CN114796583B

CN114796583B - Polythioctic acid-based biomedical patch material and preparation method thereof

Info

Publication number: CN114796583B
Application number: CN202210305032.7A
Authority: CN
Inventors: 王玮; 孔晓玲
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2023-02-10
Anticipated expiration: 2042-03-25
Also published as: CN114796583A

Abstract

The invention discloses a preparation method of a biomedical patch material based on polythiooctanoic acid, which comprises the following steps: adding double-end double-bond monomer and histamine dihydrochloride into an organic solvent to dissolve to form a mixed solution; adding organic base into the mixed solution to adjust the pH, heating the mixed solution for reaction, and purifying to obtain hyperbranched poly-beta-amino ester; dissolving dopamine in an alkaline aqueous solution, polymerizing to prepare polydopamine, and purifying to obtain polydopamine; sequentially adding the polydopamine alkaline solution and the hyperbranched poly beta-amino ester into a lipoic acid monomer, heating and stirring; and then adding a silver ion solution, continuously heating, and cooling to room temperature to obtain the poly lipoic acid-poly dopamine-hyperbranched poly beta amino ester-nano silver medical patch material. The invention also discloses a biomedical patch material based on the polythiooctanoic acid, which is prepared by the preparation method. The biomedical patch material has excellent elasticity and self-repairability, and has good adhesion to various materials; it has obvious antibacterial, antioxidant and biocompatibility.

Description

Polythioctic acid-based biomedical patch material and preparation method thereof

Technical Field

The invention belongs to the technical field of biomedical materials, and particularly relates to a biomedical patch material based on polythiooctanoic acid and a preparation method thereof.

Background

Currently, it is of great significance to develop multifunctional adhesive materials to meet the diverse requirements of medical treatment. For example, in the field of skin repair, millions of people suffer from accidental wounds or surgical wounds every year, the improvement of the wound healing rate of skin wounds is always a main clinical challenge, and a wound dressing material with multiple functions of tissue adhesion property, appropriate mechanical strength, antibiosis, antioxidation, anti-inflammation and the like can meet the requirements of wound covering and rapid healing; in the field of intelligent medical monitoring, the adhesiveness, elasticity and self-healing capability of the sensor material are of great significance to the improvement of the fitting degree and accuracy of the sensor and the human skin and the prolonging of the service life of the device.

At present, due to the extensive development of supramolecular chemistry, many reversible non-covalent or dynamic covalent materials are being explored and utilized, adhesive materials comprising multiple physicochemical actions are also emerging to replace traditional covalent materials, and reversibility, repeatability and self-healing are expected to be realized through reversible crosslinking and synergistic self-assembly characteristics, so that the adhesive becomes an 'intelligent' adhesive.

Naturally-occurring small-molecule lipoic acid is an ideal candidate unit for constructing a supramolecular structure, and disulfide bonds containing five-membered rings undergo free radical ring-opening polymerization and dynamic disulfide bond exchange under the initiation of heat above the melting temperature of the unit to form a flowing linear framework. It exhibits unstable behavior upon cooling because the reverse ring-closure depolymerization process initiated by the terminal disulfide radical will spontaneously revert to an oligomer, requiring the addition of other monomers to form a copolymer to avoid this tendency, such as quenching the terminal radical with a double bond monomer, introducing a C-S covalent bond to strengthen the network.

The lipoic acid copolymer (PALA) system has excellent performance and wide application, firstly, the lipoic acid monomer is of biological origin and has oxidation resistance, and the oxidation resistance can be still maintained after the lipoic acid monomer is polymerized; the abundant sulfydryl and carboxyl in a molecular chain bring good adhesion, and various non-covalent actions endow the molecular chain with excellent self-repairing performance; and a hierarchical self-assembly structure can be customized, such as unsaturated H bonds, high-valence ion-carboxylic acid coordination, disulfide dynamic covalent exchange and the like, so as to form a supramolecular polymer network and bring flexibly adjustable mechanical properties. For example, chinese patent publication No. CN108997575a discloses a polyethylene glycol-b-polytyrosine-lipoic acid copolymer, a polypeptide micelle, and a preparation method and an application thereof.

There are problems with lipoic acid copolymer systems used for biomedical applications. Firstly, the lipoic acid monomer has poor water solubility, which causes difficulty in the preparation process, such as post-treatment and toxicity of organic solvents; secondly, the lipoic acid copolymer has almost no adhesion to tissues, and the general solution is to introduce structures such as N-hydroxysuccinimide group (NHS) and catechol, and the structures are connected to the lipoic acid monomer through organic synthesis in the prior art, so the steps are complicated; then, toxicity of the added double bond monomer and metal ions is also a big problem, and toxicity is inevitably introduced by small molecular monomers (such as diisopropenyl benzene, acrylic acid, choline chloride) and metal ions (such as iron ions) used in the past.

