A photostimulation-responsive zinc-based coordination polymer, its preparation method, and its application in cardiovascular stents

Abstract

The present invention relates to a light-stimulus-responsive zinc-based coordination polymer, a preparation method thereof, and its application in cardiovascular stents, belonging to the field of biomedicine technology. The chemical formula of the light-stimulus-responsive zinc-based coordination polymer of the present invention is {[Zn(OAc)2(tpeb)]·2H2O} n , where OAc is acetic acid, TPEB is 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene, and n=3000-60000. This light-stimuli-responsive zinc-based coordination polymer crystal undergoes a photochemical [2+2] cycloaddition reaction under ultraviolet light, accompanied by intense and rapid mechanical motion of the crystals. Cardiovascular stents fabricated from this material can rapidly expand in a specified direction under ultraviolet light and are capable of secondary light expansion, breaking the "single-use" limitation of existing stents and endowing them with the ability to dynamically adapt to vascular pathological and 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 cardiovascular stents. Background Art

[0002] Vascular stent implantation is the mainstay of treatment for coronary artery stenosis, atherosclerosis, and other diseases. While traditional metal stents (such as stainless steel and cobalt-chromium alloys) and biodegradable polymer stents (such as polyvinyl alcohol (PVA), polylactic acid (PLA), and polycaprolactone (PCL)) can restore vascular patency in the short term, they still present key challenges: The stent's diameter is fixed after implantation, making it impossible to non-invasively adjust to dynamic vascular changes (such as secondary stenosis after restenosis or developmental vascular expansion in children), necessitating a second surgical intervention. Furthermore, they have poor adaptability to complex lesions: For bifurcated lesions, long-segment stenosis, or areas with significant differences in vessel wall elasticity, static stents struggle to dynamically adapt to 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 insights into these issues. Due to their unique appeal in energy conversion due to their non-destructive, spatiotemporal controllable, highly biosafe, and contactless nature, photoresponsive materials have become a research hotspot, with great potential applications in biomedicine, soft robotics, and flexible electronics. For example, a crystalline molecular material containing olefin groups was used to achieve photomechanical motion in single crystals and single crystal composite thin films. When film strips were shaped and folded into microrobot-like models, a variety of human-like motions were observed, which may be applicable to soft microrobots (see: Wang Y, Zhang Q, Liu Q, 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; 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, existing light-driven stent technologies primarily focus on single-shot light triggering, but exhibit significant deficiencies in secondary dynamic regulation. Most photosensitive components are susceptible to photoresponsiveness degradation after prolonged retention in the body, making them difficult to support multiple light triggering. Existing photoresponsive stents lack an on-demand secondary adjustment design for vascular restenosis or developmental dilatation, making it impossible to achieve non-destructive, precisely controlled adjustment of stent diameter. Coordination polymers (CPs) are a novel class of crystalline materials self-assembled from inorganic metal ions / metal clusters and organic bridging ligands through coordination bonds. Because coordination polymers possess precisely controllable properties, excellent biocompatibility and safety, and potential degradation, coordination polymer-based stents combine light-responsive smart materials with their structural adjustability, offering safer and more adaptable solutions for the treatment of cardiovascular diseases. These solutions are particularly suitable for growing patients and complex cases requiring personalized treatment, potentially significantly reducing reoperation rates. However, metal ions in existing coordination polymers can cause inflammation in sensitive cardiovascular areas due to 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] To address the above technical problems, the present invention provides a photoresponsive zinc-based coordination polymer, its preparation method, and its application in cardiovascular stents. Crystals of this photoresponsive zinc-based coordination polymer undergo a photochemical [2+2] cycloaddition reaction under ultraviolet light, accompanied by intense and rapid mechanical motion of the crystals. Cardiovascular stents prepared from this polymer can rapidly expand in a specified direction under ultraviolet light and exhibit the ability to expand after a second exposure to light. This overcomes the "single-use" limitation of existing stents and enables cardiovascular stents to dynamically adapt to vascular pathological and physiological changes.

