Photostimulation response zinc-based coordination polymer, preparation method thereof and application of photostimulation response zinc-based coordination polymer in cardiovascular stent

Abstract

The invention relates to a photostimulation response zinc-based coordination polymer as well as a preparation method and application thereof in a cardiovascular stent, and belongs to the technical field of biological medicines. The chemical formula of the photostimulation response zinc-based coordination polymer is {[Zn (OAc) 2 (tpeb)]. 2H2O} n, OAc is acetic acid, tpeb is 1, 3, 5-tri (2-(pyridine-4-yl) vinyl) benzene, and n is equal to 3000-60000. The photostimulation response zinc-based coordination polymer crystal can be subjected to photochemical [2 + 2] cycloaddition reaction under ultraviolet irradiation, and the reaction process is accompanied by strong and rapid crystal mechanical movement. The cardiovascular stent prepared from the material can be rapidly expanded according to a specified direction under ultraviolet irradiation, has a secondary illumination expansion capability, breaks through the disposable use limitation of the existing stent, and is endowed with the capability of dynamically adapting to vascular pathology / physiological changes.

Description

Technical Field

[0001] The present invention belongs to the field of biomedicine technology, and in particular relates to a light stimulus responsive zinc-based coordination polymer, a preparation method thereof, and an application thereof in a cardiovascular stent. Background Art

[0002] Vascular stent implantation is the main method for treating coronary artery stenosis, atherosclerosis and other diseases. Although traditional metal stents (such as stainless steel, cobalt-chromium alloy) and biodegradable polymer stents (such as polyvinyl alcohol PVA, polylactic acid PLA, polycaprolactone PCL) can restore vascular patency in the short term, they still have the following key problems: single implantation is irreversible: the diameter of the stent is fixed after implantation, and it cannot be non-invasively adjusted according to the dynamic changes of the blood vessels (such as secondary stenosis after vascular restenosis, and the developmental expansion needs of pediatric patients), requiring secondary surgical intervention; poor adaptability to complex lesions: for bifurcated lesions, long-segment stenosis or areas with significant differences in vascular wall elasticity, static stents are difficult to achieve dynamic adaptation of local mechanical properties (see: Miyashita K, Ninomiya K, Tobe A, Masuda S, Kotoku N, Kageyama S, Revaiah P, Tsai T, Wang B, Garg S, Serruys P, Onuma Y, Expert Review of Cardiovascular Therapy, 22:8, 391-407.).

[0003] In recent years, the development of photoresponsive smart materials in the biomedical field has provided new ideas for the above problems. Photoresponsive materials have become a research hotspot because they are triggered from the outside in a non-destructive, spatiotemporal controllable, highly biosafe, and non-contact manner. They have unique appeal in energy conversion and have great potential applications in biomedicine, soft robotics, and flexible electronics. For example, a crystalline molecular material containing olefin groups was used to realize photomechanical motion in single crystals and single crystal composite films. When the film strips were shaped and folded into microrobot-like models, a variety of human-like movements were observed, which may be applicable to soft microrobots (see: Wang Y, Zhang Q, LiuQ, Abrahams B, Lang J, Angew. Chem. Int. Ed, 2024, 63, e202409472.). Bone defect regeneration is promoted by near-infrared responsive 3D printed shape memory polyurethane / magnesium composite scaffolds. The scaffold can restore its original shape and mechanical rebound through near-infrared light irradiation; at the same time, it tightly fills the defect site and releases magnesium ions to promote bone repair, which can provide an effective strategy for clinical bone defect treatment (see: Zhang Y, Li C, Zhang W, Deng J, Nie Y, Du X, Qin L, Lai Y, Bioactive Materials, 2022, 16, 218-231.).

[0004] However, the existing light-driven stent technology focuses on single-shot light triggering function and has significant defects in secondary dynamic regulation. Most photosensitive components are prone to photoresponse performance attenuation after long-term retention in the body, making it difficult to support multiple light triggering. Existing photoresponsive stents lack the "on-demand secondary adjustment" design for vascular restenosis or developmental dilatation needs, and cannot achieve non-destructive, precise and controllable adjustment of the stent diameter. As we all know, coordination polymers (CP) are a new type of crystalline material formed by self-assembly of inorganic metal ions / metal clusters and organic bridging ligands through coordination bonds. Due to the precise and controllable performance, excellent biocompatibility and safety, and potential degradation performance of the structure of coordination polymers, coordination polymer-based stents combine light-responsive smart materials with their structural adjustability, providing a safer and more adaptable solution for the treatment of cardiovascular diseases, especially for growing patients and complex cases requiring personalized treatment, and are expected to significantly reduce the reoperation rate. However, metal ions in existing coordination polymers cause inflammation in sensitive cardiovascular areas due to factors such as the difficulty of material degradation and long-term accumulation in the body. At the same time, there is a mismatch between the mechanical properties of existing coordination polymers and the flexibility required for cardiovascular treatment.

