Miniature magnetic control robot with ultrasonic sensing feedback function

Abstract

The invention belongs to the crossing field of biomedical engineering, robots and acoustic metamaterials, and discloses a miniature magnetic control robot with ultrasonic sensing feedback, a magnetic soft clamp robot comprises a clamp main body and two embedded ultrasonic soft sensors, and the clamping or loosening state of a U-shaped opening of the clamp main body can be adjusted under the action of an external magnetic field; and the clamping force of the clamp main body can be wirelessly monitored in real time by ultrasonically detecting the deviation of the natural resonant frequency of the embedded ultrasonic soft sensor. According to the invention, the embedded ultrasonic soft sensor EUSS and the magnetic driving module are coupled and integrated, so that the flexible control of the magnetic driving module and the real-time feedback function of the photonic crystal sensor are integrated; the problems that a traditional magnetic control robot lacks wireless and real-time feedback capacity, and an existing capsule robot lacks a monitoring feedback function in the medicine release process can be effectively solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the cross field of biomedical engineering, robots and acoustic metamaterials, and more particularly relates to a micro magnetic control robot with ultrasonic sensing feedback. BACKGROUND

[0002] In precise robot operation, the combination of driving and feedback is the basis for the development of the field, which can improve the safety margin and operation accuracy, and provide real-time response ability to changing environmental conditions. Micro intelligent robots have high requirements for safety and accuracy in biomedical applications, however, existing micro robots lack real-time and accurate feedback capability in driving.

[0003] In targeted drug delivery, micro capsule robots have become a promising tool, but the main challenge is the lack of reliable drug delivery feedback mechanism. Existing micro robots do not have the ability to monitor drug distribution in real time, and existing wireless drug delivery systems (especially those based on radio frequency electronic devices) are usually too large and have limited communication distance, which are not suitable for integration into micro robots. SUMMARY

[0004] In view of the above defects or improvement needs of the prior art, the purpose of the present application is to provide a micro magnetic control robot with ultrasonic sensing feedback, which realizes the integration of flexible control of the magnetic driving module and real-time feedback function of the phononic crystal sensor by coupling and integrating the embedded ultrasonic soft sensor (EUSS) with the magnetic driving module, and can effectively solve the problems of lack of wireless and real-time feedback capability of traditional magnetic control robots and lack of monitoring feedback function during drug release process of existing capsule robots, and inability to accurately monitor and targetedly deliver liquid in vivo. Taking the capsule robot as an example, the micro capsule robot obtained by the present application can release drugs under the action of an external magnetic field and monitor the drug release dose in real time.

[0005] To achieve the above purpose, according to the first aspect of the present application, a magnetic soft clamp robot is provided, characterized in that it comprises a clamp body and two embedded ultrasonic soft sensors, wherein,

[0006] The clamp body is a three-dimensional U-shaped body formed by uniformly mixing magnetic particles and flexible deformable material; the magnetization direction of the magnetic particles in the clamp body is left-right symmetrical along the center line of the U-shaped body, and the unit vector of the magnetization direction of the magnetic particles at the end of the U-shaped opening and the unit vector of the magnetization direction of the magnetic particles at the midpoint of the U-shaped bottom form an acute angle or a right angle; the magnetization direction of the magnetic particles at different positions in the clamp body changes clockwise or counterclockwise from the end of the opening to the midpoint of the U-shaped bottom;

[0007] Any one of the embedded ultrasonic soft sensors comprises a first material and a second material with different material sound speeds; wherein the first material is a flexible deformable material, and the second material is distributed in the first material and arranged periodically along a distribution plane, and the number of the periodic array is m*n, wherein m>=3, n>=1, and m and n are positive integers; in the first material and the second material, the material sound speed of the material with the larger material sound speed is at least 2 times the material sound speed of the material with the smaller material sound speed;

[0008] The two embedded ultrasonic soft sensors are respectively fixedly connected to the side surfaces of the left and right two ends of the U-shaped opening of the clamp body and are located in the U-shaped opening, and the top surfaces of the two embedded ultrasonic soft sensors are flush with the top surface of the U-shaped opening; and for any one of the embedded ultrasonic soft sensors, the side surface fixedly connected thereto is parallel to the distribution plane where the periodic arrangement structure in the embedded ultrasonic soft sensor is located;

[0009] The magnetic soft clamp robot can adjust the clamping or loosening state of the U-shaped opening of the clamp body under the action of an external magnetic field, realize the clamping function, and adjust the clamping force; and the shift of the inherent resonance frequency of the embedded ultrasonic soft sensor is detected through ultrasonic detection, so that the clamping force of the clamp body can be monitored in real time.

[0010] According to the second aspect of the present application, a spiral robot for in-vivo soft tissue navigation is provided, characterized by comprising a conical tip, an embedded ultrasonic soft sensor, a cylindrical magnet and a cylindrical shell provided with a spiral protrusion outside, wherein,

[0011] The cylindrical magnet is a radially magnetized cylindrical magnet, located in the cylindrical shell and coaxially arranged with the cylindrical shell;

[0012] The conical tip is located at the front end of the cylindrical shell;

[0013] The embedded ultrasonic soft sensor comprises a first material and a second material with different material sound speeds; wherein the first material is a flexible deformable material, and the second material is distributed in the first material and arranged periodically along a distribution plane, and the number of the periodic array is m*n, wherein m>=3, n>=1, and m and n are positive integers; in the first material and the second material, the material sound speed of the material with the larger material sound speed is at least 2 times the material sound speed of the material with the smaller material sound speed;

[0014] The embedded ultrasonic soft sensor is fixed to the rear end of the cylindrical shell; the normal direction of the distribution plane where the periodic arrangement structure in the embedded ultrasonic soft sensor is located is parallel to the axial direction of the cylindrical shell;

[0015] The shift of the inherent resonant frequency of the embedded ultrasonic soft sensor can be detected by ultrasonic detection, so that the distance between the spiral robot and the blood vessel with blood flow can be monitored in real time, and navigation can be realized.

[0016] According to a third aspect of the present application, a wireless monitoring magnetic control capsule robot is provided, which is characterized in that the wireless monitoring magnetic control capsule robot comprises a storage chamber for containing liquid medicine, the storage chamber is fixedly connected with the top plate of the upper part through a support structure, and the lower part of the storage chamber is fixedly connected with a bottom plate; a micro-hole is arranged on the side wall of the storage chamber, and the liquid medicine contained in the storage chamber can be released to the outside through the micro-hole;

[0017] Further, a piston plate is arranged between the storage chamber and the top plate, the inner wall of the piston plate is tightly attached to the inner wall of the storage chamber through a sealing element; a magnet is embedded in the piston plate, and the magnetization direction of the magnet is parallel to the up-down direction; the piston plate and the top plate are connected through a soft strip, and an embedded ultrasonic soft sensor is further embedded in the soft strip;

[0018] The embedded ultrasonic soft sensor comprises a first material and a second material with different material sound speeds; wherein the first material is a flexible deformable material, and the second material is distributed in the first material and periodically arranged along a distribution plane, and the number of the periodic array is m*n, wherein m is greater than or equal to 3, and n is greater than or equal to 1, and m and n are both positive integers; among the first material and the second material, the material sound speed of the material with larger material sound speed is at least 2 times the material sound speed of the material with smaller material sound speed;

[0019] The normal direction of the distribution plane of the periodic arrangement structure in the embedded ultrasonic soft sensor is parallel to the up-down direction;

[0020] The magnetic control capsule robot can perform translational motion and / or tumbling motion under the action of an external magnetic field with constant magnetic field size; and under the action of an external gradient magnetic field in the vertical direction, the magnet and the piston plate can be relatively displaced downward relative to the storage chamber, the storage chamber can be compressed, and the liquid medicine can be released through the micro-hole; the relative displacement amount of the piston plate can be monitored in real time by detecting the shift of the inherent resonant frequency of the embedded ultrasonic soft sensor through ultrasonic detection, and the drug release dose can be monitored.