[0007] The first object of the present invention is to provide a light stimulus responsive zinc-based coordination polymer, wherein 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-tris(2-(pyridin-4-yl)vinyl)benzene, and n=3000-60000.

[0008] A 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:

[0009] The zinc salt and 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene are heated in a mixed solvent to react to obtain the light stimulus responsive zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} n ; The mixed solvent comprises acetonitrile and water;

[0010] Wherein, OAc is acetic acid, tpeb is 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene, and n=3000-60000.

[0011] In one embodiment of the present invention, the zinc salt is selected from one or more of zinc sulfate, zinc nitrate and zinc chloride.

[0012] In one embodiment of the present invention, the volume ratio of acetonitrile to water is 1:(1-4).

[0013] In one embodiment of the present invention, the molar ratio of the zinc salt to 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene is (4-5):1.

[0014] 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 12 h-24 h.

[0015] The third object of the present invention is to provide a photoresponsive film, which comprises the photostimulation-responsive zinc-based coordination polymer.

[0016] In one embodiment of the present invention, the thickness of the photoresponsive film is 50 μm-70 μm.

[0017] A fourth object of the present invention is to provide a method for preparing the photoresponsive film, comprising the following steps:

[0018] S1, grinding and dispersing the light stimulus responsive zinc-based coordination polymer in a solvent, and drying to obtain a powder;

[0019] S2: Add the powder described in S1 to the substrate, mix well, pour into a mold, and dry to obtain the photoresponsive film.

[0020] In one embodiment of the present invention, in S1, the solvent is selected from one or more of ethanol, acetonitrile and water.

[0021] In one embodiment of the present invention, in S1, the drying temperature is 40°C-60°C.

[0022] In one embodiment of the present invention, in S2, the substrate is selected from one or more of polyvinyl alcohol, polypropylene and polyvinylidene fluoride.

[0023] In one embodiment of the present invention, in S2, the drying temperature is 40°C-60°C.

[0024] A fifth object of the present invention is to provide a cardiovascular stent comprising the aforementioned photoresponsive film. This stent can be regulated for expansion by external illumination, avoiding the need for secondary surgery due to size mismatch or restenosis in conventional stents, significantly reducing the risk of infection and complications.

[0025] In one embodiment of the present invention, the cardiovascular stent further includes a waterproof layer disposed on the surface of the photoresponsive film.

[0026] 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.

[0027] The technical solution of the present invention has the following advantages over the prior art:

[0028] (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, generating photostress and thereby promoting 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-tris(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. By regulating the metal nodes and organic ligands, its biocompatibility is significantly improved, and it has unique potential in terms of 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.

[0029] (2) The preparation method of the present invention is simple, the reaction conditions are mild, and the photoconversion rate is fast.

[0030] (3) The cardiovascular stent described in the present invention can act on a specific part 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 accuracy is high, and the entire control process does not involve any chemical reagents, which is safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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:

[0032] Figure 1 {[Zn(OAc)2(tpeb)]·2H2O} of Example 1 of the present invention n One-dimensional stacking diagram of (CP1);

[0033] Figure 2 {[Zn(OAc)2(tpeb)]·2H2O} in Test Example 1 of the present invention n X-ray diffraction pattern of (CP1);

[0034] Figure 3 {[Zn(OAc)2(tpeb)]·2H2O} in Test Example 1 of the present invention n Thermogravimetric analysis of (CP1);

[0035] Figure 4 {[Zn(OAc)2(tpeb)]·2H2O} in Test Example 1 of the present invention n IR analysis of (CP1);

[0036] Figure 5 1H NMR spectra of CP1 without cycloaddition reaction and the photoproduct generated by cycloaddition reaction in Test Example 2 of the present invention;

[0037] Figure 6 The H NMR spectra of CP1 in Test Example 2 of the present invention that did not undergo cycloaddition reaction and the purified photoproduct generated by the cycloaddition reaction;

[0038] Figure 7 {[Zn(OAc)2(tpeb)]·2H2O} in Test Example 2 of the present invention n (CP1) Various mechanical motion behaviors of single crystal under 365nm and 420nm UV light;