[0005] Therefore, it is still necessary to develop a biofriendly coordination polymer with excellent mechanical properties so that it can exhibit excellent compressive strength and moderate flexibility during dynamic regulation. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a light stimulus responsive zinc-based coordination polymer and its preparation method and application in cardiovascular stents. The light stimulus responsive zinc-based coordination polymer crystal can undergo a photochemical [2+2] cycloaddition reaction under ultraviolet light irradiation, and the reaction process is accompanied by strong and rapid crystal mechanical movement. The cardiovascular stent prepared by the light stimulus responsive zinc-based coordination polymer can expand rapidly in a specified direction under ultraviolet light irradiation, and has the ability to expand under secondary light irradiation, breaking through the "one-time use" limitation of existing stents and giving the cardiovascular stent the ability to dynamically adapt to vascular pathological / physiological changes.

[0007] The first object of the present invention is to provide a light-stimulus-responsive zinc-based coordination polymer, the chemical formula of which is {[Zn(OAc) 2 (tpeb)]·2H 2 O} n , wherein OAc is acetic acid, tpeb is 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene, and n=3000-60000.

[0008] The second object of the present invention is to provide a method for preparing the light stimulus responsive zinc-based coordination polymer, comprising the following steps: The zinc salt and 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene are heated in a mixed solvent to obtain the light-stimulated responsive zinc-based coordination polymer {[Zn(OAc) 2 (tpeb)]·2H 2 O} n ; The mixed solvent comprises acetonitrile and water; Wherein, OAc is acetic acid, tpeb is 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene, and n=3000-60000.

[0009] In one embodiment of the present invention, the zinc salt is selected from one or more of zinc sulfate, zinc nitrate and zinc chloride.

[0010] In one embodiment of the present invention, the volume ratio of acetonitrile to water is 1:(1-4).

[0011] In one embodiment of the present invention, the molar ratio of the zinc salt to 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene is (4-5):1.

[0012] In one embodiment of the present invention, the pH of the heating reaction is 5-6, the temperature is 100° C.-150° C., and the time is 12h-24h.

[0013] The third object of the present invention is to provide a photoresponsive film, which comprises the light stimulus responsive zinc-based coordination polymer.

[0014] In one embodiment of the present invention, the thickness of the photoresponsive film is 50 μm-70 μm.

[0015] A fourth object of the present invention is to provide a method for preparing the photoresponsive film, comprising the following steps: S1, grinding and dispersing the light stimulus responsive zinc-based coordination polymer in a solvent, and drying to obtain a powder; S2: Add the powder described in S1 to the substrate, mix well and pour into a mold, and dry to obtain the photoresponsive film.

[0016] In one embodiment of the present invention, in S1, the solvent is selected from one or more of ethanol, acetonitrile and water.

[0017] In one embodiment of the present invention, in S1, the drying temperature is 40°C-60°C.

[0018] In one embodiment of the present invention, in S2, the substrate is selected from one or more of polyvinyl alcohol, polypropylene and polyvinylidene fluoride.

[0019] In one embodiment of the present invention, in S2, the drying temperature is 40°C-60°C.

[0020] The fifth object of the present invention is to provide a cardiovascular stent, including the photoresponsive film. The expansion of the cardiovascular stent can be regulated by extracorporeal light irradiation, thereby avoiding the problem of traditional cardiovascular stents requiring secondary surgery due to size mismatch or vascular restenosis, and significantly reducing the risk of infection and complications.

[0021] In one embodiment of the present invention, the cardiovascular stent further comprises a waterproof layer disposed on the surface of the photoresponsive film.

[0022] In one embodiment of the present invention, the material of the waterproof layer is selected from one or more of polycaprolactone, carboxylated cellulose nanofiber and genipin.

