Magnetic control capsule robot and manufacturing method and control method thereof

Abstract

The invention discloses a magnetic control capsule robot and a manufacturing method and a control method thereof, and belongs to the technical field of magnetic control soft robots, the magnetic control capsule robot comprises capsule heads and a capsule body, the capsule heads are arranged at the two ends of the capsule body, a pH sensor, an electrochemical analysis flexible circuit, a fluid chamber and a button battery are packaged in the capsule heads and the capsule body, and the button battery is arranged in the fluid chamber. The capsule head is made of a magnetic soft composite material embedded with neodymium iron boron particles. A manufacturing method and a control method are provided based on the capsule robot. The capsule robot manufactured by the invention is smaller in size, and can be used for detecting pathological changes in gastrointestinal tracts within the pH range of 3-8; and the capsule robot has the advantage of being capable of providing multiple magnetic fields through coil driving and also has the advantage of being low in permanent magnet driving difficulty, and the robot can move in the two-dimensional space and the three-dimensional space.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetically controlled soft robots, and particularly to a magnetically controlled capsule robot, a manufacturing method thereof, and a control method thereof. Background Art

[0002] Gastrointestinal diseases, including gastrointestinal inflammation, ulcers, bleeding, infections, and cancers, etc., are the most common clinical diseases with extremely high incidence and mortality rates. In the statistics of global cancer deaths in 2020, the number of deaths from esophageal cancer was 544,076 (accounting for 5.5% of the total cancer deaths), the number of deaths from gastric cancer was 768,793 (accounting for 7.7% of the total cancer deaths), and the number of deaths from colorectal cancer was 935,173 (accounting for 9.4% of the total cancer deaths). Among them, the 5-year survival rate for early diagnosis of rectal cancer is 90%, while the 5-year survival rate for late diagnosis drops to 20%. Therefore, early screening and diagnosis of gastrointestinal diseases have important scientific and clinical significance.

[0003] Capsule robots play a very important role in gastrointestinal diagnosis and treatment. Their working principle is to swallow the capsule robot into the gastrointestinal tract through the patient's mouth, and the capsule robot can be actively controlled by the operator through internal drive or external drive. Due to the small size and diverse functions of the capsule robot, it greatly reduces the discomfort of patients during medical treatment and is widely accepted by patients.

[0004] However, whether it is a capsule robot based on internal drive or an external field-driven capsule robot, there are relatively large limitations. In terms of capsule material preparation, the materials used in current commercial capsule endoscopes at home and abroad have a relatively high Young's modulus, poor mechanical compliance, and are extremely likely to cause damage to the intestinal surface; in terms of capsule drive, most current commercial capsule robots use passive drive. The path of the human digestive system is long, and most of it is healthy areas. Moreover, the movement of passive capsule robots is random, which is likely to miss the information of lesions and cause misdiagnosis of gastrointestinal diseases.

[0005] Therefore, it is very necessary to develop a capsule robot with high mechanical compliance and a stable drive method. Summary of the Invention

[0006] The purpose of the present invention is to provide a magnetically controlled capsule robot, a manufacturing method thereof, and a control method thereof to solve the problems existing in the background art.

[0007] To achieve the above purpose, the present invention provides a magnetically controlled capsule robot, including a capsule head and a capsule body. The capsule head is arranged at both ends of the capsule body. A pH sensor, an electrochemical analysis flexible circuit, a fluid chamber, and a button battery are encapsulated in the capsule head and the capsule body. The material of the capsule head is a magnetic soft composite material embedded with neodymium iron boron microparticles.

[0008] Preferably, the pH sensor is connected to the button battery through an FFC connector. The pH sensor is disposed on one side of the FFC connector and communicates with the fluid chamber, and the other side of the button battery is connected to the flexible electrochemical analysis circuit.

[0009] Preferably, the flexible electrochemical analysis circuit includes a microcontroller and an antenna disposed on the microcontroller. The microcontroller is connected to the button battery.

