Pericardium anti-adhesion patch with three-layer composite structure and preparation method of pericardium anti-adhesion patch

Abstract

The invention discloses a pericardium anti-adhesion patch with a three-layer composite structure and a preparation method of the pericardium anti-adhesion patch. The patch is composed of zwitterionic hydrogel on the inner layer and the outer layer and poly-(N-acryloylglycine amide) hydrogel on the middle layer. The inner layer simulates the lubrication characteristic of the pericardium serosa layer, and friction during cardiac pulsation is reduced; the middle layer has tensile strength and flexibility similar to those of a natural pericardium fiber layer, and the mechanical performance is enhanced; and the outer layer has the characteristic of biological adhesion resistance, so that the formation of postoperative pericardial adhesion is inhibited. All the layers are connected in an interface molecular chain interpenetrating mode to form a gradient cross-linked structure, and the overall synergy and stability are improved. The patch shows an excellent anti-adhesion effect after a sheep left ventricular auxiliary system implantation operation, is suitable for pericardium anti-adhesion treatment in a cardiac surgery operation, and has important clinical application value.

Description

Technical Field

[0001] The present invention relates to a pericardial anti - adhesion patch with a three - layer composite structure and a preparation method thereof. Background of the Invention

[0003] Pericardial adhesion refers to the adhesion between the heart and the chest wall tissue during cardiac surgery such as left ventricular assist system implantation, cardiac valve replacement, coronary artery bypass grafting, and some congenital heart malformations. After the operation, due to the inability to completely suture the own pericardium, it leads to the adhesion between the heart and large blood vessels and the chest wall tissue. They usually affect the diastolic and systolic functions of the heart after the operation, resulting in heart failure or even cardiac insufficiency. Many patients undergoing cardiac surgery need to undergo secondary or even tertiary cardiac surgery, and postoperative pericardial adhesion will cause difficult thoracotomy or even fatal massive hemorrhage during secondary thoracotomy.

[0004] Isolating the heart from the large blood vessels and chest wall tissue with biomaterials is an effective measure to prevent postoperative adhesion. Such biomaterials mainly include injectable anti - adhesion materials and solid films. Due to their high fluidity, injectable anti - adhesion materials have a short duration on the surface of dynamic cardiac and vascular tissues, are easy to flow away from the tissue surface, and are difficult to play a barrier effect. Solid films, with their regular external dimensions, can cover the heart wall surface and separate the heart from the chest wall tissue, and are considered as a better pericardial anti - adhesion material. For example, the polytetrafluoroethylene (PTFE) membrane widely used in clinical practice at present can prevent pericardial adhesion to a certain extent after cardiac surgery. However, from the latest clinical data, after using the PTFE anti - adhesion membrane, the postoperative infection rate of patients is 1.14%, and the probability of in - vivo adhesion is 37.31%. The initial manifestation of pericardial adhesion is usually protein adhesion. Therefore, reducing protein adhesion is an effective way to prevent pericardial adhesion. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a pericardial anti - adhesion patch with a three - layer composite structure and a preparation method thereof, which is simple to manufacture, has excellent performance, has excellent biocompatibility, can be used for the treatment of pericardial anti - adhesion after cardiac surgery such as left ventricular assist system implantation, cardiac valve replacement, coronary artery bypass grafting, and some congenital heart malformations, prevent pericardial adhesion after cardiac surgery, and reduce the postoperative infection rate and the probability of in - vivo adhesion.

[0006] The technical solution of the present invention is as follows:

[0007] A pericardial anti - adhesion patch with a three - layer composite structure, characterized in that: the pericardial anti - adhesion patch has a three - layer composite structure hydrogel film, including an inner layer, a middle layer, and an outer layer. The middle layer is a poly - (N - acryloylglycine amide) hydrogel material, and the inner and outer layers are zwitterionic hydrogel materials. The middle layer and the inner and outer layers are combined through a polymer molecular chain interpenetrating network, and the combination is firm.

[0008] Further, the composition of the poly-(N-acryloylglycine amide) hydrogel material in the middle layer is as follows: the concentration of N-acryloylglycinamide (NAGA) monomer is 5w%-80w%, the dosage of cross-linking agent N,N-bis(acryloyl)cysteamine accounts for 0.1w%-5w% of the mass of N-acryloylglycinamide, and the dosage of initiator accounts for 0.5w%-20w% of the mass of N-acryloylglycinamide.

[0009] Further, the composition of the zwitterionic hydrogel material in the inner and outer layers is as follows: the concentration of zwitterionic monomer is 10w%-80w%, the concentration of N-acryloylglycinamide (NAGA) monomer is 5w%-40w%, the dosage of cross-linking agent accounts for 0.5w%-15w% of the mass of zwitterionic monomer, and the dosage of initiator accounts for 0.5w%-20w% of the mass of zwitterionic monomer.

[0010] Further, the zwitterionic monomer is at least one of methacryloylethyl sulfobetaine (SBMA), 2-methacryloyloxyethyl phosphorylcholine (MPC), and carboxybetaine methacrylate (CBMA);

[0011] The cross-linking agent in the zwitterionic hydrogel is one or more of N,N-bis(acryloyl)cysteamine (BAC), N,N-bis(acryloyl)cystamine (MSBA), ethylene glycol dimethacrylate (EBA), and bis-methacryloylethyl carboxybetaine (CBBA);

[0012] In the inner and outer layer zwitterionic hydrogels, the concentration of zwitterionic monomer is 30w%-75w%, the concentration of N-acryloylglycinamide monomer is 6w%-24w%, and the dosage of cross-linking agent accounts for 0.5w%-2w% of the mass of zwitterionic monomer.

[0013] Further, the initiator is ammonium persulfate or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (I-2959).

[0014] Further, the thickness of the poly-(N-acryloylglycine amide) hydrogel layer in the middle layer is 50 - 1000 μm, and the average pore size is 3 - 5 μm; the thickness of the zwitterionic hydrogel layers in the inner and outer layers is 10 - 800 μm, and the average pore size is 2 - 70 μm.

[0015] A preparation method of the pericardial anti-adhesion patch with the above three-layer composite structure, characterized in that:

[0016] Step 1: Take distilled water and add zwitterionic monomer, N-acryloylglycinamide (NAGA), cross-linking agent and initiator to prepare the inner and outer layer precursor solutions;

[0017] Add distilled water to N - acryloylglycinamide (NAGA), N,N - bis(acryloyl)cysteamine (BAC) and an initiator to prepare an intermediate layer precursor solution;

[0018] Step 2: Inject the intermediate layer precursor solution into a mold with a rectangular groove, place it in an oven, and heat and polymerize at 50 - 80 °C for 15 - 30 min. After forming, the obtained hydrogel is washed repeatedly with deionized water, and then dried at 50 - 80 °C for 5 - 10 min to obtain an intermediate layer of poly-(N - acryloylglycinamide);

[0019] Step 3: Immerse the poly-(N - acryloylglycinamide) hydrogel in the inner and outer layer precursor solutions for 15 - 120 min to allow the intermediate layer to absorb the inner and outer layer precursor solutions, and then initiate polymerization with a 365 nm ultraviolet lamp at a temperature of 10 - 60 °C for 30 - 60 min to form a pericardial anti - adhesion patch.