[0023] The technical solution of the present invention has the following advantages over the prior art: (1) The light-stimulus-responsive zinc-based coordination polymer described in the present invention can rapidly undergo a photochemical [2+2] cycloaddition reaction under the irradiation of 365nm wavelength light, generate photostress and then promote photoinduced motion. This photoinduced stress effect can be further amplified by a photoresponsive film. In addition, zinc in the light-stimulus-responsive zinc-based coordination polymer of the present application is an essential trace element for the human body, participates in immune regulation and endothelial repair, and can reduce the risk of infection after stent implantation. The conjugated structure of 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene has fluorescent properties, and combined with the zinc coordination effect, it can be developed into a self-imaging stent, which is convenient for monitoring the position and degradation status of the stent through optical imaging after surgery. Its biocompatibility is significantly improved by regulating metal nodes and organic ligands, and it has unique potential in mechanical properties and degradability. The cardiovascular stent prepared therefrom can be gradually degraded after completing its function, avoiding chronic inflammation caused by permanent foreign body retention; non-invasive operation reduces the risk of secondary surgery.

[0024] (2) The preparation method described in the present invention is simple, the reaction conditions are mild, and the photoconversion rate is fast.

[0025] (3) The cardiovascular stent described in the present invention can act on specific parts of the cardiovascular stent by means of light stimulation response, avoiding excessive damage to the blood vessels due to overall expansion and reducing the risk of blood vessel tearing; the volume control is highly accurate, and the entire control process does not involve any chemical reagents, which is safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 is {[Zn(OAc) 2 (tpeb)]·2H 2 O} n One-dimensional stacking diagram of (CP1); Figure 2 In Test Example 1 of the present invention, {[Zn(OAc) 2 (tpeb)]·2H 2 O} n X-ray diffraction pattern of (CP1); Figure 3 In Test Example 1 of the present invention, {[Zn(OAc) 2 (tpeb)]·2H 2 O} n Thermogravimetric analysis of (CP1); Figure 4 In Test Example 1 of the present invention, {[Zn(OAc) 2 (tpeb)]·2H 2O} n (Infrared analysis of CP1); Figure 5 The H NMR spectra of CP1 that did not undergo cycloaddition reaction and the photoproduct generated by the cycloaddition reaction in Test Example 2 of the present invention; Figure 6 The nuclear magnetic hydrogen spectra of CP1 without cycloaddition reaction and the purified photoproducts generated by the cycloaddition reaction in Test Example 2 of the present invention; Figure 7 In Test Example 2 of the present invention, {[Zn(OAc) 2 (tpeb)]·2H 2 O} n (CP1) Various mechanical motion behaviors of single crystal under 365nm and 420nm UV light; Figure 8 The PXRD spectra of the front and back sides of the photoresponsive film in Test Example 3 of the present invention; Fig. 9 The SEM images of the front surface (a) and the side surface (b) of the photoresponsive film in Test Example 3 of the present invention are shown; Fig.10 Surface roughness (a) and Young's modulus (b) of the photoresponsive film in Test Example 3 of the present invention; Fig.11 The bending behavior of the photoresponsive film in Test Example 3 of the present invention under 365nm ultraviolet light; Fig.12 This is the primary expansion and secondary expansion process of the 8 mm cardiovascular stent in Test Example 4 of the present invention; Fig.13 This is the primary expansion and secondary expansion process of the 4 mm cardiovascular stent in Test Example 4 of the present invention; Fig.14 This is the primary expansion and secondary expansion process of the 2 mm cardiovascular stent in Test Example 4 of the present invention; Fig.15 This is the primary expansion and secondary expansion process of the 1 mm cardiovascular stent in Test Example 4 of the present invention; Fig.16 The PXRD spectra of the composite film in Test Example 5 of the present invention after being treated in air and in a blood simulation system; Fig.17 The SEM images of the composite film in Test Example 5 of the present invention before (a) and after (b) irradiation in air; Fig.18 The SEM images of the composite film in Test Example 5 of the present invention before (a) and after (b) illumination in a blood simulation system; Fig.19 Surface roughness (a) and Young's modulus (b) of the composite film in Test Example 5 of the present invention before irradiation in air; Fig. 20 Surface roughness (a) and Young's modulus (b) of the composite film after irradiation in air in Test Example 5 of the present invention; Fig.21 Surface roughness (a) and Young's modulus (b) of the composite film in Test Example 5 of the present invention before irradiation in a blood simulation system; Fig. 22 Surface roughness (a) and Young's modulus (b) of the composite film after irradiation in a blood simulation system in Test Example 5 of the present invention; Fig.23 This is the primary expansion and secondary expansion process of the 8 mm cardiovascular stent in Test Example 6 of the present invention; Fig.24 This is the primary expansion and secondary expansion process of the 4 mm cardiovascular stent in Test Example 6 of the present invention; Fig.25 This is the primary expansion and secondary expansion process of the 2 mm cardiovascular stent in Test Example 6 of the present invention; Fig.26 This is the primary expansion and secondary expansion process of the 1 mm cardiovascular stent in Test Example 6 of the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention. Example 1