In conclusion, the present invention has been made in an effort to provide a medical patch material based on lipoic acid having strong tissue adhesion and high biocompatibility.

Disclosure of Invention

The invention aims to provide a biomedical patch material based on polythiooctanoic acid and a preparation method thereof, the prepared biomedical patch material has multiple physicochemical actions, excellent elasticity and self-repairability, and good adhesiveness to various materials including tissues; it has obvious antibacterial, oxidation resistance and biocompatibility.

The purpose of the invention is realized by the following technical scheme:

a preparation method of a biomedical patch material based on polythiooctanoic acid comprises the following steps:

(1) Adding double-end double-bond monomer and histamine dihydrochloride into an organic solvent to dissolve to form a mixed solution; adding organic base into the mixed solution to adjust the pH, and then heating the mixed solution for reaction to obtain hyperbranched poly-beta-amino ester;

(2) Dissolving dopamine in an alkaline aqueous solution, and polymerizing to prepare polydopamine;

(3) Sequentially adding the polydopamine alkaline solution and the hyperbranched poly beta amino ester into a lipoic acid monomer, heating and stirring; and then adding a silver ion solution, continuously heating, and cooling to room temperature to obtain the poly lipoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material PALA-PDA-HPAE-Ag.

Preferably, in step (1), the double-terminal double bond monomers used include, but are not limited to, methylene Bisacrylamide (MBA) and polyethylene glycol diacrylate (PEGDA).

Preferably, in step (1), the molar ratio of the double bond in the double-ended double bond monomer to the amino-active hydrogen in histamine dihydrochloride is 3:1-1.05.

Preferably, in step (1), the organic solvent is selected from one or a combination of at least two of dimethyl sulfoxide, absolute ethanol, methanol, acetonitrile, acetone or N, N-dimethylformamide.

Preferably, in step (1), an organic base is added to adjust the pH to 8-11. Wherein the organic base can be triethylamine.

Preferably, in step (1), the reaction is carried out for 1 to 10 hours under the condition of oil bath at the temperature of between 50 and 100 ℃ and protection from light.

Preferably, in step (1), the precipitating agent used in the purification includes, but is not limited to, methyl tert-butyl ether and diethyl ether.

Preferably, in step (1), the purified HPAE is stored at a temperature below 4 ℃.

Preferably, step (1) further comprises purifying the obtained hyperbranched poly-beta-amino ester.

Preferably, in step (2), the pH of the basic aqueous solution is 8 to 10. Wherein the alkaline aqueous solution is sodium hydroxide aqueous solution.

Preferably, the step (2) further comprises purifying the prepared polydopamine.

Preferably, in step (3), the ratio of dopamine PDA to lipoic acid is in the range of 5-10% by mass.

Preferably, in step (3), the ratio of the hyperbranched poly-beta-amino ester HPAE to the lipoic acid is in the range of 10-20% by mass.

Preferably, in the step (3), the heating conditions are: the oil bath heating temperature is 60-120 ℃.

Preferably, in step (3), the silver ion solution includes, but is not limited to, silver nitrate aqueous solution and ethanol solution of silver methylsulfonate, wherein the silver ion accounts for the mass fraction range of 0.05-0.5% of the whole system.

The invention also discloses the biomedical patch material based on the polythiooctanoic acid prepared by the preparation method.

The invention also discloses a chemical structure characterization method of the biological medical patch material based on the polythiooctanoic acid, which is prepared by the preparation method.

The invention also discloses a mechanical property and self-repairing characterization method of the biomedical patch material based on the polythiooctanoic acid, which is prepared by the preparation method.

The invention also discloses a characterization method of the adhesion performance of the biological medical patch material based on the polythiooctanoic acid, which is prepared by the preparation method.

The invention also discloses a biocompatibility characterization method of the biological medical patch material based on the polythiooctanoic acid, which is prepared by the preparation method.

The invention also discloses a characterization method of the antibacterial and antioxidant properties of the biomedical patch material based on the polythiooctanoic acid prepared by the preparation method.

The poly lipoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material (PALA-PDA-HPAE-Ag) is prepared by a lipoic acid monomer dissolved in an alkaline polydopamine solution, double-bond terminated hyperbranched poly beta amino ester HPAE and silver ions under a heating condition and contains a multi-stage self-assembly physicochemical action.