[0020] Furthermore, continue to immerse the pericardial anti - adhesion patch in the inner and outer layer precursor solutions for 15 - 120 min to allow the pericardial anti - adhesion patch to continuously absorb the inner and outer layer precursor solutions, and then initiate polymerization with a 365 nm ultraviolet lamp at a temperature of 10 - 60 °C for 30 - 60 min to form a pericardial anti - adhesion patch with enhanced layer thickness.

[0021] Furthermore, when heating and polymerizing, the temperature is 60 °C and the time is 20 min; when initiating polymerization with a 365 nm ultraviolet lamp, the temperature is 25 °C and the time is 30 min.

[0022] Application of an anti - adhesion patch as described above in a pericardial anti - adhesion patch after cardiac surgery.

[0023] The present invention has a three - layer composite structure, with the inner and outer layers being zwitterionic hydrogels and the intermediate layer being a poly-(N - acryloylglycinamide) (PNAGA) hydrogel. Among them, the inner zwitterionic hydrogel layer has a lubricating function similar to the serous layer on the inner surface of the pericardium to reduce friction during cardiac pulsation; while the intermediate PNAGA hydrogel layer mimics the pericardial fibrous layer to provide tensile strength and flexibility to the patch; and the outer zwitterionic layer has an anti - biological adhesion function, thereby inhibiting the generation of postoperative pericardial adhesions. The patch has excellent biocompatibility in vivo and can be used for the treatment of pericardial anti - adhesion after cardiac surgeries such as left ventricular assist system implantation, heart valve replacement, coronary artery bypass grafting, and certain congenital heart malformations.

[0024] The pericardial adhesion prevention patch with a bionic structure of the present invention is simple to manufacture and has excellent performance. The middle layer (built-in layer) is formed by crosslinking poly(N-acryloylglycine) hydrogel (PN) and N,N'-bis(acryloyl)cysteine, containing intermolecular hydrogen bonds and covalent interactions, providing strong mechanical properties. Its inner and outer layers (outer display layer) are composed of anti-pollution zwitterionic hydrogels, effectively preventing the surface adsorption of biomolecules related to inflammatory reactions and postoperative adhesion formation, reducing protein adhesion, and decreasing the postoperative infection rate and the probability of in vivo adhesion of patients. In summary, the patch has good flexibility, mechanical strength matching that of natural pericardium, meets the requirements of surgical suture, and has excellent anti-adhesion function. Brief Description of the Drawings

[0025] To more clearly illustrate the technical solutions of the present invention, the drawings are briefly introduced below. Obviously, the following drawings only relate to some embodiments of the present invention and do not limit the present invention. Among them, the hydrogel (P N ) prepared by separately preparing the middle layer precursor solution and the hydrogel (P S ) prepared by separately preparing the inner and outer layer precursor solutions are used as control groups for testing and comparison.

[0026] Figure 1 is a schematic diagram of the composition, structure and anti-adhesion function of the patch of the present invention;

[0027] Figure 2 is the cross-section and surface SEM image of P S@N@S prepared in Example 1 of the present invention;

[0028] Figure 3 is the tensile strength diagram of P N , P S@N@S prepared in Example 1 of the present invention and P S prepared in Comparative Example 1;

[0029] Figure 4 is the surface Young's modulus of P N , P S@N@S prepared in Example 1 of the present invention and P S prepared in Comparative Example 1;

[0030] Figure 5 is the suture strength of P N , P S@N@S prepared in Example 1 of the present invention and P S prepared in Comparative Example 1;

[0031] Figure 6 is the friction coefficient diagram of P N , P S@N@S prepared in Example 1 of the present invention and P S prepared in Comparative Example 1;

[0032] Figure 7 is the P prepared in Example 1 of the present invention N , P S@N@S and the P prepared in Comparative Example 1 S water contact angle diagram;

[0033] Figure 8 is the P prepared in Example 1 of the present invention N , P S@N@S and the P prepared in Comparative Example 1 S anti-protein adhesion performance diagram;

[0034] Figure 9 is the P prepared in Example 1 of the present invention N , P S@N@S and the P prepared in Comparative Example 1 S bacterial adhesion performance diagram;

[0035] Figure 10 is the P prepared in Example 1 of the present invention S@N@S cytotoxicity diagram;

[0036] Figure 11 is the P prepared in Example 1 of the present invention S@N@S rabbit postoperative pericardial anti-adhesion model diagram;

[0037] Figure 12 is the P prepared in Example 1 of the present invention S@N@S sheep left ventricular assist device (LVAD) adhesion model diagram. Detailed Description of the Invention

[0038] The present invention will be described in detail below with reference to specific embodiments. Although the following describes the preferred embodiments of the present invention, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Those of ordinary skill in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0039] The reagents or instruments used in the present invention that are not specified by the manufacturer can all be obtained as conventional products through commercial purchase. All animal experiments were carried out strictly in accordance with the protocol approved by the Animal Experiment Ethics Committee of Tianjin Chest Hospital.

[0040] Preparation of the Pericardial Anti-Adhesion Patch in Example 1

[0041] (1) Preparation of the middle PNAGA layer hydrogel (P N )

[0042] Take 2 mL of distilled water, add 0.4 g of N - acryloylglycinamide (NAGA), 0.002 g of N,N - bis(acryloyl)cysteamine (BAC), and 0.04 g of ammonium persulfate. After mixing evenly, inject the solution into the grooves of a 2 cm×2 cm×0.5 mm silica gel mold. After polymerization at 60 °C for 20 min, wash the obtained hydrogel 5 times with deionized water, 10 minutes each time, and then dry it at 60 °C for 10 min to obtain the PNAGA (poly-(N - acryloylglycinamide)) hydrogel, denoted as P N ;

[0043] (2) Preparation of the inner and outer layer hydrogel precursor solutions

[0044] Take 10 mL of distilled water, add 3 g of methacryloylethyl sulfobetaine (SBMA), 2 g of N - acryloylglycinamide (NAGA), 0.06 g of N,N - bis(acryloyl)cysteamine (BAC), and 0.03 g of photoinitiator 2 - hydroxy - 2 - methyl - 1 - [4-(2 - hydroxyethoxy)phenyl]-1 - propanone (I - 2959) to obtain the inner and outer layer hydrogel precursor solutions;

[0045] (3) Preparation of P S@N@S

[0046] Put the PNAGA hydrogel prepared in step (1) into the inner and outer layer hydrogel precursor solutions prepared in step (2), soak at 60 °C for 120 minutes, and then polymerize under a 365 nm ultraviolet lamp at 25 °C for 30 min to obtain the pericardial anti - adhesion patch P S@N@S .