[0028] The light stimulus responsive zinc-based coordination polymer and the preparation method thereof of the present invention specifically comprise the following steps: 1,3,5-Tri(2-(pyridin-4-yl)vinyl)benzene (0.06 mmol, 23.2 mg) and ZnSO 4 7H 2 O (0.24 mmol, 86.3 mg) was added to a 15 mL thick-walled pressure bottle, and then 5.4 mL of acetonitrile and 9 mL of H 2 O mixed solution, and the pH of the system was adjusted to about 5 with 0.1 mol / L nitric acid; the bottle cap was tightened, and ultrasonic treatment was performed for 15 min, and then the bottle was sealed and placed in a programmable temperature-controlled oven for reaction, kept at 150 ° C for 24 h, cooled to room temperature at a rate of 5 ° C / h, washed with anhydrous ethanol, and vacuum dried to obtain pale yellow long needle-shaped crystals, namely, light stimulus responsive zinc-based coordination polymer {[Zn(OAc) 2 (tpeb)]·2H 2 O} n (CP1)( Figure 1), yield 32.9 mg (yield based on 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene, 80.6%). Test Example 1

[0029] The light-stimulus-responsive zinc-based coordination polymer {[Zn(OAc) 2 (tpeb)]·2H 2 O} n The elements, X-ray diffraction, thermogravimetric and infrared spectra of (CP1) were analyzed, and the specific results are as follows: (1) Elemental analysis (%): Photostimuli-responsive zinc-based coordination polymer C 31 H 31 N 3 O 6 Zn, theoretical value is (%)C, 61.39; H, 5.12; N, 6.93. Measured value is (%)C, 61.56; H, 5.22; N, 6.98.

[0030] (2) X-ray diffraction analysis Figure 2 ): {[Zn(OAc) 2 (tpeb)]·2H 2 O} n The experimental powder X-ray diffraction pattern of (CP1) is basically consistent with the simulated X-ray diffraction pattern of single crystal data, which proves the purity of the series of complex powders. In addition, based on the single crystal X-ray diffraction test, the crystal data of CP1 were collected on a diffractometer (Bruker D8-Quest), using an enhanced X-ray light source of Mo Kα (λ=0.071073nm) and a test temperature of 150K; {[Zn(OAc) 2 (tpeb)]·2H 2 O} n The diffraction data and unit cell parameters of (CP1) were restored by the Agilent Technologies (CrysAlisPro Agilent Technologies, Version 1.171.36.32, 2013) program. All the diffraction data were obtained by Lp factor correction and multi-scan absorption correction; {[Zn(OAc) 2 (tpeb)]·2H 2 O} n The crystal structure of (CP1) was solved by direct method using OLEX2 program and refined by least square matrix method; all non-hydrogen atoms were anisotropically corrected and all hydrogen atoms were theoretically hydrogenated according to reasonable geometric positions; {[Zn(OAc) 2(tpeb)]·2H 2 O} n The main crystallographic parameters and structure refinement parameters of (CP1) are shown in Table 1: Table 1

[0031] in: a R 1 =Σ|| F o |-| F c || / Σ| F o |; b wxya 2 ={Σ w ( F o 2 - F c 2 ) 2 / Σ w ( F o 2 ) 2} 1 / 2 ; c GOF={Σ w (( F o 2 - F c 2 ) 2 ) / ( np )} 1 / 2 , n is the number of reflections, and p is the total number of refined parameters.

[0032] As can be seen from Table 1, Example 1 successfully obtained a light-stimulated responsive zinc-based coordination polymer, namely {[Zn(OAc) 2 (tpeb)]·2H 2 O} n (CP1).

[0033] (3) Thermogravimetric analysis Figure 3 ): In N 2 The complex has good thermal stability under atmosphere, with no weight loss below 300°C, after which thermal decomposition occurs.

[0034] (4) Infrared spectroscopy Figure 4) (Potassium bromide tablet method) Analysis: 3415(w), 3031(w), 2484(w), 1685(m), 1608(s), 1506(m), 1431(m), 1378(s), 1328(s), 1205(m), 1066(m), 1026(m),978(s), 925(w), 846(s), 804(m), 736(m), 675(s), 617(m) cm -1 . Test Example 2