Dopamine is a common adhesion monomer, the structure of the dopamine contains catechol groups which are very active and can be oxidized and polymerized to form a polydopamine aqueous solution, and a lipoic acid monomer has good solubility in the alkaline aqueous solution and has no influence on the ring-opening polymerization behavior. Based on the mussel adhesion mechanism, polydopamine can significantly improve the tissue adhesion of the material. Based on Michael addition reaction, the acrylate-terminated hyperbranched poly beta amino ester (HPAE) is synthesized from excessive double-end double-bond small molecular monomer and histamine dihydrochloride (HIS), and is used for terminating terminal sulfur free radical of the polythiooctanoic acid and stabilizing materials, and the toxicity of small molecules can be effectively avoided. Meanwhile, imidazole in HPAE can strongly chelate silver ions in the system. The polysulfide octanoic acid reduces silver ions in situ to generate nano silver, and strong coordination action is generated between the nano silver and a disulfide bond, so that the mechanical strength can be improved, and the material has excellent antibacterial performance.

Specifically, lipoic acid monomers dissolved in polydopamine solution undergo free radical ring-opening polymerization and dynamic disulfide bond exchange under thermal initiation to form a linear skeleton; then adding a small amount of double-bond terminated hyperbranched poly beta amino ester HPAE to form a C-S covalent bond to stabilize the material; HPAE contains imidazole structure from histamine, which can play a role of framework, and rapidly complex with silver ions added subsequently, so that the silver ions are fixed in situ in a system; finally, silver ions can be reduced into nano silver by the poly lipoic acid, and the nano silver has strong complexing effect with a disulfide bond to form the poly lipoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material (PALA-PDA-HPAE-Ag).

The invention has the following beneficial effects:

the PALA-PDA-HPAE-Ag elastomer patch is prepared by taking biological source micromolecule lipoic acid as a main raw material and through structural design, the problems that the conventional lipoic acid copolymer is difficult to prepare in a water phase, has poor tissue adhesiveness and has potential toxicity are solved, and the problems that nano silver is gathered and dispersed unevenly by in-situ fixing and in-situ reduction methods are avoided.

Abundant physicochemical interaction exists in the system. Firstly, there are a number of different non-covalent and dynamic covalent bonds, such as H bonds, dynamic disulfide bonds, ag-disulfide bond coordination bonds provided by the side chain carboxyl groups of polythiooctanoic acid, the catechol of polydopamine, and the amide and amino groups in HPAE, and secondly, both HPAE and polydopamine form mild chemical crosslinks (containing multiple physicochemical interactions) to the network of lipoic acid through C — S covalent bonds. The customized graded self-assembly structure endows the material with flexibly adjustable mechanical properties and quick self-repairing capability at normal temperature.

Compared with the reported polythiooctanoic acid-based supramolecular adhesive, the patch material provided by the invention is not required to be heated to be converted into liquid and then applied to a base material for cooling, and is convenient to carry and take along. While its flexibility makes it like a liquid adhesive both surface spreading and shape-adapting. The patch disclosed by the invention has a quick and lasting adhesion effect on a metal base material, an inorganic non-metal base material, a high-molecular base material, animal tissues and the like.

Through a fine structural design, the PALA-PDA-HPAE-Ag patch material can meet the diversified requirements of medical treatment. Such as use as a wound dressing may promote wound healing on full-thickness skin defect models; the sensor is designed to be used as an adhesion strain sensor, and can accurately monitor and record external changes and human body movement.

Drawings

FIG. 1 is a schematic diagram of the synthesis of hyperbranched poly β amino ester HPAE1 in example 1.

FIG. 2 is a schematic diagram of the synthesis of hyperbranched poly β amino ester HPAE2 in example 2.

FIG. 3 is a schematic diagram of the synthesis of polydopamine PDA in the example.

FIG. 4 is a drawing of hyperbranched poly β amino ester HPAE1 of example 1 ¹ H-NMR spectrum.

FIG. 5 is a Raman spectrum of the PALA-PDA-HPAE-Ag medical patch material in example 2.

FIG. 6 is an XPS spectrum of the PALA-PDA-HPAE-Ag medical patch material of examples 1 and 2.

FIG. 7 is a photograph of a manual tensile test of the PALA-PDA-HPAE-Ag medical patch material of example 2.

FIG. 8 is a statistical graph of the stress-strain curve and elastic modulus of the medical patch material PALA-PDA-HPAE-Ag in example 1.

FIG. 9 is a self-repairing stress-strain curve and a self-repairing efficiency statistical chart of the medical PALA-PDA-HPAE-Ag patch material in example 1.

FIG. 10 shows the tissue adhesion of the PALA-PDA-HPAE-Ag medical patch material of example 1 to pig skin.

