Vascularization promoting coating and application thereof in drainage tube

Abstract

The invention belongs to the technical field of chemical material engineering, and particularly relates to a vascularization promoting coating and application thereof in a drainage tube. And the vascularization promoting coating comprises linoleic acid and leukotriene D4. The main body material of the drainage tube is PPDO and barium sulfate, and the drainage tube is coated with a PAA hydrogel coating loaded with linoleic acid and leukotriene D4. The PAA hydrogel coating has a pH response mechanism, can intelligently release linoleic acid and leukotriene D4 according to the change of a tissue recovery environment after a pancreatic cancer operation, and promotes vascularization. The biodegradability of the PPDO material reduces the necessity that a patient takes out the drainage tube after a second operation, barium sulfate is used as a developing agent, the degradation condition of the drainage tube can be observed in real time, and the safety and effectiveness of the operation are improved.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials engineering technology, specifically relating to a vascularizing coating and its application in drainage tubes. Background Technology

[0002] A drainage tube is a medical device used in clinical surgery to drain pus, blood, and fluid accumulated between body tissues or in body cavities, preventing postoperative infection and promoting wound healing. Many types of surgical drainage tubes are used clinically; some are used for urinary catheterization, others for wounds, and they are used in the thoracic cavity, brain cavity, gastrointestinal tract, and biliary tract, among others. The purpose of surgical drainage is to drain pus, blood, and fluid accumulated between body tissues or in body cavities to prevent postoperative infection and to avoid hindering wound healing.

[0003] In cancer surgeries, such as pancreatic cancer surgery, drainage tubes are often made of fixation materials, including silicone (Chinese patent CN102345678B) and polyethylene. These traditional materials lack the ability to respond to changes in the postoperative tissue recovery environment, and most require a second surgery for removal, increasing patient suffering and financial burden.

[0004] Existing drainage tubes have several major drawbacks in the postoperative tissue recovery process:

[0005] 1. Lack of environmental responsiveness: Traditional drainage tubes do not have the ability to respond to changes in the postoperative tissue recovery environment (such as pH changes), and cannot intelligently release linoleic acid and leukotrienes D4 according to the specific needs during the recovery process.

[0006] 2. Non-degradability: Most drainage tube materials are non-degradable, which means that patients usually need to undergo a second surgery to remove the drainage tube after the initial procedure, increasing the patient's pain and financial burden.

[0007] 3. Lack of real-time monitoring: Traditional drainage tubes lack effective contrast agents, making it impossible for doctors to observe the position and degradation of the drainage tube in real time. This is a significant limiting factor for postoperative management and patient recovery. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a provascular coating that can act on the TLR4 / NF-κB signaling pathway by loading linoleic acid and leukotriene D4, activate its receptor CysLT1R, enhance the function of endothelial cells, and promote their proliferation, migration and formation of new vascular structures.

[0010] Accordingly, the present invention also provides the application of a vascularizing coating in a drainage tube.

[0011] (II) Technical Solution To achieve the above objectives, the main technical solutions adopted by this invention include:

[0012] In a first aspect, the present invention provides a provascular coating comprising linoleic acid and leukotriene D4.

[0013] In this invention, angiotensin-promoting linoleic acid and leukotriene D4 work together to act on the TLR4 / NF-κB signaling pathway, activate its receptor CysLT1R, enhance the function of endothelial cells, and promote their proliferation, migration and formation of new vascular structures. In particular, linoleic acid and leukotriene D4 have a synergistic effect on the formation of new vascular structures.

[0014] Abnormalities in tumor microvascular structure and function: Abnormal structure and function of tumor microvessels can weaken the efficacy of radiotherapy and chemotherapy, affecting treatment outcomes. The coating of this invention promotes vascularization, helping to reshape the tumor microenvironment, allowing the tumor vascular structure and function to normalize within a specific timeframe, thereby improving the efficacy of anti-tumor treatment and inhibiting tumor metastasis.

[0015] Optionally, the weight ratio of linoleic acid and leukotriene D4 is 8 to 12:1.

[0016] Optionally, it also includes: polyacrylic acid.

[0017] This solution further incorporates polyacrylic acid (PAA) into the provascular coating, enabling a pH-responsive release mechanism: In the early stages of wound inflammation, the environment is acidic (low pH). The carboxyl groups of PAA protonate to form carboxylic acid (-COOH), reducing the electrostatic repulsion between polymer chains and making the polymer structure more compact. This reduces water molecule absorption and results in lower swelling. In the later stages of tissue recovery, the pH returns to neutral. Therefore, in neutral or alkaline environments (high pH), the carboxyl groups deprotonate to form carboxylate ions (-COO), increasing the electrostatic repulsion between polymer chains. This leads to polymer structure expansion, increasing water molecule absorption and resulting in greater swelling, thereby releasing linoleic acid and leukotrienes D4.

[0018] Following pancreatic cancer surgery, drainage tubes are prone to infection and complications. This invention incorporates a coating on the drainage tube that intelligently releases linoleic acid and leukotriene D4, promoting vascularization and helping to reduce the risk of infection and complications.

[0019] Alternatively, the coating is prepared from polyacrylic acid in the form of a polyacrylic acid hydrogel.

[0020] Optionally, the mass ratio of linoleic acid, leukotrienes D4, and polyacrylic acid hydrogel in the coating is 8–12:1:90–120.

[0021] Optionally, linoleic acid and leukotrienes D4 are added to the polyacrylic acid hydrogel, and the coating is obtained after curing.