[0010] A method for manufacturing a magnetically controlled capsule robot includes the following steps:

[0011] S1. 3D print capsule molds numbered 00 to 5 that comply with regulations according to the national capsule size standard;

[0012] S2. Take NdFeB@SiO2 particles and Ecoflex 00-30, mix them in a ratio of 1:1, perform degassing treatment, and then inject them into the capsule mold for curing to obtain a capsule head and a capsule body for magnetic field generation;

[0013] S3. Take the demolded capsule head and capsule body, perform surface treatment so that the surfaces of the capsule head and capsule body obtain a hydrogel skin;

[0014] S4. Place the capsule head obtained in S3 in a mold for normal magnetization, and encapsulate the capsule body obtained in S3 with electrodes, a multi-fluid chamber, and a flexible electrochemical analysis circuit;

[0015] S5. Take the capsule head and capsule body obtained in S4, and use a medical-grade adhesive Loctite 435 for concentric bonding to obtain a magnetically controlled capsule robot integrating sensing, driving, and control.

[0016] Preferably, in the surface treatment of S3, first soak it in a benzophenone ethanol solution for 20 min; then place it in a prepared PAM hydrogel solution and irradiate it under an ultraviolet lamp for 1 h; finally, clean it on a vibration cleaning machine for 12 h.

[0017] Based on the above capsule robot, the present invention proposes a control method. The capsule robot is guided by a rotating magnetic field generated by a permanent magnet to complete targeted detection in the stomach and small intestine. The permanent magnet is an N42 grade cubic permanent magnet.

[0018] Preferably, the process of the permanent magnet controlling the capsule robot is as follows: Swallow the capsule robot into the body, place the permanent magnet at a place at least 50 mm away from the robot, and control the capsule robot to perform multi-modal motions in the human body through the gradient force and magnetic moment generated by the rotation of the permanent magnet. The multi-modal motions include swinging, sliding, and rolling.

[0019] Preferably, the swinging process is as follows: under the action of the magnetic torque, the capsule robot swings left and right to adjust its direction, and swings across the crease under the traction of the gradient force;

[0020] The sliding process is as follows: when the capsule slides into the groove, the permanent magnet rotates to provide a rotating magnetic field, and the magnetic torque along the circumferential direction is used to overcome the frictional force on the surface of the groove, so as to ensure that the capsule robot slides along the groove;

[0021] The rolling process is as follows: when the capsule encounters a narrow groove, the rotating motion of the permanent magnet is used to put itself in a rolling mode, so as to pass through the groove.

[0022] Therefore, for the magnetically controlled capsule robot, its manufacturing method and control method of the present invention, the prepared capsule robot has a polyhydrogel epidermis on both the capsule head and the capsule body, effectively reducing the surface friction of the robot; in the capsule head, the content of neodymium iron boron particles is 50 wt%, improving the mechanical stability; driven by a permanent magnet, the driving difficulty is low and stable.

[0023] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0024] Figure 1 is an exploded view of the structure of the capsule robot according to an embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of the targeted detection of the capsule robot according to an embodiment of the present invention;

[0026] Figure 3 is a manufacturing flow chart of the capsule robot according to an embodiment of the present invention;

[0027] Figure 4 is the performance test of the hydrogel epidermis of the capsule robot according to an embodiment of the present invention Figure 1 ;

[0028] Figure 5 is the performance test of the hydrogel epidermis of the capsule robot according to an embodiment of the present invention Figure 2 ;

[0029] Figure 6 is the detection of the cell viability of the hydrogel epidermis of the capsule robot according to an embodiment of the present invention Figure 1 ;

[0030] Figure 7 is the detection of the cell viability of the hydrogel epidermis of the capsule robot according to an embodiment of the present invention Figure 2 ;

[0031] Figure 8 is a schematic diagram of the control strategy of the capsule robot according to an embodiment of the present invention;

[0032] Figure 9 In vitro gastric model movement experiment of the capsule robot according to an embodiment of the present invention;

[0033] Figure 10 In vitro porcine small intestine movement experiment of the capsule robot according to an embodiment of the present invention;

[0034] Figure 11 Relationship between different magnetic powder contents and lmag according to an embodiment of the present invention;

[0035] Figure 12 Quantification diagram of the magnetic suction force generated by the permanent magnet on the robot when lmag = 50 mm according to an embodiment of the present invention;

[0036] Reference numerals:

[0037] 1. Capsule head; 2. pH sensor; 3. Fluid chamber; 4. Button battery; 5. FFC connector; 6. Microcontroller; 7. Antenna. Detailed implementation manners

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0040] Embodiment

[0041] As Figure 1 shown, the present invention provides a magnetically controlled capsule robot, including a capsule head 1 and a capsule body. The capsule head 1 is arranged at both ends of the capsule body. The capsule head 1 and the capsule body are encapsulated with a pH sensor 2, an electrochemical analysis flexible circuit, a fluid chamber 3, and a button battery 4. The material of the capsule head 1 is a magnetic soft composite material embedded with neodymium iron boron microparticles, and the content of the neodymium iron boron microparticles is 50 wt%.

