expanded sampling cap 2 to roll within the stomach cavity. This allows its outer surface to contact, scrape, and adhere to and collect exfoliated cells from different areas of the gastric mucosa. After approximately 3-5 minutes, the doctor gently and continuously pulls the traction line 3 to completely remove the sampling cap 2 through the esophagus and mouth, completing the sampling process. The retrieved sample can be used for cytological smears or molecular biological testing.

[0038] Furthermore, during the retrieval process, this invention exhibits exceptional safety and self-guiding advantages: Because the sampling cap 2 is composed of a soft hydrogel membrane 21, its surface is smooth and deformable after expansion. When passing through a narrow and tortuous esophagus, it can act as a pioneer, adapting to the shape of the esophagus and effectively opening the passage, greatly reducing the risk of the magnetically controlled capsule 1 becoming stuck in folds or sphincter muscles. The traction force is first borne by the hydrogel membrane 21 and distributed throughout the entire sphere, then evenly transmitted to the magnetically controlled capsule 1, avoiding the rigid capsule directly generating high pressure on a single point of the esophageal wall, fundamentally eliminating mechanical damage. Simultaneously, the device naturally forms an optimal streamline shape under traction: the soft hydrogel sphere deforms in front to open the path, while the rigid capsule follows stably behind. This passive self-guiding mechanism significantly reduces the difficulty of operation, allowing doctors to achieve smooth and safe retrieval without precise control.

[0039] Example 2: High-speed expansion targeted sampling type This embodiment optimizes the structure and magnetocontrol function of the hydrogel membrane 21 based on Embodiment 1, aiming to achieve faster expansion speed and more precise targeted sampling. The main difference between this embodiment and Embodiment 1 is: The hydrogel membrane 21 material was changed to gelatin methacryloyl (GelMA), with a thickness of 0.2 mm. For example... Figure 2 As shown, several water-permeable pores 211 are laser-processed on the surface of the hydrogel membrane 21. The pore diameter of the water-permeable pores 211 is 50 micrometers, and the pore density is 5 pores / cm². This structure can greatly accelerate the penetration of gastric juice into the cavity, shortening the expansion start-up time of the sampling cap 2 to less than 2 minutes. At the same time, the magnetically controlled capsule 1 integrates a higher-performance high-definition pinhole camera and a more sensitive magnetic control response module, which can seamlessly cooperate with commercial magnetic navigation systems to achieve faster and more accurate intragastric navigation and fixed-point residence, thereby enabling efficient targeted sampling of suspicious lesions.

[0040] Work process: Due to the presence of the permeable pores 211, gastric juice rapidly flows into the cavity, and the water-absorbing particles 22 swell rapidly, causing the sampling cap 2 to quickly expand to the predetermined size within a short time. Guided by real-time imaging, doctors can more quickly identify suspicious areas and use a high-precision magnetic control system to precisely position and closely adhere the sampling cap 2 to the target gastric wall area, such as around suspicious lesions, for focused "scraping," achieving "targeted sampling" of specific areas. This not only improves sampling efficiency but also significantly enhances the cell acquisition rate for micro-lesions.

[0041] Example 3: Degradable and safe type This embodiment focuses on the long-term safety of the device and the convenience of subsequent examinations, and is particularly suitable for patients who are concerned about discomfort caused by the traction wire 3 or who need subsequent imaging examinations such as MRI. The main difference between this embodiment and Embodiments 1 and / or 2 is: The traction suture 3 is made of a bioabsorbable suture, such as polylactic acid (PLA) or polycaprolactone (PCL). This suture will gradually degrade within a preset time through hydrolysis in the body, its mechanical strength slowly decreasing until it is completely absorbed. Its diameter, embedment length, and total length parameters are the same as in Example 1. The hydrogel membrane 21, while ensuring strength and toughness, can be composited with materials that degrade faster, such as alginate or composite materials with alginate as the main component. Alginate can rapidly undergo ionic cross-linking upon contact with calcium ions, forming an "egg-box" structure, leading to dehydration and severe shrinkage of the hydrogel.

[0042] Work process: Its ingestion, expansion, sampling, and traction recovery process is basically the same as in Example 1. The unique advantage is that in the extremely rare event of the traction wire 3 accidentally breaking during the recovery process, the bioabsorbable traction wire remaining in the body will be safely degraded and absorbed by the human body within several weeks to several months. This avoids the risks that may be caused by the long-term retention of traditional non-absorbable cables or interference with subsequent inspections, and provides additional safety protection.

[0043] Based on the above embodiments, the samples taken by the gastric sampling device of the present invention can be used to prepare cell smears for pathological examination, or the cells can be collected by elution for subsequent molecular biological detection such as culture, drug sensitivity testing, DNA extraction, genotyping or quantitative PCR.