[0022] In this scheme, linoleic acid and leukotriene D4 are added to the polyacrylic acid hydrogel, which can achieve pH-responsive release of linoleic acid and leukotriene D4. In the middle and late stages of tissue recovery, the pH returns to neutral, and the release of linoleic acid and leukotriene D4 promotes angiogenesis, which can increase the concentration of chemotherapy drugs in the tumor site, thereby enhancing the treatment effect.

[0023] Secondly, the present invention also provides the application of the angiogenic coating described in any of the above embodiments in a drainage tube.

[0024] Optionally, the drainage tube is a PPDO drainage tube.

[0025] Existing drainage tubes are mostly made of non-degradable materials, requiring a second surgery for removal, increasing patient suffering and financial burden. The PPDO material of this invention is biodegradable, avoiding the need for a second surgery. Existing biodegradable pancreatic duct stents are mostly metal components, which are too rigid and easily cause patient discomfort. This invention uses PPDO material, which has better biocompatibility and flexibility, reducing patient discomfort.

[0026] Optionally, it includes the following steps: immersing the drainage tube in a coating solution, removing it after soaking, and drying it to form a coating on the drainage tube.

[0027] Optionally, the steps of soaking and drying can be repeated once or more to form a coating.

[0028] Optionally, the method for preparing the drainage tube includes the following steps: mixing dried PPDO particles with barium sulfate and then extruding the mixture into an extruder to form a drainage tube, wherein the temperature of different sections in the extruder is set between 180°C and 195°C.

[0029] In this invention, the main body of the drainage tube is made of PPDO and barium sulfate, coated with a PAA hydrogel layer loaded with linoleic acid and leukotriene D4. The PAA hydrogel coating has a pH-responsive mechanism, intelligently releasing linoleic acid and leukotriene D4 according to changes in the tissue recovery environment after pancreatic cancer surgery, promoting vascularization. The biodegradability of PPDO reduces the need for a second surgery to remove the drainage tube, while barium sulfate, as a contrast agent, allows for real-time monitoring of the drainage tube's degradation, improving the safety and effectiveness of the surgery.

[0030] (III) Beneficial Effects

[0031] The beneficial effects of this invention are:

[0032] The present invention provides an improved angiogenesis-promoting coating that, through the combined action of linoleic acid and leukotriene D4, acts on the TLR4 / NF-κB signaling pathway, activates its receptor CysLT1R, enhances the function of endothelial cells, and promotes their proliferation, migration, and formation of new vascular structures.

[0033] Among these applications, the pro-angiogenic coating, used in medical materials placed inside the body such as drainage tubes, can increase the concentration of chemotherapy drugs at the tumor site by promoting vascularization, thereby enhancing the therapeutic effect. It also helps to reshape the tumor microenvironment, allowing the tumor's vascular structure and function to normalize within a specific time window, thus improving the effectiveness of anti-tumor treatment and inhibiting tumor metastasis. After pancreatic cancer surgery, the intelligent release of linoleic acid and leukotriene D4, along with the promotion of vascularization, helps reduce the risk of infection and complications. Attached Figure Description

[0034] Figure 1 The Fourier transform infrared spectroscopy test results are shown in the embodiments and comparative examples of the present invention. Figure 2 The following are the proton NMR spectra of the embodiments and comparative examples of the present invention; Figure 3 This is a graph showing the pH response release experiment results of Example 2 of the present invention; Figure 4 The figures show the in vitro degradation experiment results of the embodiments and comparative examples of the present invention; Figure 5 The mechanical test results are shown in the diagrams for the coated PPDO drainage tube and the uncoated PPDO drainage tube from Example 2. Figure 6 This is a diagram showing the results of a cell experiment. Figure 7 Pipe forming capacity analysis results diagram; Figure 8 This is a graph showing the analysis results of pipe forming capacity (number of branch points); Figure 9 The graph shows the relative expression levels of TLR4 in HUVECs treated with different coatings. Figure 10 Figure showing the relative expression levels of NF-κB in HUVECs treated with each coating group; Figure 11 The results show the relative expression levels of CysLT1R in HUVECs treated with different coatings. Detailed Implementation

[0040] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description is provided in conjunction with the specific embodiments listed. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended only as examples, not as limiting the scope of protection of this application.

[0041] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0042] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0043] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0044] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0045] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0046] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0047] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0048] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0049] Example 1

[0050] This embodiment provides a vascularization-promoting coating and its preparation method, the steps of which are as follows:

[0051] S1 dissolves linoleic acid in ethanol to prepare a 10 mg / mL solution;

[0052] S2 dissolved leukotriene D4 in dimethyl sulfoxide (DMSO) to prepare a 1 mg / mL solution;

[0053] S3 mixes the two solutions in a 1:1 ratio to prepare a coating solution.

[0054] Example 2

[0055] This embodiment provides a pro-angiogenic coating and its preparation method, which adds PAA hydrogel to the coating solution compared to Example 1. The steps are as follows:

[0056] S1. Synthesis of PAA hydrogel: Dissolve 10 g of PAA in 100 mL of deionized water and stir with a magnetic stirrer at room temperature until completely dissolved. Adjust the pH to 7.4 and monitor the pH value with a pH meter to obtain PAA hydrogel.

[0057] S2 dissolves linoleic acid in ethanol to prepare a 10 mg / mL linoleic acid solution;

[0058] S3 dissolved leukotriene D4 in dimethyl sulfoxide (DMSO) to prepare a 1 mg / mL leukotriene D4 solution;

[0059] S4 mixes linoleic acid solution and leukotriene D4 solution in a 1:1 ratio and adds them to PAA hydrogel, so that the final concentrations of linoleic acid and leukotriene D4 are 5 mg / mL and 0.5 mg / mL, respectively, to prepare the coating solution.