[0021] As a further preferred embodiment of the present application, the second material is air; preferably, the second material is in the form of a cylindrical air column, a cuboid air column, a polygonal prism air column or an elliptical cylindrical air column in the embedded ultrasonic soft sensor;

[0022] The first material is Ecoflex or PDMS.

[0023] As a further preferred embodiment of the present application, the size of the embedded ultrasonic soft sensor is 1.3mmx1.3mmx1.6mm.

[0024] As a further preferred embodiment of the present application, the stereoscopic U-shaped magnetic soft clamp robot has a U-shaped height of 8-10mm and a spacing of 5-7mm at the opening.

[0025] As a further preferred embodiment of the present application, the diameter of the cylindrical shell is 2-3mm, and the projection length of the spiral robot in the axial direction of the cylindrical shell is 6-8mm.

[0026] As a further preferred embodiment of the present application, the spacing between the upper surface of the top plate and the lower surface of the bottom plate is 8mm, and the projection area of the storage chamber on the bottom plate is 50mm 2 .

[0027] Compared with the prior art, the magnetic soft clamp robot, the spiral robot for in-vivo soft tissue navigation, and the magnetic control capsule robot capable of wirelessly monitoring the drug release dose in the present application all integrate a magnetic driving module and an ultrasonic sensing module. The magnetic driving module provides motion and control under the action of an external magnetic field. The ultrasonic sensing module adopts a two-dimensional phononic crystal structure, with air columns periodically distributed in the soft polymer matrix as scatterers. The high contrast between air and solid surfaces effectively scatters ultrasonic waves, enabling wireless imaging and communication, and enabling the robot to have feedback control and wireless sensing integration. The present application can solve the problems of traditional magnetic control robots lacking wireless and real-time feedback capabilities and existing capsule robots lacking monitoring feedback functions during drug release. In the following examples, the present application uses an EUSS sensor with a size of only 1.3mmx1.3mmx1.6mm and a weight of only 4.6mg, achieving miniaturization and lightweight of the sensing module, which can work without a board-mounted power supply. Moreover, ultrasonic waves have good penetration depth in soft tissue, which can effectively overcome the defect that the communication distance of existing systems based on radio frequency electronic devices is limited.

[0028] The ultrasonic feedback micro magnetic control robot in the present application can accurately perceive external forces and vibrations, providing rich biomedical application potential, such as precise grasping, holding, and releasing as a surgical clamp, and real-time feedback of contact force to avoid tissue damage; as a spiral micro robot, it can navigate in soft tissue, detect vibration pressure generated by blood vessel pulsation, and provide real-time feedback of obstacle information to avoid invasive diagnostic risks.

[0029] And for the magnetic capsule robot in the application, the embedded magnet interacts with the external magnetic field, the drug storage chamber is compressed under the action of the external magnetic field, and the active control release of the drug is realized; the phononic crystal sensor senses the deformation degree wirelessly and in real time through the frequency shift of the reflected ultrasonic wave, so as to reflect the mechanical displacement of the drug storage chamber, and the accurate monitoring of the drug release dose is realized. The capsule robot can load various liquid drugs, is small in size, can accurately reach the target point and deliver the drug under the driving of the magnetic field, realizes high-resolution dose control, and can stably operate in the deep body, and has the ability of accurate drug delivery in vivo.

[0030] Specifically,

[0031] i) Taking the magnetic soft gripper robot as an example, the magnetic gripper equipped with the wireless force sensing function of the application can accurately perform fine tasks such as grabbing, holding and releasing, and can be used as a surgical gripper. The gripper is U-shaped and has two jaws, and each jaw is embedded with an EUSS, which can be used for wireless driving and force sensing when manipulating fragile objects (such as 3mm diameter salmon eggs). The deformation caused by the magnetic driving module through magnetic field control is transmitted to the EUSS, the peak frequency of the reflected ultrasonic wave of the phononic crystal is shifted, and by analyzing the change of the ultrasonic frequency shift, the feedback of the mechanical signal to the ultrasonic signal can be realized.

[0032] ii) Taking the spiral micro robot as an example, the spiral micro robot can be used for navigation in soft tissue matrix, such as brain environment. The robot can detect the vibration pressure generated by blood vessel pulsation by using the EUSS. The spiral micro robot comprises a spiral sleeve terminated with a conical tip, wherein a cylindrical permanent magnet (for example, the size of the cylindrical permanent magnet can be: diameter 2mm, length 2mm) is enclosed; the EUSS is fixed at the rear end of the assembly. Through the external rotating magnetic field (such as the rotating driving external cube magnet), the spiral propulsion of the micro robot in the soft tissue can be realized by using the interaction between it and the cylindrical permanent magnet.

[0033] iii) Again taking the magnetic capsule robot as an example, by setting a piston plate with embedded magnets, and cooperating with the externally applied magnetic field, the magnetic capsule robot can realize different operation. Especially under the action of the external gradient magnetic field, the magnet with the piston plate can be displaced downward relative to the storage chamber, compressing the storage chamber, so as to release the liquid medicine through the micro-hole; and the tensile strain of the EUSS is monitored by ultrasound, and the mechanical displacement of the medicine storage chamber is reflected by the frequency shift. The magnetic capsule robot allows accurate determination of the volume of the liquid according to the change of the detected ultrasonic frequency. By carefully adjusting the strength and direction of the external magnetic field, the volume of the dispensed can be accurately controlled. In addition, by manipulating the direction and rotation of the magnetic field, translational or rolling motion of the capsule robot can be achieved. Using the magnetic capsule robot, high-resolution wireless feedback of liquid release can be achieved.

[0034] In summary, the present application can achieve the following beneficial effects:

[0035] (1) The present application is based on EUSS, which has a characteristic acoustic band gap of crystal structure, and reflects deformation by frequency shift of reflected ultrasonic waves.

[0036] (2) The sensor in the present application can be used with a small external ultrasonic probe, which does not rely on large detection equipment in the hospital, providing freedom and simplicity for the physician to operate, while reducing the cost of medical treatment.

[0037] (3) The present application provides a small surgical clamp that accurately completes various clamping tasks in surgery under a magnetic field, and provides real-time and accurate feedback of contact force through ultrasonic signals, avoiding tissue damage during operation.

