Active oxygen consuming magnetic particle coating esophageal stent and preparation method thereof

Abstract

The present invention provides an active oxygen consuming magnetic particle coating esophageal stent and a preparation method thereof, belonging to the technical field of biomedical esophageal stents. The active oxygen consuming magnetic particle coating esophageal stent comprises: a self-expanding stent; and an active oxygen consuming magnetic particle coating located on the surface of the self-expanding stent, the active oxygen consuming magnetic particle coating comprising an active oxygen degradable polypeptide, a cross-linking agent and magnetic nanoparticles bonded in sequence; wherein the sequence of the active oxygen degradable polypeptide is SEQ ID No: 1, SEQ ID No: 2 or SEQ ID No: 3.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical esophageal stents, and in particular to an active oxygen consuming magnetic particle coating esophageal stent and a preparation method thereof. Background Art

[0002] Esophageal stent placement can significantly improve the symptoms of esophageal stenosis, prolong survival time and improve quality of life. It is the first choice for treating malignant esophageal stenosis.

[0003] However, inflammation and restenosis caused by local tissue hyperplasia are one of the important limiting factors for the clinical efficacy of esophageal stents. In addition, the special weak acid environment of the digestive fluid in the esophagus leads to faster drug release from the functional esophageal stents with coatings, while the inflammation and oxidative stress caused by the contact between the exposed stent and the esophageal tissue further accelerate the release of the esophageal stent coating. Furthermore, the related technology lacks dynamic monitoring of the remaining amount of stent coating. Summary of the invention

[0004] In view of this, the present invention provides an active oxygen consuming magnetic particle coating esophageal stent and a preparation method thereof.

[0005] According to an embodiment of one aspect of the present invention, there is provided an esophageal stent with an active oxygen-consuming magnetic particle coating, comprising: a self-expanding stent; and an active oxygen-consuming magnetic particle coating located on the surface of the self-expanding stent, wherein the active oxygen-consuming magnetic particle coating comprises an active oxygen-degradable polypeptide, a cross-linking agent and magnetic nanoparticles bonded in sequence; wherein the sequence of the active oxygen-degradable polypeptide is SEQ ID No: 1, SEQ ID No: 2 or SEQ ID No: 3.

[0006] According to an embodiment of the present invention, the surface of the self-expanding stent is modified with polydopamine, and the polydopamine is bonded to the carboxyl group of lysine of the reactive oxygen degradable polypeptide.

[0007] According to an embodiment of the present invention, the surface of the magnetic nanoparticles is modified with amino groups; the cross-linking agent has a maleimide group and a succinimide ester group; wherein the maleimide group reacts with the thiol group of the active oxygen degradable polypeptide, and the succinimide ester group reacts with the amino groups on the surface of the magnetic nanoparticles, so that the active oxygen degradable polypeptide, the cross-linking agent and the magnetic nanoparticles are bonded in sequence.

[0008] According to an embodiment of the present invention, the sequence of the reactive oxygen degradable polypeptide is SEQ ID No: 1; and the cross-linking agent is 4-(N-maleimidomethyl)cyclohexane-1-carboxylic acid sulfonic acid succinimide ester sodium salt.

[0009] According to an embodiment of the present invention, the self-expanding stent is a nickel-titanium alloy self-expanding stent; and the magnetic nanoparticles are nano-ferroferric oxide.

[0010] According to an embodiment of the present invention, the mass ratio of the reactive oxygen degradable polypeptide, the cross-linking agent and the iron in the magnetic nanoparticles is (1-2): (2-4): (5-15).

[0011] According to another aspect of the embodiments of the present invention, a method for preparing an esophageal stent with an active oxygen-consuming magnetic particle coating is provided, and the preparation method comprises the following steps: grafting an active oxygen-degradable polypeptide onto the surface of magnetic nanoparticles through a cross-linking agent to obtain active oxygen-consuming magnetic particles; immersing a self-expanding stent in a solution including active oxygen-consuming magnetic particles to form an active oxygen-consuming magnetic particle coating on the surface of the self-expanding stent to obtain the active oxygen-consuming magnetic particle coating esophageal stent; wherein the sequence of the active oxygen-degradable polypeptide is SEQ ID No: 1, SEQ ID No: 2 or SEQ ID No: 3.

[0012] According to an embodiment of the present invention, the cross-linking agent has a maleimide group and a succinimide ester group; the surface of the magnetic nanoparticles is modified with an amino group; the above-mentioned grafting of the active oxygen degradable polypeptide on the surface of the magnetic nanoparticles through the cross-linking agent to obtain the active oxygen consuming magnetic particles includes: adding the cross-linking agent to a solution containing the magnetic nanoparticles, and obtaining a mixed solution of the cross-linking agent modified magnetic nanoparticles through an amidation reaction; adding the active oxygen degradable polypeptide to the mixed solution of the cross-linking agent modified magnetic nanoparticles, and obtaining the active oxygen consuming magnetic particles through an addition reaction.

