A magnetically guided gel and use of the gel for cell delivery

Abstract

The application discloses a magnetic guiding gel, comprising the following components: a shear-thinning hydrogel composed of one or more of hyaluronic acid gel, carboxymethyl cellulose gel and methyl cellulose gel, the mass concentration of the polymer in the shear-thinning hydrogel being 1-50 mg / L; and magnetic nanoparticles and cells doped in the shear-thinning hydrogel, the mass concentration of the magnetic nanoparticles in the shear-thinning hydrogel being 1-10000 μg / ml. The magnetic shear-thinning gel of the application does not need other treatment of cells when used for magnetic guiding delivery, has universal applicability to different cell types, and has obvious advantages over existing cell targeting delivery methods. Moreover, the magnetic force on the cells can be regulated by adjusting the doping amount of the magnetic nanoparticles.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to a magnetically guided gel and its use in cell delivery. Technical Background

[0002] Cell therapy technology refers to the use of the characteristics of certain cells with specific functions, obtained through bioengineering methods and / or processed through in vitro expansion and special culture, and then reinfused into the body to achieve the purpose of treating diseases. Common applications of cell therapy include modifying lymphocytes for tumor treatment, autologous / allogeneic stem cells for tissue repair, and treatment of tissue fibrosis. For tissue damage repair, especially for tissues that are difficult to heal on their own, cell therapy is a very promising treatment method.

[0003] The most common method of cell therapy is to directly inject cells suspended in a solution into the vicinity of the target site. The cells reach the target site through diffusion, sedimentation, and migration. However, in this method, only a small number of cells ultimately reach the target site, significantly reducing the efficiency of cell transplantation. For example, in the treatment of corneal endothelial injury, a promising new treatment method involves injecting a suspension of corneal endothelial cells directly into the anterior chamber of the eye, using cell transplantation to repair the damaged endothelium. During the treatment, the patient needs to remain in a prone position for more than 3 hours after the injection to allow the cells to fully settle into the inner corneal layer. Even so, uncontrolled aggregation and adhesion of endothelial cells can still occur in the anterior chamber, resulting in a reduced number of cells adhering to the damaged corneal endothelium and decreasing the treatment's effectiveness.

[0004] Precisely delivering cells to their target locations remains one of the biggest challenges in cell therapy. In tumor immunotherapy and stem cell-targeted therapy, methods such as modifying cell surface receptors and using specific chemokines can be employed to induce cells to target specific tissues and cells. However, these methods rely on complex genetic modifications or only work on specific cell types, thus having certain limitations. Furthermore, existing technologies also utilize magnetic particles, using external magnetic force to concentrate drugs or cells locally. For example, Chinese patent document CN101173250A discloses a magnetic cell and its method of use. This magnetic cell consists of cells and magnetic particles, with the magnetic particles having specific polypeptides on their surface that act as cell adhesives. After the magnetic particles adhere to the cell surface, they remain locally under the influence of an external magnetic force.

[0005] However, in the methods described above, cells are dispersed in saline or cell culture medium, and they disperse rapidly after injection, which is not conducive to targeted cell delivery. Furthermore, magnetic cells rely on the specific binding of cells to magnetic nanoparticles, requiring the design of different adhesion peptides for different cell types, resulting in poor general applicability. Additionally, the specific binding mechanism limits the number of magnetic particles on the cell surface, hindering the control of the cell's magnetic force. Summary of the Invention

[0006] This application addresses the technical problems of poor applicability of existing magnetic cells and the difficulty in controlling the magnitude of cell magnetic force, as well as the problems of traditional hydrogel cell delivery technology failing to achieve precise delivery and poor tissue adhesion. It provides a magnetically guided gel suitable for precise delivery of different cells, with adjustable magnetic force, which can be used for tissue damage repair, and the use of the gel for cell delivery.

[0007] The technical solution adopted by this application to solve the above-mentioned technical problems is as follows:

[0008] A magnetically guided gel comprises the following components: a shear-thinning hydrogel composed of one or more of hyaluronic acid gel, carboxymethyl cellulose gel, and methyl cellulose gel, wherein the mass concentration of the polymer in the shear-thinning hydrogel is 1-50 mg / ml; magnetic nanoparticles and cells, doped into the shear-thinning hydrogel, wherein the mass concentration of the magnetic nanoparticles in the shear-thinning hydrogel is 1-10000 μg / ml.

[0009] The viscosity of the shear-thinning hydrogel decreases under the shear force during injection, allowing it to be directly injected through the syringe needle. After injection, the rheological properties are restored to their pre-injection state, preventing cells and magnetic nanoparticles from diffusing outside the gel.

[0010] The shear-thinning hydrogel contains at least one aldehyde-modified gel.

[0011] The magnetic nanoparticles are iron oxide-based magnetic nanoparticles.