[0038] (4) The present application provides an interventional medical robot that navigates in soft tissue under the drive of a magnetic field, and provides real-time and accurate feedback of obstacles such as blood vessels through ultrasonic signals, avoiding the dangers in invasive diagnosis.

[0039] (5) The micro-capsule robot proposed in the present application can load various liquid medicines, and the volume is small enough to enter the human body blood vessels and various complex passages to realize drug delivery.

[0040] (6) The micro-capsule robot proposed in the present application is driven by a magnetic field, and can accurately reach the target to realize accurate drug delivery.

[0041] (7) The micro-capsule robot proposed in the present application can accurately perceive the force and vibration of the external environment, and provide real-time and accurate feedback through ultrasonic signals, while the traditional magnetic control robot does not have wireless and real-time feedback capability.

[0042] (8) The deformation of the drug storage chamber caused by the change of the dose is converted to the EUSS, and finally the wireless sensing is realized through the ultrasonic signal. Real-time and accurate feedback during the release of the drug.

[0043] The application overcomes the compatibility problem of sensing and driving. Traditional magnetic control robots are difficult to integrate sensing and driving functions at the same time, mainly limited by space and magnetic field interference. The application uses embedded ultrasonic soft sensor (EUSS), which does not rely on battery and on-board electronic components, realizes the extreme miniaturization and passivity of the sensing module, and fundamentally solves the volume and weight problem. At the same time, the ultrasonic communication mechanism adopted by EUSS is not sensitive to the magnetic field, realizing the synchronous sensing and driving without interference. Moreover, the application also overcomes the conversion problem from micro deformation to macro signal. The application uses the two-dimensional phononic crystal structure of EUSS to convert micron-level deformation into ultrasonic frequency shift (Δf) that can be wirelessly, highly accurately and remotely perceived, realizing highly sensitive capture of micro deformation. In addition, the application modularly designs EUSS with different magnetic driving modules, and combines the flexible design of "actuator as sensing interface", so that it can solve various sensing problems such as force and vibration at the same time, thereby providing a universal technical platform suitable for various application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is the flow chart of the EUSS sensor made by the application. First, a negative mold with a cylinder array is made by 3D printing technology. Then, using this 3D printed mold, the Ecoflex 00-30 soft matrix material is poured and cured to form. After molding, the unsealed sensor is demolded from the mold. Finally, in order to maintain the formation of air cavity inside the soft matrix, a thin film of the same Ecoflex 00-30 soft matrix material is spin-coated on the glass plate, and the bottom surface of the sensor is sealed using adhesive. Finally, a complete ultrahydrogel sensor containing an internal air cavity is formed.

[0045] Figure 2 is the finite element analysis (FEA) simulation result of the EUSS sensor made by the application under different strain conditions. Among them, Figure 2 a, b, c in a group, Figure 2 d, e, f in another group. Figure 2 a and Figure 2 d in are respectively the acoustic scattering field simulation diagrams of EUSS under different tensile strains (5%, 10%, 15% and 20%) and different compression strains (2.5%, 5%, 7.5% and 10%), showing the propagation and scattering of ultrasonic waves under different strain states. Figure 2 b and Figure 2e in FIG. 6 is the corresponding reflection spectrum, which depicts the reflection characteristics of EUSS to ultrasonic waves. Figure 2 c in FIG. 7 and Figure 2 f in FIG. 8 is the corresponding transmission spectrum, which shows the transmission characteristics of ultrasonic waves through EUSS.

[0046] Figure 3 is a manufacturing flow chart of the magnetic soft clamp component in the clamp robot prepared in Example 5 of the present application. Figure 3 a in FIG. 9 is a 3D printed mold, which has a U-shaped groove for forming the initial structure of the clamp, Figure 3 b in FIG. 10 is a pouring composite step, in which the magnetic composite material composed of ferromagnetic particles and soft polymer matrix is uniformly poured into the mold, Figure 3 c in FIG. 11 is a curing process, in which the composite material is cured to form a U-shaped clamp, Figure 3 d in FIG. 12 is the final clamp product after demolding, which has a U-shaped form, is magnetic and remains soft, and is convenient for subsequent integration with the EUSS sensor.

[0047] Figure 4 is a magnetization and assembly flow chart of the magnetic soft clamp in the clamp robot of Example 5 of the present application. Among them, Figure 4 a in FIG. 13 shows shape programming, in which an external magnetic field is applied to the cured U-shaped clamp in the mold to arrange the internal ferromagnetic particles in a predetermined direction, thereby forming a specific magnetization pattern, Figure 4 b in FIG. 14 shows the shape of the clamp after being released from the magnetization mold, which has a magnetization direction along the U-shaped arc, Figure 4 c in FIG. 15 is a schematic diagram of the assembly of the clamp with the EUSS sensor, in which the magnetized soft clamp and the EUSS sensor are precisely assembled by adhesion, Figure 4 d in FIG. 16 is a real object diagram after assembly, which clearly shows the compact integration of the magnetic soft clamp and the EUSS sensor, which together constitute a clamp robot with wireless force sensing capability, wherein the yellow and red parts are salmon egg models.

[0048] Figure 5 is a finite element analysis (FEA) schematic diagram of the clamp robot prepared in Example 5 of the present application when grabbing salmon eggs. Figure 5 a in FIG. 17 shows the initial state of the EUSS sensor (Ultrasonic metasensor) in the clamp and the salmon egg (Salmon egg) before contact,Figure 5 b in FIG. 13 shows the stress distribution of the gripper jaw and salmon eggs when the gripper exerts a clamping force of 15 mN (applied force), and the stress concentration area is indicated by a color gradient, Figure 5 c in FIG. 14 shows the stress distribution of the gripper and salmon eggs when the clamping force is increased to 20 mN, at which the maximum stress on the surface of the salmon eggs reaches the cell rupture threshold of 12.5 kPa (Max stress at 12.5 kPa), indicating that this force value is the critical point that may cause damage. This figure directly illustrates the relationship between the clamping force and the contact pressure, providing a key theoretical basis for the present application to avoid tissue damage through real-time mechanical sensing feedback.

[0049] Figure 6 FIG. 15 shows the force calibration process and performance comparison of the gripper robot prepared in Example 5 of the present application. Figure 6 a in FIG. 15 is a photograph of the force calibration experimental device, in which a magnetic gripper (Magnetic gripper) is connected to a commercial force sensor (Commercial force sensor; here, the ZLBS106 sensor from Zhongcheng Sensor is used) through a connecting rod (Connect rod), and an ultrasound probe (Ultrasound probe) is used to monitor the signal of the EUSS sensor in real time. Figure 6 a in FIG. 16 clearly shows the close contact between the gripper and the connecting rod. Figure 6 b in FIG. 17 is a calibration result curve, in which the red curve represents the measurement data of the commercial force sensor, and the black curve represents the frequency shift (Δf) measured by the EUSS sensor of the present application. The curve is divided into three stages: when the external magnetic field is increased (Magnetic field increased), the gripper exerts force, and the Δf of the EUSS and the reading of the commercial sensor increase synchronously; when the magnetic field is stable (Magnetic field stable), the readings of both remain stable; when the magnetic field decreases (Magnetic field decrease), the readings of both decrease synchronously. This figure directly proves that the performance of the EUSS sensor of the present application in wireless force sensing is highly consistent with that of commercial equipment.