[0013] According to an embodiment of the present invention, the iron concentration in the solution including the active oxygen consuming magnetic particles is 1-4 mg / ml.

[0014] According to an embodiment of the present invention, the immersion is performed by low-speed shaking on a shaker, the shaking frequency of the shaker is 50-60 rpm, the temperature is 20-25° C., and the time is 2-5 h.

[0015] The active oxygen consuming magnetic particle coating esophageal stent provided in the embodiment of the present invention has a self-expanding stent as the stent skeleton and active oxygen consuming magnetic particles as the coating, wherein the active oxygen consuming magnetic particle coating includes active oxygen degradable polypeptides, cross-linking agents and magnetic nanoparticles bonded in sequence. The active oxygen consuming magnetic particle coating can consume reactive oxygen species (ROS) for a long time and stably, which is beneficial to alleviate the local oxidative stress environment caused by ROS overload and further accelerate the release of the coating, thereby reducing the risk of inflammation and restenosis; in addition, the active oxygen consuming magnetic particle coating esophageal stent can be used for magnetic particle imaging (MPI), and the remaining amount of the coating can be judged according to the change of the MPI signal intensity of the active oxygen consuming magnetic particle coating esophageal stent.

[0016] According to the embodiments of the present invention, the preparation method of the active oxygen-consuming magnetic particle-coated esophageal stent is simple, low-cost, and more suitable for batch conversion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The appearance morphology and MPI imaging of the ROS-MNPs scaffold provided in Example 1, the bare scaffold provided in Comparative Example 1, and the MNPs scaffold provided in Comparative Example 2 are shown;

[0018] Figure 2 The MPI signal changes of the ROS-MNPs scaffold provided in Example 1 and the MNPs scaffold provided in Comparative Example 2 treated in a phosphate buffer containing hydrogen peroxide for 30 days are shown;

[0019] Figure 3 The MPI signal changes of the ROS-MNPs scaffold provided in Example 1 and the MNPs scaffold provided in Comparative Example 2 after being treated in a weak acid buffer for 30 days are shown;

[0020] Figure 4 The MPI signal changes of the ROS-MNPs scaffold provided in Example 1 and the MNPs scaffold provided in Comparative Example 2 after being treated in a weak acid buffer containing hydrogen peroxide for 30 days are shown. DETAILED DESCRIPTION

[0021] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0022] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0023] In the case of using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, or C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0024] Esophageal stent placement can significantly improve the symptoms of esophageal stenosis, prolong survival time and improve quality of life. It is the first choice for treating malignant esophageal stenosis.

[0025] However, the implantation of esophageal stents may cause a series of complications, including increased inflammatory response and oxidative stress, which are related to the formation of esophageal restenosis. After the implantation of esophageal stents, the esophageal tissue will produce an inflammatory response due to the stimulation of foreign substances. This inflammatory response may cause swelling and pain of the esophageal wall. Long-term existence may promote tissue fibrosis, leading to the formation of esophageal restenosis. ROS are active molecules produced during cell metabolism and are normally balanced by the body's antioxidant system. However, after the implantation of esophageal stents, the production of ROS may increase due to increased tissue damage and inflammatory response. Excessive ROS can damage cell structures, including lipids, proteins, and DNA, leading to cell dysfunction and tissue damage, which may also promote the development of esophageal restenosis. There is a mutually reinforcing relationship between ROS and inflammation. On the one hand, inflammatory cells produce ROS during activation, exacerbating oxidative stress; on the other hand, ROS can act as signal molecules to activate inflammatory responses and promote the release of inflammatory mediators, forming a vicious cycle.

[0026] In summary, oxidative stress, inflammation and restenosis caused by local tissue hyperplasia are one of the important limiting factors for the clinical efficacy of esophageal stents. In addition, the special weak acid environment of the esophageal digestive fluid leads to faster drug release from the functional esophageal stents with coatings, while the inflammation caused by the contact between the bare stent and the esophageal tissue leads to overload of reactive oxygen species, thus creating a local oxidative stress environment, which further accelerates the release of the esophageal stent coating.

[0027] In addition, the lack of control over ROS and dynamic monitoring of the remaining amount of esophageal stent coating makes it difficult to avoid restenosis caused by the vicious cycle of inflammation-ROS-inflammation. How to ease the release of coating and monitor the remaining amount of stent coating after esophageal stent implantation is an urgent problem to be solved in the application of functional esophageal stents.

[0028] In the process of realizing the concept of the present invention, it was found that the ROS content can be reduced by consuming the ROS generated by the esophageal stent segment after stent implantation; in addition, reducing ROS can prevent the coating of the self-expanding stent from being accelerated in the dual environment of ROS and weak acid digestive fluid, thereby preventing restenosis caused by esophageal stent exposure. Oligoproline-containing polypeptides can be degraded by reactive oxygen species, so they can consume reactive oxygen species.

