Self-deformation soft micro-robot

Abstract

The self-deformation soft microrobot comprises a petal-shaped structure capable of being closed to form a closed space, the petal-shaped structure comprises a magnetic particle layer and a pH response layer capable of responding to pH stimulation, and the magnetic particle layer and the pH response layer are both soft material layers; the magnetic particle layer is a PDMS hydrogel layer mixed with magnetic particles; the pH response layer is a PHEMA hydrogel layer; the magnetic particle layer and the pH response layer form a bridging network through a thermocuring method; the pH response layer can assist the magnetic particle layer, so that the soft micro-robot can generate a better deformation effect; the outer edges of the petal-shaped structures are provided with micro burr structures with hydrophobic performance, the micro burr structures are arranged along the outer edges of the petal-shaped structures in an array mode, a hydrophobic array can be formed between every two adjacent petal-shaped structures, a solid-gas-liquid three-phase diaphragm is formed, edge gap sealing after deformation of the soft micro-robot is achieved, liquid permeation can be effectively prevented, and the service life of the soft micro-robot is prolonged. And it is ensured that drugs and collected objects loaded by the soft micro-robot cannot be polluted in the intestinal environment.

Description

Technical Field

[0001] The invention relates to the technical field of soft micro-robots, and in particular to a self-deformed soft micro-robot. Background Art

[0002] Intestinal flora is deeply involved in the human metabolic process and is related to 90% of human diseases. It is regarded as the most important immune organ of the human body. Accurate sampling of the intestine is of great significance to revealing the mechanism of disease and conducting flora intervention diagnosis and treatment. However, due to the tortuous and narrow intestinal environment, wrinkled adhesions, and mixed multiphase components, effective sampling has become a challenging task.

[0003] Traditional intestinal flora sampling techniques include fecal sampling, intestinal mucosal biopsy, intestinal fluid aspiration sampling, etc. Fecal sampling is to collect microorganisms on fecal samples and regard them as representatives of the intestinal microbiome. However, there are significant differences in the microbial composition between feces and the intestine, and it is impossible to accurately reveal the composition of the intestinal flora. Intestinal mucosal biopsy uses an endoscope to enter the sampling site from the mouth or anus and collect samples, and intestinal fluid aspiration sampling uses a catheter to enter the vicinity of the sampling site to aspirate intestinal fluid samples. Both have serious defects such as high invasive damage, easy sample contamination, and insufficient sampling volume.

[0004] As a new generation of low-invasive remote sampling technology, capsule robots have opened up a new situation for intestinal sampling. Generally speaking, capsule robots are composed of an external shell and internal micro-hardware, which can follow the peristalsis of the intestine to achieve remote propulsion. After reaching the sampling point, the capsule robot can adjust its macro-posture under the drive of the external magnetic field so that the sampling port of the body is aligned with the collection target. Then, the negative pressure suction principle is used to control the opening and closing of the sampling chamber valve to perform a one-time sampling operation of the intestinal flora. The collected samples can be transported in a closed manner under the mechanical protection of the robot's external shell. The current soft sampling microrobots generally have the problem of single response, which is limited to one signal, and the motion mode and deformation strategy are relatively single. When performing grasping or self-locking tasks, due to this singleness, the robot may face the situation of being unable to close completely, which directly affects its operational efficiency in complex tasks. This defect may lead to the failure to achieve the ideal execution effect in specific operations, limiting the flexibility and application scope of soft microrobots in various complex environments.

[0005] Therefore, how to design a self-deformable soft microrobot that can respond to multiple stimuli and achieve better deformation effect is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] The purpose of the present invention is to provide a self-deformable soft microrobot in view of the defects and shortcomings in the prior art, which can respond to two different stimuli, namely magnetic field and pH value, so as to improve the deformation effect of the self-deformable soft microrobot.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] The present invention provides a self-deformed soft micro-robot, comprising a petal-shaped structure that can be closed to form a closed space, the petal-shaped structure comprising a magnetic particle layer and a pH response layer that can respond to pH stimulation, and the magnetic particle layer and the pH response layer are both soft material layers.