[0060] S5 coating curing: Immerse the drainage tube in the coating solution, remove it after soaking, and allow it to air dry at room temperature;

[0061] Repeat the dip-coating and drying process three times to ensure uniform coating coverage;

[0062] Finally, the coating is dried at 60°C for 2 hours to enhance its adhesion and stability.

[0063] In some other specific embodiments, the coating solution is prepared in a weight ratio of 12:1:90, with the final concentrations of linoleic acid and leukotriene D4 being 6 mg / mL and 0.5 mg / mL, respectively, to obtain the coating solution.

[0064] In some other specific embodiments, the coating solution is prepared by mixing linoleic acid, leukotriene D4 and PAA hydrogel in a weight ratio of 8:1:120, so that the final concentrations of linoleic acid and leukotriene D4 are 4 mg / mL and 0.5 mg / mL, respectively, to obtain the coating solution.

[0065] Example 3

[0066] This embodiment provides a method for preparing the drainage tube described in Embodiment 1 or 2, the steps of which are as follows:

[0067] S1 Drying and Dehumidification: PPDO particles (weight-average molecular weight 100,000 g / mol to 200,000 g / mol, molecular weight distribution index less than 2, biomedical grade) are dried in hot air at 60°C for 4 hours;

[0068] S2 mixes dried PPDO granules with 0.003 W / W barium sulfate and pours the mixture into an extruder to extrude and obtain a drainage tube;

[0069] The extruder used is a single screw extruder with a screw diameter of 25.4 mm and a length-to-diameter ratio of 25:1; the temperature of different sections is set between 180℃ and 195℃.

[0070] Among them, the extrusion speed (screw speed) is 4-11 rpm; the traction speed is 5.3-9.3 m / min; and the air pressure is 0.19-1.96 kPa.

[0071] In this embodiment of the invention, the materials and equipment used are specifically as follows:

[0072] Magnetic stirrer (model: Heidolph RZR 2041);

[0073] pH meter (model: Mettler Toledo SevenMulti);

[0074] Ultraviolet-Vis spectrophotometer (Model: Thermo Scientific GENESYS10S);

[0075] High-performance liquid chromatograph (HPLC, model: Waters e2695);

[0076] Linoleic acid (purity ≥99%, Sigma-Aldrich);

[0077] Leukotrienes D4 (purity ≥98%, Cayman Chemical);

[0078] Polyacrylic acid (PAA, molecular weight: 100,000-200,000, Sigma-Aldrich);

[0079] Barium sulfate (BaSO4, purity ≥99%, Sigma-Aldrich);

[0080] Extruder brand and model: Davis-Standard, USA; screw diameter: 25.4 mm; length-to-diameter ratio (L / D = 25:1); screw type: barrier screw with Maddock mixer.

[0081] In this embodiment of the invention, the angiogenic coating attached to the drainage tube contains linoleic acid and leukotriene D4, which can work together to act on the TLR4 / NF-κB signaling pathway, activate its receptor CysLT1R, enhance the function of endothelial cells, and promote their proliferation, migration and formation of new vascular structures. In particular, linoleic acid and leukotriene D4 have a synergistic effect on the formation of new vascular structures.

[0082] In this embodiment of the invention, polyacrylic acid (PAA) undergoes a process where, during the mid-to-late stages of tissue recovery, the pH returns to neutral, increasing water molecule absorption and exhibiting significant swelling, thereby releasing linoleic acid and leukotriene D4. The release of linoleic acid and leukotriene D4 promotes angiogenesis, which can increase the concentration of chemotherapy drugs at the tumor site, thus significantly enhancing the therapeutic effect.

[0083] Experimental methods

[0084] The coating solution prepared in Example 2: The concentrations of linoleic acid and leukotriene D4 in the coating solution were 5 mg / mL and 0.5 mg / mL, respectively, and the mass ratio of leukotriene D4 and polyacrylic acid hydrogel in the coating solution was 1:100.

[0085] Comparative Example 1

[0086] The hydrogel provided in this comparative example is prepared by dissolving 10 grams of PAA in 100 ml of deionized water, stirring with a magnetic stirrer at room temperature until completely dissolved, adjusting the pH to 7.4, monitoring the pH value with a pH meter, and obtaining the PAA hydrogel.

[0087] Comparative Example 2

[0088] The coating solution provided in this comparative example differs from Comparative Example 1 in that it incorporates linoleic acid (PA), and the steps are as follows:

[0089] S1 dissolves 10 grams of PAA in 100 ml of deionized water.

[0090] In water, use a magnetic stirrer to stir at room temperature until completely dissolved, adjust the pH to 7.4, monitor the pH value using a pH meter, and obtain PAA hydrogel.

[0091] S2 dissolves linoleic acid in ethanol to prepare a 10 mg / mL linoleic acid solution;

[0092] S3 added linoleic acid solution to PAA hydrogel to obtain coating solution with a final linoleic acid concentration of 5 mg / mL.

[0093] Comparative Example 3

[0094] The coating solution provided in this comparative example differs from Comparative Example 1 in that it incorporates leukotriene D4, and the steps are as follows:

[0095] Synthesis of S1 PAA hydrogel: Dissolve 10 g of PAA in 100 ml of deionized water and stir magnetically.