[0047] The composition, structure, and anti - adhesion function schematic diagram of the patch of the present invention are as shown in Figure 1 . As can be seen from Figure 1 , the patch is a three - layer composite structure hydrogel, where the middle layer (inner layer) is a poly N - acryloylglycinamide (PNAGA) hydrogel, and the inner and outer layers (outer layer) are zwitterionic hydrogels. The hierarchical structures are combined through a polymer molecular chain inter - transmission network, and the combination is firm.

[0048] Comparative Example 1

[0049] Inject the inner and outer layer hydrogel precursor solutions into the grooves of a 2 cm×2 cm×0.5 mm silica gel mold. After polymerization at 60 °C for 20 min, the obtained hydrogel is denoted as P S .

[0050] In the subsequent experimental process, P S and P prepared in step (1) of Example 1 N are used as control groups.

[0051] ​Example 2

[0052] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.4 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.05 mm; the others are the same as in Example 1.

[0053] Example 3

[0054] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.4 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.1 mm; the others are the same as in Example 1.

[0055] Example 4

[0056] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.4 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.2 mm; the others are the same as in Example 1.

[0057] Example 5

[0058] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.4 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.4 mm; the others are the same as in Example 1.

[0059] Example 6

[0060] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.4 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.8 mm; the others are the same as in Example 1.

[0061] Example 7

[0062] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.4 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 1.0 mm; the others are the same as in Example 1.

[0063] Example 8

[0064] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.1 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.5 mm; the others are the same as in Example 1.

[0065] Example 9

[0066] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.2 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.5 mm; the others are the same as in Example 1.

[0067] Example 10

[0068] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.6 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.5 mm; the others are the same as in Example 1.

[0069] Example 11

[0070] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 0.8 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.5 mm; the others are the same as in Example 1.

[0071] Example 12

[0072] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 1.0 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.5 mm; the others are the same as in Example 1.

[0073] Example 13

[0074] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 1.2 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.5 mm; the others are the same as in Example 1.

[0075] Example 14

[0076] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 1.4 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.5 mm; the others are the same as in Example 1.

[0077] Example 15

[0078] In step (1) of this example, the amount of N - acryloylglycinamide (NAGA) used is 1.6 g; the groove specifications of the silicone mold are 2 cm × 2 cm × 0.5 mm; the others are the same as in Example 1.

[0079] Example 2 - 15 According to the method of Example 1, the operation is the same as in Example 1, except that the amount of the monomer used in the intermediate layer is changed (from 5% - 80%, that is, 0.05 - 0.8 g / mL) and the thickness of the intermediate layer, and the tensile strength, suture strength and pore size of the P prepared with different amounts of monomers are measured, as shown in Table 1. S@N@S as shown in Table 1.

[0080] Table 1 Tensile strength and suture strength of P prepared with different amounts of monomers S@N@S as shown in Table 1.

[0081]

[0082] As can be seen from Table 1, with the increase in the concentration of NAGA monomer, the mechanical strength of the patch increases, but when the strength is too high, the toughness will decrease, affecting the fit with the surface of the heart wall. After suturing, it will increase mechanical irritation and stress concentration, thereby triggering an inflammatory reaction or secondary injury, affecting the postoperative effect. It can be seen that the pore size has nothing to do with the thickness of the intermediate layer, but with the increase in the concentration of NAGA monomer, the pore size of the intermediate layer hydrogel shows a gradually decreasing trend, which is due to the increase in the density of the NAGA cross-linking network. According to Examples 1-7, it can be seen that as the thickness of the intermediate layer increases, its tensile strength remains basically unchanged, and its suture strength gradually increases.

[0083] Example 16

[0084] In this example, 2-methacryloyloxyethyl phosphorylcholine (MPC) was used to replace sulfobetaine methacrylate (SBMA) in step (2) of Example 1, and the others were the same as in Example 1.

[0085] Example 17

[0086] In this example, carboxybetaine methacrylate (CBMA) was used to replace sulfobetaine methacrylate (SBMA) in step (2) of Example 1, and the others were the same as in Example 1.

[0087] Example 16 - 17 According to the method of Example 1, the operation was the same as in Example 1, except that only the types of zwitterionic monomers used in the inner and outer layers were changed, and the surface water contact angles, bovine serum albumin, platelet, bacteria, and cell adhesion amounts of the pericardial anti-adhesion patches prepared with different types of monomers were measured, as shown in Table 2.

[0088] Table 2 Performance analysis of pericardial anti-adhesion patches prepared with different types of zwitterionic monomers

[0089] Example Monomer type Water contact angle <![CDATA[Ad pro (μg / cm 2 )]]> <![CDATA[Ad pla (per mm 2 )]]> <![CDATA[Ad bac (per mm 2 )]]> <![CDATA[Ad cel (per mm 2 )]]> 1 SBMA 6.9 0.015 0 0 0 16 MPC 6.3 0.018 0 0 0 17 CBMA 5.9 0.011 0 0 0

[0090] Ad pro : Protein adhesion amount; Ad pla : Platelet adhesion amount; Ad bac : Bacteria adhesion amount; Ad cel : Cell adhesion amount.

[0091] As can be seen from the data in Table 2, compared with the zwitterionic monomer SBMA in Example 1 of the present invention, the pericardial anti-adhesion patches prepared with the other two zwitterionic monomers in Example 16 and Example 17 also showed very excellent superhydrophilic, anti-protein adhesion, anti-platelet adhesion (zero platelet adhesion), anti-bacteria adhesion, and anti-cell adhesion properties, which benefited from the high hydrophilicity of the zwitterionic polymer and its extremely low interaction with proteins, platelets, bacteria, cells, etc.

[0092] Example 18

[0093] In this example, N,N-bis(acryloyl)cystamine (MSBA) is used to replace N,N-bis(acryloyl)cysteamine (BAC) in step (2) of Example 1, and ammonium persulfate is used to replace the photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) in step (2) of Example 1. Other conditions are the same as those in Example 1.

[0094] Example 19

[0095] In this example, N,N-bis(acryloyl)cystamine (MSBA) is used to replace N,N-bis(acryloyl)cysteamine (BAC) in step (2) of Example 1. Other conditions are the same as those in Example 1.

[0096] Example 20

[0097] In this example, ethylene glycol dimethacrylate (EBA) is used to replace N,N-bis(acryloyl)cysteamine (BAC) in step (2) of Example 1, and ammonium persulfate is used to replace the photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) in step (2) of Example 1. Other conditions are the same as those in Example 1.

[0098] Example 21

[0099] In this example, ethylene glycol dimethacrylate (EBA) is used to replace N,N-bis(acryloyl)cysteamine (BAC) in step (2) of Example 1. Other conditions are the same as those in Example 1.

[0100] Example 22

[0101] In this example, carboxybetaine dimethacrylate (CBBA) is used to replace N,N-bis(acryloyl)cysteamine (BAC) in step (2) of Example 1, and ammonium persulfate is used to replace the photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) in step (2) of Example 1. Other conditions are the same as those in Example 1.