[0029] Specifically, according to an embodiment of one aspect of the present invention, there is provided an esophageal stent with an active oxygen-consuming magnetic particle coating, comprising: a self-expanding stent; and an active oxygen-consuming magnetic particle coating located on the surface of the self-expanding stent, wherein the active oxygen-consuming magnetic particle coating comprises an active oxygen-degradable polypeptide, a cross-linking agent and magnetic nanoparticles bonded in sequence; wherein the sequence of the active oxygen-degradable polypeptide is SEQ ID No: 1, SEQ ID No: 2 or SEQ ID No: 3.

[0030] Specifically, the amino acid sequence shown in SEQ ID No: 1 is: CPPPPPPL; the amino acid sequence shown in SEQ ID No: 2 is: CPPPPPL; the amino acid sequence shown in SEQ ID No: 3 is: CPPPL.

[0031] According to an embodiment of the present invention, bonding refers to connection through strong interaction between two or more adjacent atoms, and the bonding method may include covalent bonding, ionic bonding, hydrogen bonding, van der Waals force, etc. In an embodiment of the present invention, the bonding method may include covalent bonding and hydrogen bonding, etc.

[0032] According to the embodiment of the present invention, the self-expanding stent can reach the lesion through a compression-grip delivery catheter, and after the fixation is released, it can self-expand to allow blood to flow freely and provide support for the lesion.

[0033] According to an embodiment of the present invention, the magnetic nanoparticles may include one or more of iron, nickel, cobalt, chromium, manganese, gadolinium and their compound nanoparticles. The preferred magnetic nanoparticles of the present invention have strong stability and are easy to be surface modified.

[0034] According to an embodiment of the present invention, the active oxygen consuming magnetic particle coating has both the function of long-term and stable consumption of ROS and the MPI imaging performance.

[0035] The active oxygen consuming magnetic particle coating esophageal stent provided in an embodiment of the present invention has a self-expanding stent as a stent skeleton and active oxygen consuming magnetic particles as a coating, wherein the active oxygen consuming magnetic particle coating includes active oxygen degradable polypeptides, cross-linking agents and magnetic nanoparticles bonded in sequence. The active oxygen consuming magnetic particle coating can consume ROS for a long time and stably, which is beneficial to alleviate the local oxidative stress environment caused by ROS overload and further accelerate the release of the coating, thereby reducing the risk of inflammation and restenosis in the long-term range of stent implantation for the treatment of esophageal stenosis; in addition, the active oxygen consuming magnetic particle coating esophageal stent can be used for MPI imaging, and the remaining amount of the coating can be judged according to the change in the MPI signal intensity of the active oxygen consuming magnetic particle coating esophageal stent.

[0036] The active oxygen consuming magnetic particle coating esophageal stent provided in the embodiment of the present invention has excellent ROS response performance and can effectively consume ROS.

[0037] According to an embodiment of the present invention, the surface of the self-expanding stent is modified with polydopamine, and the polydopamine is bonded to the carboxyl group of lysine of the active oxygen degradable polypeptide.

[0038] According to an embodiment of the present invention, the polydopamine modified on the surface of the self-expandable stent includes functional groups such as amino and hydroxyl groups, which can be bonded to the carboxyl group of lysine in the active oxygen degradable polypeptide.

[0039] According to an embodiment of the present invention, the active oxygen consuming magnetic particles can also be attached to the surface of the self-expanding stent by utilizing the adhesion effect of polydopamine itself.

[0040] According to an embodiment of the present invention, polydopamine can be modified on the surface of the self-expanding stent in the following manner:

[0041] Dopamine was dissolved in a tris(hydroxymethyl)aminomethane buffer solution with a pH of 8.5 to prepare a solution with a mass concentration of 1 mg / ml;

[0042] The self-expanding stent was placed in the above-configured solution and soaked for 12 hours, rinsed with deionized water, and dried with nitrogen flow;

[0043] The above-mentioned soaking-rinsing-drying operation is repeated 3 to 5 times to obtain a self-expanding stent with surface modified with polydopamine.

[0044] According to an embodiment of the present invention, the stability of the active oxygen consuming magnetic particle coated esophageal stent is improved by bonding polydopamine to the carboxyl group of lysine of an active oxygen degradable polypeptide.

[0045] According to an embodiment of the present invention, the surface of the magnetic nanoparticles is modified with amino groups. The magnetic nanoparticles are water-soluble magnetic nanoparticles, and the particle size of the water-soluble magnetic nanoparticles is 40-100 nm.

[0046] According to an embodiment of the present invention, the cross-linking agent has a maleimide group and a succinimide ester group.

[0047] According to an embodiment of the present invention, the active oxygen degradable polypeptide, the crosslinker and the magnetic nanoparticles are bonded in sequence by reacting the maleimide group with the sulfhydryl group of the active oxygen degradable polypeptide and reacting the succinimide ester group with the amino group on the surface of the magnetic nanoparticles.

[0048] According to an embodiment of the present invention, the amino terminus of the cysteine ​​in the reactive oxygen degradable polypeptide includes a thiol group.