[0009] Preferably, the magnetic particle layer is a PDMS hydrogel layer mixed with magnetic particles.

[0010] Preferably, the pH responsive layer is a PHEMA hydrogel layer.

[0011] Preferably, the magnetic particle layer and the pH responsive layer form a bridge network by thermal curing.

[0012] Preferably, the outer edge of the petal-shaped structure is provided with a micro-burr structure with hydrophobic properties, and the micro-burr structure is arranged in an array along the outer edge of the petal-shaped structure and can form a hydrophobic array between adjacent petal-shaped structures.

[0013] Preferably, the micro-burr structure is cylindrical or rectangular with a square cross-section, the diameter or side length of the micro-burr structure is 200nm, the aspect ratio of the micro-burr structure is 5:1 to 10:1, and the spacing between adjacent micro-burr structures does not exceed 1.5 times the radius of the micro-burr structure.

[0014] Preferably, the petal-like structure has a central area, a tip area and a connecting area for connecting the central area and the tip area, the material density of the central area is the largest, the material density of the connecting area is the smallest, and the material density of the tip area is between the central area and the connecting area.

[0015] Preferably, the petal-shaped structure and the micro-burr structure are integrally formed by a photocuring 3D printer.

[0016] Preferably, the petal-like structure is a three-petal structure.

[0017] Preferably, the petal-like structure in the expanded state is in the shape of an equilateral triangle, and the petal-like structure in the closed state is in the shape of a rice dumpling.

[0018] Compared with the prior art, the present invention has achieved the following technical effects:

[0019] 1. The present invention sets a petal-shaped structure including a magnetic particle layer and a pH response layer, so that the self-deformed soft microrobot can respond to two different signals, namely, a magnetic field and a pH signal. Generally, a single response can only make the robot bend 90° to 100°. The pH response layer of the present application produces a specific deformation by responding to pH changes, which assists the magnetic particle layer to produce a better deformation effect, thereby improving the operating efficiency of the soft microrobot in complex tasks, enabling the soft microrobot to achieve an ideal execution effect, and improving the flexibility and applicability of the soft microrobot in various complex environments.

[0020] Other technical solutions of the present invention have achieved the following technical effects compared with the prior art:

[0021] 2. The present invention arranges a micro-burr structure on the outer edge of the petal structure, so that a hydrophobic array can be formed between adjacent petal structures in a closed state, forming a "solid-gas-liquid" three-phase diaphragm. This diaphragm structure forms a gas-liquid barrier layer by adsorbing microbubbles, thereby sealing the edge gaps of the soft microrobot after deformation, and can effectively prevent liquid penetration, ensuring that the drugs and collected materials loaded by the soft microrobot will not be contaminated in the intestinal environment.

[0022] The hydrophobic structure described in this application can improve the hydrophobic angle of the surface of the soft micro-robot body material. Moreover, the structure can be manufactured by a photocuring one-piece molding method, eliminating the secondary processing process, and greatly improving the performance of the robot without affecting the manufacturing efficiency of the robot body.

[0023] 3. This application uses soft materials PDMS and PHEMA to effectively reduce the possible physical damage of the robot body to human tissue; by transforming the soft robot from a two-dimensional film to a three-dimensional structure, the robot's single sample collection capacity has been greatly improved; at the same time, PDMS and PHEMA have good biocompatibility, chemical inertness, and no biological toxicity, and are suitable for in vivo operations.

[0024] 4. This application designs the shape of the microrobot body into a three-lobed structure, taking into account the requirements of the contact gap and sample collection capacity, and the structure has distribution uniformity and deformation stability. In the diastolic state, the body is similar to an equilateral triangle; after deforming in response to stimulation, the body contracts into a shape similar to a zongzi. This structure can ensure deformation stability to a large extent while ensuring a large sample collection volume, while reducing the number of edge gaps, and can better meet the needs of intestinal sampling operations of soft robots. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 It is a schematic diagram of the structure of the soft micro-robot in the stretched, curled and closed states disclosed in a specific embodiment of the present invention;

[0027] Figure 2 It is a schematic structural diagram of a hydrophobic array disclosed in a specific embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the gradient distribution of the cross-linked network structure density of the local material of a soft microrobot disclosed in a specific embodiment of the present invention.