[0035] The light-stimulus-responsive zinc-based coordination polymer {[Zn(OAc) 2 (tpeb)]·2H 2 O} n (CP1) undergoes a photochemical cycloaddition reaction. When the CP1 crystal is placed under a 365nm high-pressure mercury lamp for a period of time and then taken out, the single crystal bends and explodes. An attempt was made to determine its crystal structure after illumination, but the diffraction points of the crystal after illumination gradually weakened and disappeared as the illumination time increased, so the crystal structure of the complex after illumination could not be obtained. Therefore, the NMR results of CP1 that did not undergo cycloaddition reaction and the photoproduct generated by the cycloaddition reaction are as follows Figure 5 As shown. Figure 5 It can be seen that the H NMR spectrum (400 MHz, 298 K, d 6 -DMSO, ppm): δH=8.90(d,6H), δH=8.25(d,6H), δH=8.18(s,3H), δH=8.07(d,3H), δH=7.69(d,3H); H NMR spectrum of the photoproducts generated by the cycloaddition reaction (400MHz, 298K, d 6 -DMSO,ppm): δH=9.08(d,3H), δH=8.90(d,3H), δH=8.38(d,3H), δH=8.25(d,3H), δH=8.18(s,3H), δH=8.03(d,2H), δH=7.69(d,2H), δH=4.2-3.4(s,2H). That 1 The appearance of cyclobutane peak (in the range of 3.4ppm to 4.2ppm) and the migration of pyridine peak (8.9ppm to 9.1ppm and 8.2ppm to 8.3ppm) can be observed in the HNMR spectrum, so it can be determined that the photostimulation-responsive zinc-based coordination polymer undergoes a cycloaddition reaction.

[0036] In order to further determine the true reaction degree of the photoresponsive zinc-based coordination polymer, an experimental operation was performed to separate and purify the CP1 after illumination. 0.5 g of CP1 powder was irradiated under a 365 nm high pressure mercury lamp for 48 h, and then the photoproduct and the tpeb monomer that did not undergo the cycloaddition reaction were separated, weighed, and the ratio of the cycloaddition reaction of the complex was calculated. The separation and ratio calculation are as follows: the complex powder (about 0.5 g) irradiated under a 365 nm high pressure mercury lamp was mixed with 2 mol / L HNO 3 The solution (20 mL) was mixed and stirred for 24 h to decompose the complex structure. The precipitate was then filtered and washed three times with chloroform, and then vacuum dried for 24 h to obtain a dark yellow solid product as the photoreaction organic product, with a calculated yield of 51.2% (based on TPEB). The CP1 that did not undergo cycloaddition reaction and the photoproduct generated by the cycloaddition reaction were purified and the NMR results were as follows: Figure 6 As shown. Figure 6 It can be seen that the NMR results after the commission are Figure 5 The results are basically consistent, indicating that the zinc-based coordination polymer undergoes cycloaddition reaction in response to light stimulation.

[0037] Based on the above experiments, the Zn-based coordination polymer {[Zn(OAc) 2 (tpeb)]·2H 2 O} n The mechanical motion behavior of (CP1) is shown in Figure 7. Figure 7 It can be seen that under 365nm ultraviolet light, CP1 bends 30° at 1s, 70° at 2s, bends into a ring at 3s, explodes at 4s, and the remaining crystal fragments vibrate at 4.5s. Under 420nm ultraviolet light, CP1 bends 12° at 2s, 20° at 3s, 40° at 5s, 70° at 8s, and bends into a hook at 11s. This shows that CP1 has faster photomechanical behavior at 365nm. Test Example 3

[0038] CP1 was ground into a uniform powder using a ball mill (about 30 min), and then 100 mg of the powder was dispersed in 5 mL of ethanol and ultrasonicated for 5 h, and then dried at 40 ° C; then 10 g of 7.7% polyvinyl alcohol (PVA) aqueous solution was mixed with the above powder and stirred for 12 h to obtain a uniform viscous liquid; then the viscous liquid was coated on a mold assembled with a clean surface and a transparent polyethylene terephthalate (PET) film and white polytetrafluoroethylene (Teflon) dried in an oven at 40 ° C for 24 h to remove the residual solvent; after the solvent was completely volatilized, it was peeled off from the mold to obtain a light yellow light-responsive film (PVA-CP1); The photoresponsive film was analyzed by X-ray powder diffraction (PXRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), bending behavior, etc. The specific results are as follows: (1) X-ray powder diffraction analysis ( Figure 8 ): By comparing the XRD patterns of the photoresponsive zinc-based coordination polymer powder and its photoresponsive film, it was found that the photoresponsive film still had characteristic diffraction peaks consistent with those of the original coordination polymer, indicating that CP1 in the photoresponsive film maintained its crystalline integrity.

[0039] (2) Scanning electron microscopy analysis Fig. 9 ): (resolution 5μm) The surface flatness of the photoresponsive film is excellent, and the microscopic morphology has no obvious fluctuations; (resolution 50μm) shows that the thickness of the photoresponsive film is 50μm, and the light stimulus responsive zinc-based coordination polymer is evenly distributed in the internal pores to form a multi-level composite structure, which significantly improves the mechanical properties of the photoresponsive film.

