A hydrogel precision delivery system based on acupuncture needles, its preparation method and application

Abstract

This invention provides a hydrogel-based precision delivery system for acupuncture needles, its preparation method, and its application, belonging to the field of biomedical materials technology. The hydrogel-based precision delivery system for acupuncture needles includes an acupuncture needle and a hydrogel coating. A threaded groove is formed on the needle body, and the hydrogel coating adheres to this groove. The hydrogel coating is prepared by photocrosslinking N-[2-(3,4-dihydroxyphenyl)ethyl]-2-methylacrylamide and methacrylated hyaluronic acid to obtain an adhesive hydrogel, which is then encapsulated in a liposome and loaded into the threaded groove. After drying, the hydrogel coating is formed. The hydrogel-based precision delivery system provided by this invention enables the smooth, minimally invasive delivery of drugs or biological materials to the subchondral bone via the acupuncture needle, regulating abnormal TGF-β1 secretion and constructing stem cell migration channels in the subchondral bone, achieving precise localization and treatment of the subchondral bone.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials technology, and relates to drug delivery in precision treatment, specifically to a hydrogel precision delivery system based on acupuncture needles, its preparation method, and its application. Background Technology

[0002] Precision medicine generally includes optimized disease control strategies and optimized iatrogenic damage control strategies, and it currently occupies an important position in the medical field. Compared with conventional treatments, the advantage of precision medicine lies in its ability to accurately target drugs to the lesion and create an enrichment effect at the lesion site, greatly improving clinical efficacy and significantly reducing the risk of side effects that may result from treatments.

[0003] Currently, with the continuous development and application of functionalized biomaterials, precise localization and treatment of various diseases have been achieved, such as hydrogel microspheres and electrospun materials. However, due to their unique physiological structures (such as the spinal cord and cartilage), some tissues or organs create natural physical barriers to external treatment methods, greatly hindering the implementation of precision treatment. Therefore, how to design a drug delivery system that can powerfully overcome the physical barriers of various tissues and organs to achieve precise lesion localization is a major medical challenge that urgently needs to be overcome.

[0004] Extensive clinical applications have demonstrated that Chinese acupuncture is the most mature and precise treatment method in traditional medicine. With a history of thousands of years, the efficacy of Chinese acupuncture has stood the test of time and is now widely practiced worldwide. The principle of acupuncture is to utilize microneedles with a tip diameter of 200-300 micrometers and a length of 100-120 millimeters. These microneedles powerfully penetrate the physical barriers of various tissues and organs, directly reaching the lesion to precisely stimulate it, altering the lesion's microenvironment, thereby alleviating or even treating the disease.

[0005] The material commonly used in acupuncture is the acupuncture needle, which is a microneedle made of metal. It has a physical hardness that organic polymers and silicon-based materials cannot match. Microneedles with a length of hundreds of millimeters can be made to easily reach various deep tissues in the human body. It also has the ability to powerfully penetrate the physical barriers of various hard tissues, easily achieving the effect of inserting the needle through the skin and powerfully breaking through the physical barriers of various tissues to reach the deep lesions in the human body.

[0006] Because the diameter of acupuncture needle tips is on the micrometer scale, it is extremely minimally invasive. Patients experience almost no pain during acupuncture treatment, and there is virtually no bleeding at the acupuncture site. After the treatment, the micrometer-sized wounds left by the acupuncture needles heal rapidly on their own, and patients can leave the treatment room and resume their normal lives without the need for bandaging or other medical treatment. Therefore, in China, patients have a very high acceptance rate for acupuncture treatment and do not have the same aversion to invasive Western medicine treatments. Patients generally accept a frequency of 3 to 5 acupuncture treatments per week. This high-frequency and non-invasive treatment method ensures the significant efficacy of acupuncture.

[0007] Chinese acupuncture therapy has many advantages, but traditional acupuncture needles made of metal materials have a single chemical composition and lack chemical groups that can be used for chemical modification, making it difficult to carry out targeted functional modifications.

[0008] Currently, acupuncture therapy mainly intervenes and treats lesions through single physical stimulation. However, it often lacks specificity when facing different diseases and different pathological microenvironments, which severely limits the further expansion of acupuncture in the field of precise positioning treatment.

[0009] Therefore, if acupuncture needles can be functionally modified to achieve precise positioning and treatment effects targeting the microenvironment of different diseases, the application of acupuncture in the field of precise positioning and treatment will be further expanded.

[0010] Building upon acupuncture treatment, microneedle patches have been developed. Due to their diverse functional designs, microneedle patches can target and precisely treat various disease microenvironments, and have been widely used in the medical field. Microneedle patches can effectively penetrate various tissues and organs, and can deliver medication to specific sites, making them an ideal biomaterial for precise localization therapy. Currently, microneedle patches are used in various solid tumors and organs, achieving drug release and precise localization therapy. However, current microneedle patch materials still have two shortcomings when targeting deep tissues for precise treatment: firstly, the penetration depth is insufficient, only acting on superficial tissues; secondly, they lack sufficient hardness to overcome the hard physical barriers of some tissues and organs, such as cartilage and ligaments. The materials used to manufacture microneedle patches have primarily focused on organic polymers and silicon-based materials, resulting in these two major shortcomings remaining unresolved, severely hindering the application and expansion of microneedle patches in the field of deep, precise localization therapy.

[0011] To address the shortcomings of Chinese acupuncture and microneedle patches in deep and precise treatment, and to fully leverage their respective advantages, researchers have attempted to combine Chinese acupuncture with microneedle patch technology to prepare drug delivery carrier materials with multiple functions, thereby enriching their application in the field of precision-targeted treatment.

[0012] Patent document CN 108245418 A discloses a spiral acupuncture needle with a threaded structure on the needle body. Through the spiral structure on the needle body, human tissue or body fluid can be extracted during acupuncture treatment for disease detection or gene detection. However, the spiral acupuncture needle has threads on the outer surface of its needle body, and the threads are convex on the needle body to facilitate the extraction of tissue fluid. This acupuncture needle structure cannot be applied in the field of precision treatment. When the convex threads are used to load drugs, they are prone to drug loss and cannot accurately reach the lesion.

[0013] Patent document CN 108338917 A discloses an acupuncture needle with grooves on its body, which can extract human tissue or body fluids through the groove structure for disease detection or gene detection. However, the aforementioned patent document's structural improvement of the acupuncture needle only involves the basic extraction of human tissue or body fluids for disease detection or gene detection, and does not explore the in-depth application of the acupuncture needle in the field of precision medicine. How to fully utilize the groove structure of the acupuncture needle to achieve precise drug delivery, overcome the hard physical barriers of tissues and organs, and achieve precise disease treatment still requires further research.

[0014] Patent document CN 106061455 A discloses a porous acupuncture needle, which has multiple micron-sized recessed pores on its surface. Drug is loaded into these pores to effectively deliver the drug into the body, improving the therapeutic effect of acupuncture. While this method achieves basic drug delivery through the acupuncture needle, it places high demands on the needle. The numerous recessed pores on the needle surface result in low needle strength, making it prone to breakage upon insertion into the body. Furthermore, although the pore structure can hold drug, the effective drug loading is low, and the drug does not easily dissolve from the pores, leading to uncontrollable drug release. When the acupuncture needle is removed, a large amount of drug remains in the recessed pores, resulting in low drug delivery efficiency and failing to achieve the desired precise therapeutic effect.