[0029] Among them, 1. Petal-like structure; 2. Hydrophobic array; 3. Micro-burr structure; 4. Central area; 5. Connection area; 6. Leaf tip area. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] like Figures 1 to 3 As shown, the present invention provides a self-deformed soft micro-robot, including a petal-shaped structure 1 that can be closed to form a closed space, the petal-shaped structure 1 includes a magnetic particle layer and a pH response layer that can respond to pH stimulation, and the magnetic particle layer and the pH response layer are both soft material layers. Figure 1 (1) is a schematic diagram of the petal-like structure 1 in a stretched state; (2) to (4) are schematic diagrams of the petal-like structure 1 corresponding to different degrees of curling during the curling process.

[0033] After the soft microrobot is manufactured, it is placed in a magnetizer for magnetization. During the magnetization process, the mold is used to keep the soft microrobot in a closed shape. After the magnetization is completed, the soft microrobot has the function of automatic expansion and closing. Specifically, an external magnetic field (a small one is fine) is applied to the soft microrobot, and the soft microrobot can be deformed to the state during magnetization, wrapping the loaded drugs or collected objects inside; when the external magnetic field is removed, the soft microrobot can be deformed to a relaxed state, making it easier for the loaded drugs or collected objects to enter the interior of the soft microrobot. The pH response layer can produce specific deformations at different pH values, and can assist the magnetic particle layer to produce better deformation effects.

[0034] In one embodiment, the magnetic particle layer is a PDMS hydrogel layer mixed with magnetic particles, the pH response layer is a PHEMA hydrogel layer, and the magnetic particle layer and the pH response layer form a bridge network by thermal curing. Specifically, through the two-photon curing process, ultraviolet light is irradiated on the photoinitiator to induce a cross-linking reaction of the hydrogel to polymerize the material, thereby preparing the PHEMA layer; the PDMS polymer mixed with magnetic particles is poured on the PHEMA layer, and the PDMS polymer is thermally cured for 8 hours at a temperature of about 60°C to form a bridge network with the PHEMA layer. As a result, the two layers are tightly connected, which effectively prevents the two response layers from falling off, better maintains the overall stability, and enables the robot to achieve better deformation effects.

[0035] PDMS (Polydimethylsiloxane, Chinese full name: polydimethylsiloxane) is one of the ideal materials for the manufacture of soft microrobots. Its excellent softness and elasticity enable soft microrobots to adapt to complex environments, reduce resistance and avoid damaging surrounding tissues. At the same time, PDMS has good biocompatibility and can be safely used in biomedical applications. Its excellent processing performance and optical transparency make its manufacturing cost low and its design flexible, and it can realize complex microstructures. In addition, PDMS is also chemically inert, allowing soft microrobots to operate stably in various environments. PHEMA (Poly (2-Hydroxyethyl Methacrylate), Chinese full name: polyhydroxymethyl methacrylate) is another ideal material for the manufacture of soft microrobots. Its high hydration and biocompatibility enable soft microrobots to interact well with biological tissues, reduce friction and damage with surrounding tissues, and effectively reduce the possible physical damage of soft microrobots to human tissues. PHEMA hydrogel has good chemical stability, which enables soft microrobots to effectively resist corrosion and damage in environments such as digestive fluids. The properties of these materials enable soft microrobots to operate stably in complex biological environments and be harmless to the body.

[0036] The outer edge of the petal structure 1 is provided with a micro-burr structure 3 with hydrophobic properties. The micro-burr structures 3 are arranged in an array along the outer edge of the petal structure 1. When closed, a hydrophobic array 2 can be formed between adjacent petal structures 1. The overall structure of the hydrophobic array 2 is similar to the micro-burr structure on the surface of the sundew. In an ideal state, the micro-burr structure 3 is cylindrical or rectangular with a square cross-section. The diameter or side length of the micro-burr structure 3 is 200nm, the aspect ratio of the micro-burr structure 3 is 5:1 to 10:1, and the spacing between adjacent micro-burr structures 3 does not exceed 1.5 times the radius of the micro-burr structure 3.