[0040] (3) Atomic force microscopy analysis Fig.10 ): (tapping mode, scanning range 5×5μm²) Characterization shows that the surface roughness (Ra) of the photoresponsive film is 3.30±0.15nm, indicating that it has excellent surface flatness; through nanoindentation test combined with DMT contact mechanics model (load rate of 50μN / s, maximum load of 1mN), the elastic modulus of the photoresponsive film is measured to be 1.334±0.08GPa, confirming that it has significant compressive deformation resistance.

[0041] (4) Bending behavior analysis Fig.11 ): The photoresponsive film exhibits a rapid photoinduced bending response (135° within 50s, rate 2.7° / s) under 365nm ultraviolet light irradiation, meeting the needs of cardiovascular stents for dynamic light-controlled deformation. Test Example 4

[0042] Study on the expansion of cardiovascular stents with a diameter of 8mm: The photoresponsive film was cut into a 2.6cm×5cm rectangular sample, folded in half along the long axis to form a double-layer structure; after retaining a 0.3mm uncut area on both sides of the folded edge (closed edge), 10 parallel incisions were made along the closed edge, with a single incision width of 0.3mm; after unfolding the film, an 8mm×50mm cardiovascular stent was prepared by bonding the end strips. The cardiovascular stent was fixed on a glass tube with an outer diameter of 8mm, and a 365nm LED light source (working distance of about 10cm) was used with a camera (acquisition rate of 30fps) to record the deformation process in real time. The results are shown in the figure. Fig.12 As shown. Fig.12It can be seen that under the excitation of 365nm ultraviolet light, the stent strips show the characteristic of expanding toward the light; by axially rotating the glass tube, each strip is faced to the light source in turn, and it is observed that each structural unit can complete the first expansion within 30s after irradiation; after the first light-driven expansion, the sample is left to stand in a standard environment for 240h; the secondary illumination experiment adopts a continuous dynamic rotating illumination mode, which lasts for 50min. The results show that the cardiovascular stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reaches 220% of the initial diameter.

[0043] Study on the expansion of cardiovascular stents with a diameter of 4mm: The photoresponsive film was cut into a 1.3cm×5cm rectangular sample, folded in half along the long axis to form a double-layer structure; after retaining a 0.3mm uncut area on both sides of the folded edge (closed edge), 10 parallel incisions were made along the closed edge, with a single incision width of 1.3mm; after unfolding the film, a 4mm×50mm cardiovascular stent was prepared by bonding the end strips. The cardiovascular stent was fixed on a glass tube with an outer diameter of 4mm, and a 365nm LED light source (working distance of about 10cm) was used with a camera (acquisition rate of 30fps) to record the deformation process in real time. The results are shown in the figure. Fig.13 As shown. Fig.13 It can be seen that under the excitation of 365nm ultraviolet light, the stent strips show the characteristic of expanding toward the light; by axially rotating the glass tube, each strip is faced to the light source in turn, and it is observed that each structural unit can complete the first expansion within 30s after irradiation; after the first light-driven expansion, the sample is left to stand in a standard environment for 240h; the secondary illumination experiment adopts a continuous dynamic rotating illumination mode, which lasts for 50min. The results show that the stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reaches 340% of the initial diameter.

[0044] Study on the expansion of cardiovascular stents with a diameter of 2mm: The photoresponsive film was cut into a rectangular sample of 0.7cm×4cm, and folded in half along the long axis to form a double-layer structure; after retaining a 0.3mm uncut area on both sides of the folded edge (closed edge), 10 parallel incisions were made along the closed edge, with a single incision width of 0.07mm; after unfolding the film, a 2mm×40mm cardiovascular stent was prepared by bonding the end strips. The cardiovascular stent was fixed on a glass tube with an outer diameter of 2mm, and a 365nm LED light source (working distance of about 10cm) was used with a camera (acquisition rate of 30fps) to record the deformation process in real time. The results are shown in the figure. Fig.14 As shown. Fig.14It can be seen that under the excitation of 365nm ultraviolet light, the stent strips show the characteristic of expanding toward the light; by axially rotating the glass tube, each strip is faced to the light source in turn, and it is observed that each structural unit can complete the first expansion within 30s after irradiation; after the first light-driven expansion, the sample is left to stand in a standard environment for 240h; the secondary illumination experiment adopts a continuous dynamic rotating illumination mode, which lasts for 50min. The results show that the stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reaches 480% of the initial diameter.