[0042] The movement characteristics of the capsule robot with a magnetic soft capsule head directly depend on the magnetization intensity, and the magnetization intensity is closely related to the mass fraction of neodymium iron boron particles in its composite material. Keeping the Young's modulus of the capsule head low can reduce the damage to the intestinal wall by the capsule. In fact, too high or too low content of neodymium iron boron particles is not suitable for practical applications, because too high content will affect the Young's modulus of the material, and then affect the final capsule manufacturing results, such as poor tensile properties, difficult demolding, uneven distribution of magnetic particles after mixing, etc., while too low content will affect the manipulation performance of the capsule.

[0043] To experimentally explore which design can meet this requirement, we tested a class of capsule head prototypes with different Young's moduli Er ranging from 0.05 MPa to 0.25 MPa. As Figure 11 shown, by testing the relationship between different magnetic powder contents and Iamg, we found that a magnetic powder content of 50 wt% just meets the usage requirements.

[0044] We quantified the magnetic suction force generated by the permanent magnet on the robot when Iamg = 50 mm. As Figure 12 shown, the modeling results are in good agreement with the experimental data, with only slight differences in a small range when Iamg = 65 mm. Under the Iamg condition, the magnetic suction force within the range of 50 - 80 mm is less than the critical value for human cell rupture, indicating that the capsule robot designed in the present invention meets the safety standards and can conduct in vitro motion experiments.

[0045] The pH sensor 2 is connected to the button battery 4 through the FFC connector 5. The pH sensor 2 is arranged on one side of the FFC connector 5 and communicates with the fluid chamber 3. The other side of the button battery 4 is connected to the electrochemical analysis flexible circuit. The diameter of the button battery 4 is less than 10 mm. The electrochemical analysis flexible circuit includes a microcontroller 6 and an antenna 7 arranged on the microcontroller. The microcontroller 6 is connected to the button battery 4, and the above components are sealed together and encapsulated in the capsule body.

[0046] To flexibly manipulate the robot in clinical applications, we combined a rotating cubic neodymium iron boron permanent magnet (50 mm long) with a seven - degree - of - freedom (DoF) robotic arm to achieve three - dimensional (3D) magnetic drive in space. Using the rotating magnetic field generated by the permanent magnet, the capsule performs rotational propulsion in the gastrointestinal tract, thereby improving the efficiency of gastrointestinal fluid information update. As Figure 2 shown,

[0047] As Figure 2 shown, it shows the movement of the capsule robot in the gastric folds. After the robot is orally administered into the human body ( Figure 2 A), it can be guided by the rotating magnetic field generated by the permanent magnet to complete targeted detection in the stomach ( Figure 2 C) and the narrow small intestine ( Figure 2 D). Specifically, when the capsule robot reaches the target position A and rotates continuously to collect pH information, then it reaches one side of the crease point, and the permanent magnet activates the reverse function to make the robot flip over the crease and reach the target point B by rolling. In the intestine, the robot advances along the lumen path under the navigation of the permanent magnet. After reaching the intestinal lesion site, the robot system autonomously promotes the collection and update of intestinal fluid data and then expels it from the body.