[0049] According to an embodiment of the present invention, by using a cross-linking agent having a maleimide group and a succinimide ester group, the reactive oxygen degradable polypeptide, the cross-linking agent and the magnetic nanoparticles are bonded in sequence, thereby improving the stability of the reactive oxygen consuming magnetic particle coated esophageal stent, so that it can consume ROS for a long time and stably.

[0050] According to an embodiment of the present invention, the active oxygen degradable polypeptide contains an amino acid sequence as shown in SEQ ID No: 1. The sequence of the active oxygen degradable polypeptide is CPPPPPPL.

[0051] According to an embodiment of the present invention, the preferred reactive oxygen species degradable polypeptide can improve the efficiency of the reactive oxygen species consuming magnetic particle coated esophageal stent in degrading ROS.

[0052] According to an embodiment of the present invention, the cross-linking agent is 4-(N-maleimidomethyl)cyclohexane-1-carboxylic acid sulfonic acid succinimide ester sodium salt. The cross-linking agent is a water-soluble cross-linking agent.

[0053] According to an embodiment of the present invention, the self-expanding stent is a nickel-titanium alloy self-expanding stent.

[0054] According to an embodiment of the present invention, the nickel-titanium alloy self-expanding stent can be a self-expanding stent, which is a superelastic stent made of a nickel-titanium superelastic alloy thin-wall tube through laser precision engraving. The nickel-titanium alloy self-expanding stent can reach the lesion through a compression-grip delivery catheter, and after the fixation is released, it will expand by itself to allow blood to flow freely and support the lesion.

[0055] According to an embodiment of the present invention, the magnetic nanoparticles are nano-iron tetroxide. Specifically, the magnetic nanoparticles can be water-soluble nano-iron tetroxide with amino groups modified on the surface, and more specifically, can be PEGylated iron tetroxide magnetic nanoparticles (amino terminal).

[0056] According to the embodiment of the present invention, the preferred ferrosoferric oxide nanoparticles have low cytotoxicity and good modifiability, which improves the safety and stability of the active oxygen consuming magnetic particle coated esophageal stent.

[0057] According to an embodiment of the present invention, the mass ratio of iron in the reactive oxygen degradable polypeptide, the cross-linking agent and the magnetic nanoparticles is (1-2): (2-4): (5-15). Specifically, the mass ratio of iron in the reactive oxygen degradable polypeptide, the cross-linking agent and the magnetic nanoparticles is 1:2:5, 1:2:8, 1:2:10, 1:2:15, 1:3:5, 1:3:10, 1:3:15, 1:4:5, 1:4:10, 1:4:15, 1.5:3:10, 2:2:5, 1:1:5, 2:2:15, 2:3:5, 2:3:10, 2:3:15, 2:4:5, 2:4:9 or 2:4:15.

[0058] According to the embodiment of the present invention, the preferred mass ratio can ensure both the efficiency of the active oxygen consuming magnetic particle coated esophageal stent in degrading ROS and the MPI imaging effect thereof.

[0059] According to another aspect of the present invention, there is provided a method for preparing an active oxygen consuming magnetic particle coated esophageal stent, comprising the following steps:

[0060] The active oxygen degradable polypeptide is grafted onto the surface of magnetic nanoparticles through a cross-linking agent to obtain active oxygen consuming magnetic particles;

[0061] Soaking the self-expanding stent in a solution including active oxygen consuming magnetic particles to form an active oxygen consuming magnetic particle coating on the surface of the self-expanding stent to obtain an active oxygen consuming magnetic particle coated esophageal stent;

[0062] Wherein, the sequence of the active oxygen degradable polypeptide is SEQ ID No: 1, SEQ ID No: 2 or SEQ ID No: 3.

[0063] According to an embodiment of the present invention, the self-expanding stent can be immersed in a solution including active oxygen-consuming magnetic particles for a period of time, and then rinsed and dried; the above-mentioned immersion-rinsing-nitrogen drying operation is repeated 3 to 5 times to form an active oxygen-consuming magnetic particle coating on the surface of the self-expanding stent, thereby obtaining an active oxygen-consuming magnetic particle coated esophageal stent.

[0064] According to the embodiments of the present invention, the preparation method of the active oxygen-consuming magnetic particle-coated esophageal stent is simple, low-cost, and more suitable for batch conversion and application.

[0065] The active oxygen-consuming magnetic particle-coated esophageal stent prepared according to the embodiment of the present invention has a more stable coating and a longer service time window.

[0066] According to an embodiment of the present invention, a self-expanding esophageal stent is used as the stent skeleton, and active oxygen consuming magnetic particles with the function of long-term and stable consumption of ROS are used as the coating to prepare an esophageal stent that can be used for long-term and stable consumption of ROS and can monitor the remaining amount of the coating through magnetic MPI.

[0067] According to an embodiment of the present invention, the cross-linking agent has a maleimide group and a succinimide ester group.

[0068] According to an embodiment of the present invention, the surface of the magnetic nanoparticles is modified with amino groups.