[0102] Example 23

[0103] In this example, carboxybetaine dimethacrylate (CBBA) is used to replace N,N-bis(acryloyl)cysteamine (BAC) in step (2) of Example 1. Other conditions are the same as those in Example 1.

[0104] Example 18 - 23According to the method of Example 1, the operation is the same as that of Example 1, except that only the types of crosslinking agents and initiators used in the inner and outer layers are changed. The surface water contact angles of the pericardial anti-adhesion patches prepared with different types of crosslinking agents, as well as the adhesion amounts of bovine serum albumin, platelets, bacteria, and cells, are measured and shown in Table 3.

[0105] Table 3 Performance analysis of pericardial anti-adhesion patches prepared with different types of crosslinking agents

[0106]

[0107] As can be seen from the data in Table 3, compared with the crosslinking agent BAC, the patches formed by the other three crosslinking agents (MSBA, EBA, CBBA) also exhibit very excellent superhydrophilic, anti-protein adhesion, anti-platelet adhesion (zero platelet adhesion), anti-bacterial adhesion, and anti-cell adhesion properties, and these initiators all have good effects on the performance of the pericardial anti-adhesion patches.

[0108] Example 24

[0109] In this example, the addition amount of sulfobetaine methacrylate (SBMA) in step (2) is 1 g, and the addition amount of N-acryloylglycinamide (NAGA) is 4 g, and the others are the same as in Example 1.

[0110] Example 25

[0111] In this example, the addition amount of sulfobetaine methacrylate (SBMA) in step (2) is 1.5 g, and the addition amount of N-acryloylglycinamide (NAGA) is 3.5 g, and the others are the same as in Example 1.

[0112] Example 26

[0113] In this example, the addition amount of sulfobetaine methacrylate (SBMA) in step (2) is 2 g, and the addition amount of N-acryloylglycinamide (NAGA) is 3.1 g, and the others are the same as in Example 1.

[0114] Example 27

[0115] In this example, the addition amount of sulfobetaine methacrylate (SBMA) in step (2) is 2.5 g, and the addition amount of N-acryloylglycinamide (NAGA) is 2.7 g, and the others are the same as in Example 1.

[0116] Example 28

[0117] In this example, the addition amount of sulfobetaine methacrylate (SBMA) in step (2) is 3 g, and the addition amount of N-acryloylglycinamide (NAGA) is 2.4 g, and the others are the same as in Example 1.

[0118] Example 29

[0119] In step (2) of this example, the addition amount of 2-(Methacryloyloxy)ethyl dimethylammonium propane sulfonate (SBMA) is 3.5 g, and the addition amount of N-acryloylglycinamide (NAGA) is 2.0 g. Other conditions are the same as those in Example 1.

[0120] Example 30

[0121] In step (2) of this example, the addition amount of 2-(Methacryloyloxy)ethyl dimethylammonium propane sulfonate (SBMA) is 4 g, and the addition amount of N-acryloylglycinamide (NAGA) is 1.7 g. Other conditions are the same as those in Example 1.

[0122] Example 31

[0123] In step (2) of this example, the addition amount of 2-(Methacryloyloxy)ethyl dimethylammonium propane sulfonate (SBMA) is 4.5 g, and the addition amount of N-acryloylglycinamide (NAGA) is 1.4 g. Other conditions are the same as those in Example 1.

[0124] Example 32

[0125] In step (2) of this example, the addition amount of 2-(Methacryloyloxy)ethyl dimethylammonium propane sulfonate (SBMA) is 5 g, and the addition amount of N-acryloylglycinamide (NAGA) is 1.2 g. Other conditions are the same as those in Example 1.

[0126] Example 33

[0127] In step (2) of this example, the addition amount of 2-(Methacryloyloxy)ethyl dimethylammonium propane sulfonate (SBMA) is 6.5 g, and the addition amount of N-acryloylglycinamide (NAGA) is 1.0 g. Other conditions are the same as those in Example 1.

[0128] Example 34

[0129] In step (2) of this example, the addition amount of 2-(Methacryloyloxy)ethyl dimethylammonium propane sulfonate (SBMA) is 7 g, and the addition amount of N-acryloylglycinamide (NAGA) is 0.8 g. Other conditions are the same as those in Example 1.

[0130] Example 35

[0131] In step (2) of this example, the addition amount of 2-(Methacryloyloxy)ethyl dimethylammonium propane sulfonate (SBMA) is 7.5 g, and the addition amount of N-acryloylglycinamide (NAGA) is 0.6 g. Other conditions are the same as those in Example 1.

[0132] Example 36

[0133] In step (2) of this example, the addition amount of 2-(Methacryloyloxy)ethyl dimethylammonium propane sulfonate (SBMA) is 8 g, and the addition amount of N-acryloylglycinamide (NAGA) is 0.5 g. Other conditions are the same as those in Example 1.

[0134] Example 24 - 36 According to the method of Example 1, the operation is the same as that of Example 1, except that the dosages of zwitterionic monomers used in the inner and outer layers are changed. The surface water contact angles, bovine serum albumin, platelet, bacteria, and cell adhesion amounts of the pericardial anti-adhesion patches prepared with different dosages of monomers are measured, as shown in Table 4.

[0135] Table 4 Performance analysis of pericardial anti-adhesion patches prepared with different dosages of monomers

[0136]

[0137] It can be seen from the data in Table 4 that as the concentration of SBMA monomer increases, both the hydrophilicity and anti-bioadhesion performance of the anti-adhesion layer increase, but the swelling rate also increases; as the concentration of NAGA monomer increases, the swelling rate of the anti-adhesion layer decreases, but both its hydrophilicity and anti-bioadhesion performance decrease. From the comparison between Example 1 and Example 28, it can be obtained that when the concentration of SBMA monomer is the same, the greater the concentration of NAGA monomer, the smaller the average pore size; from the comparison between Example 1 and Example 29, it can be obtained that when the concentration of NAGA monomer is the same, the greater the concentration of SBMA monomer, the larger the average pore size. The larger the average pore size, the higher the water absorption rate of the gel, the better the anti-bioadhesion performance, and the better the anti-adhesion effect.

[0138] Example 37

[0139] In step (2) of this example, the usage amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.015 g, and the usage amount of photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) is 0.6 g. Other conditions are the same as those in Example 1.

[0140] Example 38

[0141] In step (2) of this example, the usage amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.03 g, and the usage amount of photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) is 0.45 g. Other conditions are the same as those in Example 1.

[0142] Example 39

[0143] In step (2) of this example, the usage amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.06 g, and the usage amount of photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) is 0.6 g. Other conditions are the same as those in Example 1.

[0144] Example 40

[0145] In step (2) of this example, the usage amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.06 g, and the usage amount of photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) is 0.33 g. Other conditions are the same as in Example 1.