[0039] Figure 8 The PXRD spectra of the front and back surfaces of the photoresponsive film in Test Example 3 of the present invention are shown;

[0040] Figure 9 SEM images of the front (a) and side (b) surfaces of the photoresponsive film in Test Example 3 of the present invention;

[0041] Figure 10 Surface roughness (a) and Young's modulus (b) of the photoresponsive film in Test Example 3 of the present invention;

[0042] Figure 11 The bending behavior of the photoresponsive film in Test Example 3 of the present invention under 365nm ultraviolet light;

[0043] Figure 12 This is the primary expansion and secondary expansion process of the 8mm cardiovascular stent in Test Example 4 of the present invention;

[0044] Figure 13 This is the primary expansion and secondary expansion process of the 4 mm cardiovascular stent in Test Example 4 of the present invention;

[0045] Figure 14 This is the primary expansion and secondary expansion process of the 2 mm cardiovascular stent in Test Example 4 of the present invention;

[0046] Figure 15 This is the primary expansion and secondary expansion process of the 1 mm cardiovascular stent in Test Example 4 of the present invention;

[0047] Figure 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;

[0048] Figure 17 SEM images of the composite film in Test Example 5 of the present invention before (a) and after (b) irradiation in air;

[0049] Figure 18 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;

[0050] Figure 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;

[0051] Figure 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;

[0052] Figure 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;

[0053] Figure 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;

[0054] Figure 23 This is the primary expansion and secondary expansion process of the 8mm cardiovascular stent in Test Example 6 of the present invention;

[0055] Figure 24 This is the primary expansion and secondary expansion process of the 4 mm cardiovascular stent in Test Example 6 of the present invention;

[0056] Figure 25 This is the primary expansion and secondary expansion process of the 2 mm cardiovascular stent in Test Example 6 of the present invention;

[0057] Figure 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

[0058] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention. Example 1

[0059] The light-stimulus-responsive zinc-based coordination polymer and the preparation method thereof of the present invention specifically comprise the following steps:

[0060] 1,3,5-Tris(2-(pyridin-4-yl)vinyl)benzene (0.06 mmol, 23.2 mg) and ZnSO4·7H2O (0.24 mmol, 86.3 mg) were added to a 15 mL thick-walled pressure bottle, and a mixed solution of 5.4 mL acetonitrile and 9 mL H2O was added. The pH of the system was adjusted to about 5 with 0.1 mol / L nitric acid. The bottle cap was tightened and ultrasonicated for 15 min. The bottle was then sealed and placed in a programmable temperature-controlled oven for reaction. The reaction was maintained at 150°C for 24 h, cooled to room temperature at a rate of 5°C / h, washed with anhydrous ethanol, and then vacuum-dried to obtain pale yellow long needle-like crystals, i.e., light stimulus-responsive zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} n (CP1)( Figure 1 ), yield 32.9 mg (80.6% based on 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene).

[0061] Test Example 1

[0062] The light-stimulated zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} of Example 1 n The elements, X-ray diffraction, thermogravimetric and infrared spectroscopy of (CP1) were analyzed, and the specific results are as follows:

[0063] (1) Elemental analysis (%): Photostimulation-responsive zinc-based coordination polymer C 31 H 31 N3O6Zn, theoretical value: (%)C, 61.39; H, 5.12; N, 6.93. Measured value: (%)C, 61.56; H, 5.22; N, 6.98.