[0048] The manufacturing method of the above - mentioned magnetically controlled capsule robot, as Figure 3 shown, includes the following steps:

[0049] S1. According to the national capsule size standard (Specifications, Dimensions and Appearance Quality of Empty Capsules (T / CNPPA 3008-2020)), 3D print capsule molds of size 00 to size 5 that comply with the regulations;

[0050] S2. Take NdFeB@SiO2 particles and Ecoflex 00-30, mix them in a ratio of 1:1, perform degassing treatment, and then inject them into the capsule mold for curing to obtain the capsule head and capsule body for magnetic field generation;

[0051] S3. Take the demolded capsule head and capsule body, first soak them in a benzophenone ethanol solution for 20 min; then place them in a prepared PAM hydrogel solution, place them under an ultraviolet lamp for irradiation for 1 h; finally, clean them on a vibrating washing machine for 12 h to make the surfaces of the capsule head and capsule body obtain a hydrogel skin;

[0052] S4. Place the capsule head treated in S3 in a mold for normal magnetization, and encapsulate the capsule body obtained in S3 with electrodes, a multi-fluid chamber, and an electrochemical analysis flexible circuit;

[0053] S5. Take the capsule head and capsule body treated in S4, and use a medical-grade adhesive Loctite 435 for concentric bonding to obtain an integrated magnetic control capsule robot for sensing, driving, and controlling.

[0054] For the obtained magnetic control capsule robot, as Figure 4 shown, we tested the mechanical stability and coefficient of friction (CoF) of the hydrogel epidermis in the fabricated specimens. The measurement results are as Figure 5 shown; it shows that under all given conditions, due to the lubricity of the hydrogel epidermis, when the load is 0.5 N, the CoF decreased by 6 times compared with the uncoated one. In addition, after continuous detection for about 600 s, the CoF tended to be stable, that is, compared with the uncoated sample, the CoF stability of the coated sample was lower, which indicates that the hydrogel epidermis not only effectively reduced the coefficient of friction but also exhibited quite high mechanical stability.

[0055] Then, we analyzed the cytotoxicity of the PAM hydrogel epidermis using the Caco-2 cell line, which is widely used as an intestinal epithelial barrier model. The leaching experiment was used to collect the chemicals released by the magnetic hydrogel in fresh medium for 1-7 days. Then the Caco-2 cells were exposed to the medium containing the released compounds and left standing for 2 days, and the cell viability was analyzed using the live / dead cell staining method. As Figure 6 、 7 shown, there was no significant difference in cell viability between the Caco-2 cells and the released compounds, and there was no obvious difference in cell viability between the original medium (positive control) and the medium exposed to the PAM hydrogel epidermis for 1-7 days.

[0056] The above capsule robot is guided by a rotating magnetic field generated by a permanent magnet to complete targeted detection in the stomach and small intestine. The permanent magnet is an N42 grade cubic permanent magnet, and its control strategy is as follows:

[0057] As Figure 8 shown, after the swallowed robot enters the body and reaches the stomach, the magnet rotates around the y mag axis at a frequency f a and translates at a speed of v mag and relocates at an angle of α mag to coincide with the current route in the y a -z a plane. Considering the distance between the gastrointestinal tract and the abdominal cortex, the permanent magnet should be placed along the z r axis at least 50 mm away from the robot, that is, l mag ≥50 mm. At this distance, it fully meets the requirement of controlling the robot's advancement in the gastrointestinal tract from the outside.

[0058] Through experiments on an anatomical stomach model, the adaptive motion characteristics of the capsule and its controllability in detecting targeted lesion areas in a more complex environment were verified. Similarly, the gradient force and magnetic torque generated by an N42 grade permanent magnet with a cubic permanent magnet (side length 50 mm) were used to control the multimodal motion of the capsule in the anatomical stomach model of the human body, such as swinging (the first stage), sliding (the second stage), and rolling (the third stage).

[0059] As Figure 9 shown, under the excitation of the permanent magnet, the capsule achieved different motion modes including rotation, sliding, and rolling to adapt to different environments in the stomach wall. For example, when lmag = 50 mm, under the action of the magnetic torque, the capsule swayed left and right to adjust its direction to prepare to enter the folded area, and swung over the crease under the traction of the gradient force. At this time, the permanent magnet swayed to adjust the direction (the first-stage swing). When the capsule slid into the groove, the permanent magnet rotated to provide a rotating magnetic field, and the magnetic torque along the circumferential direction was used to overcome the frictional force on the surface of the folded groove, so as to slide along the groove (the second-stage sliding). When the capsule encountered a folded protrusion, the permanent magnet started to reverse, causing itself to rotate along the side of the folded protrusion and enter the rolling mode, so as to roll over the protruding fold to reach the lesion area (the third-stage rolling). The experimental results show that even in the face of challenges such as slippery surfaces and frictional resistance of the stomach wall model, the motion of the capsule robot is still controllable and adaptable in different environments.