[0146] Example 41

[0147] In step (2) of this example, the usage amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.12 g, and the usage amount of photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) is 0.21 g. Other conditions are the same as in Example 1.

[0148] Example 42

[0149] In step (2) of this example, the usage amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.21 g, and the usage amount of photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) is 0.12 g. Other conditions are the same as in Example 1.

[0150] Example 43

[0151] In step (2) of this example, the usage amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.33 g, and the usage amount of photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) is 0.06 g. Other conditions are the same as in Example 1.

[0152] Example 44

[0153] In step (2) of this example, the usage amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.45 g, and the usage amount of photoinitiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959) is 0.015 g. Other conditions are the same as in Example 1.

[0154] Example 37 - 44 According to the method of Example 1, the operation is the same as in Example 1, except that the usage amounts of the crosslinking agent and initiator used in the inner and outer layers are changed. The surface water contact angle, bovine serum albumin, platelet, bacteria, cell adhesion amount, and swelling rate of the pericardial anti-adhesion patch prepared with different amounts of crosslinking agent and initiator are measured, as shown in Table 5.

[0155] Table 5 Performance analysis of the anti-adhesion layer prepared with different amounts of crosslinking agent and initiator

[0156]

[0157] From the data in Table 5, it can be seen from Examples 37-44 that as the concentration of the crosslinking agent BAC increases, the anti-swelling properties of the inner and outer layers are improved, the average pore size shows a downward trend, and both the hydrophilicity and anti-bioadhesion properties decrease. This is because as the crosslinking agent content increases, the polymer segments are more tightly entangled with each other, resulting in a decrease in water absorption, a decline in surface hydration ability, and thus a decrease in the swelling rate, a decrease in the average pore size, and a decrease in the anti-bioadhesion property. From the comparison between Examples 39 and 40, it can be seen that as the amount of the photoinitiator I-2959 changes, the hydrophilicity and anti-bioadhesion properties of the inner and outer layers remain almost unchanged, indicating that the overall properties of the hydrogel are almost independent of the initiator content.

[0158] Example 45

[0159] In this example, during the soaking in step (3), the soaking temperature is 10°C and the soaking time is 15 minutes, and the others are the same as in Example 1.

[0160] Example 46

[0161] In this example, during the soaking in step (3), the soaking temperature is 10°C and the soaking time is 30 minutes, and the others are the same as in Example 1.

[0162] Example 47

[0163] In this example, during the soaking in step (3), the soaking temperature is 35°C and the soaking time is 100 minutes, and the others are the same as in Example 1.

[0164] Example 48

[0165] In this example, during the soaking in step (3), the soaking temperature is 45°C and the soaking time is 100 minutes, and the others are the same as in Example 1.

[0166] Example 49

[0167] In this example, during the soaking in step (3), the soaking temperature is 60°C and the soaking time is 90 minutes, and the others are the same as in Example 1.

[0168] Example 50

[0169] In this example, during the soaking in step (3), it is soaked in two times. The first soaking temperature is 10°C and the soaking time is 15 minutes, and polymerization is initiated under a 365 nm ultraviolet lamp at a temperature of 25°C for 30 minutes; the second soaking temperature is 10°C and the soaking time is 15 minutes; the others are the same as in Example 1.

[0170] Example 51

[0171] In step (3) of this embodiment during soaking, it is soaked in two times. The temperature of the first soaking is 15°C, the soaking time is 30 minutes, and polymerization is initiated under a 365 nm ultraviolet lamp at a temperature of 25°C for 30 min; the temperature of the second soaking is 15°C, and the soaking time is 45 minutes; other conditions are the same as in Embodiment 1.

[0172] Example 52

[0173] In step (3) of this embodiment during soaking, it is soaked in two times. The temperature of the first soaking is 15°C, the soaking time is 45 minutes, and polymerization is initiated under a 365 nm ultraviolet lamp at a temperature of 25°C for 30 min; the temperature of the second soaking is 15°C, and the soaking time is 30 minutes; other conditions are the same as in Embodiment 1.

[0174] Example 53

[0175] In step (3) of this embodiment during soaking, it is soaked in two times. The temperature of the first soaking is 25°C, the soaking time is 60 minutes, and polymerization is initiated under a 365 nm ultraviolet lamp at a temperature of 25°C for 30 min; the temperature of the second soaking is 25°C, and the soaking time is 60 minutes; other conditions are the same as in Embodiment 1.

[0176] Example 54

[0177] In step (3) of this embodiment during soaking, it is soaked in two times. The temperature of the first soaking is 40°C, the soaking time is 90 minutes, and polymerization is initiated under a 365 nm ultraviolet lamp at a temperature of 25°C for 30 min; the temperature of the second soaking is 40°C, and the soaking time is 90 minutes; other conditions are the same as in Embodiment 1.

[0178] Example 55

[0179] In step (3) of this embodiment during soaking, it is soaked in two times. The temperature of the first soaking is 40°C, the soaking time is 90 minutes, and polymerization is initiated under a 365 nm ultraviolet lamp at a temperature of 25°C for 30 min; the temperature of the second soaking is 40°C, and the soaking time is 120 minutes; other conditions are the same as in Embodiment 1.

[0180] Example 56

[0181] In step (3) of this embodiment during soaking, it is soaked in two times. The temperature of the first soaking is 60°C, the soaking time is 120 minutes, and polymerization is initiated under a 365 nm ultraviolet lamp at a temperature of 25°C for 30 min; the temperature of the second soaking is 60°C, and the soaking time is 120 minutes; other conditions are the same as in Embodiment 1.

[0182] Example 45 - 56According to the method of Example 1, the operation is the same as that of Example 1, except that the number of immersions, temperature, and time in the inner and outer layer precursor solutions are changed. The surface water contact angle, bovine serum albumin, platelet, bacteria, cell adhesion amount, swelling rate, and the thickness of the inner and outer layers of the pericardial anti-adhesion patch prepared under different immersion conditions are measured, as shown in Table 6.

[0183] Table 6 Performance analysis of the anti-adhesion layer prepared under different immersion conditions

[0184]

[0185] It can be seen from the data in Table 6 that the thickness of the inner and outer layers is positively correlated with the number of immersions, immersion temperature, and immersion time, and the greater the thickness of the inner and outer layers, the greater the swelling rate. This is because the inner and outer layers are prepared by swelling. The more the number of immersions, the higher the immersion temperature, and the longer the immersion time, the more molecules swell from the precursor solution into the patch, and the thicker the obtained patch. However, the hydrophilicity and anti-bioadhesion properties of the inner and outer layers are independent of the immersion conditions, because the immersion conditions change the thickness of the inner and outer layers, while the above properties are only related to the surface properties of the inner and outer layers. From the comparison between Examples 51 and 52, when the total immersion time is the same and the immersion times of the first and second times are different, the thicknesses of the inner and outer layers are different. This is because a zwitterionic hydrogel layer has been formed before the second immersion, and its swelling ability is greater than that of the first immersion, so the swelling effect of the second immersion is better.