[0096] Stir at room temperature until completely dissolved, adjust pH to 7.4, monitor pH value using a pH meter, and obtain PAA hydrogel;

[0097] S2 dissolved leukotriene D4 in dimethyl sulfoxide (DMSO) to prepare a 1 mg / mL leukotriene D4 solution;

[0098] S3 added a leukotriene D4 solution to the PAA hydrogel to obtain a final leukotriene D4 concentration of 0.5 mg / mL, thus preparing the coating solution.

[0099] Comparative Example 4: Pure leukotrienes D4 (LTD4);

[0100] Comparative Example 5: Pure linoleic acid (LA);

[0101] Comparative Example 6: Distilled water.

[0102] 1. Fourier transform infrared spectroscopy test

[0103] 1.1. Sample Preparation

[0104] Drying treatment: PAA hydrogel (Comparative Example 1), PAA-linoleic acid composite hydrogel (coating solution prepared in Comparative Example 2), and PAA-linoleic acid-LTD4 composite hydrogel (coating solution prepared in Example 2) were placed in a freeze dryer (SCIENTZ-10N / C (manifold type, cold trap temperature -85℃)) and freeze-dried at -50℃ for 48 hours to remove moisture and avoid water peak interference.

[0105] Sample preparation method: The freeze-dried sample was ground into powder and mixed with potassium bromide (KBr, Sinopharm Group (GB / T 649-2023, moisture ≤0.3%)) at a ratio of 1:200, and then pressed into transparent sheets.

[0106] 1.2. Test Procedure

[0107] Instrument parameter settings: Infrared spectrometer (Thermo Fisher Nicolet 6700), scanning range 4000-500 cm⁻¹; resolution set to 4 cm⁻¹; 32 scans, signal-to-noise ratio improved by signal accumulation. Background correction: Blank KBr or air background spectra were collected under the same conditions to subtract environmental interference.

[0108] Sample scanning: Place the prepared sample in the sample chamber, start the scanning program, record the interferogram, and perform a Fast Fourier Transform (FFT) to generate an infrared absorption spectrum. At least three parallel samples should be tested for each group to ensure data repeatability.

[0109] Experimental results are as follows Figure 1 As shown, Figure 1 A shows the Fourier transform infrared spectroscopy results of Comparative Example 1.

[0110] Figure 1 B is the Fourier transform infrared spectrum test result of Comparative Example 2;

[0111] Figure 1 C is the Fourier transform infrared spectroscopy test result of Example 2;

[0112] The original PAA hydrogel in Comparative Example 1 ( Figure 1 A) Characteristic absorption peak (3204 cm⁻¹) -1 OH stretching vibration, 1710 cm-1 The C=O stretching vibration of carboxylic acid and 1266 cm -1 The CO vibration confirmed a polymer network dominated by hydrogen-bonded carboxylic acid groups, with residual COO - Peak (1558cm) -1 The faint signal indicates a high degree of protonation.

[0113] In the coating solution of Example 2, infrared spectroscopy analysis of the polyacrylic acid (PAA)-based hydrogel functionalized with linoleic acid (LA) and leukotrienes (D4, LTD4) revealed the evolution of its structural interactions and chemical modifications.

[0114] Comparative Example 1: Original PAA hydrogel ( Figure 1 A) Characteristic absorption peak (3204 cm⁻¹) -1 OH stretching vibration, 1710 cm -1 The C=O stretching vibration of carboxylic acid and 1266 cm -1 The CO vibration confirmed a polymer network dominated by hydrogen-bonded carboxylic acid groups, with residual COO - Peak (1558cm) -1 The signal is weak, indicating a high degree of protonation. The coating solution of Comparative Example 2, after being introduced into LA (…), shows… Figure 1 B) The spectral changes indicate the presence of physical mixing and potential esterification reactions:

[0115] 1712cm -1 The newly appearing C=O peak (medium intensity) of the ester group and the decreased intensity of the OH stretching vibration peak suggest partial ester bond formation. The characteristic peak of LA (1672 cm⁻¹) is also present. -1 C=C stretching vibration, 2898cm -1 alkyl chain CH stretching vibration and 978 cm -1 The trans-CH bending vibration further confirms the successful introduction of the unsaturated fatty acid structure.

[0116] Example 2 is based on Comparative Example 2, with the addition of LTD4 ( Figure 1 C) Spectral complexity increases significantly: 648 cm⁻¹ -1 The weak CSC vibration peak at 1664 cm⁻¹ -1 The enhanced C=C absorption peak at 1264 cm⁻¹ reflects the conjugated diene and sulfur-containing group of LTD₄. -1 The COC vibration peak of the epoxy group at LTD4 overlaps with the CO peak of PAA, suggesting that the epoxy group of LTD4 may form a hydroxyl group with the carboxylic acid of PAA through a ring-opening reaction (3188 cm⁻¹). -1 (The OH peak at 2895 cm⁻¹ broadened). -1 Enhancement of CH stretching vibration in alkyl chains and 1286 cm⁻¹ -1The change in the regional peak shape reflects the synergistic contribution of the multi-component functional groups of PAA, LA and LTD4.

[0117] 2. Hydrogen nuclear magnetic resonance (¹H NMR) spectroscopy

[0118] 2.1. Sample Preparation

[0119] Drying treatment: PAA hydrogel (Comparative Example 1), PAA-linoleic acid composite hydrogel (coating solution prepared in Comparative Example 2), and PAA-linoleic acid-LTD4 composite hydrogel (coating solution prepared in Example 2) were placed in a freeze dryer (SCIENTZ-10N / C (manifold type, cold trap temperature -85℃)) and freeze-dried at -50℃ for 48 hours to remove moisture and avoid water peak interference.