[0064] (2) X-ray diffraction analysis ( Figure 2 ): {[Zn(OAc)2(tpeb)]·2H2O} n The experimental powder X-ray diffraction pattern of (CP1) is essentially identical to the simulated X-ray diffraction pattern from single crystal data, confirming the purity of the complex powders. Furthermore, based on single crystal X-ray diffraction measurements, crystal data for CP1 were collected on a Bruker D8-Quest diffractometer using an intensified Mo Kα (λ = 0.071073 nm) X-ray source at 150 K. The results are presented in Figure 2. The results are presented in Figure 2. The results are presented in Figure 2. The results are presented in Figure 2. nThe diffraction data and unit cell parameters of (CP1) were obtained using the CrysAlisPro program (Agilent Technologies, Version 1.171.36.32, 2013). All diffraction data were obtained using Lp factor correction and multi-scan absorption correction; {[Zn(OAc)2(tpeb)]·2H2O} n The crystal structure of (CP1) was solved by direct method using the OLEX2 program and refined by least-squares matrix fit. All non-hydrogen atoms were anisotropically corrected, and all hydrogen atoms were theoretically hydrogenated according to reasonable geometric positions. {[Zn(OAc)2(tpeb)]·2H2O} n The main crystallographic parameters and structure refinement parameters of (CP1) are shown in Table 1:

[0065] Table 1

[0066]

[0067] in: a R 1=Σ|| F o |-| F c || / Σ| F o |;

[0068] b wxya 2={Σ w ( F o 2 - F c 2 ) 2 / Σ w ( F o 2 ) 2} 1 / 2 ;

[0069] 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.

[0070] As can be seen from Table 1, Example 1 successfully obtained a light-stimulated responsive zinc-based coordination polymer, namely {[Zn(OAc)2(tpeb)]·2H2O} n (CP1).

[0071] (3) Thermogravimetric analysis Figure 3 ):The complex has good thermal stability under N2 atmosphere, with no weight loss below 300℃, after which thermal decomposition occurs.

[0072] (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 .

[0073] Test Example 2

[0074] The light-stimulated zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} of Example 1 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 the crystal structure after illumination, but the diffraction points of the crystal after illumination gradually weakened and disappeared as the illumination time increased. Therefore, 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, d6-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 HNMR spectrum shows the appearance of cyclobutane peaks (in the range of 3.4ppm to 4.2ppm) and the migration of pyridine peaks (8.9ppm to 9.1ppm and 8.2ppm to 8.3ppm), thus indicating that the photostimulation-responsive zinc-based coordination polymer undergoes a cycloaddition reaction.

[0075] In order to further determine the true reaction degree of the photostimulation-responsive zinc-based coordination polymer, an experimental operation was carried out to separate and purify the CP1 after illumination. 0.5 g of CP1 powder was placed under a 365 nm high-pressure mercury lamp and irradiated for 48 hours. Then the photoproduct and the tpeb monomer that did not undergo 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 HNO3 solution (20 mL) and stirred for 24 hours to decompose the complex structure. The precipitate was then filtered and washed three times with chloroform, and then the precipitate was vacuum dried for 24 hours to obtain a dark yellow solid product as the organic product of the photoreaction, with a calculated yield of 51.2% (based on tpeb). The nuclear magnetic resonance results of the purified CP1 that did not undergo cycloaddition reaction and the photoproduct generated by the cycloaddition reaction are as follows Figure 6 As shown. Figure 6 It can be seen that the NMR results after the extraction are similar to Figure 5 The results are basically consistent, indicating that the photostimulation-responsive zinc-based coordination polymer undergoes a cycloaddition reaction.

[0076] Based on the above experiments, the Zn-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} was investigated under 365nm and 420nm UV light. n The mechanical motion behavior of (CP1) is shown in Figure 7. Figure 7 As can be seen, under 365nm UV light, CP1 bends 30° at 1s, 70° at 2s, forms a ring at 3s, explodes at 4s, and the remaining crystal fragments vibrate at 4.5s. Under 420nm UV light, CP1 bends 12° at 2s, 20° at 3s, 40° at 5s, 70° at 8s, and forms a hook at 11s, indicating that CP1 exhibits faster photomechanical behavior at 365nm.

[0077] Test Example 3

[0078] CP1 was ground into a uniform powder using a ball mill (approximately 30 min). 100 mg of the powder was then dispersed in 5 mL of ethanol, ultrasonicated for 5 h, and dried at 40°C. 10 g of a 7.7% polyvinyl alcohol (PVA) aqueous solution was then mixed with the powder and stirred for 12 h to obtain a uniform viscous solution. The viscous solution was then applied to a mold composed of a clean, nitrogen-dried transparent polyethylene terephthalate (PET) film and white polytetrafluoroethylene (Teflon). The film was then dried in a 40°C oven for 24 h to remove any residual solvent. After the solvent had completely evaporated, the film was peeled off from the mold to obtain a light yellow photoresponsive film (PVA-CP1).