[0186] Example 57

[0187] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.0004 g, and the others are the same as in Example 1.

[0188] Example 58

[0189] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.0004 g, and the initiator ammonium persulfate in step (1) of Example 1 is replaced with 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959), and the others are the same as in Example 1.

[0190] Example 59

[0191] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.0012 g, and the others are the same as in Example 1.

[0192] Example 60

[0193] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.0012 g. Replace the initiator ammonium persulfate in step (1) of Example 1 with 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959), and the others are the same as in Example 1.

[0194] Example 61

[0195] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.0024 g, and the others are the same as in Example 1.

[0196] Example 62

[0197] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.0024 g. Replace the initiator ammonium persulfate in step (1) of Example 1 with 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959), and the others are the same as in Example 1.

[0198] Example 63

[0199] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.004 g, and the others are the same as in Example 1.

[0200] Example 64

[0201] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.004 g. Replace the initiator ammonium persulfate in step (1) of Example 1 with 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959), and the others are the same as in Example 1.

[0202] Example 65

[0203] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.008 g, and the others are the same as in Example 1.

[0204] Example 66

[0205] In step (1) of this example, the addition amount of N,N-bis(acryloyl)cysteamine (BAC) is 0.008 g. Replace the initiator ammonium persulfate in step (1) of Example 1 with 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959), and the others are the same as in Example 1.

[0206] Example 67

[0207] In step (1) of this example, the addition amount of N, N-bis(acryloyl)cysteamine (BAC) is 0.02 g, and the others are the same as in Example 1.

[0208] Example 68

[0209] In step (1) of this example, the addition amount of N, N-bis(acryloyl)cysteamine (BAC) is 0.02 g. The initiator ammonium persulfate in step (1) of Example 1 is replaced with 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I-2959), and the others are the same as in Example 1.

[0210] Example 57 - 68 According to the method of Example 1, the operation is the same as in Example 1, except that the dosage of the crosslinking agent BAC used in the intermediate layer (the mass percentage of the crosslinking agent dosage in NAGA is 0.1 w%-5 w%) and the type of initiator are changed. The tensile strength, suture strength and pore size of the intermediate layer prepared with different BAC dosages and different types of initiators are measured, as shown in Table 7.

[0211] Table 7 Tensile strength and suture strength of P prepared with different dosages of crosslinking agent and different types of initiators in the intermediate layer S@N@S of the intermediate layer

[0212]

[0213] As can be seen from Table 7, within a certain range, as the content of the crosslinking agent BAC increases, the mechanical strength of the intermediate layer patch increases. However, when the W BAC / W NAGA content exceeds 1%, as the content of WBAC further increases, the tensile strength and suture strength of the intermediate layer patch will instead decrease. This is because too high a crosslinking agent content will cause the network structure of the patch to become brittle. The enhanced brittleness limits the ability of the material to produce elastic deformation during tension or shear, thus weakening its mechanical strength. In addition, excessive BAC may inhibit the mobility of polymer segments and reduce the energy dissipation ability of the hydrogel network. As the content of the crosslinking agent BAC increases, the pore size of the intermediate layer gradually becomes smaller, which is because the increase in crosslinking density restricts the spatial expansion of polymer chains, resulting in network contraction and the formation of a denser internal structure.

[0214] The characterization method of P prepared by the present invention is as follows: S@N@S Specific contents are as follows:

[0215] 1. Surface and cross-section morphology test of P under scanning electron microscope: S@N@S

[0216] The surface and cross-sectional morphologies of the hydrogel anti-adhesion film were analyzed using a field emission scanning electron microscope (S-4800, HITACHI). First, the samples were immersed in PBS solution, ultrasonically cleaned, and then freeze-dried. The samples were cut into 1×1 cm 2 sizes, sputter-coated with gold on the surface, and fixed on the observation platform with conductive glue. During observation, the acceleration voltage was set to 15 eV.

[0217] The cross-section and surface SEM images of the P prepared in Example 1 of the present invention S@N@S are shown as follows. As can be seen from Figure 2 it, the patch exhibits an obvious three-layer composite structure, and the layers are tightly bonded to each other. This is because an interfacial molecular chain interpenetration method is used for connection, thus forming a stable gradient cross-linked structure. In addition, the pore size of the middle-layer hydrogel is significantly smaller than that of the inner and outer-layer hydrogels, mainly because the middle layer has a higher cross-linking degree, resulting in a denser pore structure. Figure 2

[0218] 2. Tensile strength test:

[0219] The mechanical behaviors of P N , P S and P S@N@S were evaluated using a universal testing machine QC-506 (Shanghai Jiaye Precision Instrument Co., Ltd.), and the tensile experiments were carried out at room temperature. First, the samples were prepared into standard dumbbell-shaped specimens (20×4×3 mm) and fixed on the tensile machine. Then, the tensile experiment was carried out at a rate of 100 mm / min under a 50 N load cell. Five samples of each type of film were tested, and the load-extension behavior of the film specimens was recorded. Finally, the stress-strain curves were plotted using the original data.

[0220] The tensile strength diagrams of the P N , P S@N@S prepared in Example 1 of the present invention and the P S prepared in Comparative Example 1 are shown as follows. As can be seen from Figure 3 it: The tensile strength of P Figure 3 is the weakest, while that of P S is comparable to that of P S@N@S and P N , indicating that the middle P S@N@S layer in P N effectively improves the tensile strength of the entire three-layer composite structure, enabling it to meet the surgical requirements.

[0221] 3. Surface Young's modulus test:

[0222] The surface Young's modulus of the hydrogel was tested using a bench-top PIUMA nanoindenter (Optics 11, Netherlands). First, the samples were cut into small pieces (10×10 mm​2 ) It was then fixed on the sample stage, and then tested with a standard three-sided pyramidal Berkovich probe. This experiment was measured in an underwater environment at room temperature. In this experiment, the grid scan was 5×5 points, the point spacing was 20 μm, and the detection area was 100×100 μm 2 . The loading / unloading rate was set at 1.2 mN / s, and the loading holding time was 0.1 s. Data processing was performed by the accompanying analysis software.

[0223] P prepared in Example 1 of the present invention N , P S@N@S and P prepared in Comparative Example 1 S The surface Young's modulus is as Figure 4 shown. It can be seen from Figure 4 that: compared with P N , the surface Young's modulus of P S@N@S and P S is lower, indicating that it has better surface softness.

[0224] 4. Suture strength test:

[0225] The suture strength of three groups of hydrogel films was tested using a universal testing machine QC-506, and the experiment was carried out at room temperature. The specific experimental steps are as follows: A suture of size 5 / 0 was penetrated through the hydrogel film 5 mm from the end, and the suture was stretched at a speed of 50 mm / min. Five samples of each type of film were tested, and the average force required to pull through each group of hydrogel films was recorded and calculated, which is the suture strength.