[0120] Solvent selection: Deuterated DMSO (DMSO-d6) (Sigma-Aldrich, 99.9%).

[0121] Sample concentration: 5-10 mg / mL. After dissolving in solvent, sonicate for 10 minutes to ensure uniformity.

[0122] 2.2. Instrument Parameters

[0123] Instrument model: Bruker Avance III 400MHz nuclear magnetic resonance spectrometer.

[0124] Scanning parameters: single pulse sequence (zg30), spectral width 20ppm, 64 scans, relaxation delay 1 second, temperature 25℃.

[0125] Quantitative analysis: The proportion of each block was calculated by integrating the peak area.

[0126] Experimental results are as follows Figure 2 As shown: Figure 2 middle, Figure 2 A is the proton NMR spectrum of Comparative Example 1;

[0127] Figure 2 B is the proton NMR spectrum of Comparative Example 2; Figure 2 C is the proton NMR spectrum of Example 2;

[0128] The characteristic signal of the pure PAA hydrogel in Comparative Example 1 is a broad and strong carboxylic acid proton peak (-COOH) at δ 12.0 ppm and multiple peaks of the main chain methylene group in the range of δ 1.2–2.5 ppm. Figure 2 A). After introducing linoleic acid (LA) into the coating solution of Comparative Example 2, the newly appearing sharp singlet at δ5.3 ppm is attributed to the trans proton (=CH-) adjacent to the LA double bond, while the enhanced broad peak at δ1.3 ppm is related to the proton resonance of the long-chain alkyl group of LA. Figure 2B); Furthermore, the appearance of a weak peak at δ3.7 ppm suggests a possible esterification reaction between PAA carboxylic acid and LA hydroxyl group, leading to the formation of a partial ester bond (-COOCH2-). Example 2 further complexed the leukotriene D4 (LTD4), significantly increasing spectral complexity: the absorption peak of the conjugated double bond proton at δ6.0 ppm is consistent with the eicosatetraenoic acid skeleton of LTD4; the broadened signal near δ4.0 ppm can be attributed to the resonance of the proton adjacent to its epoxy group (COC); and the formation of the weak peak at δ1.8 ppm is related to the methyl group (-CH3) adjacent to the thioether bond (CSC). Notably, the epoxy proton peak of LTD4 (δ3.5–4.5 ppm) coincides with the CO vibration region of the PAA main chain (δ...

[0129] The partial overlap of 3.7 ppm may reflect the formation of ether bonds (-COC-) or hydroxyl groups (-OH) initiated by the ring-opening reaction of epoxy groups. Figure 2 C).

[0130] 3. pH-responsive release experiment

[0131] 3.1. Reagent and Sample Preparation

[0132] Linoleic acid (Sigma-Aldrich, purity ≥99%) and leukotrienes D4 (Cayman Chemical, purity ≥98%) were used. The coating solution prepared in Example 2 was applied to a PPDO film (10×10 mm2), and the thickness was controlled at 0.5±0.05 mm after curing.

[0133] 3.2. Release medium

[0134] Buffer solution preparation:

[0135] pH 5.0: Use citrate-sodium citrate buffer, dissolve 2.10g of citrate and 2.94g of sodium citrate in 100mL of deionized water; pH 7.4: Use phosphate buffer (PBS), add 1.36g of potassium dihydrogen phosphate and 11.50g of disodium hydrogen phosphate to 1000mL; pH 8.0: Phosphate buffer (0.2M Na₂HPO₄ and 0.2M NaH₂PO₄ mixed at a volume ratio of 94.7:5.3). After preparation, test with a pH meter (Mettler Toledo SevenMulti). The buffer contains 0.1% Tween-80 (to increase drug solubility) and is kept at 37℃.

[0136] 3.3. Release process

[0137] Immerse the coated sample in 20 mL of release medium and place it in a constant temperature shaker (New Brunswick Innova 44, 100 rpm, 37 °C).

[0138] Sampling should be performed at regular intervals: 0, 2, 4, 6, 12, and 24 hours. Take 1 mL of solution each time and replenish with an equal volume of fresh medium.

[0139] 3.4. Detection Methods

[0140] HPLC analysis (Waters e2695):

[0141] Chromatographic column: Waters XBridge C18 (4.6×250mm, 5μm).

[0142] Mobile phase: acetonitrile-water (containing 0.1% formic acid), gradient elution (linoleic acid: 70% acetonitrile; leukotrienes D4: 50% acetonitrile).

[0143] Flow rate: 1.0 mL / min, detection wavelength: linoleic acid 210 nm, leukotrienes D 4280 nm.

[0144] Standard curve: Prepare standard solutions of linoleic acid and leukotriene D4 at concentrations of 0.1–50 μg / mL, and calculate the cumulative release.

[0145] Experimental results are as follows Figure 3 As shown,

[0146] Depend on Figure 3 It was observed that the initial release rate was low (<20%) at pH 5.0 because the carboxyl group protonation of PAA led to a denser structure. At pH 7.4–8.0, the release rate significantly increased (>60%), due to swelling caused by carboxyl group deprotonation. In summary, the release rate was significantly higher in neutral / alkaline environments than in acidic environments, consistent with the protonation / deprotonation mechanism of PAA. Furthermore, the release rate changed synchronously after pH switching, demonstrating the coating's dynamic adaptability.

[0147] 4. In vitro degradation experiment

[0148] 4.1. Sample Preparation

[0149] Form: Thin film (thickness 0.1~0.2mm).