[0060] As Figure 10 shown, to explain the driving strategy in the small intestine, the motion path is discretized into points (a) to (d). When the robot enters the curved path and moves to the path (b)-(c), slowly make the y aThe axial direction is parallel to the (c)-(d) direction, guiding the robot to rotate around the positive y r axis simultaneously. Therefore, the torque from the magnetic pulling force F mag causes the robot to bend towards (b)-(c). Meanwhile, T mag,Zr tends to align x r with x a axis, causing the robot to bend in the same direction. Finally, the rotation tends to roll the robot to the positive side of the x r axis. When the robot contacts the small intestinal wall, the reaction force F react and the magnetic pulling force F mag push the robot towards the (c)-(d) section. This experiment shows that the capsule robot has the ability to move in a narrow lumen and can achieve smooth and efficient movement in the small intestine.

[0061] Therefore, for a magnetically controlled capsule robot, its manufacturing method and control method of the present invention, the manufactured capsule robot is smaller in size and can perform gastrointestinal lesion detection within the pH range of 3 to 8; and while this capsule robot has the advantages of coil drive that can provide multiple magnetic fields, it also has the advantage of low driving difficulty of a permanent magnet, enabling the robot to move in two-dimensional and three-dimensional spaces.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements do not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A magnetically controlled capsule robot, characterized in that: It includes a capsule head and a capsule body. The capsule head is arranged at both ends of the capsule body. A pH sensor, an electrochemical analysis flexible circuit, a fluid chamber, and a button battery are encapsulated in the capsule head and the capsule body. The material of the capsule head is a magnetic soft composite material embedded with neodymium iron boron particles.

2. The magnetically controlled capsule robot according to claim 1, wherein: The pH sensor is connected to the button battery through an FFC connector. The pH sensor is arranged on one side of the FFC connector and communicates with the fluid chamber. The other side of the button battery is connected to the electrochemical analysis flexible circuit.

3. The magnetically controlled capsule robot according to claim 2, wherein: The electrochemical analysis flexible circuit includes a microcontroller and an antenna arranged on the microcontroller. The microcontroller is connected to the button battery.

4. A manufacturing method of the magnetically controlled capsule robot according to any one of claims 1-3, characterized in that, It includes the following steps: S1. 3D print capsule molds of size 00 to 5 that comply with regulations according to the national capsule size standard; S2. Take NdFeB@SiO2 particles and Ecoflex 00-30, mix them in a ratio of 1:1, perform degassing treatment, and then inject them into the capsule mold and cure to obtain the capsule head and capsule body for magnetic field generation; S3. Take the demolded capsule head and capsule body, and perform surface treatment so that the surfaces of the capsule head and capsule body obtain a hydrogel skin; S4. Place the capsule head treated in S3 in the mold for normal magnetization, and encapsulate the capsule body obtained in S3 with electrodes, a multi-fluid chamber, and an electrochemical analysis flexible circuit; S5. Take the capsule head and capsule body treated in S4, and use the medical-grade adhesive Loctite 435 for concentric bonding to obtain a magnetically controlled capsule robot integrated with sensing, driving, and control.

5. The manufacturing method of a magnetically controlled capsule robot according to claim 4, wherein: In the surface treatment of S3, first soak it in a benzophenone ethanol solution for 20 minutes; then place it in a prepared PAM hydrogel solution and irradiate it under an ultraviolet lamp for 1 hour; finally, wash it on a vibrating washing machine for 12 hours.

6. A control method for a magnetically controlled capsule robot according to any one of claims 1-3, characterized in that: The capsule robot is guided by a rotating magnetic field generated by a permanent magnet to complete targeted detection in the stomach and small intestine. The permanent magnet is an N42 grade cubic permanent magnet.

7. The control method of a magnetically controlled capsule robot according to claim 6, wherein, The process of the targeted detection is as follows: Swallow the capsule robot into the body, place the permanent magnet at a place at least 50 mm away from the robot, and control the multi-modal movement of the capsule robot in the human body through the gradient force and magnetic moment generated by the rotation of the permanent magnet.

Images