[0044] In addition to the gastric sampling and drug release applications mentioned above, the high-performance hydrogel material and its composite structure (modular design separating mechanical and expansion properties) of this invention can also be widely used in the following fields: Biomedical field: drug delivery systems, implantable or wearable medical devices, tissue engineering scaffolds, minimally invasive sampling and testing devices, etc.

[0045] Flexible electronics and sensors: flexible physiological monitors, soft robot drive units, environmental monitoring sensors, etc.

[0046] Food and agriculture sector: slow-release food packaging, slow-release fertilizer carriers for agriculture.

[0047] Emergency and protection field: expandable sealing materials, adsorption and purification devices.

[0048] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A gastric sampling device based on a tough, biocompatible hydrogel membrane, characterized in that: Includes an expandable sampling cap (2) and an external traction device; The sampling cap (2) is made of a strong and tough hydrogel membrane (21) forming a closed cavity. The hydrogel membrane (21) encapsulates water-absorbing particles (22) and a magnetically controlled capsule (1). The magnetically controlled capsule (1) integrates a camera (11), a wireless transmission module (12), an illumination source (13), and a power supply module (14). The magnetically controlled capsule (1) can cooperate with external magnetically controlled devices to realize the movement and positioning of the sampling cap (2) in the stomach cavity through the action of magnetic field. The external traction device includes a traction wire (3) and an extraoral fixation card (4). One end of the traction wire (3) is fixed inside the sampling cap (2), and the other end is connected to the extraoral fixation card (4). In this process, after the sampling cap (2) is swallowed and enters the stomach, the water-absorbing particles (22) absorb gastric juice and swell, so that the outer surface of the hydrogel membrane (21) comes into large-area contact with the gastric mucosa to adhere to the cells. During or after the expansion of the sampling cap (2), the sampling cap (2) in the entire expanded state is driven by an external magnetic control device to actively move and position itself in the gastric cavity to the target area, thereby achieving targeted sampling. After sampling is completed, the sampling cap (2) is completely retrieved through the esophagus by pulling the traction line (3).

2. The gastric sampling device based on a tough, biocompatible hydrogel membrane according to claim 1, characterized in that: The sampling cap (2) is a slender cylinder or olive shape in a dry, unexpanded state, with a diameter of 2-8 mm and a length of 5-40 mm; The sampling cap (2) expands into an approximately spherical or ellipsoidal shape in the gastric juice, with a diameter of 10-60 mm.

3. The gastric sampling device based on a tough, biocompatible hydrogel membrane according to claim 1, characterized in that: The material of the traction suture (3) is selected from polyester, nylon, silk or bioabsorbable suture, and the diameter of the traction suture (3) is 0.5-3mm and the total length is 5-60cm.

4. The gastric sampling device based on a tough, biocompatible hydrogel membrane according to claim 1, characterized in that: The length of the traction line (3) embedded in the sampling cap (2) is 5-60 mm.

5. The gastric sampling device based on a tough, biocompatible hydrogel membrane according to claim 1, characterized in that: The hydrogel membrane (21) is made of one or more composite materials selected from polyvinyl alcohol, gelatin methacryloyl, alginate, chitosan or polylactic acid-hydroxyacetic acid copolymer.

6. The gastric sampling device based on a tough, biocompatible hydrogel membrane according to claim 1, characterized in that: The thickness of the hydrogel membrane (21) is 0.05-0.5 mm, the tensile breaking strength is not less than 1 MPa, and the elongation at break is not less than 200%.

7. The gastric sampling device based on a tough, biocompatible hydrogel membrane according to claim 1, characterized in that: The surface of the hydrogel membrane (21) is provided with a plurality of water-permeable pores (211), the pore diameter of the water-permeable pores (211) is 10-500 micrometers, and the pore density is 1-10 pores / cm². The absorbent particles (22) are made of one of sodium polyacrylate, sodium carboxymethyl cellulose, gelatin particles or chitosan derivatives, and the particle size of the absorbent particles (22) is 50-500 micrometers.

8. The gastric sampling device based on a tough, biocompatible hydrogel membrane according to claim 7, characterized in that: The diameter of the water-absorbing particles (22) is larger than the pore size of the water-permeable pores (211) on the surface of the hydrogel membrane (21).

9. The gastric sampling device based on a tough, biocompatible hydrogel membrane according to claim 1, characterized in that: The camera (11) integrated inside the magnetically controlled capsule (1) is a high-definition pinhole camera.

10. The gastric sampling device based on a tough, biocompatible hydrogel membrane according to claim 1, characterized in that: The shell portion of the magnetically controlled capsule (1) is bonded and fixed to the inner wall of the hydrogel membrane (21) with a biocompatible adhesive to prevent the magnetically controlled capsule (1) from rolling or shifting inside the sampling cap (2).

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