[0050] Figure 7 FIG. 18 is a schematic diagram of the grasping operation of the gripper robot prepared in Example 5 of the present application under wireless force sensing. In this figure, Figure 7Fig. 1a is a schematic diagram of the structure and working principle of the magnetic gripper, showing the integrated design of the magnetic gripper and the EUSS sensor, realizing grasping through magnetic actuation and wireless force sensing and feedback control through the EUSS sensor, Figure 7 Fig. 1b is a sequence of photographs of the grasping operation, clearly showing the entire process of the gripper from the initial state (i) to grasping (iv), holding (v), and releasing (vi) the salmon eggs, and indicating the working state of the gripper through the external magnetic field (B) and green arrows, Figure 7 Fig. 1c is an ultrasound imaging diagram, sequentially showing the ultrasound images of the magnetic gripper during grasping, holding, and releasing the salmon eggs, with the red circle indicating the contact area between the gripper and the salmon eggs, proving the guiding role of ultrasound imaging in the operation process. Figure 7 Fig. 1d is a frequency shift (Δf) curve of the EUSS sensor during the grasping operation, which can be divided into three stages. In the grasping (Grasp) stage from 0s to about 50s, as the external magnetic field increases, the gripper gradually closes, the EUSS sensor deforms, and the frequency shift increases from 0MHz to about -0.08MHz and remains at this stable value, which is lower than the cell rupture threshold of -0.12MHz. Subsequently, in the holding (Hold) stage from about 50s to about 95s, the external magnetic field remains constant, the gripper holds the salmon eggs with a stable gripping force, and the frequency shift also maintains around -0.08MHz. Finally, in the release (Release) stage from about 95s to 125s, the external magnetic field weakens, the gripper opens, the EUSS sensor deforms decreases, and the frequency shift gradually recovers to the initial state close to 0MHz, completing the operation. This graph records the Δf changes from grasping (Grasp), lifting (Lift) to releasing (Release), verifying that the gripper can avoid damage to fragile objects by monitoring Δf during actual operation.

[0051] Figure 8 Fig. 2 is a schematic diagram of the design of the spiral robot and the experimental device for vibration sensing according to an embodiment of the present application. Among them, Figure 8 Fig. 2a is a photograph of the experimental device, showing the spiral robot performing experiments in a soft tissue model made of gelatin. The model contains a simulated blood vessel filled with fluid by a pulsation pump. An external magnet is used to drive the robot, and an ultrasound probe is used for real-time monitoring. Figure 8Figure 1 is a schematic diagram of the magnification structure of a helix-type robot, which is mainly composed of a conical tip, a helical sleeve (housing), a cylinder magnet, and an EUSS sensor fixed at the rear end. The robot is driven forward by an external rotating magnetic field, and the EUSS sensor can sense the vibrations caused by the simulated blood vessel pulsation in real time and convert the vibration signals into ultrasonic frequency shifts to achieve wireless sensing.

[0052] Figure 9 Figure 2 is a schematic diagram of the principle and experimental graph of vibration sensing and feedback navigation of the helix-type robot prepared in Example 9 of the present application. Among them, Figure 9 Figure 2a is a schematic diagram of the vibration sensing principle, which shows how the helix-type robot (Helix-type robot) senses the vibrations caused by blood vessel pulsation (Blood vessel pulsation) when it approaches the simulated blood vessel in soft tissue model (Soft tissue e.g. brain) through EUSS sensor. The vibration sensing signal of EUSS is used for robot feedback navigation (Feedback navigation) to maintain a safe distance (Safe distance). Figure 9 Figure 2b is a side view of the experimental, which shows the real sequence diagram of the robot navigating in the soft tissue model, including moving at different distances (Distance 1 and Distance 2) and changing direction (Change direction) during navigation (the ruler in the figure represents 1mm). Figure 9 Figure 2c is a vibration signal curve graph detected by EUSS sensor at different distances. The left curve shows that when the robot is at a distance of 1 (far from the blood vessel), the frequency shift (Δf1) caused by vibration is small, and the oscillation amplitude is weak; The right curve shows that when the robot is at a distance of 2 (closer to the blood vessel), the frequency shift (Δf2) caused by vibration is significantly increased, and the oscillation amplitude is significantly enhanced. This graph intuitively illustrates that the EUSS sensor can provide real-time distance feedback for the robot according to the strength of the vibration signal, so as to realize feedback navigation.

[0053] Figure 10 Figure 3 is a schematic diagram of the structure and working principle of the wireless drug monitoring capsule robot prepared in Example 11 of the present application. Among them, Figure 10Figure 1 is a schematic diagram of the capsule robot in the present application. The main components include: a top plate and a soft plate, a piston plate, a drug storage chamber, a magnet embedded in the piston plate, and an EUSS sensor and a soft strip connecting the piston plate and the top plate. The piston plate is tightly attached to the inner wall of the capsule by seals, and a small hole at the bottom is used for drug release. Figure 10 Figure 2 is a schematic diagram of the principle of drug dose monitoring. The system drives the piston plate to move downward by an externally generated magnetic field gradient pointing downward. The movement of the piston plate causes the drug storage chamber to be compressed, releasing the liquid drug. At the same time, the displacement of the piston plate will cause the EUSS sensor to produce micro-deformation. This deformation will cause the frequency of the ultrasonic waves reflected by the EUSS to shift. The size of Δf is directly related to the displacement of the piston plate, i.e. the liquid volume per actuation. Therefore, by measuring and analyzing the frequency shift in a wireless manner, the release dose of the drug can be accurately and real-time monitored.

[0054] Figure 11 Figure 3 shows the calculation method of the liquid volume released by the capsule robot prepared in Example 11 in the in vitro experiment. The left side is a schematic diagram of the geometric model, and the shape of the released liquid is approximated as a combined shape composed of a cylinder (parameters: cylinder diameter D and cylinder length L) and a spheroid (parameters: spheroid width W and spheroid height H). The middle is the actual profile of the released liquid, which matches the geometric model, and its parameters can be obtained by measurement. The right side is the ultrasonic image when the liquid is released, showing that the ultrasonic probe can monitor the process in real time. The total volume V is calculated by the sum of the volume of the cylinder and the volume of the spheroid .

[0055] Figure 12 Figure 4 shows the principle and calibration results of drug dose monitoring of the capsule robot prepared in Example 11. Figure 12The diagram 'a' represents the principle of wireless dose sensing. Its core logic is as follows: In the initial state, the frequency offset of the EUSS sensor is 0 MHz. When an increased magnetic field is applied to move the piston plate, the capsule releases a certain volume of liquid (V1), causing the EUSS sensor to deform and generate a frequency offset Δf1. When the magnetic field is applied again, releasing another volume of liquid (V2), the total frequency offset further increases to Δf2. This demonstrates a direct, stepwise correspondence between the EUSS's frequency offset (Δf) and the volume of liquid (V) released in each drive. Figure 12 In the figure, 'b' represents the linear calibration curve for this relationship. The horizontal axis represents the frequency shift (Δf, in MHz), and the vertical axis represents the released liquid volume (μL). The blue crosses (Average Data Points) in the figure represent the average data points from multiple in vitro experiments, and the red solid line (Linear Fit) is the linear regression curve fitted based on these data points, with the equation y = -0.3743 + 208.0176x (where y represents the drug release dose in μL; x represents Δf, in MHz). This calibration curve provides crucial quantitative evidence for this invention to inversely estimate the drug release dose by measuring Δf in in vivo experiments.