[0015] The journal article "Improvement in antigen-delivery using fabrication of agrooves-embedded microneedle array, Sensors and Actuators B 137(2009)274-280" discloses a microneedle patch structure in which the microneedle array is designed as a grooved microneedle structure. Drugs are loaded within the grooves of the microneedles and delivered into the body, achieving precise treatment. This article studied the loading of antigens or proteins within the grooves of the microneedle patch, showing that its microneedle structure can release antigens or proteins into the body and can be used for targeted precision treatment. However, its microneedle array structure is only suitable for superficial tissues and cannot perform targeted precision treatment on deep tissues, nor can it penetrate hard physical barriers such as the spinal cord or cartilage.

[0016] Regarding the aforementioned precision treatment methods, on the one hand, traditional acupuncture methods have the disadvantages of poor drug delivery, uncontrollable drug release, and lack of sustained-release efficacy. On the other hand, existing microneedle patches are only suitable for superficial tissues and cannot accurately target and treat deep tissues. These problems urgently need to be solved.

[0017] Hydrogels are multifunctional drug-loaded biomaterials with broad application prospects. Due to their abundant chemical groups, hydrogels have great potential for functionalization and play an important role in realizing the functionalization of acupuncture needles. Achieving hydrogel loading on acupuncture needles and developing hydrogel-acupuncture needle systems with minimally invasive and precise positioning functions are the main breakthrough directions for expanding the application of acupuncture needles in the field of precise positioning therapy in deep tissues.

[0018] Previously, researchers have combined hydrogels with microneedles to endow them with more physiological functions. For example, Xingjie Yin et al. combined hydrogels with syringe needles, leaving the hydrogel at the needle puncture site while using the syringe to reduce bleeding. Tsai-Yu Chen et al. combined acupuncture with drug-loaded hydrogels to promote wound healing in diabetic patients. However, the above cases are all limited to the treatment of skin or superficial blood vessels. For treatments that need to penetrate deep into the body, passing through several tissues such as skin, tendons, muscles, and cartilage, and ultimately reaching lesions in the subchondral bone, no hydrogel microneedles capable of achieving this precise therapeutic effect have yet been developed. These significant physiological obstacles would cause the hydrogel to easily detach from the acupuncture needle "midway," failing to reach the lesion smoothly. Therefore, ensuring that the hydrogel loaded on the needle tip does not detach during the insertion of the acupuncture needle has always been a major challenge for researchers.

[0019] Osteoarthritis (OA) is the most common chronic degenerative joint disease worldwide. Numerous functionalized biomaterials have been developed for the precision treatment of OA. While these biomaterials can precisely target the knee cartilage, effectively improving cartilage damage and degeneration, almost no biomaterials can overcome the physical barrier of cartilage to precisely treat one of the most important early factors of OA: subchondral bone disease.

[0020] Existing research has found that abnormal secretion of the cytokine TGF-β1 in the subchondral bone of osteoarthritis (OA) leads to subchondral bone lesions (including abnormal remodeling, sclerosis, and mineralization), ultimately accelerating OA progression. However, regulating abnormal TGF-β1 secretion through systemic drug administration will inevitably lead to significant side effects. Meanwhile, subchondral bone stem cells are a key factor in repairing cartilage damage. In clinical practice, drilling is typically performed during knee surgery at the site of cartilage injury to induce subchondral bone stem cells to migrate to the cartilage defect, thereby repairing the cartilage. However, this treatment method can only be performed on surgical patients.

[0021] In summary, precise subchondral bone localization therapy can improve the biomechanical environment of cartilage and alleviate cartilage damage at its root. Subchondral bone mesenchymal stem cells also play a crucial role in repairing cartilage damage. Therefore, precise subchondral bone localization therapy is an ideal method for treating osteoarthritis. However, developing appropriate drug delivery materials to achieve precise subchondral bone localization therapy remains a pressing technical challenge. Summary of the Invention

[0022] To address the aforementioned technical problems, this invention provides a hydrogel-based precision drug delivery system for acupuncture needles, along with a method for preparing the system and its application in precise drug delivery to deep tissues. The technical objectives of this invention are twofold: firstly, to improve the acupuncture needle by addressing the limitation of traditional acupuncture needles to limited functionality, thus hindering their precise drug delivery; and secondly, to overcome the issues of existing improved acupuncture needle methods where drugs or hydrogels easily detach from the needle, failing to penetrate the physical barriers of deep tissues and resulting in low drug delivery efficiency.

[0023] To achieve the above-mentioned technical objectives and solve the above-mentioned technical problems, one aspect of the present invention is to provide a hydrogel precision delivery system based on acupuncture needles; another aspect is to provide a method for preparing the above-mentioned hydrogel precision delivery system based on acupuncture needles; and a third aspect is to provide the application of the above-mentioned hydrogel precision delivery system based on acupuncture needles in precise positioning and treatment of deep tissues.

[0024] This invention first provides a hydrogel precision delivery system based on acupuncture needles, the technical solution of which is as follows:

[0025] A hydrogel precision delivery system based on acupuncture needles includes an acupuncture needle and a hydrogel coating. The acupuncture needle has a threaded groove on its body, and the hydrogel coating is adhered to the threaded groove of the acupuncture needle. The hydrogel coating is prepared by photocrosslinking of N-[2-(3,4-dihydroxyphenyl)ethyl]-2-methylacrylamide and methacrylated hyaluronic acid to obtain an adhesive hydrogel, which is then loaded into the threaded groove after encapsulating a carrier liposome and dried to form the hydrogel coating.

[0026] The technical concept of this invention is based on the Chinese acupuncture needle (CA-needle) as a precise delivery material for penetrating deep cartilage tissue. Utilizing the CA-needle's ability to strongly overcome physical barriers, as well as its minimally invasive and precise positioning capabilities, a threaded acupuncture needle (ST-needle) with threaded grooves on its surface is designed. This ST-needle can reach deep lesions minimally invasively. Its threaded grooves are loaded with an adhesive hydrogel, and liposomes are encapsulated within the hydrogel, enabling the smooth delivery of drugs or biomaterials to the subchondral bone to regulate abnormal TGF-β1 secretion and construct stem cell migration channels in the subchondral bone, achieving the goal of precise targeted treatment of the subchondral bone.

[0027] However, due to the micrometer-scale diameter of acupuncture needles and the extremely small volume of the threaded grooves in ST-needles, the amount of medication that can be carried is very limited. Initially, the applicant attempted to load the medication directly into the threaded grooves, but found that this method could not deliver a large quantity of medication to the subchondral bone, resulting in low delivery efficiency and an inability to achieve precise localization and treatment of the subchondral bone. Therefore, a novel drug delivery system is needed to achieve the enrichment and sustained release of medication within the acupuncture needle grooves, and to successfully deliver it to the lesion for separation, thus enabling better precise localization and treatment of the subchondral bone.

[0028] Based on the above, the inventors chose hydrogel as the drug delivery carrier and prepared a drug-loaded hydrogel system. However, when the inventors tried to combine the hydrogel with ST-needle, they found that although the hydrogel could be loaded into the threaded grooves of the ST-needle, there were two major problems that were difficult to solve during acupuncture treatment: First, the hydrogel on the acupuncture needle was prone to "midway" detachment. When passing through human skin, tendons, muscles, and cartilage, it was easy to fall off from the threaded grooves and fail to reach the deep subchondral bone lesions smoothly, resulting in a very low drug delivery rate. Second, when removing the needle after acupuncture treatment, the hydrogel could not automatically separate from the threaded grooves and remain in the body. Most of the hydrogel was still tightly attached to the deep threaded grooves of the acupuncture needle and was carried out of the body, resulting in a very low drug delivery amount and poor precise positioning and treatment effect.