[0226] P prepared in Example 1 of the present invention N , P S@N@S and P prepared in Comparative Example 1 S The suture strength is as Figure 5 shown. It can be seen from Figure 5 that: P S@N@S and P N patches can withstand the pulling force during suture and maintain integrity and stability.

[0227] 5. Coefficient of friction test:

[0228] The coefficient of friction of the surfaces of three groups of hydrogel films was tested using a TRB tribometer (CSM, Switzerland). The specific experimental operation was as follows: First, the surface of the sample to be tested was rinsed with deionized water and thoroughly hydrated, and then the sample was cut into a suitable size (10×10 mm 2On the left and right), and fix it on the platform with double-sided tape. Under a normal load of 800 μN, a glass ball with a diameter of 3 mm was slid on the substrate at a sliding speed of 30 mm / min for 20 mm. The same sample was subjected to 5 repeated experiments, and the final result was the average value. The friction coefficient was calculated as the frictional force divided by the corresponding normal load (800 μN).

[0229] P prepared in Example 1 of the present invention N , P S@N@S and P prepared in Comparative Example 1 S The friction coefficient diagrams are as shown in Figure 6 shown. It can be seen from Figure 6 that: compared with the P N patch, P S@N@S and P S have extremely low friction coefficients on the surface and exhibit superlubricity. This is because the introduction of zwitterions forms a hydrated layer on the surface, greatly reducing the friction coefficient.

[0230] 6. Anti-bioadhesion test:

[0231] Protein adhesion test: The test method used in the protein adsorption experiment was the BCA protein kit method. The adhesion behavior of bovine serum albumin on the sample was tested and characterized. First, the sample was cut into a size of 1×1 cm 2 , soaked in PBS solution at 37 °C for 6 h, then the cut samples were grouped and immersed in the protein solution (2.0 mg·mL -1 bovine serum albumin solution) and soaked at 37 °C for 2 h. Subsequently, the samples were rinsed with fresh PBS solution and transferred to a 96-well plate containing 1.0 wt% sodium dodecyl sulfate (SDS) solution, and ultrasonically treated at room temperature for 20 min to separate the adsorbed protein. Finally, the absorbance at 562 nm was measured using a BCA protein analysis kit to obtain the protein concentration.

[0232] Bacterial adhesion test: Escherichia coli was used for the bacterial adhesion experiment. First, the sample was cut into a square of 1 cm×1 cm, sterilized by irradiation under ultraviolet light for 30 min, and then transferred to a 24-well plate. Then, 1 mL of bacterial suspension (concentration of 1.0×10 8 / mL) was used to completely soak the sample. After incubation at 37 °C for 4 h, the sample was washed three times with PBS to remove the bacteria that were not adhered or loosely adhered on the surface. At 4 °C, it was fixed with 4% glutaraldehyde for 12 h, then dehydrated with a series of ethanol with increasing concentrations (50%, 60%, 70%, 80%, 90% and 100%, each for 30 min), and then dried at room temperature for 24 h. The adhered bacteria were observed by SEM.

[0233] P prepared in Example 1 of the present inventionN , P S@N@S and the P prepared in Comparative Example 1 S 's anti-protein and bacterial adhesion performance diagrams are as shown in Figure 8 , Figure 9 . As can be seen from Figure 8 and Figure 9 , compared with the P N patch, the P S@N@S and the P S patch have good anti-bioadhesion performance on the surface; compared with the P N patch, a small amount of bacteria adheres to the surface of the P S@N@S and the P S .

[0234] 7. Water contact angle test:

[0235] The hydrophilicity of both sides of the three-layer zwitterionic hydrogel anti-adhesion film was characterized using a DSA100 (Kruss GmbH, Germany) contact angle measuring instrument. The dried three-layer zwitterionic hydrogel anti-adhesion film was attached to a glass slide and installed on the goniometer. In static contact angle measurement, at room temperature and a relative humidity of 80%, a total of 3 μL of double-distilled water was dropped on the air-side surface of the sample, and the water contact angle of the surface was measured. Each group was measured five times, and the average value was taken.

[0236] The water contact angle measurement diagrams of the P N , P S@N@S prepared in Example 1 of the present invention and the P S prepared in Comparative Example 1 are as shown in Figure 7 . As can be seen from Figure 7 : compared with the P N patch, the P S@N@S and the P S have extremely low water contact angles on the surface and have good hydrophilicity, which is due to the strong interaction between the zwitterionic hydrogel surface and water, reducing the water contact angle.

[0237] 8. Cytotoxicity test:

[0238] After sterilizing the sample (2×2 mm 2 ) by ultraviolet irradiation at room temperature for 4 h, it was placed in a 96-well plate, and the cells were diluted to a concentration of 1×10 5 cell / mL. 100 μL was added to each well in the 96-well plate, and after 24 h, the cell proliferation rate was detected using the Cell Counting Kit-8 (CCK8) method.

[0239] The cytotoxicity of the P S@N@S prepared in Example 1 of the present invention is as shown in Figure 10 . As can be seen from Figure 10It can be seen that the patch has good cell compatibility.

[0240] 9. Postoperative pericardial anti-adhesion model in rabbits:

[0241] New Zealand white rabbits (aged 3 - 4 months, weighing 2.5 - 3.5 kg) were divided into 5 groups (n = 5 in each group). Anesthesia was provided by intramuscular injection of 20 mg / kg ketamine and 3 mg / kg diazepam. The rabbits were fixed in the supine position on the operating table, and 2.0% isoflurane was continuously provided using a respiratory anesthesia machine. The anterior chest was shaved and cleaned with povidone-iodine. Under sterile conditions, a left anterior thoracotomy was performed through the fourth intercostal space, and a pericardiectomy of approximately 2 cm 2 was carried out. The exposed epicardial surface was dried with sterile gauze and rubbed for 3 minutes to induce adhesions. In the control group (control group), the pericardium was left open, while in the treatment group, the membrane was used for isolation, and the membrane was sutured to the pericardium with 6-0 Prolene ( S@N@S Cincinnati, OH, USA). The sternum was closed with four interrupted 2-0 silk sutures. The muscle and skin were closed with 3-0 Dexon-II continuous sutures. The postoperative pericardial anti-adhesion model of rabbits prepared in Example 1 of the present invention is as

[0242] shown. It can be seen from S@N@S that the patch has a good function of preventing postoperative pericardial adhesion. Figure 11 From Figure 11 It can be seen that the patch has good postoperative pericardial anti-adhesion prevention function.