[0069] According to an embodiment of the present invention, the active oxygen degradable polypeptide is grafted onto the surface of magnetic nanoparticles through a cross-linking agent to obtain active oxygen consuming magnetic particles, which includes:

[0070] adding a cross-linking agent to a solution containing magnetic nanoparticles to obtain a mixed solution of cross-linking agent-modified magnetic nanoparticles through an amidation reaction;

[0071] The active oxygen degradable polypeptide is added into the mixed solution of the cross-linking agent modified magnetic nanoparticles, and the active oxygen consuming magnetic particles are obtained through addition reaction.

[0072] According to an embodiment of the present invention, the pH of the mixed solution of the cross-linking agent modified magnetic nanoparticles is 7-8.

[0073] According to an embodiment of the present invention, a cross-linking agent is first added to a solution containing magnetic nanoparticles, and the cross-linking agent is modified on the surface of the magnetic nanoparticles through an amidation reaction (reaction of the succinimide ester group with the amino group on the surface of the magnetic nanoparticles); then, an active oxygen degradable polypeptide is added to the mixed solution of the cross-linker-modified magnetic nanoparticles, and through an addition reaction (reaction of the maleimide group with the thiol group of the active oxygen degradable polypeptide), the active oxygen degradable polypeptide, the cross-linking agent and the magnetic nanoparticles are bonded in sequence to improve the stability of the active oxygen consuming magnetic particles.

[0074] According to an embodiment of the present invention, the iron concentration in the solution comprising the active oxygen consuming magnetic particles is 1-4 mg / ml, preferably 1-3 mg / ml. Specifically, the iron concentration in the solution comprising the active oxygen consuming magnetic particles is 1 mg / ml, 2 mg / ml, 3 mg / ml or 4 mg / ml.

[0075] According to an embodiment of the present invention, the immersion is a low-speed shaking immersion on a shaking table, the shaking frequency of the shaking table is 50-60 rpm, the preferred temperature is 20-25°C, and the time is 2-5 hours. Specifically, the shaking frequency of the shaking table is 50 rpm, 52 rpm, 55 rpm, 57 rpm or 60 rpm; the shaking temperature of the shaking table is 20°C, 21°C, 22°C, 23°C, 24°C or 25°C; the shaking time of the shaking table is 2 hours, 3 hours, 4 hours or 5 hours.

[0076] The following lists a number of specific embodiments to illustrate the technical solution of the present invention in detail. It should be noted that the specific embodiments below are only used for illustration and are not used to limit the present invention.

[0077] Example 1

[0078] The present embodiment provides an active oxygen consuming magnetic particle coated esophageal stent, comprising a nickel-titanium alloy self-expanding stent and an active oxygen consuming magnetic particle coating located on the surface of the nickel-titanium alloy self-expanding stent, wherein the active oxygen consuming magnetic particle coating comprises an active oxygen degradable polypeptide, a cross-linking agent and magnetic nanoparticles bonded in sequence.

[0079] Among them, the sequence of the active oxygen degradable polypeptide is SEQ ID No: 1. The surface of the nickel-titanium alloy self-expandable stent is modified with polydopamine, which has excellent adhesion and can bond with the carboxyl group of lysine of the active oxygen degradable polypeptide. The magnetic nanoparticles are polyethylene glycol-treated iron oxide magnetic nanoparticles (amino terminal) with a particle size of 60nm. The cross-linking agent is 4-(N-maleimidemethyl) cyclohexane-1-carboxylic acid sulfonic acid succinimide ester sodium salt, which has a maleimide group and a succinimide ester group. The maleimide group reacts with the thiol group of the active oxygen degradable polypeptide, and the succinimide ester group reacts with the amino group on the surface of the magnetic nanoparticle, so that the active oxygen degradable polypeptide, the cross-linking agent and the magnetic nanoparticles are bonded in sequence. The mass ratio of iron in the active oxygen degradable polypeptide, the cross-linking agent and the magnetic nanoparticles is 1:2:10.

[0080] This embodiment also provides a method for preparing the above-mentioned active oxygen consuming magnetic particle coating esophageal stent, comprising the following steps:

[0081] (1) 0.8 mg of the cross-linker was dissolved in dimethyl sulfoxide and added to a solution containing PEGylated ferroferric oxide magnetic nanoparticles (amino terminus) (iron content: 4 mg). Subsequently, phosphate buffer was added and the volume was adjusted to 4 ml (pH = 7.2). The mixture was reacted at room temperature for 45 minutes to obtain a mixed solution of cross-linker-modified magnetic nanoparticles.

[0082] 0.4 mg of reactive oxygen degradable peptide was dissolved in dimethyl sulfoxide and added to the mixed solution of the cross-linker-modified magnetic nanoparticles. Stirring was continued and the reaction was carried out at room temperature for 4 hours to obtain reactive oxygen consuming magnetic particles (denoted as ROS-MNPs).

[0083] The mixture including ROS-MNPs was added with 1×10 5 The solution was dialyzed using a dialysis bag with a molecular weight of Da to remove excess reactive oxygen-degradable peptides and cross-linking agents to obtain a solution including ROS-MNPs.