[0056] Figure 13 This is an experimental diagram showing the capsule robot prepared in Example 11 of this invention performing wireless drug dosage monitoring in vitro. Figure 13 The image 'a' shows a capsule robot performing controlled movement and release in an isolated pig stomach, demonstrating how the robot moves across complex tissue surfaces through tumbling motions (dashed lines indicate its trajectory) and precisely releases liquid drugs at predetermined locations. Figure 13 Figure 'b' represents the frequency offset curve for drug dosage monitoring. This curve records the frequency offset (Δf) changes detected by the EUSS sensor as the piston plate moves under an increasing external magnetic field applied at different time intervals. The curve is stepped, with each step corresponding to one drug release. The gray areas in the figure represent the release of different volumes of liquid sample, and their volume values ​​are labeled, such as V1 being 2.98 μL and V2 being 1.86 μL. This figure visually demonstrates that this invention, by monitoring the frequency offset of the EUSS sensor, can accurately and in real-time wirelessly monitor the dosage of each drug release.

[0057] Figure 14 This is an experimental diagram showing the capsule robot prepared in Example 11 of this invention undergoing in vivo drug delivery and dose monitoring. Figure 14Fig. 1a is a schematic diagram of in vivo dose sensing, showing the whole process of target delivery and dose sensing of a capsule robot in a live rabbit stomach. The process is driven by external magnetic actuation, and guided by real-time imaging by ultrasound and X-ray. Figure 14 Fig. 1b is an in vivo flouscopy imaging image, clearly showing the process of contrast agent release by the robot in vivo, confirming its ability of controllable drug delivery. Figure 14 Fig. 1c is an ultrasound imaging image, showing the location of the capsule robot in the rabbit stomach, and the area of the EUSS sensor, proving that ultrasound imaging can be used to accurately locate the robot in vivo and perform sensing. Figure 14 Fig. 1d is a frequency shift curve graph of in vivo dose monitoring, recording the change in frequency shift (Δf) detected by the EUSS sensor after applying an increased external gradient magnetic field. The curve is in steps, each step representing one drug release, and the released liquid volume is labeled, for example, V1 is 4.49 μL, V2 is 4.91 μL, V3 is 4.53 μL, etc. This graph directly verifies the effectiveness of the present application in monitoring the dose of drugs in vivo by monitoring Δf. DETAILED DESCRIPTION

[0058] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0059] The external magnetic field applied in the following examples is provided by a cubic magnet (5x5x5 cm) with a residual magnetic flux density of 1.38 T as the actuation source, loaded on a six-degree-of-freedom (6-DoF) mechanical arm capable of precise position adjustment.

[0060] Example 1: Design and fabrication of EUSS sensor

[0061] In this embodiment, the EUSS sensor is designed as a cuboid structure, with overall dimensions (length x width x height) of 1.3 mm x 1.3 mm x 1.6 mm and a weight of 4.6 mg. There are 5 x 5 air cavities distributed in the length-width plane, each air cavity being a cylinder (the projection in the length-width plane is a circle), with a height of 1.5 mm and a diameter of 0.19 mm, and a spacing (i.e., the distance between the projections of the centers of two adjacent air cavities to the centers of the projections) of 0.28 mm. The EUSS sensor is manufactured using a mold casting method, which first uses a 3D printer to create a positive sensor model. A soft material Ecoflex 00-30 purchased from Smooth-On Company is mixed according to a mass ratio of A liquid to B liquid of 1:1 and poured into a mold, and cured at room temperature for 4 hours to obtain the upper part of the EUSS sensor. After curing, the part is removed from the mold. To build an air chamber array in the soft matrix and seal the other side of the sensor, a 200 μιη thick film is spin-coated on a glass plate. The opening side of the sensor is pressed against the film to seal it, and the entire assembly is cured in an 80°C oven for 1.5 hours.

[0062] The EUSS obtained in this embodiment uses Ecoflex 00-30 as a soft matrix, and its Young's modulus and density are very close to those of human soft tissue, thereby ensuring good biocompatibility.

[0063] Example 2: Strain simulation of the EUSS sensor

[0064] In this example, the simulation analysis is mainly carried out through finite element analysis (FEA), aiming to elaborate the acoustic scattering field, reflectance spectrum and transmittance spectrum characteristics of EUSS under various strain conditions (including stretching and compression). The EUSS design and fabrication has been described in Example 1, designed as a two-dimensional phononic crystal structure with air cavities embedded in a soft polymer matrix such as Ecoflex 00-30 as periodic scatterers. In simulation, the macroscopic and periodic unit cell of the sensor are modeled to analyze the structural changes before and after deformation. The soft matrix of the sensor is modeled using the Neo-Hookean hyperelastic framework, and the material is assumed to be isotropic and incompressible. By applying controlled tensile or compressive strain, the dispersion relation of the structure can be effectively manipulated. The change in cell size and air cavity diameter after deformation will lead to the change of the sensor's Brillouin zone. Green-Lagrange strain and the second Piola-Kirchhoff stress are used to describe the constitutive behavior of the material. The nonlinear equilibrium equations of the sensor unit cell under periodic boundary conditions and preset boundary displacement are solved iteratively by the Newton-Raphson method. After obtaining the deformed configuration, the band performance of the sensor after stretching is analyzed by the finite element method. When ultrasonic waves are transmitted into the phononic crystal, the Bloch condition is followed. Through simulation, the reflectance spectrum and transmittance spectrum under different strains can be calculated, such as the acoustic scattering field, reflectance spectrum and transmittance spectrum of EUSS under different tensile strains (5%, 10%, 15% and 20%) (a, b, c in Figure 2 Similarly, similar analysis is also carried out under different compression strains (2.5%, 5%, 7.5% and 10%) (d, e, f in Figure 2

[0065] Example 3: Flexibility of EUSS sensor air column morphology

[0066] Although the cylindrical air hole structure is more suitable for the air hole design in the present application due to its isotropic geometric characteristics, replacing the cylindrical air hole in Example 1 with other morphologies of air column such as rectangular column, polygonal prism, elliptical column, etc. can also obtain a flexible metamaterial with similar narrow-band reflection ability and strain-induced reflection band frequency shift function. The present application does not limit the morphology of the air hole, which can be changed to other morphologies of air column structure without affecting the performance of the EUSS sensor in moving the characteristic reflection peak frequency during deformation.