[0045] Study on the expansion of cardiovascular stents with a diameter of 1mm: Cut the photoresponsive film into a rectangular sample of 0.35cm×3.5cm, fold it in half along the long axis to form a double-layer structure; after retaining a 0.3mm uncut area on both sides of the folded edge (closed edge), make 5 parallel incisions along the closed edge, with a single incision width of 0.07mm; after unfolding the film, prepare a 1mm×35mm cardiovascular stent by bonding the end strips. The cardiovascular stent was fixed on a glass tube with an outer diameter of 1mm, and a 365nm LED light source (working distance of about 10cm) was used with a camera (acquisition rate of 30fps) to record the deformation process in real time. The results are shown in the figure. Fig.15 As shown. Fig.15 It can be seen that under the excitation of 365nm ultraviolet light, the stent strips show the characteristic of expanding toward the light; but the difference is that the 1mm×50mm cardiovascular stent is smaller in size, and its expansion behavior under ultraviolet light excitation is sequential and overall synchronous expansion, and the first expansion is completed within 30s after irradiation; after the first light-driven expansion, the sample is left to stand in a standard environment for 240h; the secondary illumination experiment adopts a continuous dynamic rotating illumination mode, which lasts for 50min. The results show that the stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reaches 520% ​​of the initial diameter. Test Example 5

[0046] A 1 wt % polycaprolactone chloroform solution was brushed on the surface of the photoresponsive film. After each brushing, it was placed in an oven at 40°C to dry until the solvent was completely evaporated. This process was repeated several times to ensure that a dense waterproof layer was formed on the surface of the photoresponsive film to obtain a composite film (PVA / PCL-CP1).

[0047] The X-ray powder diffraction (PXRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), bending behavior, etc. of the composite film were analyzed in air and in a blood simulation system (prepared with a 0.9% sodium chloride solution, weighed 0.9g sodium chloride, added to 100ml distilled water to prepare a uniform solution; using a Tris-HCl buffer solution, the pH was adjusted to a pH close to that of blood (7.4); the solution temperature was adjusted to 37°C). The specific results are as follows: (1) X-ray powder diffraction analysis ( Fig.16): By comparing the XRD patterns of the coordination polymer powder and the composite film, it was found that the composite film still had characteristic diffraction peaks consistent with the original coordination polymerization, indicating that CP1 in the composite film maintained its crystalline integrity.

[0048] (2) Scanning electron microscopy analysis: Scanning electron microscopy analysis before (a) and after (b) irradiation in air ( Fig.17 ): (resolution 1μm) The surface flatness of the composite film before photoreaction is excellent, and the microscopic morphology has no obvious fluctuations; (resolution 10μm) The surface of the composite film is still flat after photoreaction.

[0049] Scanning electron microscopy analysis of the blood-simulating system before (a) and after (b) irradiation. Fig.18 ): (resolution 5μm) The surface flatness of the composite film before photoreaction is excellent, and the microscopic morphology has no obvious fluctuations; (resolution 20μm) The surface of the composite film is still flat after photoreaction.

[0050] (3) Atomic force microscopy analysis: Before exposure to light in air ( Fig.19 ) and after illumination ( Fig. 20 )Atomic force microscopy analysis of the nanostructured film: AFM characterization (Ra=120nm, Ra=19.4nm) and DMT model analysis (elastic modulus is 1.339GPa, elastic modulus is 1.706GPa) show that the composite film has both high surface flatness and excellent compressive resistance, meeting the biocompatibility requirements of cardiovascular stents.

[0051] After treatment in the blood simulation system and before illumination ( Fig.21 ) and after illumination ( Fig. 22 )Atomic force microscopy analysis of the nanostructured film: AFM characterization (Ra=32.9nm, Ra=23.2) and DMT model analysis (elastic modulus is 1.339GPa, elastic modulus is 1.554GPa) show that the composite film has both high surface flatness and excellent compressive resistance, meeting the biocompatibility requirements of cardiovascular stents. Test Example 6

[0052] Study on the expansion of cardiovascular stents with a diameter of 8 mm: Same as test example 4, the results are as follows Fig.23 As shown. Fig.23It can be seen that under the excitation of 365nm ultraviolet light, the stent strips show the characteristic of expanding toward the light. By axially rotating the glass tube, each strip is facing the light source in turn, and it is observed that each structural unit can complete the first expansion within 30s after irradiation. After the first light-driven expansion, the sample was left to stand in a standard environment for 240h. The secondary illumination experiment used a continuous dynamic rotating illumination mode for 50min. The results showed that the stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reached 220% of the initial diameter.