[0029] To address the aforementioned issues, the inventors consulted numerous documents and conducted extensive research. However, they encountered significant difficulties and experienced several failures, some of which are illustrated in Comparative Examples 1-7 of this invention. These failures demonstrated that combining hydrogel with spiral acupuncture needles for precise treatment of subchondral bone is not as easily achieved as the inventors envisioned. In practical applications, the delivery efficiency of the hydrogel is very low, reaching only about 20-30%. Therefore, ensuring that the hydrogel loaded within the spiral grooves of the acupuncture needle does not prematurely detach from the body during insertion, and ensuring that the hydrogel can be smoothly separated from the grooves and retained within the body during needle removal, has remained a major challenge for researchers.

[0030] Ultimately, through continuous innovation, the inventors unexpectedly obtained a successful solution and innovatively designed a precise delivery system of "adhesive hydrogel coating @ threaded acupuncture needle". In an extremely ingenious way, it simultaneously achieved the good application effects of "resisting huge obstacles to prevent detachment" and "achieving separation of acupuncture and hydrogel at the lesion site", making the delivery efficiency of hydrogel reach more than 85%.

[0031] The inventors innovatively designed a hydrogel system capable of adhering to metals and encapsulated drug-carrying liposomes within it, achieving long-term sustained drug release. Methacrylated hyaluronic acid (HAMA), in addition to possessing the properties of general hydrogels, exhibits a certain protective effect on cartilage, while N-[2-(3,4-dihydroxyphenyl)ethyl]-2-methylacrylamide (DMA, CAS No.: 471915-89-6, molecular formula: C...) 12 H 15 NO3 can participate in the photocrosslinking reaction of HAMA through its methacryloyl group, thereby obtaining HAMA modified with dopamine groups, which is a novel HAMA hydrogel with an adhesive polymer interface (denoted as DMA@HAMA). Subsequently, liposomes were combined with hydrogels, and the synthesized Lipo@DMA@HAMA hydrogel system was loaded into the threaded groove of an acupuncture needle. After drying, a hydrogel coating was formed, resulting in a hydrogel precision delivery system based on acupuncture needles.

[0032] The hydrogel precision delivery system constructed in this invention, when acupuncture needles penetrate human tissue, allows the hydrogel coating to adhere tightly to the deep grooves of the threads, thus protecting it and eliminating the need for strong adhesion to resist significant obstacles and prevent detachment. When the hydrogel enters the lesion along with the acupuncture needle, it cleverly utilizes the characteristics of the threads and the swelling properties of the hydrogel. After absorbing body fluids and swelling, the hydrogel rapidly expands in volume, protruding beyond the threads and thus making close contact and adhesion to the surrounding tissue. Subsequently, by rotating the acupuncture needle and withdrawing it along the direction of the threads, the hydrogel is successfully retained within the lesion.

[0033] The inventors also attempted to combine other hydrogel components with acupuncture needles, including anchoring drugs to the hydrogel network with covalent bonds and preparing hydrogel drug-carrying systems with stronger adhesion. However, none of these methods could accurately deliver the drugs to the subchondral bone lesions. The delivery efficiency of the drug-carrying hydrogel was only 40-65%, which could not achieve the technical effect of the present invention.

[0034] Therefore, the present invention effectively overcomes the limitation of conventional hydrogel and acupuncture needle combination in achieving precise subchondral bone localization treatment, and provides an innovative hydrogel precision delivery system based on acupuncture needles. This system can effectively deliver hydrogel-loaded drugs or biomaterials through the threaded acupuncture needles, penetrating the hard physical barrier of cartilage and successfully reaching the subchondral bone lesion, thus achieving precise localization treatment of the subchondral bone.

[0035] The hydrogel precision delivery system based on acupuncture needles provided by this invention is a highly promising precision treatment system. It can be used not only for the precise delivery of drugs to deep tissues such as subchondral bone, but also for the precise delivery of drugs to other lesion sites with strong physical barriers. Furthermore, it can also achieve precise delivery to various biomaterials.

[0036] Furthermore, the mass ratio of N-[2-(3,4-dihydroxyphenyl)ethyl]-2-methylacrylamide to methacrylated hyaluronic acid in the hydrogel of this invention is 1:3 to 5. The hydrogel prepared at this ratio ensures that the hydrogel accurately reaches the subchondral bone under the protection of the threaded acupuncture needle, and easily separates from the threaded groove and remains in the body. The hydrogel coating adheres well to the threaded groove and does not extend beyond the surface of the acupuncture needle.

[0037] Furthermore, the mass ratio of the adhesive hydrogel to the liposome is 4 to 6:1.

[0038] Furthermore, the acupuncture needle has a needle body diameter of 0.2-0.5 mm, a thread pitch of 0.5-1 mm, and a thread groove depth of 0.05-0.085 mm.

[0039] Furthermore, the liposomes are used to load drugs or biological materials.

[0040] Furthermore, the drug includes baicalein.

[0041] This invention further provides a method for preparing the above-mentioned hydrogel precision delivery system based on acupuncture needles, comprising the following steps:

[0042] (1) A groove is carved on the surface of a regular acupuncture needle and extended along the needle body to form a spiral shape, thus preparing a spiral microneedle;

[0043] (2) Uniform liposomes were prepared by thin film method and reacted with a mixed solution of N-[2-(3,4-dihydroxyphenyl)ethyl]-2-methylacrylamide and methacrylated hyaluronic acid to perform photocrosslinking and obtain hydrogel solution;

[0044] (3) Load the hydrogel solution from step (2) into the threaded groove of the threaded microneedle from step (1), cure it by photocrosslinking, and then dry it to obtain a precision delivery system.

[0045] Furthermore, the preparation steps of the thin film method in step (2) are as follows: lecithin and cholesterol are dissolved in chloroform at a mass ratio of 3:1, and after heating to remove the organic solvent, a lipid film is obtained. Distilled water is added for further ultrasonic dissolution to obtain a bilayer liposome.

[0046] In the above-mentioned method for preparing liposomes, drugs or biological materials can be added to form liposomes loaded with drugs or biological materials, which are then combined with hydrogels.

[0047] This invention also provides applications of the aforementioned hydrogel precision delivery system based on acupuncture needles, which uses the precision delivery system as a carrier for the precise delivery of drugs or biomaterials to lesion sites. Specifically, this includes using the precision delivery system as a carrier for the precise delivery of drugs to the spinal cord or cartilage tissue, particularly for the precise delivery to subchondral bone.

[0048] The beneficial effects of this invention are as follows:

[0049] (1) This invention provides a hydrogel precision delivery system based on acupuncture needles. This precision delivery system can firmly adhere the hydrogel carrier to the threaded groove of the acupuncture needle and accurately deliver it into the lesion to be treated under the protection of the threaded groove. At the same time, after absorbing body fluid and expanding, the hydrogel compresses and adheres to the surrounding tissue, thus remaining in the lesion and realizing the continuous release of the drug.

[0050] (2) The present invention is based on a hydrogel precision delivery system for acupuncture needles, which can easily break through the physical barrier of cartilage and enter the subchondral bone to achieve precise treatment of the subchondral bone. It has a high drug delivery rate and the transmission efficiency of hydrogel can reach 80-85%, which is significantly higher than the transmission efficiency of hydrogel of traditional acupuncture needles (only 25%).

[0051] (3) When the hydrogel precision delivery system based on acupuncture needles is used to precisely target and treat the subchondral bone of OA rats, it can effectively inhibit the abnormal remodeling of the subchondral bone, thereby alleviating the degeneration and degradation of cartilage and improving the condition of OA. Attached Figure Description

[0052] Figure 1 Schematic diagrams of CA-needle and ST-needle; A) Clinical application of CA-needle; B) morphological diagram of CA-needle; C) 360° macro photography of microneedle; D) 360° view of CA-needle tip; E) 360° view of ST-needle tip.