[0084] (2) The polydopamine-attached nickel-titanium alloy self-expandable stent was placed in a round-bottom flask containing a solution of ROS-MNPs and immersed in a shaker at a low speed of 55 rpm and a temperature of 22°C for 3 h; then the solution was gently rinsed and dried with nitrogen.

[0085] (3) The above step (2) is repeated three times to form an active oxygen consuming magnetic particle coating on the surface of the nickel-titanium alloy self-expanding stent, thereby obtaining an active oxygen consuming magnetic particle coated esophageal stent (referred to as ROS-MNPs stent).

[0086] Example 2

[0087] This embodiment provides an active oxygen consuming magnetic particle coated esophageal stent and a preparation method thereof.

[0088] The active oxygen consuming magnetic particle coated esophageal stent and the preparation method thereof refer to Example 1, except that the sequence of the active oxygen degradable polypeptide is SEQ ID No: 2.

[0089] Example 3

[0090] This embodiment provides an active oxygen consuming magnetic particle coated esophageal stent and a preparation method thereof.

[0091] The active oxygen consuming magnetic particle coated esophageal stent and the preparation method thereof refer to Example 1, except that the sequence of the active oxygen degradable polypeptide is SEQ ID No:3.

[0092] Example 4

[0093] This embodiment provides an active oxygen consuming magnetic particle coating esophageal stent and a preparation method thereof; the reference may be made to Example 1, except that the preparation method of the active oxygen consuming magnetic particle coating esophageal stent, step (1) is:

[0094] (1) Preparation of active oxygen-consuming magnetic particles

[0095] 0.4 mg of the active oxygen degradable polypeptide was dissolved in dimethyl sulfoxide to obtain an active oxygen degradable polypeptide solution.

[0096] 0.8 mg of the cross-linking agent and the reactive oxygen-degradable polypeptide solution were added to a solution containing magnetic nanoparticles (iron content of 4 mg), and the volume was adjusted to 4 ml (pH = 7.2), and the reaction was carried out at room temperature for 4 hours and 45 minutes to obtain reactive oxygen-consuming magnetic particles.

[0097] The mixture including ROS-MNPs was added with 1×10 5 The solution is dialyzed using a dialysis bag with a molecular weight of Da to remove excess active oxygen-degradable polypeptides and cross-linking agents to obtain a solution including active oxygen-consuming magnetic particles.

[0098] The iron content of the active oxygen consuming magnetic particle coated esophageal stent provided in this embodiment was detected by using an inductively coupled plasma mass spectrometer. The detection showed that the mass percentage of iron was 17.2%.

[0099] Comparative Example 1

[0100] This comparative example provides an esophageal stent (referred to as a bare stent), the surface of which is not modified with polydopamine.

[0101] Comparative Example 2

[0102] This comparative example provides a magnetic particle coated esophageal stent (referred to as MNPs stent), comprising a nickel-titanium alloy self-expanding stent and magnetic nanoparticles located on the surface of the nickel-titanium alloy self-expanding stent.

[0103] The surface of the nickel-titanium alloy self-expandable stent is modified with polydopamine. The magnetic nanoparticles are polyethylene glycol-coated ferroferric oxide magnetic nanoparticles (amino terminal) with a particle size of 60 nm.

[0104] This comparative example also provides a method for preparing the above-mentioned magnetic particle coated esophageal stent, comprising the following steps:

[0105] (1) The nickel-titanium alloy self-expandable stent was immersed in a 4 ml solution containing magnetic nanoparticles (iron content 4 mg) in a round-bottom flask and shaken at low speed for 3 h at a shaking frequency of 55 rpm and a temperature of 22°C; then gently rinsed and dried with nitrogen.

[0106] (2) Repeat the above step (1) three times to form a magnetic particle coating on the surface of the nickel-titanium alloy self-expandable stent to obtain a magnetic particle coated esophageal stent.

[0107] The following MPI imaging was performed using a magnetic particle imaging device (MOMENTUM, Magnetic Insight). MPI imaging parameter settings: scanning range: 6×4 cm; scanning mode: isotropic; scanning time: 3 minutes.

[0108] The ROS-MNPs scaffold provided in Example 1, the bare scaffold provided in Comparative Example 1, and the MNPs scaffold provided in Comparative Example 2 were subjected to MPI imaging. The appearance and MPI imaging were as follows: Figure 1 As shown in A and B. Figure 1 Analysis shows that the bare stent does not have the MPI imaging function. Compared with the MNPs stent, the ROS-MNPs stent provided in Example 1 has a better MPI imaging effect.