[0150] Size: 5×5mm 2 Each tablet contains approximately 20mg of glucose. The exact weight is ( ).

[0151] Buffer preparation: pH 5.0 (0.1M NaH2PO4 (Sinopharm Group, AR) / Na2HPO4 (Alfa Aesar, 99.0%)), adjusted pH with HCl. pH 7.4 (0.1M PBS (137mM NaCl, 2.7mM KCl)). After preparation, the pH was checked using a Mettler Toledo SevenMulti pH meter.

[0152] Degradation media: Acidic conditions: 0.1M phosphate buffer (pH 5.0), neutral conditions: 0.1M PBS buffer (pH 7.4).

[0153] Volume: 10 mL / sample, constant temperature shaking at 37℃ (New Brunswick Innova 44, 100 rpm).

[0154] 4.2. Experimental Procedure

[0155] Time points: 0, 7, 14, 21, 28 days.

[0156] Sample drying treatment: PAA hydrogel (Comparative Example 1), PAA-linoleic acid composite hydrogel (coating solution prepared in Comparative Example 2), and PAA-linoleic acid-LTD4 composite hydrogel (coating solution prepared in Example 2) were placed in a freeze dryer (SCIENTZ-10N / C (manifold type, cold trap temperature -85℃)) and freeze-dried at -50℃ for 48 hours to remove moisture and avoid water peak interference.

[0157] Periodic sampling: Take out the sample, rinse it three times with ultrapure water, and vacuum dry it to constant weight.

[0158] Change the buffer solution every 3 days to maintain pH stability.

[0159] 4.3. Detection Indicators

[0160] Quality loss rate:

[0161] Experimental results are as follows Figure 4 As shown:

[0162] The degradation behavior of the coating solution group in Example 2 was evaluated using an in vitro degradation experiment system. Figure 4 Experimental data showed that all groups exhibited time-dependent degradation characteristics. The degradation rate of the coating solution group in Comparative Example 1 was significantly higher than that of the control group (28-day degradation rate: 88.2±5.3% vs 72.4±5.0%), while the LTD4 group showed intermediate degradation characteristics (80.1±4.9%). In the early stage of degradation (0-7 days), the degradation rate increase in the coating solution group of Comparative Example 1 (Δ34.7%) was 35.5% higher than that in the control group (Δ25.6%), indicating that it may accelerate PAA backbone breakage through oxidative free radicals. The phased degradation fluctuations in the coating solution group of Comparative Example 2 (e.g., Δ14.9% between 14-21 days) suggest that its degradation mechanism may involve a synergistic enzymatic effect mediated by inflammatory factors.

[0163] 5. Mechanical property testing

[0164] 5.1. Tensile strength and elongation at break

[0165] 5.1.1. Sample Preparation

[0166] The PPDO drainage tube was cut into an ASTM D638 Type V dumbbell-shaped specimen (effective dimensions: 25×6×0.5mm). 3 ).

[0167] Coating group: PPDO substrate + coating prepared in Example 2 (thickness 0.5 mm); Control group: pure PPDO.

[0168] 5.1.2. Test Conditions

[0169] Instrument: Instron 5966 universal testing machine, equipped with a 10kN load cell.

[0170] Tensile speed: 50 mm / min, room temperature 25℃, humidity 50%.

[0171] Data Recording: Tensile Strength (MPa), Elongation at Break (%)

[0172] 5.2. Energy storage modulus (E') and loss modulus (E”)

[0173] 5.2.1. Sample Preparation

[0174] The coated hydrogel was made into a cylinder (8 mm in diameter and 2 mm in thickness), and after curing, it was soaked in PBS until swelling equilibrium was reached.

[0175] 5.2.2. Test Conditions

[0176] Instrument: TA Instruments DMA Q800, compression mode.

[0177] Parameters: Frequency 1Hz, strain 0.1%, temperature range -50–150℃, heating rate 3℃ / min.

[0178] Analyze the energy storage modulus (E') and loss factor (tanδ=E” / E').

[0179] 5.3. Changes in tensile strength during degradation

[0180] Degradation environment: PPDO samples were immersed in PBS (pH 7.4, 37℃) containing 0.02% NaN3 to inhibit microbial growth.

[0181] Samples were taken periodically (0, 7, 14, 21, 28 days), and tensile properties were tested after rinsing and drying.

[0182] Experimental results are as follows Figure 5 As shown, Figure 5 The diagram shows the mechanical test results of the coated PPDO drainage tube and the uncoated PPDO drainage tube from Example 2.

[0183] Figure 5 A is covered with the tensile strength of the coated PPDO drainage tube and the uncoated PPDO drainage tube in Example 2. Figure 5 B is the elongation at break of the coated PPDO drainage tube and the uncoated PPDO drainage tube in Example 2. Figure 5 C shows the change in tensile strength during the degradation process of the coated PPDO drainage tube from Example 2 and the uncoated PPDO drainage tube. Figure 5 D is covered with the energy storage modulus and loss modulus of the coated PPDO drain tube in Example 2 at different temperatures.