[0012] The magnetic nanoparticles in the shear-thinning hydrogel have a mass concentration of 1-1000 μg / ml.

[0013] The cell density in the shear-thinning hydrogel is 10. 4 -10 7 per ml.

[0014] The method for preparing the magnetically guided gel includes the following steps: (1) dissolving one or more of hyaluronic acid, carboxymethyl cellulose, and methyl cellulose in physiological saline to prepare a hydrogel; (2) preparing a suspension containing magnetic nanoparticles, and mixing the suspension with the hydrogel prepared in step (1) to obtain a hydrogel doped with magnetic nanoparticles; (3) adding a cell suspension to the hydrogel doped with magnetic nanoparticles in step (2) and mixing to obtain a shear-thinned hydrogel doped with magnetic nanoparticles and cells.

[0015] The magnetically guided gel is used to achieve precise cell delivery in an external magnetic field.

[0016] The magnetically guided gel is used for precise delivery of injectable cell-derived products.

[0017] The advantages of the magnetically guided gel described in this invention are:

[0018] The magnetically guided gel of this invention employs a shear-thinning hydrogel. This shear-thinning hydrogel enables the injectability of the gel-cell complex and prevents cell diffusion to other areas before delivery to the target site. The shear-thinning hydrogel is doped with magnetic nanoparticles. Under the influence of an external magnetic field, the gel rapidly degrades after being magnetically guided to the target site without affecting normal cell adhesion or other behaviors, enabling non-invasive and precise cell delivery. This invention's magnetically guided delivery method based on magnetic shear-thinning gel requires no further cell treatment, is universally applicable to different cell types, including corneal endothelial cells, corneal epithelial cells, and induced pluripotent stem cells, offering significant advantages over existing cell-targeting delivery methods. Furthermore, the magnetic force on the cell can be controlled by adjusting the doping amount of magnetic nanoparticles.

[0019] This invention utilizes hydrogels for cell delivery, physically binding cells within the gel and overcoming cell dispersion issues compared to saline or culture medium delivery. The magnetically guided gel of this invention, preferably a shear-thinning hydrogel containing at least one aldehyde-modified gel, offers advantages over traditional hydrogels as a precise cell delivery carrier. The aldehyde-modified gel effectively enhances tissue adhesion, allowing cells to precisely reach the target location after injection, while ensuring sufficient adhesion between the hydrogel and tissue, preventing detachment due to insufficient adhesion. Furthermore, hydrogel degradation typically takes several days to months, while most cell delivery requires rapid cell release upon reaching the target location. This invention, by adding aldehyde-modified gel, promotes rapid cell adhesion to the target tissue, enabling cells to quickly engage in cellular behavior at the target tissue.

[0020] To make the technical solution of the magnetically guided gel and its use in cell delivery of the present invention clearer, the present invention will be further described below in conjunction with specific embodiments. Detailed Implementation

[0021] Example 1

[0022] This embodiment provides a magnetically guided gel, which is composed of a shear-thinning gel polymer, magnetic nanoparticles, and cells. The magnetically guided gel thins under injection pressure due to shear thinning, allowing it to be injected using a syringe. Under the guidance of an external magnetic field such as a magnet, the gel carries the cells to a target location.

[0023] The method for preparing the magnetically guided gel described in this embodiment is as follows:

[0024] (1) Dissolve 15 mg of hyaluronic acid in 1 ml of physiological saline to prepare a single-component hydrogel with a concentration of 1.5% (w / v);

[0025] (2) Magnetic iron oxide nanoparticles were dispersed in an aqueous solution to prepare a nanoparticle suspension with a concentration of 1 mg / ml. The hydrogel and the nanoparticle suspension were thoroughly mixed at a volume ratio of 2:1 to obtain a hydrogel doped with magnetic iron oxide nanoparticles.

[0026] (3) Add the cell suspension to the hydrogel prepared in step (2). The volume ratio of the cell suspension to the hydrogel prepared in step (2) is 1:10. In this embodiment, the cell suspension is a corneal endothelial cell suspension. Carefully disperse the cells using a pipette until fully mixed to obtain a shear-thinned hydrogel containing magnetic nanoparticles and cells. The cell density in the shear-thinned hydrogel is 1 x 10⁻⁶. 6 / ml. The shear-thinned hydrogel containing magnetic nanoparticles and cells is drawn into a syringe for later use.

[0027] Example 2

[0028] This embodiment provides a magnetically guided gel, which is composed of a shear-thinning gel polymer, magnetic nanoparticles, and cells.

[0029] The method for preparing the magnetically guided gel described in this embodiment is as follows:

[0030] (1) Dissolve 10 mg of hyaluronic acid and 10 mg of methylcellulose together in 1 ml of physiological saline to prepare a 2% (w / v) two-component hydrogel;

[0031] (2) Magnetic iron oxide nanoparticles were dispersed in an aqueous solution to prepare a nanoparticle suspension with a concentration of 1 mg / ml. The hydrogel and the nanoparticle suspension were thoroughly mixed at a volume ratio of 2:1 to obtain a hydrogel doped with magnetic iron oxide nanoparticles.