[0053] Figure 2 A) Schematic diagram of hydrogel-modified ST-needle; B) Schematic diagram of hydrogel synthesis with metal surface bonding properties; C) Transmission electron micrograph of liposomes; D) Particle size distribution of liposomes in aqueous solution; E) Scanning electron micrograph of Lipo@DMA@HAMA hydrogel; F) Schematic diagram of hydrogel-modified ST-needle; G) 360° view of CA-needle tip after hydrogel loading; H) 360° view of ST-needle tip after hydrogel loading (hydrogel stained dark blue for easy observation); H) In vitro release of BAI from Lipo-BAI and Lipo-BAI@DMA@HAMA (n=3).

[0054] Figure 3 To conduct perforation experiments on porcine articular cartilage using CA-needles and ST-needles; A) Three major articular cartilages of pigs; B) Perforation experiments on articular cartilages of the femur, tibia, and talus: i) Full-view photograph; ii) Partial-view photograph; iii) CA-needle within the cartilage; iv) ST-needle within the cartilage; F) Time of penetration of CA-needle and ST-needle into the cartilage (n=3) (Black dashed lines represent cartilage outlines, blue dashed lines represent CA-needle and ST-needle outlines; NS: meaningless).

[0055] Figure 4A) Schematic diagram of hydrogel transport via ST-needle; i) CA-needle cannot transport hydrogel into tissue, while ST-needle successfully transports hydrogel into tissue; ii) The dried hydrogel absorbs liquid from the tissue, the liquid swells, and comes into close contact with the surrounding tissue. ST-needle rotates and removes the hydrogel, leaving it in the tissue (blue arrows indicate liquid absorbed by the hydrogel in the surrounding tissue); B) In vitro experiments verify the role of ST-needle in transporting hydrogel. The study included: i) inserting CA-needles loaded with hydrogel into porcine cartilage (black arrows indicate hydrogel blocked by cartilage); ii) histological sections of subchondral bone; iii) inserting ST-needles loaded with hydrogel into porcine cartilage; iv) histological sections of subchondral bone (black arrows indicate successful hydrogel transport to subchondral bone); c) Cy-7 labeled hydrogels were used to verify that ST-needles could transport more hydrogel into cartilage than CA-needles; and d) quantitative analysis of fluorescence intensity (n=3) (***P<0.001).

[0056] Figure 5 Cellular and molecular mechanisms of ST-needle in treating osteoarthritis (OA); A) Schematic diagram of ST-needle inhibiting cytokine synthesis and promoting stem cell migration; B) X-ray showing ST-needle accurately reaching subchondral bone; C) Western blot of 15-LOX-1 and TGF-β1; D) Quantitative analysis of Western blot results of 15-LOX-1 and TGF-β1; FG) PCR diagram of 15-LOX-1 and TGF-β1 mRNA; H) Schematic diagram of the experiment, ST-needle promotes MSC migration; I) Representative fluorescent images showing in vivo staining of MSCs migrating in cartilage; J) Quantitative analysis of live cells (n=3) (*P<0.05, **P<0.01, ***P<0.001).

[0057] Figure 6 For ST-needle treatment of OA rats: A) Cy-7 labeled hydrogel, verifying that the hydrogel can remain in rats for a long time and continuously release the drug; B) Quantitative analysis of fluorescence intensity (n=3); C) Micro-CT showing subchondral bone of rats at 4 weeks and 8 weeks; E) Quantitative analysis of BMD, BV / TV, Tb, and Th in subchondral bone (n=3); (ns: no significant difference, *P<0.05, **P<0.01, ***P<0.001).

[0058] Figure 7To treat OA-reducing cartilage degeneration in rats (6 cases per group); A) Representative images of articular cartilage stained with H&E in each group; B) OARSI scores of articular cartilage in each group; C) Representative images of cartilage stained with safflower O-fast green, showing histological changes in the five groups; D) Relative glycosaminoglycan content in each group; E) Representative sections of apoptotic cells stained with TUNEL; F) Quantitative analysis of TUNEL-positive cells; G) Representative sections of type II collagen immunofluorescence staining; H) Quantitative analysis of type II collagen-positive cells; I) Representative sections of MMP-13 immunofluorescence staining; J) Quantitative analysis of MMP-13-positive cells; (ns: no significant difference, *P<0.05, **P<0.01, ***P<0.001).

[0059] Figure 8 This is a schematic diagram of hydrogel delivery using a horizontal grooved acupuncture needle, as shown in Comparative Example 1.

[0060] Figure 9 This is a schematic diagram of hydrogel delivery using the threaded groove acupuncture needles used in Comparative Example 2. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described in detail below with reference to embodiments. It should be noted that the following embodiments are for explanation and illustration only and are not intended to limit the invention. Non-essential improvements and adjustments made by those skilled in the art based on the above description are still within the scope of protection of this invention.

[0062] Example 1

[0063] (I) Design of Threaded Groove Acupuncture Needles

[0064] Taking traditional Chinese acupuncture needles (CA-needles) made of stainless steel as an example, examples of acupuncture therapy applications are as follows: Figure 1 In section A, the appearance of the CA-needle is as follows: Figure 1 Part B involves using a macro lens to photographically observe the tip of the CA-needle (e.g., ...). Figure 1 In section C, it can be seen that the CA-needle tip is sharp and smooth, without any special structure to support hydrogel (such as...). Figure 1 Part D).

[0065] To enable the CA-needle to load hydrogels, a special threaded structure was designed at the tip of the acupuncture needle, resulting in a threaded acupuncture needle (ST-needle). Macro photography shows that the groove width of the ST-needle is approximately 200 μm, and the grooves are threaded from the needle tip to the needle tail (e.g., ...). Figure 1 Part E of the middle section).

[0066] It should be noted that the threaded acupuncture needle designed in this invention is merely an example. Those skilled in the art can continuously improve the threaded acupuncture needle, including the width and depth of the groove, the density of the thread, and the extension distance of the thread at the needle tip, so that the threaded acupuncture needle can be adapted to hydrogels with different physical properties and meet the different treatment needs of various diseases.

[0067] (II) Preparation of hydrogels

[0068] To ensure the hydrogel is well-loaded into the threaded grooves of the ST-needle for precise drug delivery, the inventors conducted extensive research on the hydrogel design, the process of which is described in Comparative Examples 1-7. However, as shown in Comparative Examples 1-7, the hydrogel and the threaded acupuncture needle have several problems: the hydrogel easily slips out of the threaded grooves, and it cannot be easily separated from the grooves during needle removal. This results in a low hydrogel delivery rate of only 20-65%, leading to poor drug delivery efficiency and therapeutic effect.

[0069] Ultimately, through extensive research and innovation, the inventors designed a hydrogel with metal adhesion capabilities and constructed drug-loaded liposomes within it. Furthermore, by drying the hydrogel to form a coating, they achieved successful drug delivery to the subchondral bone and smooth separation from the threaded grooves. The hydrogel achieved a delivery efficiency of 80-85%, demonstrating high drug delivery efficiency, significant therapeutic effect, and long sustained-release time (e.g., Figure 2 Part A of the middle section.