[0079] The photoresponsive film was analyzed by X-ray powder diffraction (PXRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and bending behavior. The specific results are as follows:

[0080] (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 the CP1 in the photoresponsive film maintained its crystalline integrity.

[0081] (2) Scanning electron microscopy analysis Figure 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, forming a multi-level composite structure, which significantly improves the mechanical properties of the photoresponsive film.

[0082] (3) Atomic force microscopy analysis Figure 10 ): (tapping mode, scanning range 5×5μm²) Characterization showed that the surface roughness (Ra) of the photoresponsive film was 3.30±0.15nm, indicating that it has excellent surface flatness; through nanoindentation testing combined with the DMT contact mechanics model (load rate of 50μN / s, maximum load of 1mN), the elastic modulus of the photoresponsive film was measured to be 1.334±0.08GPa, confirming that it has significant compressive deformation resistance.

[0083] (4) Bending behavior analysis Figure 11 ): The photoresponsive film exhibits rapid photoinduced bending response under 365nm ultraviolet light irradiation (135° within 50s, rate 2.7° / s), meeting the requirements of cardiovascular stents for dynamic light-controlled deformation.

[0084] Test Example 4

[0085] Study on the expansion of cardiovascular stents with a diameter of 8mm: The photoresponsive film was cut into a 2.6cm×5cm rectangular sample 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 0.3mm; 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 as follows: Figure 12 As shown. Figure 12 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 cardiovascular stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reaches 220% of the initial diameter.

[0086] 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 as follows Figure 13 As shown. Figure 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 to make each strip face the light source in turn, it was 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 adopted a continuous dynamic rotating illumination mode, which lasted for 50min. The results showed that the stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reached 340% of the initial diameter.

[0087] 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, 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 as follows Figure 14 As shown. Figure 14 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 to make each strip face the light source in turn, it was 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 adopted a continuous dynamic rotating illumination mode, which lasted for 50min. The results showed that the stent can achieve controllable expansion again, and the cumulative radial expansion rate of the two times reached 480% of the initial diameter.

[0088] Study on the expansion of cardiovascular stents with a diameter of 1mm: The photoresponsive film was cut into rectangular specimens of 0.35cm×3.5cm, 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), 5 parallel incisions were made along the closed edge, with a single incision width of 0.07mm; after unfolding the film, a 1mm×35mm cardiovascular stent was prepared 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 as follows: Figure 15 As shown. Figure 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.

[0089] Test Example 5

[0090] A 1 wt% polycaprolactone solution in chloroform was brushed on the surface of the photoresponsive film. After each application, the film was dried in an oven at 40°C 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).

[0091] The composite film was analyzed by X-ray powder diffraction (PXRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and bending behavior in air and in a blood simulation system (prepared with a 0.9% sodium chloride solution by weighing 0.9 g of sodium chloride and adding it to 100 ml of distilled water to form a uniform solution; using a Tris-HCl buffer solution, the pH was adjusted to a value close to the pH of blood (7.4); and the solution temperature was adjusted to 37°C). The specific results are as follows:

[0092] (1) X-ray powder diffraction analysis ( Figure 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.

[0093] (2) Scanning electron microscopy analysis:

[0094] Scanning electron microscopy analysis before (a) and after (b) irradiation in air ( Figure 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 remains flat after photoreaction.

[0095] Scanning electron microscopy analysis of the blood-simulating system before (a) and after (b) illumination. Figure 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 remains flat after photoreaction.

[0096] (3) Atomic force microscopy analysis:

[0097] Before exposure to light in air ( Figure 19 ) and after illumination ( Figure 20 ) Atomic force microscopy analysis of the composite 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.

[0098] After treatment in the blood simulation system and before illumination ( Figure 21 ) and after illumination ( Figure 22 ) Atomic force microscopy analysis: 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.