[0053] Study on the expansion of cardiovascular stents with a diameter of 4 mm: Same as test example 4, the results are as follows Fig.24 As shown. Fig.24 It can be seen that under the excitation of 365nm ultraviolet light, the stent strips show the characteristic of expanding toward the light. By axially rotating the glass tube, each strip is facing the light source in turn, and it is observed that each structural unit can complete the first expansion within 30s after irradiation. After the first light-driven expansion, the sample was left to stand in a standard environment for 240h. The secondary illumination experiment used a continuous dynamic rotating illumination mode for 50min. The results showed that the stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reached 390% of the initial diameter.

[0054] Study on the expansion of cardiovascular stents with a diameter of 2 mm: Same as test example 4, the results are as follows Fig.25 As shown. Fig.25 It can be seen that under the excitation of 365nm ultraviolet light, the stent strips show the characteristic of expanding toward the light. By axially rotating the glass tube, each strip is facing the light source in turn, and it is observed that each structural unit can complete the first expansion within 30s after irradiation. After the first light-driven expansion, the sample was left to stand in a standard environment for 240h. The secondary illumination experiment used a continuous dynamic rotating illumination mode for 50min. The results showed that the stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reached 290% of the initial diameter.

[0055] Study on the expansion of cardiovascular stents with a diameter of 1 mm: Same as test example 4, the results are as follows Fig.26 As shown. Fig.26 It can be seen that under the excitation of 365nm ultraviolet light, the stent strips show the characteristic of expanding toward the light. However, the difference is that due to its small size, the 1mm×50mm cardiovascular stent expands sequentially and synchronously under ultraviolet light excitation, and the first expansion is completed within 30s after irradiation. After the first light-driven expansion, the sample was left to stand in a standard environment for 240h. The secondary illumination experiment used a continuous dynamic rotating illumination mode for 50min. The results showed that the stent could achieve controllable expansion again, and the cumulative radial expansion rate of the two times reached 290% of the initial diameter.

[0056] The test results of the photoresponsive film and composite film show that after adding a waterproof layer, the surface roughness and elastic modulus of the cardiovascular stent still meet clinical needs, and the expansion performance is not affected (expansion rate>95%), indicating that the photoresponsive zinc-based coordination polymer of the embodiment has excellent functionality and mechanical stability when applied to cardiovascular stents.

[0057] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A light-stimulus-responsive zinc-based coordination polymer, characterized in that: The chemical formula of the light-stimulus-responsive zinc-based coordination polymer is {[Zn(OAc)2(tpeb)]·2H2O} n , wherein OAc is acetic acid, tpeb is 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene, and n=3000-60000.

2. A method for preparing the light stimulus responsive zinc-based coordination polymer according to claim 1, characterized in that: The following steps are involved: The zinc salt and 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene are heated in a mixed solvent to react to obtain the light-stimulated responsive zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} n ; The mixed solvent comprises acetonitrile and water; Wherein, OAc is acetic acid, tpeb is 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene, and n=3000-60000.

3. The method for preparing a light-stimulus-responsive zinc-based coordination polymer according to claim 2, characterized in that: The zinc salt is selected from one or more of zinc sulfate, zinc nitrate and zinc chloride.

4. The method for preparing a light-stimulus-responsive zinc-based coordination polymer according to claim 2, characterized in that: The volume ratio of acetonitrile to water is 1:(1-4).

5. The method for preparing a light-stimulus-responsive zinc-based coordination polymer according to claim 2, characterized in that: The molar ratio of the zinc salt to 1,3,5-tri(2-(pyridin-4-yl)vinyl)benzene is (4-5):

1.

6. The method for preparing a light stimulus responsive zinc-based coordination polymer according to claim 2, characterized in that: The pH of the heating reaction is 5-6, the temperature is 100° C.-150° C., and the time is 12h-24h.

7. A photoresponsive film, characterized in that: The photoresponsive film comprises the photostimulus responsive zinc-based coordination polymer according to claim 1.

8. A method for preparing the photoresponsive film according to claim 7, characterized in that: The following steps are involved: S1. Grinding and dispersing the light stimulus responsive zinc-based coordination polymer according to claim 1 in a solvent, and drying to obtain a powder; S2: Add the powder described in S1 to the substrate, mix well and pour into a mold, and dry to obtain the photoresponsive film.

9. The method for preparing a photoresponsive film according to claim 8, characterized in that: In S2, the substrate is selected from one or more of polyvinyl alcohol, polypropylene and polyvinylidene fluoride.

10. A cardiovascular stent, characterized in that: Includes the photoresponsive film as described in claim 7.

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