[0184] Depend on Figure 5 It can be seen that the PPDO drainage tube coated with the pro-angiogenic coating exhibits excellent comprehensive mechanical properties and functional synergy. Tensile testing showed that the tensile strength of the experimental group (Example 2) was (38.0±1.5) MPa, which was significantly higher than that of the control group (35.0±2.0) MPa. Figure 5 A), the elongation at break reached (250±8)%, which was 13.6% higher than that of the control group (220±10)%. Figure 5 B) confirms that the coating process enhances the strength of the substrate without compromising its ductility. After 28 days of in vitro degradation, the tensile strength retention rate of the experimental group was (68.0±2.5)%, significantly higher than that of the control group (45.0±3.2)%. Figure 5 C) indicates that the rate of chain segment detangling during degradation is controllable, consistent with the behavior of biodegradable materials. Furthermore, the storage modulus (E') exhibits a nonlinear decreasing trend near the glass transition temperature (Tg = 30℃) (25℃: 3500MPa → 37℃: 2700MPa), while the loss modulus (E”) shows a characteristic peak at Tg (peak value 150MPa), consistent with the viscoelastic relaxation behavior of poly(p-dioxanone) (PPDO). Figure 5 D). In summary, this coated drainage tube combines high mechanical strength with controllable degradation properties, providing an ideal material platform for postoperative infection control and angiogenesis.

[0185] 6. Cell experiments

[0186] Experimental Groups:

[0187] Control group: HUVECs without any treatment (basal culture medium only).

[0188] LA group (comparative example 5): Linoleic acid (LA, final concentration 10 mg / mL) was added to the culture medium.

[0189] LTD4 group (comparative example 4): Leukotriene D4 (LTD4, final concentration 1 mg / mL) was added to the culture medium.

[0190] (Example 1) LA+LTD4 group: LA (10mg / mL) and LTD4 (1mg / mL) were added simultaneously and mixed at a weight ratio of 10:1.

[0191] (Comparative Example 1) PAA group: Polyacrylic acid hydrogel (concentration consistent with Example 2, without drugs) was added to the culture medium.

[0192] LTD4+PAA group (Comparative Example 3)

[0193] LTD4+LA+PAA group (Example 2)

[0194] VEGF group: 20 ng / mL VEGF (vascular endothelial growth factor) was added as a positive control.

[0195] TritonX group: 0.1% TritonX-100 was added as a toxicity control.

[0196] Distilled water group (Comparative Example 6).

[0197] The hydrogels prepared in each group were placed in a freeze dryer (SCIENTZ-10N / C (manifold type, cold trap temperature -85℃)) and freeze-dried at -50℃ for 48 hours to remove moisture and avoid water peak interference.

[0198] 6.1. Cell viability (CCK-8)

[0199] 6.1.1. Sample Preparation

[0200] Preparation of extraction solution: The hydrogel samples of each group were immersed in EGM-2 basal medium (37℃, 24 hours).

[0201] 6.1.2. Experimental Procedure

[0202] HUVECs (Lonza, C2519A) were inoculated into 96-well plates (5 × 10⁻⁶ wells). 3 Cells / well), cultured at 37°C and 5% CO2 for 24 hours.

[0203] Replace with a culture medium containing different extracts (50% concentration) and continue culturing for 72 hours.

[0204] Add 10 μL of CCK-8 reagent (Dojindo, CK04) to each well, incubate for 2 hours, and then measure the absorbance at 450 nm using a microplate reader (BioTek Synergy H1).

[0205] The results of the 72-hour cell viability assay (CCK-8) are shown in the figure below. Figure 6 As shown;

[0206] from Figure 6 The results are shown in the image:

[0207] Compared with the uncoated control group, the coating in Example 1 (LA+LTD4 group) significantly enhanced the biological activity of human umbilical vein endothelial cells (HUVECs). Specifically, the cell viability of LA+LTD4 (Example 2) reached 120.2±8.1% (mean ± standard deviation, n=6), which was 23.6% and 20.0% higher than that of the LA group alone (105.3±7.2%) and the LTD4 group (108.5±6.8%), respectively, indicating that the two had a synergistic effect.

[0208] Limited single-drug efficacy: Pure LA or LTD4 activity increased by ≤7.8%, while LA and LTD showed significant synergistic effects (↑18.6% without a carrier). PAA carrier enhancement: Example 2 (containing PAA) showed an additional 11.9% enhancement compared to Example 1 (without PAA).

[0209] LTD4+LA+PAA group (Example 2): Cell viability was close to that of the positive control VEGF (approximately 130%), and significantly higher than that of other groups.

[0210] LA+LTD4 hydrogel assembly (Example 1): Activity approximately 120%, second best but significantly better than the base material.

[0211] TritonX group: lowest activity (approximately 40%), highlighting the advantages of the new regimen as a control group for traditional drugs.

[0212] LA (Comparative Example 4) or LTD4 (Comparative Example 5) alone: ​​moderate activity (approximately 80-100%), demonstrating synergistic effects of the composition.

[0213] Furthermore, it was found that the LA+LTD4+PAA hydrogel group, compared with the PAA hydrogel group, as well as the LA+LTD4 hydrogel group and the LA+PAA hydrogel group, showed significantly improved cell viability. Moreover, the comparison showed that LA, LTD4 and PAA have a synergistic effect in improving cell viability.

[0214] Efficacy of the control group:

[0215] The reliability of the experimental system was verified by VEGF (approximately 140%) and THP-1 (approximately 100%).

[0216] The PAA hydrogel group (approximately 80%) showed that the carrier itself had no significant activity, and the technical effect stemmed from the combination of active ingredients and the interaction of active ingredients with PAA.

[0217] 6.2. Pipe Formation Capacity Analysis

[0218] Matrigel gelation: Pre-cool the 96-well plate, add 50 μL of Matrigel (Corning, 356234) to each well, and gel at 37°C for 30 minutes. Seed HUVECs (2 × 10⁻⁶) 4 Cells / wells were cultured in medium containing different extracts for 6 hours. Images were taken with an inverted microscope (Nikon Eclipse Ti2), and the lumen length and number of branch points were analyzed using ImageJ software.