[0067] Example 4: Material substitution of EUSS sensor

[0068] Ecoflex 00-30 (Young's modulus of about 98 kPa, density of about 1.07 g / cm 3 ​) can be replaced by other soft materials with Young's modulus in the range of 50 kPa to 1 MPa and density in the range of 0.89 g / cm 3 to 1.25 g / cm 3 , such as polydimethylsiloxane (PDMS, which has a Young's modulus adjustable to about 73 kPa and a density of about 0.97 g / cm 3 to 1.028 g / cm 3 , or thermoplastic elastomer SEBS (which has a Young's modulus up to about 0.3 MPa and a density of about 0.89 g / cm 3 to 1.25 g / cm 3 , etc. The same process as in Example 1 is used for preparation, and the corresponding resonant frequency is basically unchanged, i.e. the same acoustic performance. This shows that the present application has flexibility in material selection, which can be adjusted according to the specific application requirements and biocompatibility requirements.

[0069] Example 5: Design, manufacture, assembly and magnetic driving method of gripper robot

[0070] This example designs an ultrasonic mechanical gripper robot in combination with the EUSS sensor of Example 1. The gripper body is prepared by mixing PDMS (mass ratio of precursor to curing agent is 10:1) with non-magnetized ferromagnetic NdFeB particles (average diameter 5 μm) at a mass ratio of 1:1, placing it in a U-shaped mold obtained by 3D printing (the U-shaped mold can obtain a U-shaped size parameter after demolding: the U-shaped gripper of the present application has a thickness of 1.6 mm. The outermost distance of the two arms of the gripper is 9.6 mm, and the innermost distance is 6.4 mm. The straight arm part of the gripper has a length of 3.2 mm. The curved part is a circular ring with a radius of 1 / 2, an inner diameter of 6.4 mm and an outer diameter of 9.6 mm), and is made after curing at 60°C for 24 hours, and then demolding; then, the demolded U-shaped gripper is placed in a new mold with the end expanded, and magnetized by a 2.5T pulse magnetic field (the magnetic field direction is parallel to the plane where the U-shaped gripper is located, and points to the midpoint of the bottom of the U-shaped gripper). Two EUSS sensors prepared by Example 1 are adhered to the inner side of the gripper jaws. The gripper can be driven by an external magnetic field generated by a permanent magnet mounted on a six-degree-of-freedom (6-DoF) mechanical arm. By adjusting the position and direction of the magnet, the opening and closing of the gripper can be accurately controlled, and the actions of grabbing, holding and releasing can be completed.

[0071] This example ensures sufficient driving force and flexibility of the material by mixing ferromagnetic NdFeB particles with a soft polymer substrate.

[0072] Example 6: Finite element analysis of contact pressure of gripper robot

[0073] This example describes in detail how to verify the contact pressure of the gripper robot designed in Example 5 when grabbing salmon eggs through finite element analysis (FEA). This FEA simulation aims to provide a theoretical basis for real-time feedback and damage avoidance, and the steps are as follows: First, a geometric model containing the gripper jaw, embedded EUSS and 3mm diameter salmon eggs is established, and it is defined as a hyperelastic material (Ecoflex 00-30) and a linear elastic body, respectively, and the contact between the gripper and the salmon eggs is set as frictionless. Subsequently, a nonlinear static analysis is performed using a commercial FEA software to simulate the application of 15mN and 20mN clamping force. By analyzing the calculated stress distribution, the results show that the maximum stress generated by a clamping force of 15mN is below the cell rupture threshold of salmon eggs (about 12.5kPa), while a clamping force of 20mN reaches the threshold. This conclusion also provides a theoretical basis for the subsequent Example 8, which indirectly controls the clamping force by monitoring the frequency shift of the EUSS in real time and ensures that the contact pressure does not exceed the safety threshold.

[0074] Example 7: Test of the correspondence between the contact pressure of the gripper robot and the frequency shift

[0075] This example aims to establish a quantitative mapping relationship between the clamping force applied by the gripper robot designed in Example 5 and the frequency shift (Δf) of the EUSS sensor. In the experiment, the magnetic gripper integrated with the EUSS sensor is placed on a calibration platform connected to a commercial force sensor through a connecting rod, and the Δf of the EUSS is monitored in real time using an ultrasonic probe. The experimental procedure is divided into three stages: First, in the magnetic field increasing stage with gradually increasing external magnetic field, the clamping force is applied by driving the gripper, and the commercial force sensor readings and the Δf of the EUSS are recorded simultaneously. Second, in the magnetic field stable stage, the maximum magnetic field strength is maintained to verify the signal stability under constant clamping force. Finally, in the magnetic field decreasing stage, the magnetic field strength is gradually reduced, and the data is continuously recorded until the clamping force returns to zero. By synchronously comparing the two sets of recorded data, the present invention successfully establishes a calibration curve between the clamping force and the frequency shift of the EUSS. As shown in Figure 6 .

[0076] Example 8: Demonstration of the mechanical sensing and live operation of the gripper robot (taking grabbing salmon eggs as an example)

[0077] This example demonstrates how to use the gripper robot prepared in Example 5 to avoid tissue damage through real-time feedback. The gripper robot, as described in Example 5, is composed of a U-shaped magnetic soft gripper and two EUSSs bonded to it.

[0078] In a simulated in vivo environment, using an ultrasound imaging system and permanent magnets on a six-degree-of-freedom robotic arm, the operator controls a gripper to approach and grasp salmon eggs approximately 3 mm in diameter. During this process, the EUSS monitors and records the ultrasonic frequency shift (Δf) caused by the contact force in real time. Based on the threshold stress for salmon egg cell rupture (approximately 12 kPa, corresponding to Δf of -0.12 MHz), the computer can compare the monitored Δf with this threshold in real time.

[0079] like Figure 7 As shown in b, the direction and magnitude of the magnetic field used by the clamp throughout the entire process of grasping (iv), holding (v), and releasing (vi) the salmon eggs are as follows:

[0080] State (i) to State (iii): Without using an external magnetic field, the connecting arm is used to continuously bring the clamp closer to the salmon eggs, eventually placing the salmon eggs in the middle of the clamp jaws; State (iii) to State (iv) is Grasp: An external magnetic field is applied, with the magnetic field direction from the midpoint of the bottom of the U-shape to the opening of the U-shape, and the magnetic field magnitude is 40mT; State (iv) to State (v) is Hold and Lift: An external magnetic field is applied, with the magnetic field direction from the midpoint of the bottom of the U-shape to the opening of the U-shape, and the magnetic field magnitude is 40mT; holding and lifting are achieved through the connecting arm; State (v) to State (vi) is Release: An external magnetic field is applied, with the magnetic field direction from the opening of the U-shape to the midpoint of the bottom of the U-shape, and the magnetic field magnitude is 40mT.

[0081] Experimental results show that the Δf generated by a single successful grasping operation in this embodiment did not exceed the threshold, proving the gripper's ability to perform delicate operations without damaging salmon eggs. If the object being gripped changes, the Δf can be controlled to ensure it does not exceed the threshold requirement for the corresponding object by adjusting the shape parameters of the U-shaped gripper and the magnitude of the external magnetic field applied during gripping. The core of this embodiment lies in combining highly sensitive passive ultrasonic sensing with magnetic actuation, achieving real-time mechanical feedback in micrometer-scale operations, and providing a safe and reliable technical solution for precision biomedical operations.