[0099] Test Example 6

[0100] Study on the expansion of cardiovascular stent with a diameter of 8mm: Same as test example 4, the results are as follows Figure 23 As shown. Figure 23 It can be seen that under 365nm ultraviolet light excitation, the stent strips exhibit the characteristic of expanding toward the light. By axially rotating the glass tube to make each strip face the light source in turn, it was observed that each structural unit was able to complete the first expansion within 30 seconds after irradiation. After the first light-driven expansion, the sample was left to stand in a standard environment for 240 hours. The secondary illumination experiment used a continuous dynamic rotation illumination mode for 50 minutes. The results showed that the stent could achieve controllable expansion again, and the cumulative radial expansion rate of the two times reached 220% of the initial diameter.

[0101] Study on the expansion of a 4mm diameter cardiovascular stent: Same as test example 4, the results are as follows Figure 24 As shown. Figure 24 It can be seen that under 365nm ultraviolet light excitation, the stent strips exhibit the characteristic of expanding toward the light. By axially rotating the glass tube to make each strip face the light source in turn, it was observed that each structural unit was able to complete the first expansion within 30 seconds after irradiation. After the first light-driven expansion, the sample was left to stand in a standard environment for 240 hours. The secondary illumination experiment used a continuous dynamic rotation illumination mode for 50 minutes. The results showed that the stent could achieve controllable expansion again, and the cumulative radial expansion rate of the two times reached 390% of the initial diameter.

[0102] Study on the expansion of cardiovascular stent with a diameter of 2mm: Same as test example 4, the results are as follows Figure 25 As shown. Figure 25 It can be seen that under 365nm ultraviolet light excitation, the stent strips exhibit the characteristic of expanding toward the light. By axially rotating the glass tube to make each strip face the light source in turn, it was observed that each structural unit was able to complete the first expansion within 30 seconds after irradiation. After the first light-driven expansion, the sample was left to stand in a standard environment for 240 hours. The secondary illumination experiment used a continuous dynamic rotation illumination mode for 50 minutes. 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.

[0103] Study on the expansion of cardiovascular stent with a diameter of 1mm: Same as test example 4, the results are as follows Figure 26 As shown. Figure 26It can be seen that under 365nm ultraviolet light excitation, the stent strips exhibit the characteristic of light-directed expansion. However, due to its smaller size, the 1mm×50mm cardiovascular stent's expansion behavior under ultraviolet light excitation is characterized by sequential and overall synchronous expansion, with the first expansion completed within 30 seconds after irradiation. After the initial light-driven expansion, the sample was left to stand in a standard environment for 240 hours. A secondary illumination experiment using a continuous dynamic rotation illumination mode lasting 50 minutes showed that the stent could once again achieve controllable expansion, with the cumulative radial expansion rate reaching 290% of the initial diameter.

[0104] The test results of the photoresponsive film and composite film show that after adding the waterproof layer, the surface roughness and elastic modulus of the cardiovascular stent still meet clinical requirements, and the expansion performance is not affected (expansion rate >95%), indicating that the photostimulation-responsive zinc-based coordination polymer of the embodiment has excellent functionality and mechanical stability when applied to cardiovascular stents.

[0105] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present 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-tris(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-tris(2-(pyridin-4-yl)vinyl)benzene are heated in a mixed solvent to react to obtain the light stimulus 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-tris(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, wherein: 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, wherein: The volume ratio of the acetonitrile to water is 1:(1-4).

5. The method for preparing a light-stimulus-responsive zinc-based coordination polymer according to claim 2, wherein: The molar ratio of the zinc salt to 1,3,5-tris(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, wherein: The pH of the heating reaction is 5-6, the temperature is 100° C.-150° C., and the time is 12 h-24 h.

7. A photoresponsive film, characterized in that The photoresponsive film comprises the photostimulation-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, pour into a mold, and dry to obtain the photoresponsive film.

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

10. A cardiovascular stent, characterized in that: Comprising the photoresponsive film according to claim 7.

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