[0070] The preparation method of the hydrogel system successfully constructed in this invention is as follows:

[0071] First, uniformly sized drug-loaded liposomes (using baicalein as an example) were prepared using a thin-film method. The specific preparation method was as follows: 60 mg of lecithin, 20 mg of cholesterol, and 8.0 mg of baicalein were dissolved in a round-bottom flask containing 30 mL of chloroform. The solution was heated at 35°C for 1 hour to completely evaporate the organic solvent, resulting in a lipid film adhering to the bottom of the flask. Then, 3 mL of redistilled water was added to the flask, and the mixture was ultrasonically decomposed at 25°C for 20 minutes to completely dissolve the lipid film in the water, yielding a micron-sized bilayer liposome. Instrumental analysis showed that the diameter of this liposome was approximately 100 nm (e.g., ...). Figure 2 Part B), its particle size distribution is as follows Figure 2 Part C. Drug-loaded liposomes with smaller particle sizes can be prepared by treatment with a high-intensity probe sonication solution (60 single pulses / min, 130 W) for 5 minutes.

[0072] Secondly, the adhesive hydrogel was prepared using the following steps: Appropriate amounts of HAMA (methacrylated hyaluronic acid) lyophilized powder and DMA (N-[2-(3,4-dihydroxyphenyl)ethyl]-2-methylacrylamide) powder were weighed and dissolved in distilled water, controlling the HAMA concentration to be 3%–5% and the DMA concentration to be 1%. After thorough dissolution and stirring, 1% liposomes were added to the mixed solution to prepare Lipo@DMA@HAMA. This hydrogel can be cured under 350nm ultraviolet light crosslinking to form a solid hydrogel loaded with liposomes and possessing adhesive function. Electron microscopy observation of Lipo@DMA@HAMA revealed that liposome nanoparticles with a diameter of approximately 100nm (e.g., ...) are uniformly distributed within the porous hydrogel. Figure 2 Part D).

[0073] The adhesion properties of the DMA@HAMA hydrogel prepared above with spiral acupuncture needles were tested, and the method is as follows:

[0074] Take approximately 0.5 mL each of the prepared DMA@HAMA solution and HAMA solution of the same concentration, and place them at the bottom of a centrifuge tube. Insert the tip of the ST-needle between the two hydrogels and irradiate with ultraviolet light to solidify them. Then, hold the ST-needle by its tail and lift it up. The results showed that the ST-needle could be easily pulled out of the non-adhesive HAMA hydrogel, while the adhesive DMA@HAMA hydrogel adhered well to the ST-needle, preventing it from detaching.

[0075] (III) Construction of a hydrogel-based precision delivery system for acupuncture needles

[0076] To prepare a hydrogel-based precision delivery system for acupuncture needles, the aforementioned Lipo@DMA@HAMA hydrogel was combined with an ST-needle. Specifically, a 1mL syringe was used to draw an appropriate amount of Lipo@DMA@HAMA aqueous solution, which was then dripped onto the tip of the CA-needle and into the threaded groove of the ST-needle, respectively. Simultaneously, ultraviolet light was applied to solidify the solution (e.g., ...). Figure 2 Part E of the middle section).

[0077] The hydrogel was stained dark blue, and macro photography was performed on the acupuncture needles loaded with the hydrogel. The results showed that the hydrogel on the CA-needle needle tip was directly exposed to the metal surface and significantly raised above the outline of the acupuncture needle (e.g., ...). Figure 2 (Middle F section); while the hydrogel on the ST-needle is contained within the threaded grooves, and the hydrogel does not protrude above the acupuncture contour (e.g., Figure 2(Part G in the middle). As can be seen, the threaded groove structure of the ST-needle can effectively protect the hydrogel loaded within it during the puncture of human tissue, indicating that the hydrogel precision delivery system based on acupuncture needles of the present invention has been successfully constructed.

[0078] (iv) Drug release performance test after hydrogel loading

[0079] Baicalein (BAI) was loaded onto liposomes (Lipo) and Lipo@DMA@HAMA hydrogels, respectively, to obtain two biomaterials: Lipo-BAI and Lipo-BAI@DMA@HAMA-BAI. Both biomaterials were placed in dialysis membranes and immersed in PBS at 37°C, and the drug content in the PBS was periodically monitored. Results showed that Lipo-BAI released the drug more rapidly, with approximately 80% released by day 5; while the Lipo-BAI@DMA@HAMA-BAI biomaterial exhibited better sustained-release performance, releasing only about 50% of the drug by day 5. Further testing showed that drug release could be sustained for approximately 3 weeks (e.g., ...). Figure 2 (H portion). Therefore, Lipo@DMA@HAMA hydrogel materials have very ideal drug sustained-release properties.

[0080] Example 2

[0081] (I) Verification of the ability of a hydrogel precision delivery system based on acupuncture needles to penetrate cartilage and reach subchondral bone

[0082] To verify ST-needle's ability to penetrate cartilage and deliver hydrogel to the subchondral bone, pigs were selected as the in vitro experimental model. Three of the most common articular cartilage surfaces in clinical practice were chosen: the femoral condyle, tibial plateau, and talus, to demonstrate that ST-needle can be widely applied to the precise treatment of joint diseases in multiple different locations (e.g., Figure 3 Part A). Meanwhile, a standard acupuncture needle (CA-needle) was selected as the control group. CA-needles were used on the left side of each articular surface, and ST-needles on the right side. Macro photography was used to record images of the microneedles penetrating the cartilage. After completing the microneedle cartilage penetration test, the puncture site was dissected to observe whether the microneedles could penetrate the subchondral bone, and the depth of penetration into the subchondral bone was measured (e.g., ...). Figure 3 (BD section).

[0083] The measurement data shows that the insertion depth of both types of microneedles on the cartilage of the femur, tibia, and talus exceeded the thickness of the cartilage (e.g., Figure 3(Part E). This demonstrates that Chinese acupuncture needles can effectively penetrate the cartilage physical barrier to reach the subchondral bone. Furthermore, modifying the needle tip with a threaded groove did not weaken the ST-needle's ability to overcome the physical barrier. The insertion time of the acupuncture needles in each experiment was statistically analyzed (e.g.,...). Figure 3 (In the middle F section), although the cartilage of the talus is relatively hard and it takes more time to insert the needle into the subchondral bone, overall, the insertion time of all acupuncture needles is less than 1 minute.

[0084] In summary, ST-needle has excellent ability to penetrate cartilage and enter subchondral bone, and has great potential for clinical application.

[0085] (II) Verification of the hydrogel delivery capability of a hydrogel precision delivery system based on acupuncture needles

[0086] When inserting into cartilage, the hydrogel coating on the tip of a standard acupuncture needle (CA-needle) is blocked by the cartilage surface, while the hydrogel coating on an ST-needle, protected by its threaded grooves, is released as the acupuncture needle reaches the subchondral bone (such as...). Figure 4 (See diagram i in section A). After the ST-needle reaches the subchondral bone, the hydrogel it carries absorbs water from the body fluid and swells, thus adhering firmly to the surrounding subchondral bone. As the ST-needle rotates and retracts, the hydrogel is successfully retained within the subchondral bone (e.g., ...). Figure 4 Part A (ii sub-diagram).

[0087] Due to the micron-sized dimensions of acupuncture needles, it is difficult to obtain clear photographs of the above process. Therefore, a screw was chosen as a magnified model of the ST-needle. Firstly, as can be seen from the actual photographs, after loading the hydrogel into the threaded grooves and performing photocuring and proper air drying, the hydrogel successfully "hides" within the threaded grooves (e.g., ...). Figure 4 (See Figure i in Part B of the diagram). Subsequently, using a wooden board to simulate cartilage and subchondral bone, screws loaded with hydrogel were inserted into the holes in the board, and PBS was added to simulate body fluid, causing the hydrogel to absorb water and swell (e.g., ...). Figure 4 (See Figure ii in Part B of the diagram). As the screw rotates and retracts, it can be clearly seen in the photograph that the hydrogel is left inside the hole in the wooden board (as shown in the image). Figure 4 Part B, iiii and vi subplots.