[0219] The results of the tube-forming capacity (lumen length) analysis are as follows: Figure 7 As shown:

[0220] from Figure 7 It can be seen that the LA+LTD4+PAA hydrogel group, compared with the PAA hydrogel group, the LA+LTD4 hydrogel group, and the LA+PAA hydrogel group, has a significantly improved tube-forming ability (lumen length). Furthermore, the comparison shows that LA, LTD4, and PAA have a synergistic effect on tube-forming ability (lumen length).

[0221] The results of the pipe forming capacity (number of branch points) analysis are as follows: Figure 8 As shown:

[0222] LA showed superior vascularization ability compared to LTD4: compared to Comparative Examples 2 and 3, the lumen length was increased by 9.6%.

[0223] Example 1 (without carrier): The lumen length was increased by ≥38.8% compared to the single-drug group, and the number of branch points was ≥46.0%.

[0224] PAA sustained release enhancement: Example 2 showed a 36.0% increase in length and a 37.0% increase in points compared to Example 1.

[0225] Careful comparison of the results from each group shows that LA, LTD4, and PAA have a synergistic effect on tube formation capability (number of branch points).

[0226] Matrigel tube formation experiments further confirmed that the number of branch points (22.4±3.2) and lumen length (1205±152μm) of capillary-like structures induced by the LA+LTD4 group were 2.8 times and 2.4 times that of the control group, respectively, and the effect was comparable to that of the VEGF group (25.1±4.0 branch points, 1503±200μm).

[0227] 6.3. Detection of TLR4 / NF-κB / VEGF (vascular endothelial growth factor) expression

[0228] RT-qPCR:

[0229] 6.3.1. Cell treatment:

[0230] HUVECs were co-cultured with the coating extract for 24 hours, and RNA was extracted from the cells using the Qiagen RNeasy Kit.

[0231] 6.3.2. Primer Design:

[0232] TLR4-F:5'-GACCTGTACCTTGCTAGTTCC-3';

[0233] TLR4-R:5'-CAGGGTTCTTGTCCCTCTGAA-3';

[0234] VEGF-F:5'-AGGGCAGAATCATCACGAAGT-3';

[0235] VEGF-R:5'-AGGGATTTCTTGCGCTTTCG-3';

[0236] GAPDH is used as an internal reference.

[0237] 6.3.3. Instrument: Bio-Rad CFX96, SYBR Green method (ThermoFisher, 4367659).

[0238] TLR4, short for Toll-Like Receptor 4, is a key receptor for the innate immune system that recognizes pathogens (such as LPS) and triggers an inflammatory response.

[0239] Figure 9 The relative expression levels of TLR4 in HUVECs treated with each coating group are shown.

[0240] Figure 10 The relative expression levels of NF-κB in HUVECs treated with each coating group.

[0241] Figure 11 The relative expression levels of CysLT1R in HUVECs treated with each coating group.

[0242] CysLT1R is the core target: CysLT1R expression increased by 58% in the LTD4 group (comparative examples 3 and 4), which was significantly higher than that of TLR4 / NF-κB (28-32%).

[0243] In Example 1, the expression of CysLT1R was 1.3 times the sum of Comparative Examples 2 and 3 (2.15 vs 1.42 + 1.58 = 3.00 → Synergy Index = 2.15 / 3.00 ≈ 0.72).

[0244] PAA-enhanced pathway activation: Example 2 showed a 23.3% increase in CysLT1R compared to Example 1.

[0245] In conclusion, Figure 9-11 It can be seen that LA, LTD4 and PAA overcome each other's side effects and work synergistically to improve the gene expression of TLR4, NF-κB and CysLT1R, and have a qualitative improvement in gene expression effect, with unexpected technical effects.

[0246] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vascularizing coating, characterized in that: It includes linoleic acid and leukotriene D4.

2. The angiogenesis-promoting coating as described in claim 1, characterized in that, The linoleic acid and leukotriene D4 are in a weight ratio of 8 to 12:

1.

3. The angiogenesis-promoting coating as described in claim 1, characterized in that, It also includes: polyacrylic acid.

4. The angiogenesis-promoting coating as described in claim 3, characterized in that: The coating is prepared by using polyacrylic acid in the form of a polyacrylic acid hydrogel.

5. The angiogenesis-promoting coating as described in claim 1, characterized in that: The mass ratio of linoleic acid, leukotrienes D4, and polyacrylic acid hydrogel in the coating is 8-12:1:90-120.

6. The angiogenesis-promoting coating as described in claim 4, characterized in that: The linoleic acid and leukotrienes D4 are added to the polyacrylic acid hydrogel, and the coating is obtained after curing.

7. The application of the angiogenic coating as described in any one of claims 1-6 in a drainage tube.

8. The application of the angiogenesis-promoting coating as described in claim 7 in a drainage tube, characterized in that: The drainage tube is a PPDO drainage tube.

9. The application of the angiogenesis-promoting coating as described in claim 7 in a drainage tube, characterized in that, It includes the following steps: The drainage tube is immersed in the coating solution, then removed and dried to form a coating on the drainage tube.

10. The application of the angiogenic coating as described in claim 7 in a drainage tube, characterized in that, The preparation method of the drainage tube includes the following steps: the dried PPDO particles are mixed with barium sulfate and then poured into an extruder to be extruded into a drainage tube. The temperature of different sections in the extruder is set between 180°C and 195°C.

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