[0109] The ROS-MNPs scaffold provided in Example 1 and the MNPs scaffold provided in Comparative Example 1 were treated with a phosphate buffer solution (pH 7) containing 20 μmol / L hydrogen peroxide, and the MPI signal changes were detected. The test results are detailed in Figure 2 . Figure 2 The MPI signal changes of ROS-MNPs scaffold and MNPs scaffold treated in hydrogen peroxide solution for 30 days are shown. Figure 2 Analysis shows that after 30 days of hydrogen peroxide treatment, the signal intensity of the ROS-MNPs scaffold is significantly higher than that of the MNPs scaffold, which is consistent with the iron content test results of Example 1 and Comparative Example 1 (see Table 1 below). At the same time, the ROS-MNPs scaffold can be in hydrogen peroxide solution for up to 30 days without obvious MPI signal changes, indicating that the ROS-MNPs scaffold is released slowly in the ROS environment and is more suitable for treatment and MPI imaging applications in the ROS environment.

[0110] The ROS-MNPs scaffold provided in Example 1 and the MNPs scaffold provided in Comparative Example 1 were treated with a phosphate buffer solution having a pH of 6, and the changes in the MPI signals were detected. The test results are shown in Figure 3 . Figure 3 The MPI signal changes of ROS-MNPs scaffold and MNPs scaffold treated in weak acid buffer for 30 days are shown. Figure 3 Analysis shows that after being treated with a phosphate buffer solution at a pH of 6 for 30 days, the signal intensity of the ROS-MNPs scaffold is significantly higher than that of the MNPs scaffold, which is consistent with the iron content test results of Example 1 and Comparative Example 1 (see Table 1 below). At the same time, the ROS-MNPs scaffold can be in a phosphate buffer solution at a pH of 6 for up to 30 days without obvious MPI signal changes, indicating that the ROS-MNPs scaffold is slowly released in the same weak acid environment of esophageal digestive fluid, and is more suitable for treatment and MPI imaging applications in the weak acid environment of digestive fluid.

[0111] The ROS-MNPs scaffold provided in Example 1 and the MNPs scaffold provided in Comparative Example 1 were treated with a phosphate buffer solution (pH 6) containing 20 μmol / L hydrogen peroxide, and the MPI signal changes were detected. The detection results are detailed in Figure 4 . Figure 4The MPI signal changes of ROS-MNPs scaffold and MNPs scaffold treated in weak acid buffer containing hydrogen peroxide for 30 days are shown. Figure 4 Analysis shows that after being treated with hydrogen peroxide and phosphate buffer with a pH of 6 for 30 days, the signal intensity of the ROS-MNPs scaffold is significantly higher than that of the MNPs scaffold, which is consistent with the iron content test results of Example 1 and Comparative Example 1 (see Table 1 below for details). At the same time, the ROS-MNPs scaffold can be in a phosphate buffer including hydrogen peroxide for up to 30 days without obvious MPI signal changes, indicating that the ROS-MNPs scaffold is slowly released in the same weak acid environment as the esophageal digestive fluid, and is more suitable for treatment and MPI imaging applications in scenarios where inflammatory ROS is excessive and the weak acid environment of the digestive fluid coexists. The active oxygen-consuming magnetic particle coating improves the sustained release time and imaging specificity of the stent in a weak acid plus oxidative stress environment, and improves the release controllability of the active oxygen-consuming magnetic particle coated esophageal stent.

[0112] In addition, analysis Figure 3 and Figure 4 It can be seen that the addition of hydrogen peroxide in the phosphate buffer including hydrogen peroxide accelerates the release of the coating compared with the phosphate buffer, but this accelerated release is improved in the ROS-MNPs scaffold provided in Example 1 of the present invention, indicating that the coating release is alleviated by consuming hydrogen peroxide.

[0113] The ROS-MNPs scaffold (Example 1), ROS-MNPs scaffold + hydrogen peroxide (the ROS-MNPs scaffold treated with phosphate buffer (pH 7) containing 20 μmol / L hydrogen peroxide for 30 days), ROS-MNPs scaffold + weak acid buffer (the ROS-MNPs scaffold treated with phosphate buffer (pH 6) for 30 days), ROS-MNPs scaffold + hydrogen peroxide + weak acid buffer (the ROS-MNPs scaffold treated with phosphate buffer (pH 6) containing 20 μmol / L hydrogen peroxide for 30 days) were analyzed by inductively coupled plasma mass spectrometry. The iron content of the ROS-MNPs scaffold, MNPs scaffold (Comparative Example 2), MNPs scaffold + hydrogen peroxide (the MNPs scaffold treated with phosphate buffer (pH 7) containing 20 μmol / L hydrogen peroxide for 30 days), MNPs scaffold + weak acid buffer (the MNPs scaffold treated with phosphate buffer (pH 6) for 30 days), and MNPs scaffold + hydrogen peroxide + weak acid buffer (the MNPs scaffold treated with phosphate buffer (pH 6) containing 20 μmol / L hydrogen peroxide for 30 days) was detected, and the test results are shown in Table 1. It can be seen from the analysis of Table 1 that the active oxygen-consuming magnetic particle-coated esophageal stent provided in an embodiment of the present invention has a higher iron content. This may be because the active oxygen-degradable polypeptide and the cross-linking agent improve the distribution of magnetic nanoparticles in the solution including the active oxygen-consuming magnetic particles, which is more conducive to the attachment of the active oxygen-consuming magnetic particles to the nickel-titanium alloy self-expanding stent.