[0082] Example 9: Design, Manufacturing and Driving of a Helical Robot

[0083] This embodiment, based on the EUSS sensor prepared in Embodiment 1, designs a helical robot for soft tissue navigation. The robot consists of a helical shell (3D printed from 3D printing resin; the helical shell facilitates forward and backward movement), a radially magnetized cylindrical NdFeB (N52 grade) permanent magnet (2mm in diameter and 2mm in length), and an EUSS sensor fixed at the rear end (EUSS design and fabrication details are provided in Embodiment 1). Its front end has a tapered tip (made of the same 3D printing resin as the helical shell) to facilitate penetration of soft tissue. The overall projected length of the helical robot in the axial direction of the cylindrical shell is 6mm. External drive is achieved through a six-degree-of-freedom (6-DoF) robotic arm equipped with a permanent magnet and a stepper motor, which generates a rotating magnetic field to drive the robot's helical propulsion within the soft tissue.

[0084] Example 10: Vibration Sensing and Feedback Navigation Principle of a Helical Robot

[0085] This embodiment details the experimental procedure for achieving spatial distance feedback using the helical robot prepared in Example 9, aiming to verify its ability to perform feedback navigation in soft tissue. The experimental setup includes: a soft tissue model made of 5.1 wt.% gelatin; a silicone rubber tube with an inner diameter of 2 mm connected to a pulsating pump as a simulated blood vessel, generating pulsations at a frequency of approximately 100 bpm; a helical robot consisting of a 3D-printed helical sleeve, a conical tip, a cylindrical permanent magnet with a diameter of 2 mm and a length of 2 mm, and a rear-end EUSS sensor; and a drive and sensing system consisting of a six-degree-of-freedom (6-DoF) robotic arm, a permanent magnet, and an ultrasonic probe.

[0086] First, the robot is navigated using a magnetic field to a relatively distant location near a simulated blood vessel, defined as "distance 1" (e.g., ...). Figure 9 As shown in b, Distance 1 (i.e., 5mm). At this point, the pulsatile pump is activated, and the ultrasound probe acquires the frequency shift (Δf) signal of the EUSS, recording signal fluctuations with small amplitudes (Δf1 < 0.005MHz). Subsequently, the magnetic field drives the robot to move closer to the blood vessel to a "distance 2" (e.g., ...). Figure 9 As shown in b, Distance2 (i.e., 1 mm). While the pulsating pump remained running, the ultrasound probe acquired the Δf signal again, recording a significantly increased signal fluctuation (Δf2 > 0.04 MHz). This experiment, by comparing the amplitudes of the two acquired Δf signals, verified a negative correlation between the intensity of the vibration signal and the distance between the robot and the vibration source. This relationship provides real-time spatial distance feedback for robot navigation, allowing the operator to adjust the direction and intensity of the magnetic field based on changes in the amplitude of the Δf signal, thereby achieving effective avoidance and precise navigation of obstacles such as blood vessels.Figure 9 For example, the change direction shown by b in the navigation process can be achieved by adjusting the direction of the external rotating magnetic field.

[0087] Example 11: Design, fabrication and driving of the capsule robot

[0088] The EUSS sensor designed in Example 1 is combined to design a magnetic capsule robot capable of wireless monitoring of drug release dose. The main body of the robot is made of 3D printed resin (such as photosensitive resin), which has a storage chamber for containing liquid medicine, and the volume can reach 150 μL. The core actuator of the robot is a piston plate embedded with a cylindrical neodymium iron boron (NdFeB) magnet magnetized in the axial direction, which is connected to an embedded ultrasonic soft sensor (EUSS) through a soft strip made of Ecoflex. The bottom of the capsule is provided with a micropore with a diameter of about 50 μm for controlling drug release. The piston plate is connected to the top cover of the capsule body at the other end of the soft strip, and the piston plate and the lower cavity form a drug storage cavity which is sealed except for the micropore. The movement control of the capsule is mainly achieved by the external magnetic field, including two ways: one is to use the external magnetic field (constant size) to drive the robot to move in a specified direction, or to use the external rotating magnetic field to drive the robot to roll to realize its navigation in complex biological environment; the second is to drive the piston plate to move by increasing the external magnetic field gradient force, and to compress the storage chamber, so as to realize the on-demand and controllable release of the drug.

[0089] The distance between the upper surface of the top plate and the lower surface of the bottom plate of the capsule robot obtained in this embodiment is 8 mm, and the projection area of the storage chamber on the bottom plate is 50 mm 2 .

[0090] Example 12: Principle and in vitro calibration of drug amount monitoring of the capsule robot

[0091] This embodiment details the core principle of drug amount monitoring of the capsule robot made in Example 11. The principle is based on the coupling between magnetic driving, mechanical deformation and acoustic frequency shift. When the external gradient magnetic field interacts with the magnet in the piston plate, an attractive force is generated, which drives the piston plate to move downward. This displacement of the piston plate directly compresses the drug storage chamber, causing the liquid medicine to be discharged through the micropore at the bottom. At the same time, the movement of the piston plate will stretch the EUSS soft strip connected thereto, causing the micron-level deformation of the periodic air column array inside the EUSS, thereby causing the characteristic peak frequency of the reflected ultrasonic wave of the EUSS to shift (Δf).

[0092] To calibrate the robot in vitro, the capsule robot made in Example 11 was placed in a water tank, using the external magnetic field driving system and the ultrasonic probe. Subsequently, the liquid sample was released in several steps by controlling the magnetic field to drive the piston plate to move step by step. At each release, the ultrasonic probe recorded the Af value of the EUSS sensor synchronously. Meanwhile, to measure the released volume independently, the shape of the liquid spread after release was approximated as a combination of a cylinder and an oblate spheroid, and their geometric dimensions were measured. The total volume V = V c + V s was calculated by the sum of the cylinder volume and the oblate spheroid volume . Finally, by correlating the volume measurement of each release with the corresponding Af value, a calibration curve between Af and V was established as shown in Figure 12 . This method provides a key foundation for establishing the calibration relationship between the EUSS sensor frequency shift and the drug release dose in vitro experiments.

[0093] Example 13: In vitro application of capsule robot dose wireless monitoring

[0094] This example verifies the feasibility of the capsule robot made in Example 11 for dose wireless monitoring through in vitro experiments. The experimental device includes a water tank containing the capsule robot (used to simulate the in vivo acoustic environment), an ultrasonic probe, a mechanical hand and a magnet for controlling the spatial distribution of the external magnetic field. The experimental steps are as follows: First, the ultrasonic probe is used for positioning and continuous monitoring of the robot. Subsequently, the operator gradually increases the distance between the magnet and the robot through the mechanical hand, causing the magnetic field strength to change in steps, thereby driving the piston plate to move in a segmented manner, releasing a certain dose of liquid each time. The ultrasonic probe synchronously receives and records the reflection signal of the EUSS, calculating its frequency shift (Af). The experimental results show that the change in Af presents a clear stepwise correspondence with the volume of the released liquid (such as 2.98 μL, 1.86 μL, 0.735 μL, 0.655 μL and 0.618 μL). This proves the effectiveness of this method in high-resolution dose wireless monitoring in vitro.