[0088] In addition, ST-needles loaded with fluorescently labeled hydrogels were fabricated, and cartilage from isolated porcine femurs was harvested to verify the ability of ST-needles to deliver hydrogels (e.g., Figure 4(See diagram C). In terms of fluorescence intensity, after the CA-needle was inserted into the cartilage and then withdrawn, the fluorescence value at the needle tip only decreased by 25% compared to the initial value, indicating that only a small amount of hydrogel remained within the cartilage. In contrast, the fluorescence value of the ST-needle decreased by 82% of the initial value, indicating that the ST-needle can better deliver the hydrogel to the subchondral bone (e.g.,...). Figure 4 (D-part plot and E-part plot).

[0089] (III) Biocompatibility test of hydrogel precision delivery system based on acupuncture needles

[0090] To evaluate the potential clinical application of drug-loaded Lipo@DMA@HAMA, the in vitro cytotoxicity of Lipo-BAI and Lipo-GA@DMA@HAMA to MSCs was investigated. Live / dead assays and CCK-8 assays were performed after co-culturing with different percolates for 1, 3, and 5 days. Live / dead staining showed that after 5 days of culture, almost all three groups of cells were viable, with only a small number of dead cells. Cell density increased with prolonged culture time. Furthermore, the CCK-8 assay results indicated no significant difference in proliferative activity among the three groups of cells at all time points. These results demonstrate that the biomaterial prepared in this invention has good biocompatibility with chondrocytes.

[0091] (IV) Clinical treatment cytotoxicity testing of a hydrogel precision delivery system based on acupuncture needles

[0092] Sterile ST-needles were taken and co-cultured with MSCs for 1 hour to simulate the situation of acupuncture needles in the body. Live and dead cell staining was performed; it was observed that the MSCs surrounding the ST-needles were entirely stained green (live cells), with almost no dead cells stained red. After removing the ST-needles, the MSCs were cultured for another 24 hours, and live and dead cell staining was performed again. It was observed that the MSC cell density was significantly increased compared to 24 hours prior, and again, almost no dead cells were stained red.

[0093] In summary, when ST-needle is used for precise treatment by inserting it into the human body, ST-needle is not toxic to surrounding cells and tissues, and no toxic substances remain after ST-needle is removed, thus not affecting subsequent cell growth. (V) Verification of the cellular and molecular mechanism of hydrogel delivery for OA treatment based on acupuncture needle hydrogel precision delivery system

[0094] The mechanism of ST-needle for precise treatment of osteoarthritis (OA) using hydrogel delivery has two aspects: 1. After ST-needle delivers the hydrogel to the subchondral bone, the hydrogel remains within the subchondral bone, continuously releasing BAI (basic amino acids) to regulate abnormal subchondral bone remodeling. 2. After the cartilage is removed upon completion of treatment, ST-needle leaves micron-sized pores in the cartilage. These pores can serve as channels for MSC (mesenchymal stem cells) migration, allowing MSCs from the subchondral bone to migrate to the cartilage surface, promoting cartilage repair (e.g., ...). Figure 5 Part A of the middle section.

[0095] A rat OA model was established, and a control group and a treatment group were set up (treated with ST-eedle, e.g.) Figure 5 Part B of the study involved extracting subchondral bone cells from rats, extracting proteins and RNA, and then performing Western blotting and PCR detection (e.g., [missing information]). Figure 5 (CG section). Results showed that in the OA group, the mRNA and protein levels of 15-LOX-1 and TGF-β1 in the subchondral bone of rats were significantly increased compared to the control group, proving that OA does indeed cause abnormal secretion of subchondral bone cytokines. However, after treatment with ST-needle loaded with BAI, the mRNA and protein levels of 15-LOX-1 and TGF-β1 were significantly decreased compared to the OA group, demonstrating that precise treatment with ST-needle can effectively reverse the abnormal secretion of cytokines.

[0096] To verify that the micropores left after ST-needle treatment can aid MSC migration, a cell migration assay was designed (e.g., Figure 5 (Part H). Cartilage discs from rabbit knee joints were harvested, and dozens of perforated micropores were punctured into the discs using ST-needle to simulate ST-needle-treated cartilage, serving as the perforated cartilage group. Simultaneously, intact cartilage discs that had not been punctured by ST-needle were used as the intact cartilage group. Both types of cartilage were placed in Transwell chambers, and MSCs and culture medium were added according to standard Transwell procedures. Cells within the Transwell chambers were stained at 12h and 24h (e.g., ...). Figure 5 (Part I). It is clearly visible that the number of migrating cells in the Cartilage group was significantly less than that in the control group due to the obstruction of the cartilage disc; while in the Perforated Cartilage group, because the ST-needle leaves micropores in the cartilage disc, it helps MSCs to pass through the cartilage barrier and complete cell migration, therefore, the number of migrating cells was significantly higher than that in the Cartilage group (e.g., ...). Figure 5(Part J in the middle). In summary, the micropores created by ST-needle treatment can effectively help MSCs migrate from the subchondral bone to the cartilage surface.

[0097] (VI) Research on the effect of hydrogel precision delivery system based on acupuncture needles on alleviating subchondral bone lesions

[0098] To investigate the long-term retention effect of Lipo@DMA@HAMA in subchondral bone, liposomes were labeled with the lipophilic fluorescent dye DiI. The labeled Lipo@DMA@HAMA was delivered to the subchondral bone via an ST-needle, and fluorescence imaging was performed continuously for 5 weeks using IVIS (e.g., Figure 6 Part A). Intra-articular injection of the fluorescent dye DiI alone served as a control.

[0099] The results showed that the fluorescence intensity of the control group decreased sharply in the first two days, with almost no fluorescence signal detected on the second day, indicating a weak retention effect of the free drug in the joint cavity. Conversely, the fluorescence intensity of Lipo@DMA@HAMA hydrogel decreased very slowly, only decreasing by about 50% in the third week, and the fluorescence signal persisted for more than a month, indicating that Lipo@DMA@HAMA hydrogel has an excellent retention effect in subchondral bone, ensuring long-term sustained release of BAI (e.g., ...). Figure 6 Part B).

[0100] To further verify the efficacy of ST-needle precision treatment for OA, a rat OA model was established by intra-articular injection of iodoacetic acid, with a blank control group (Control group). After successful model establishment, OA rats were treated with intra-articular injection of PBS (PBS group), BAI (BAI group), and ST-needle, respectively.

[0101] MicroCT is currently widely used for bone tissue measurement. Compared to the uncertainties of bone tissue sections and the limitations of two-dimensional images, microCT can perform X-ray scanning and three-dimensional reconstruction of bone tissue, allowing for more intuitive observation and measurement of data such as bone density, bone morphology, and trabecular bone structure. At two sampling time points, 4 weeks and 8 weeks, microCT was used to scan the subchondral bone of rats to obtain a three-dimensional model of the rat knee joint (e.g., Figure 6 The CD portion of the rat subchondral bone was analyzed, and three-dimensional correlation parameters related to it were obtained (e.g., the CD portion of the rat subchondral bone). Figure 6 (The EG section).

[0102] Experimental results showed that compared with the Control group, the PBS group exhibited significantly increased bone mineral density (BMD), bone fractional volume (BV / TV), and trabecular bone thickness (Tb.Th). The treatment group treated with BAI showed lower BMD, BV / TV, and trabecular bone thickness than the PBS group. Furthermore, the ST-needle group, treated with ST-needle, showed significantly lower BMD, BV / TV, and trabecular bone thickness than the PBS group. In conclusion, precise treatment of subchondral bone in OA rats using ST-needle can significantly improve abnormal subchondral bone remodeling.