[0037] The petal structure 1 has a central area 4, a blade tip area 6 and a connecting area 5 for connecting the central area 4 and the blade tip area 6. The material density of the central area 4 is the largest and almost no deformation occurs. The material density of the connecting area 5 is the smallest and can produce a large deformation to achieve the closure of the petal structure 1. The material density of the blade tip area 6 is between the central area 4 and the connecting area 5, and the degree of deformation is relatively small. This distribution form of material density is conducive to the robot to achieve envelope closure, while maintaining a certain shape and having a certain wrapping space after closure. In one embodiment, the petal structure 1 and the micro-burr structure are integrally formed using a photocuring 3D printer. Generally speaking, the stronger the laser energy in a certain area, the higher the degree of material cross-linking, the higher the Young's modulus of the material, the harder it behaves, and thus the lower the degree of deformation of the area. The faster the spatial scanning speed, the faster the material solidifies. The higher the spatial positioning accuracy, the more accurate the material density distribution. When processing and manufacturing the edge of the robot body, the parameters such as the laser energy, spatial scanning speed, and spatial positioning accuracy are discretely and accurately controlled, thereby realizing the gradient distribution and non-uniform stress storage of the cross-linked network structure density of the local material of the robot body.

[0038] Failure is inevitable during the magnetization deformation process. The more leaflets there are, the higher the risk of failure. In addition, too many leaflets will also lead to more contact gaps when the deformation is closed, affecting the sealing effect when closed. If there are too few leaflets, the sample volume collected at a single time is relatively small. For this reason, in one embodiment of the present application, the petal structure 1 is set to a three-leaf structure, and the petal structure 1 in the diastolic state is an equilateral triangle (see Figure 1 (1)), the petal-like structure 1 in the closed state is in the shape of a rice dumpling (see Figure 1 (4)).

[0039] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

Claims

1. A self-morphing soft micro robot, characterized in that: The invention comprises a petal-shaped structure which can be closed to form a closed space, wherein the petal-shaped structure comprises a magnetic particle layer and a pH response layer which can respond to pH stimulation, and both the magnetic particle layer and the pH response layer are soft material layers.

2. The self-morphing soft micro-robot according to claim 1, characterized in that: The magnetic particle layer is a PDMS hydrogel layer mixed with magnetic particles.

3. The self-morphing soft micro-robot according to claim 2, characterized in that: The pH response layer is a PHEMA hydrogel layer.

4. The self-morphing soft micro-robot according to claim 3, characterized in that: The magnetic particle layer and the pH response layer form a bridge network by thermal curing.

5. The self-morphing soft micro-robot according to any one of claims 1 to 4, characterized in that: The outer edge of the petal-shaped structure is provided with a micro-burr structure with hydrophobic properties. The micro-burr structures are arranged in an array along the outer edge of the petal-shaped structure and can form a hydrophobic array between adjacent petal-shaped structures.

6. The self-morphing soft micro-robot according to claim 5, characterized in that: The micro-burr structure is cylindrical or rectangular with a square cross-section. The diameter or side length of the micro-burr structure is 200nm. The aspect ratio of the micro-burr structure is 5:1 to 10:

1. The spacing between adjacent micro-burr structures does not exceed 1.5 times the radius of the micro-burr structure.

7. The self-morphing soft micro-robot according to any one of claim 6, characterized in that: The petal-like structure comprises a central area, a blade tip area and a connecting area for connecting the central area and the blade tip area. The material density of the central area is the largest, the material density of the connecting area is the smallest, and the material density of the blade tip area is between the central area and the connecting area.

8. The self-morphing soft micro-robot according to claim 7, characterized in that: The petal-shaped structure and the micro-burr structure are integrally formed by using a light-curing 3D printer.

9. The self-morphing soft micro-robot according to any one of claims 1 to 4, 6, 7 and 8, characterized in that: The petal-like structure is a three-petal structure.

10. The self-morphing soft micro-robot according to claim 9, characterized in that: The petal-like structure in the expanded state is in the shape of an equilateral triangle, and the petal-like structure in the closed state is in the shape of a rice dumpling.

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