[0095] Example 14: In vivo application of capsule robot in vivo drug delivery and dose monitoring

[0096] This example demonstrates the drug delivery and dose monitoring capability of the capsule robot fabricated in Example 11 in a living environment. Male New Zealand rabbits were used as animal models and the robot was sterilized with water and ethanol before the operation. The robot was placed into the rabbit stomach through an endoscope and iodinated glycerol was injected to enhance its visibility under X-ray fluoroscopy imaging. Under the real-time guidance of fluoroscopy and ultrasound imaging, the robot was driven to roll to the predetermined target point using an external magnetic field and the piston was precisely controlled to release the drug. During the drug delivery process, the frequency shift (Af) of the EUSS was continuously monitored by the ultrasound probe to record the released dose in real time. The experiment successfully performed three dose-controlled releases in the living rabbit stomach, and the monitored release volumes were 4.49 μL, 4.91 μL and 4.53 μL, respectively, demonstrating the ability of the robot to accurately deliver drugs in vivo.

[0097] Those skilled in the art will easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A magnetic soft gripper robot, characterized in that, It includes a fixture body and two embedded ultrasonic soft sensors, among which, The main body of the clamp is a three-dimensional U-shape, formed by uniformly mixing magnetic particles with flexible deformable material; the magnetization direction of the magnetic particles in the main body of the clamp is symmetrical about the center line of the U-shape, and the unit vector of the magnetization direction of the magnetic particles at the opening end of the U-shape forms an acute angle or a right angle with the unit vector of the magnetization direction of the magnetic particles at the bottom midpoint of the U-shape; the magnetization direction of the magnetic particles at different positions in the main body of the clamp changes clockwise or counterclockwise from the opening end to the bottom midpoint of the U-shape. Any one of the embedded ultrasonic soft sensors includes a first material and a second material with different sound velocities; wherein the first material is a flexible deformable material, and the second material is distributed within the first material and arranged periodically along the distribution plane, the number of periodic arrays being m×n, where m≥3, n≥1, and m and n are both positive integers; among the first material and the second material, the material with the larger sound velocity has a sound velocity at least twice that of the material with the smaller sound velocity; These two embedded ultrasonic soft sensors are fixedly connected to the two sides of the left and right ends of the U-shaped opening of the fixture body, respectively, and are both located inside the U-shaped opening. The top surface of these two embedded ultrasonic soft sensors is flush with the top surface of the U-shaped opening. Furthermore, for any one of the embedded ultrasonic soft sensors, the side fixedly connected to it is parallel to the distribution plane of the periodic arrangement structure in the embedded ultrasonic soft sensor. The magnetic soft gripper robot can adjust the clamping or releasing state of the U-shaped opening of the gripper body under the action of an external magnetic field to achieve the clamping function and adjust the clamping force; and by ultrasonically detecting the shift of the inherent resonant frequency of the embedded ultrasonic soft sensor, the clamping force of the gripper body can be wirelessly monitored in real time.

2. A spiral robot for navigation in in vivo soft tissue, characterized in that, It includes a tapered tip, an embedded ultrasonic soft sensor, a cylindrical magnet, and an external cylindrical shell with spiral protrusions. The cylindrical magnet is a radially magnetized cylindrical magnet located inside the cylindrical shell and coaxially arranged with the cylindrical shell; The tapered tip is located at the front end of the cylindrical outer shell; The embedded ultrasonic soft sensor includes a first material and a second material with different sound velocities; wherein, the first material is a flexible deformable material, and the second material is distributed within the first material and arranged periodically along the distribution plane, with the number of periodic arrays being m×n, where m≥3, n≥1, and m and n are both positive integers; among the first material and the second material, the material with the larger sound velocity has a sound velocity at least twice that of the material with the smaller sound velocity; The embedded ultrasonic soft sensor is fixed to the rear end of the cylindrical shell; the normal direction of the distribution plane where the periodic arrangement structure in the embedded ultrasonic soft sensor is located is parallel to the axial direction of the cylindrical shell; By detecting the shift in the inherent resonant frequency of the embedded ultrasonic soft sensor using ultrasound, the distance between the spiral robot and nearby blood vessels with blood flow can be monitored in real time, thereby enabling navigation.

3. A magnetically controlled capsule robot capable of wirelessly monitoring drug delivery dosage, characterized in that, It includes a storage chamber for containing liquid drugs, which is fixedly connected to an upper top plate by a support structure, and a bottom plate is fixed to the lower part of the storage chamber; the side wall of the storage chamber is provided with micropores, which can release the contained liquid drugs to the outside through the micropores; Furthermore, a piston plate is provided between the storage chamber and the top plate, and the piston plate is tightly fitted to the inner wall of the storage chamber by a sealing element; a magnet is embedded in the piston plate, and the magnetization direction of the magnet is parallel to the vertical direction; the piston plate and the top plate are connected by a flexible strip, and an embedded ultrasonic soft sensor is also embedded in the flexible strip. The embedded ultrasonic soft sensor includes a first material and a second material with different sound velocities; wherein, the first material is a flexible deformable material, and the second material is distributed within the first material and arranged periodically along the distribution plane, with the number of periodic arrays being m×n, where m≥3, n≥1, and m and n are both positive integers; among the first material and the second material, the material with the larger sound velocity has a sound velocity at least twice that of the material with the smaller sound velocity; The normal direction of the distribution plane containing the periodically arranged structure in the embedded ultrasonic soft sensor is parallel to the vertical direction. The magnetically controlled capsule robot is capable of translational and / or tumbling motions under the influence of an external magnetic field with a constant magnitude. Furthermore, under the influence of an external gradient magnetic field in the vertical direction, the magnet, along with the piston plate, can be displaced downward relative to the storage chamber, compressing the storage chamber and thereby releasing the liquid drug through micropores. By detecting the shift in the inherent resonant frequency of the embedded ultrasonic soft sensor using ultrasound, the relative displacement of the piston plate can be monitored in real time, thereby monitoring the drug release dosage.

4. The magnetic soft gripper robot as described in claim 1, the spiral robot as described in claim 2, or the magnetically controlled capsule robot as described in claim 3, characterized in that, The second material is air; preferably, the second material exists in the embedded ultrasonic soft sensor in the form of a cylindrical air column, a cuboid air column, a polygonal prism air column, or an elliptical cylindrical air column. The first material is Ecoflex or PDMS.

5. The magnetic soft gripper robot as described in claim 1, or the spiral robot as described in claim 2, or the magnetically controlled capsule robot as described in claim 3, characterized in that, The dimensions of the embedded ultrasonic soft sensor are 1.3mm × 1.3mm × 1.6mm.

6. The magnetic soft gripper robot as described in claim 1, characterized in that, The magnetic soft gripper robot has a three-dimensional U-shape with a height of 8-10 mm and a spacing of 5-7 mm at the openings.

7. The spiral robot as described in claim 2, characterized in that, The diameter of the cylindrical shell is 2-3 mm, and the overall projected length of the spiral robot in the axial direction of the cylindrical shell is 6-8 mm.

8. The magnetically controlled capsule robot as described in claim 3, characterized in that, The distance between the upper surface of the top plate and the lower surface of the bottom plate is 8 mm, and the projected area of ​​the storage chamber on the bottom plate is 50 mm². 2 .

Images