[0243] 10. Sheep left ventricular assist device (LVAD) adhesion model:

[0244] The Tailhan sheep (age: 16 - 18 months; weight: 54 - 62 kg; gender: male) were divided into two groups (5 sheep in each group). All sheep were fasted for 24 hours and water - deprived for 20 hours before surgery. Before surgery, the sheep were sedated by intramuscular injection of detomidine (1.0 mg / kg). Intravenous anesthesia was induced by injecting propofol (60 - 200 mg) through the marginal ear vein, followed by endotracheal intubation and mechanical ventilation. A positive - pressure ventilator and a 7 - mm endotracheal tube were used to supply oxygen to the sheep at a flow rate of 1.2 L / min. Anesthesia was maintained by continuous infusion of detomidine (0.5 - 1 mg / kg / h) and succinylcholine (50 - 100 mg / h). The chest area was disinfected with 7.5% povidone - iodine solution. Thoracotomy was performed at the left fifth intercostal space, incising the skin, subcutaneous tissue, and muscle layer to enter the thoracic cavity. Lidocaine (2 mg / min) was infused to prevent arrhythmia. The pericardium was incised from the cardiac apex to the pulmonary artery, and the heart was suspended on a pericardial support. The placement position of the pump was determined according to the apex position. Heparin (1.0 mg / kg) was intravenously infused, and after the whole - blood clotting time exceeded 450 seconds, the descending aorta was dissected for outflow - tube anastomosis. Using partial occlusion clamps, a 10 - mm outflow tube was sutured to the side - end of the descending aorta with 4 - 0 Prolene. Hemostatic measures were applied at the anastomosis site to reduce the impact of excessive bleeding on volume load. An eight - interrupted - suture fixation ring was made at the left ventricular apex. Warm saline was injected into the left thoracic cavity. A cross - shaped incision was made on the beating heart. Subsequently, the ventricular septum was advanced through the ventricular suture ring, the left ventricular core was removed, and the pump was inserted into the left ventricular cavity and fixed. The pump was started at a speed of 2000 rpm. Subsequently, the heart was closed. The control group (control group) left the pericardium open, while the treatment group sutured an 8 cm × 10 cm P S@N@S patch. The patch was sutured to the pericardium with 6 - 0 Prolene. The sternum was closed with four interrupted 2 - 0 silk sutures. The muscle and skin were closed in layers with 3 - 0 Dexon - II continuous sutures.

[0245] The P prepared in Example 1 of the present invention S@N@S The adhesion model of the left ventricular assist device (LVAD) in sheep is as Figure 12 shown. It can be seen from Figure 12 that the patch has a good function of preventing postoperative pericardial adhesion.

[0246] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above - mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention. In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A pericardial anti-adhesion patch with a three-layer composite structure, characterized in that: The pericardial anti-adhesion patch has a three-layer composite structure hydrogel film, including an inner layer, a middle layer and an outer layer. The middle layer is a poly-(N-acryloylglycine amide) hydrogel material, and the inner and outer layers are zwitterionic hydrogel materials. The middle layer is combined with the inner and outer layers through an interpenetrating polymer network.

2. The pericardial anti-adhesion patch with a three-layer composite structure according to claim 1, characterized in that: The composition of the poly-(N-acryloylglycine amide) hydrogel material in the middle layer is as follows: the concentration of N-acryloylglycine amide monomer is 5w%-80w%, the dosage of cross-linking agent N,N-bis(acryloyl)cysteamine accounts for 0.1w%-5w% of the mass of N-acryloylglycine amide, and the dosage of initiator accounts for 0.5w%-20w% of the mass of N-acryloylglycine amide.

3. The pericardial anti-adhesion patch with a three-layer composite structure according to claim 1, characterized in that: The composition of the zwitterionic hydrogel materials in the inner and outer layers is as follows: the concentration of zwitterionic monomer is 10w%-80w%, the concentration of N-acryloylglycine amide monomer is 5w%-40w%, the dosage of cross-linking agent accounts for 0.5w%-15w% of the mass of zwitterionic monomer, and the dosage of initiator accounts for 0.5w%-20w% of the mass of zwitterionic monomer.

4. The pericardial anti-adhesion patch with a three-layer composite structure according to claim 3, characterized in that: The zwitterionic monomer is at least one of methacryloylethylsulfobetaine, 2-methacryloyloxyethylphosphorylcholine, and carboxybetaine methacrylate; The cross-linking agent in the zwitterionic hydrogel is at least one of N,N-bis(acryloyl)cysteamine, N,N-bis(acryloyl)cystamine, ethylene glycol dimethacrylate, and bis-methacryloylethylcarboxybetaine; In the zwitterionic hydrogels of the inner and outer layers, the concentration of zwitterionic monomer is 30w%-75w%, the concentration of N-acryloylglycine amide monomer is 6w%-24w%, and the dosage of cross-linking agent accounts for 0.5w%-2w% of the mass of zwitterionic.

5. The pericardial anti-adhesion patch with a three-layer composite structure according to claim 2 or 3, characterized in that: The initiator is ammonium persulfate or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone.

6. The pericardial anti-adhesion patch with a three-layer composite structure according to claim 1, wherein: The thickness of the poly-(N-acryloylglycine amide) hydrogel layer in the middle layer is 50-1000μm, and the average pore size is 3-5μm; the thickness of the zwitterionic hydrogel layers in the inner and outer layers is 10-800μm, and the average pore size is 2-70μm.

7. A preparation method of the pericardial anti-adhesion patch with a three-layer composite structure as described in claim 1, characterized in that: Step 1: Add distilled water to zwitterionic monomer, N-acryloylglycine amide, cross-linking agent and initiator to prepare the precursor solution for the inner and outer layers; Add distilled water to N-acryloylglycine amide, N,N-bis(acryloyl)cysteamine and initiator to prepare the precursor solution for the middle layer; Step 2: Inject the precursor solution for the middle layer into a mold with a rectangular groove, put it into an oven, and heat and polymerize at 50-80°C for 15-30 minutes. After molding, the obtained hydrogel is repeatedly washed with deionized water, and then dried at 50-80°C for 5-10 minutes to obtain the poly-(N-acryloylglycine amide) in the middle layer; Step 3: Place the poly-(N-acryloylglycine amide) hydrogel in the inner and outer precursor solutions for 15 - 120 min to allow the middle layer to absorb the inner and outer precursor solutions, and then initiate polymerization with a 365 nm ultraviolet lamp at a temperature of 10 - 60 °C for 30 - 60 min to form a pericardial anti-adhesion patch.

8. The preparation method of the pericardial anti-adhesion patch with a three-layer composite structure according to claim 7, characterized in that: Continue to soak the pericardial anti-adhesion patch in the inner and outer precursor solutions for 15 - 120 min to allow the pericardial anti-adhesion patch to continuously absorb the inner and outer precursor solutions, and then initiate polymerization with a 365 nm ultraviolet lamp at a temperature of 10 - 60 °C for 30 - 60 min to form a pericardial anti-adhesion patch with enhanced layer thickness.

9. The preparation method of the pericardial anti-adhesion patch with a three-layer composite structure according to claim 7 or 8, characterized in that: When heating for polymerization, the temperature is 60 °C and the time is 20 min; when initiating polymerization with a 365 nm ultraviolet lamp, the temperature is 25 °C and the time is 30 min.

10. Use of an anti-adhesion patch as claimed in claim 1 in a pericardial anti-adhesion patch after cardiac surgery.

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