[0103] (vii) The ability of a hydrogel precision delivery system based on acupuncture needles to improve cartilage lesions

[0104] Rats at week 8 of the animal experiment underwent paraffin embedding and sectioning, followed by morphological staining and immunofluorescence detection. Hematoxylin and eosin (H&E) staining (e.g.) Figure 7 Part A) and Safranin O-fast green staining (e.g. Figure 7 Part B shows typical osteoarthritis features. The PBS group showed the most obvious surface irregularities and erosion fissures, followed by the BAI group, while the ST-needle group showed the least obvious features.

[0105] OARSI score results are as follows Figure 7 As shown in section C. Compared with the PBS group, the OARSI scores of other treatment groups all decreased, with the ST-needle group showing the best effect, a decrease of 53.50%, followed by the BAI group with a decrease of 27.95%. This indicates that ST-needle is more effective in maintaining cartilage matrix (e.g., Figure 7 (Part D of the middle section). Subsequently, TUNEL staining was used to detect chondrocyte apoptosis (e.g., ...). Figure 7 (Part E) The results showed that, compared with the control group, the ST-needle group had the fewest apoptotic cells (green staining), followed by the BAI group.

[0106] Quantitative detection of positively stained cells (e.g.) Figure 7 (Part F) Results showed that, compared with the PBS group, the ST-needle group had the lowest apoptosis rate, decreasing by 66.48%, while the BAI group showed a decrease of 25.88%. After ST-needle precise treatment, the apoptosis rate of chondrocytes under oxidative stress decreased from 38.36±5.48% to 12.86±4.27%, significantly better than the 28.43±5.87% in the BAI group.

[0107] The expression of the major cartilage biomarkers Collagen II and MMP-13 was detected using immunofluorescence staining (e.g., Figure 7(GJ section). Results showed that compared with the control group, the expression level of type II collagen (red staining) decreased in all treatment groups, with the ST-needle group showing the smallest decrease, followed by the BAI group. The number of positively stained cells is shown in [reference needed]. Figure 7 As shown in section H, compared with the PBS group, the ST-needle group had the highest collagen II expression level, increasing by 128%, followed by the BAI group, which increased by 100%.

[0108] MMP-13 is a key enzyme targeting cartilage degradation, capable of degrading not only type II collagen in cartilage but also proteoglycans, type IV and IX collagen, osteonectin, and basement membrane proteoglycans. Therefore, MMP-13 plays a crucial role in osteoarthritis (OA). Experimental results showed a significant increase in MMP-13 expression in the PBS group, which contributed to the degradation of the cartilage matrix and disease progression in OA. Compared to the PBS group, the ST-needle group showed a 66.48% decrease in MMP-13 expression, followed by the BAI group with a 25.88% decrease (e.g., ...). Figure 7 (Part J in the middle).

[0109] The above results demonstrate that, compared to intra-articular injection of BAI, precise treatment using ST-needle can significantly inhibit abnormal subchondral bone remodeling, thereby alleviating cartilage damage and degeneration. This invention provides an attractive strategy for the treatment of osteoarthritis (OA).

[0110] The following comparative examples examined the use of drug delivery systems constructed by different combinations of hydrogel and spiral acupuncture needles for precise localization treatment of subchondral bone. The results showed that none of the following methods could deliver drugs accurately to the subchondral bone, and their drug delivery efficiency was very low.

[0111] Comparative Example 1

[0112] Referring to the improved method of acupuncture needles in patent document CN 108338917 A, the inventors constructed multiple horizontal grooves on the needle body and prepared HAMA hydrogel and Lipo@DMA@HAMA hydrogel according to the scheme described in Example 1. By loading the hydrogel onto the acupuncture needle with this horizontal groove structure, a hydrogel precision delivery system based on acupuncture needles was constructed (e.g., Figure 8 (As shown). The results showed that the acupuncture needle with the horizontal groove structure could protect the hydrogel from detaching from the needle body and directly reach the subchondral bone lesion. However, subsequent experiments revealed that when the acupuncture needle was withdrawn, the horizontal groove also carried the hydrogel loaded within it out, failing to retain the hydrogel within the lesion. Testing according to the method in Example 1 showed that the hydrogel reduction was only 35%, indicating that the hydrogel precision delivery system had a low hydrogel delivery efficiency, not exceeding 35%.

[0113] Comparative Example 2

[0114] To address the problems of Comparative Example 1, the inventors constructed an acupuncture needle with a threaded groove structure and prepared a hydrogel according to the scheme described in Example 1. By loading HAMA hydrogel onto this threaded groove acupuncture needle, a precise hydrogel delivery system based on the acupuncture needle was constructed to achieve the goal of leaving the hydrogel within the lesion (e.g., when the acupuncture needle is withdrawn) upon removal. Figure 9 (As shown). However, subsequent experiments revealed that because the threaded groove is constructed around the entire acupuncture needle body, its depth is significantly shallower than the horizontal groove in Comparative Example 1 to ensure the mechanical strength of the acupuncture needle. This results in the threaded groove providing weaker protection for the hydrogel when inserted into the human body compared to the horizontal groove. During acupuncture treatment, a large amount of HAMA hydrogel falls out of the threaded groove and cannot reach the subchondral bone smoothly. Its hydrogel transport efficiency is lower than that of the horizontal groove. According to the method in Example 1, the hydrogel reduction was only 30%, indicating that the hydrogel precision delivery system has a low hydrogel transport efficiency, not exceeding 30%, and its hydrogel transport efficiency is lower than that of the horizontal groove.

[0115] Comparative Example 3

[0116] To address the problems identified in Comparative Example 2, the inventors attempted to develop a hydrogel with adhesive properties to enhance its protective performance within threaded grooves and improve its transport efficiency. The inventors explored various "adhesive hydrogel" methods and discovered numerous difficulties in adhering the hydrogel to the surface of metal acupuncture needles.

[0117] (1) ST-needles were prepared according to the scheme of Example 1 to load hydrogels. Following the method for preparing adhesive hydrogels reported by Yang Gao et al. (AUniversal Strategy for Tough Adhesion of Wet Soft Material, DOI:10.1002 / adfm.202003207), polymer chains were inserted into the hydrogel and the adhesive to trigger polymer cross-linking and form new topological entanglements with the existing network, achieving topological adhesion. However, when the hydrogel prepared by topological adhesion is combined with ST-needles, this scheme requires chemical modification of the acupuncture needle surface, which further reduces the depth of the threaded grooves, hindering hydrogel adhesion and preventing accurate delivery of the hydrogel to the subchondral bone. Testing according to the method of Example 1 showed that the hydrogel delivery rate was still low, only 28%.

[0118] (2) ST-needle was prepared according to the scheme of Example 1 for loading hydrogel, and an adhesive hydrogel was prepared by referring to a biomimetic octopus suction cup microstructure adhesive patch that can be reversibly used in wet / dry adhesive systems, as reported by Sangyul Baik et al. (A wet-tolerant adhesive patch inspired by protuberances in suction cups ofoctopi, DOI:10.1038 / nature22382). This adhesive hydrogel showed strong, reversible, and highly repeatable adsorption effects on silicon wafers and glass. However, this adhesion method is only suitable for relatively flat surfaces, and its adhesion ability on irregular surfaces is not high, which greatly limits its application. When the inventors attempted to combine this adhesive hydrogel with a threaded acupuncture needle, they found that it could not be used for adhesion to the threaded grooves of the acupuncture needle. The delivery efficiency of the hydrogel was only 35% when tested according to the method of Example 1.