[0114] Table 1

[0115]

[0116] From Table 1 and Figures 2~4 Analysis shows that the MPI signal intensity is approximately positively correlated with the iron mass percentage of the stent, so the remaining amount of the stent coating can be reflected based on the stent MPI signal intensity.

[0117] In summary, the embodiments of the present invention provide an active oxygen-consuming magnetic particle-coated esophageal stent that can be used to consume active oxygen in a long-term and stable manner and can monitor the remaining amount of the coating by magnetic particle imaging. The active oxygen-consuming magnetic particle-coated esophageal stent provided by the embodiments of the present invention lays a foundation for improving the excess of ROS caused by inflammation after stent implantation and applying MPI to quantitative monitoring of the remaining content of the stent coating, and also lays a foundation for using the active oxygen-consuming magnetic particle-coated esophageal stent to alleviate the oxidative stress of esophageal stenosis.

[0118] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An active oxygen consuming magnetic particle coated esophageal stent, It is characterized in that include: Self-expanding stents; as well as an active oxygen consuming magnetic particle coating located on the surface of the self-expanding stent, wherein the active oxygen consuming magnetic particle coating comprises an active oxygen degradable polypeptide, a cross-linking agent and magnetic nanoparticles bonded in sequence; Wherein, the sequence of the active oxygen degradable polypeptide is SEQ ID No: 1, SEQ ID No: 2 or SEQ ID No:

3.

2. The active oxygen consuming magnetic particle coated esophageal stent according to claim 1, It is characterized in that The surface of the self-expanding stent is modified with polydopamine, and the polydopamine is bonded to the carboxyl group of lysine of the active oxygen degradable polypeptide.

3. The active oxygen consuming magnetic particle coated esophageal stent according to claim 1 or 2, It is characterized in that The surface of the magnetic nanoparticles is modified with amino groups; The cross-linking agent has a maleimide group and a succinimide ester group; The maleimide group reacts with the sulfhydryl group of the active oxygen degradable polypeptide, and the succinimide ester group reacts with the amino group on the surface of the magnetic nanoparticle, so that the active oxygen degradable polypeptide, the crosslinker and the magnetic nanoparticle are bonded in sequence.

4. The active oxygen consuming magnetic particle coated esophageal stent according to claim 1 or 2, It is characterized in that The sequence of the active oxygen degradable polypeptide is SEQ ID No: 1; The cross-linking agent is 4-(N-maleimidomethyl)cyclohexane-1-carboxylic acid sulfonic acid succinimide ester sodium salt.

5. The active oxygen consuming magnetic particle coated esophageal stent according to claim 1 or 2, It is characterized in that The self-expanding stent is a nickel-titanium alloy self-expanding stent; The magnetic nanoparticles are nano-iron tetroxide.

6. The active oxygen consuming magnetic particle coated esophageal stent according to claim 1 or 2, It is characterized in that The mass ratio of the active oxygen degradable polypeptide, the cross-linking agent and the iron in the magnetic nanoparticles is (1-2): (2-4): (5-15).

7. A method for preparing an esophageal stent coated with active oxygen-consuming magnetic particles, It is characterized in that The preparation method comprises the following steps: The active oxygen degradable polypeptide is grafted onto the surface of magnetic nanoparticles through a cross-linking agent to obtain active oxygen consuming magnetic particles; Soaking the self-expanding stent in a solution including active oxygen consuming magnetic particles to form an active oxygen consuming magnetic particle coating on the surface of the self-expanding stent to obtain the active oxygen consuming magnetic particle coated esophageal stent; Wherein, the sequence of the active oxygen degradable polypeptide is SEQ ID No: 1, SEQ ID No: 2 or SEQ ID No:

3.

8. The preparation method according to claim 7, It is characterized in that The cross-linking agent has a maleimide group and a succinimide ester group; The surface of the magnetic nanoparticles is modified with amino groups; The step of grafting the active oxygen degradable polypeptide onto the surface of magnetic nanoparticles through a cross-linking agent to obtain active oxygen consuming magnetic particles comprises: adding a cross-linking agent to a solution containing the magnetic nanoparticles to obtain a mixed solution of cross-linking agent-modified magnetic nanoparticles through an amidation reaction; The active oxygen degradable polypeptide is added to the mixed solution of the cross-linking agent modified magnetic nanoparticles to obtain the active oxygen consuming magnetic particles through addition reaction.

9. The preparation method according to claim 7 or 8, It is characterized in that The iron concentration in the solution including the active oxygen consuming magnetic particles is 1-4 mg / ml.

10. The preparation method according to claim 7 or 8, It is characterized in that The soaking is performed by low-speed shaking on a shaker, the shaking frequency of the shaker is 50-60 rpm, the temperature is 20-25° C., and the time is 2-5 h.

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