[0032] (3) Add the cell suspension to the hydrogel prepared in step (2). The volume ratio of the cell suspension to the hydrogel prepared in step (2) is 1:10. In this embodiment, the cell suspension is a corneal epithelial cell suspension. Carefully disperse the cells using a pipette until fully mixed to obtain a shear-thinned hydrogel containing magnetic nanoparticles and cells. The cell density in the shear-thinned hydrogel is 1 x 10⁻⁶. 7 / ml. The shear-thinned hydrogel containing magnetic nanoparticles and cells is drawn into a syringe for later use.

[0033] Example 3

[0034] This embodiment provides a method for preparing a tissue adhesion magnetically guided gel, which is composed of a shear-thinning gel polymer, magnetic nanoparticles, and cells.

[0035] The method for preparing the tissue adhesion gel described in this embodiment is as follows:

[0036] (1) Dissolve 10 mg of aldehyde-modified hyaluronic acid (molecular weight 1 million Da) and 10 mg of methylcellulose in 1 ml of physiological saline to prepare a 2% (w / v) two-component hydrogel.

[0037] (2) Magnetic iron oxide nanoparticles were dispersed in an aqueous solution to prepare a nanoparticle suspension with a concentration of 1 mg / ml. The hydrogel and the nanoparticle suspension were thoroughly mixed at a volume ratio of 2:1 to obtain a hydrogel doped with magnetic iron oxide nanoparticles.

[0038] (3) Add the cell suspension to the hydrogel prepared in step (2). The volume ratio of the cell suspension to the hydrogel prepared in step (2) is 1:10. In this embodiment, the cell suspension is a corneal epithelial cell suspension. Carefully disperse the cells using a pipette until fully mixed to obtain a shear-thinned hydrogel containing magnetic nanoparticles and cells. The cell density in the shear-thinned hydrogel is 1 x 10⁻⁶. 7 / ml. The shear-thinned hydrogel containing magnetic nanoparticles and cells is drawn into a syringe for later use.

[0039] The hydrogel in this embodiment contains aldehyde-modified hyaluronic acid. After implantation into the human body, the aldehyde groups on the hyaluronic acid covalently bind to the tissue, exhibiting good tissue adhesion properties.

[0040] Test case

[0041] The magnetically guided gels prepared in Examples 1 and 2 were injected into 12-well plates containing cell culture medium. An 8 mm diameter magnet was placed at the center of the bottom of each well. During injection, the gel was injected along the well wall furthest from the magnet, and it was observed that the gel quickly positioned itself to the magnet under magnetic guidance after injection. Six-well plates were then placed in a cell culture incubator for 6 hours to observe cell adhesion. Microscopic observation showed that the cell adhesion area existed only above the magnet, indicating that the magnetically guided method based on magnetic shear-thinning hydrogels can achieve precise cell delivery. Furthermore, observation revealed that cells adhered normally to the well walls 6 hours after delivery, indicating that the gel can rapidly release cells without affecting normal cell adhesion. Cell viability staining showed high cell survival rate and good cell condition.

[0042] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the claims.

Claims

1. A magnetically guided gel, characterized in that, It includes the following components: shear-thinned hydrogel and aldehyde-modified hyaluronic acid gel; Magnetic nanoparticles and cells are doped into the shear-thinning hydrogel, wherein the mass concentration of the magnetic nanoparticles in the shear-thinning hydrogel is 1-1000 μg / ml; and the cell density in the shear-thinning hydrogel is 10. 4 -10 7 pcs / ml; The method for preparing the magnetically guided gel includes the following steps: (1) dissolving one or more of hyaluronic acid, carboxymethyl cellulose, and methyl cellulose in physiological saline to prepare a hydrogel; (2) preparing a suspension containing magnetic nanoparticles, and mixing the suspension with the hydrogel prepared in step (1) to obtain a hydrogel doped with magnetic nanoparticles; (3) adding a cell suspension to the hydrogel doped with magnetic nanoparticles in step (2) and mixing to obtain a shear-thinned hydrogel doped with magnetic nanoparticles and cells.

2. The magnetically guided gel according to claim 1, characterized in that, The mass concentration of the polymer in the shear-thinning hydrogel is 1-50 mg / ml.

3. The magnetically guided gel according to claim 1, characterized in that, The viscosity of the shear-thinning hydrogel decreases under the shear force during injection, allowing it to be directly injected through the syringe needle. After injection, the rheological properties are restored to their pre-injection state, preventing cells and magnetic nanoparticles from diffusing outside the gel.

4. The magnetically guided gel according to claim 3, characterized in that, The magnetic nanoparticles are iron oxide-based magnetic nanoparticles.