[0119] In summary, due to the metal material of acupuncture needles, their limited surface area, and uneven threaded structure, finding a suitable adhesion solution is extremely difficult.

[0120] Comparative Example 4

[0121] To address the issues identified in Comparative Example 3, inspired by the catechol groups in mussel mucus, the inventors modified HAMA hydrogel with dopamine to obtain a hydrogel capable of adhering to metals. This method requires no chemical modification of the metal surface and has no special requirements regarding the physical properties of the adhesion surface, allowing the hydrogel to firmly adhere to the threaded grooves of the acupuncture needle, ensuring it does not detach. However, subsequent research revealed that although a hydrogel with strong adhesion was prepared, it could not detach smoothly from the threaded grooves once it reached the lesion, failing to achieve the goal of sustained drug release at the lesion site during needle removal. Testing according to the method in Example 1 showed that the hydrogel delivery system had a delivery efficiency of only 55%.

[0122] Comparative Example 5

[0123] To address the issues identified in Comparative Example 4, the inventors dried the hydrogel prepared in Example 4 that adhered to the grooves of the acupuncture needle. However, because the adhesive hydrogel loaded the drug through its internal aqueous solution, a significant amount of the drug was lost after drying to form a coating. The results showed that although the hydrogel delivery system achieved a delivery efficiency of 62%, the drug loading within the hydrogel decreased by more than 60%, and this method still could not successfully and accurately deliver the drug within the hydrogel to the subchondral bone.

[0124] Comparative Example 6

[0125] To address the issues identified in Comparative Example 5, the inventors attempted to covalently bond the drug to the adhesive hydrogel network prepared in Comparative Example 4. The goal was to anchor the drug within the hydrogel network via covalent bonds, preventing leakage during drying. However, subsequent experiments revealed that the strong covalent bonds made drug release extremely difficult, with a significant amount remaining within the hydrogel network structure. Five days after delivery, only 50% of the drug was released.

[0126] Comparative Example 7

[0127] Based on Comparative Example 6, an improvement was made by using ionic bonds with relatively weak binding ability to connect the drug and the hydrogel network prepared in Example 4. Although this method has a good effect on water-soluble drugs, it has a very limited drug loading capacity in the hydrogel due to the very low solubility of lipid-soluble drugs in water. The loading capacity of lipid-soluble drugs does not exceed 10%, which greatly limits the application of the "hydrogel + acupuncture system" in medicine.

[0128] The results of the comparative examples 1-7 above indicate that there are significant challenges in the practical application of combining acupuncture needles with hydrogels to construct a "hydrogel + acupuncture needle" drug delivery system. Developing an acupuncture needle structure that can effectively load hydrogels to deliver them to deep tissue lesions such as subchondral bone, achieving high delivery efficiency of the hydrogel during acupuncture, and successfully separating the hydrogel from the lesion site upon needle removal is extremely difficult.

[0129] Ultimately, this invention chose to construct a liposome secondary structure within the hydrogel, forming a "liposome-hydrogel drug delivery system." Due to the unique structure of liposomes, they can load both water-soluble and lipid-soluble drugs in large quantities. Simultaneously, chemical bonds such as ionic bonds form between the liposomes and the hydrogel network, allowing the liposomes to stably bind to the hydrogel network, thus constructing a physically stable "liposome-hydrogel drug delivery system" capable of loading multiple drugs. Based on this, this invention innovatively designed a "hydrogel coating@acupuncture system," achieving ingeniously both "resisting significant obstacles to prevent detachment" and "separating the acupuncture needle and hydrogel at the lesion site."

[0130] This invention first constructs a threaded groove at the tip of an acupuncture needle and prepares a DMA@HAMA hydrogel with an adhesive polymeric interface using the photocrosslinking reaction of DMA and HAMA. Subsequently, the synthesized Lipo@DMA@HAMA hydrogel system is loaded into the threaded groove and dried to form a hydrogel coating. When the acupuncture needle penetrates human tissue, the hydrogel coating adheres tightly to the depth of the threaded groove and is protected by it. Therefore, it does not require very strong adhesive force to resist significant obstacles and prevent detachment. After entering the lesion, the characteristics of the thread and the swelling properties of the hydrogel are cleverly utilized. After the hydrogel absorbs body fluid and swells, its volume rapidly expands, protruding from the threaded groove, thus making close contact and adhesion to the surrounding tissue. When the acupuncture needle is rotated and withdrawn along the thread direction, the hydrogel is successfully placed within the lesion, thus effectively constructing the acupuncture needle-based hydrogel precision delivery system of this invention. Experiments show that the hydrogel precision delivery system of this invention can achieve a delivery efficiency of 80-85%.

Claims

1. A hydrogel-based precision delivery product based on acupuncture needles, characterized in that, The precision delivery product includes an acupuncture needle and a hydrogel coating. The acupuncture needle has a threaded groove on its body, and the hydrogel coating is adhered to the threaded groove of the acupuncture needle. The hydrogel coating is prepared by photocrosslinking of N-[2-(3,4-dihydroxyphenyl)ethyl]-2-methylacrylamide and methacrylated hyaluronic acid to obtain an adhesive hydrogel, which is then loaded into the threaded groove after encapsulating a carrier liposome and dried to form the hydrogel coating.

2. The hydrogel precision delivery product based on acupuncture needles according to claim 1, characterized in that, The mass ratio of N-[2-(3,4-dihydroxyphenyl)ethyl]-2-methylacrylamide to methacrylated hyaluronic acid is 1:3 to 5.

3. The hydrogel-based precision delivery product for acupuncture needles according to claim 1, characterized in that, The mass ratio of the adhesive hydrogel to the liposome is 4–6:

1.

4. The hydrogel-based precision delivery product for acupuncture needles according to claim 1, characterized in that, The acupuncture needle has a needle body diameter of 0.2-0.5 mm, a thread pitch of 0.5-1 mm, and a thread groove depth of 0.05-0.085 mm.

5. The hydrogel precision delivery product based on acupuncture needles according to claim 1, characterized in that, The liposomes are loaded with drugs or biomaterials.

6. The hydrogel-based precision delivery product for acupuncture needles according to claim 5, characterized in that, The drug includes baicalein.

7. A method for preparing a hydrogel-based precision delivery product based on acupuncture needles as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) A groove is carved on the surface of a regular acupuncture needle and extended along the needle body to form a spiral shape, thus preparing a spiral microneedle; (2) Uniform liposomes were prepared by thin film method and reacted with a mixed solution of N-[2-(3,4-dihydroxyphenyl)ethyl]-2-methylacrylamide and methacrylated hyaluronic acid to perform photocrosslinking and obtain hydrogel solution; (3) Load the hydrogel solution from step (2) into the threaded groove of the threaded microneedle from step (1), cure it by photocrosslinking, and form a hydrogel coating after drying to obtain the hydrogel precision delivery product based on acupuncture needle.

8. The preparation method according to claim 7, characterized in that, The preparation steps of the thin film method in step (2) are as follows: lecithin and cholesterol are dissolved in chloroform at a mass ratio of 3:1, and after heating to remove the organic solvent, a lipid film is obtained. Distilled water is added for further ultrasonic dissolution to obtain a bilayer liposome.

9. The use of the hydrogel precision delivery product based on acupuncture needles as described in any one of claims 1-6 or the hydrogel precision delivery product based on acupuncture needles prepared by the method described in any one of claims 7-8 in the preparation of drug carriers for treating spinal cord or cartilage tissue injuries.

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