FIG. 11 shows the adhesion of the PALA-PDA-HPAE-Ag medical patch material of example 2 to various tissues and organs.

FIG. 12 shows the results of the lap shear test of the adhesion of the PALA-PDA-HPAE-Ag medical patch material of example 1 to different kinds of substrates.

FIG. 13 shows the survival rate of L929 cells measured using MTT method for PALA-PDA-HPAE-Ag medical patch materials in examples 1 and 2.

Fig. 14 shows the results of the relative activity of bacteria measured using the bacterial suspension experiment for the PALA-PDA-HPAE-Ag medical patch materials of examples 1 and 2.

FIG. 15 shows the ROS trapping efficiency of the PALA-PDA-HPAE-Ag medical patch materials of examples 1 and 2 measured using DPPH scavenging method.

Detailed Description

The following is a detailed description of the present invention with reference to specific examples, which are not intended to limit the invention.

The invention discloses a poly lipoic acid-poly dopamine-hyperbranched poly beta amino ester-nano silver patch material (PALA-PDA-HPAE-Ag) containing multi-stage self-assembly physicochemical action, which is constructed by lipoic acid monomers, double-bond-terminated hyperbranched poly beta amino ester HPAE and silver ions dissolved in an alkaline poly dopamine solution, and comprises the following steps:

(1) Double-ended double bond monomer and histamine dihydrochloride (HIS) were added to the organic solvent and allowed to dissolve well in the round-bottom flask. Adding organic base into the mixed solution to adjust the pH value, and then placing the mixed solution in an oil bath to be heated and react in a dark place. And naturally cooling to room temperature after the reaction is finished. Filtering the reaction mixed solution to remove salt precipitate generated in the reaction process; then, the reaction mixture was sufficiently washed with 5 times the amount of the precipitant for the product to remove the solvent and the unreacted monomer, and the polymer was vacuum-dried to remove the excessive purifying agent.

(2) Polydopamine was prepared by dissolving dopamine in aqueous sodium hydroxide and autopolymerized for 1 day with stirring. Then purifying by an acetone precipitation method: taking 2mL of dispersion, slowly dripping acetone (16 mL) into the dispersion under a rapid stirring state, standing and settling after dripping, collecting precipitates by low-speed centrifugation (500 r/min,5 min) after settling for 10min, removing supernate, washing the precipitates for 3 times by using acetone, naturally drying, weighing 0.1g of polydopamine, and re-dispersing the polydopamine into 2mL of sodium hydroxide aqueous solution for storage.

(3) Adding 2.0g of lipoic acid monomer into a 50mL centrifuge tube, sequentially adding a certain amount of polydopamine solution and the synthesized hyperbranched poly-beta-amino ester, heating and stirring in an oil bath for 20min, adding a silver ion solution, continuously heating and stirring for 10min, cooling to room temperature to obtain a patch material, and placing in an oven at 60 ℃ for balancing for 3 days.

(4) And (3) characterizing the chemical structure of the poly lipoic acid-poly dopamine-hyperbranched poly beta amino ester-nano silver medical patch material (PALA-PDA-HPAE-Ag).

(5) The mechanical properties and self-repairing characteristics of the medical patch material (PALA-PDA-HPAE-Ag) are represented.

(6) And (3) characterization of adhesion performance of the polythiooctanoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material (PALA-PDA-HPAE-Ag).

(7) And (3) characterization of biocompatibility of the poly lipoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material (PALA-PDA-HPAE-Ag).

(8) And (3) characterization of antibacterial and antioxidant properties of the polythiooctanoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material (PALA-PDA-HPAE-Ag).

Example 1

(1) Preparation of hyperbranched poly-beta-amino ester HPAE 1:

methylene bisacrylamide (MBA, 6.940g, 45mmol) and histamine dihydrochloride (HIS, 1.900g, 10mmol) were added to 30mL of dimethyl sulfoxide and sufficiently dissolved in a round-bottomed flask, wherein the molar ratio of the double bond to the amino active hydrogen was 3:1. And adding triethylamine into the mixed solution to adjust the pH value to 8, and then placing the mixed solution in an oil bath at 60 ℃ to be heated and react for 6 hours in a dark place. And naturally cooling to room temperature after the reaction is finished. Filtering the reaction mixed solution to remove salt precipitate generated in the reaction process; then, the reaction mixture was sufficiently washed with 5 times the amount of methyl t-butyl ether as the product to remove the solvent and unreacted monomers, and the polymer was vacuum-dried to remove the excess purifying agent. The purified HPAE1 was stored in a refrigerator at-20 ℃.

(2) Preparation of polydopamine:

polydopamine was prepared by dissolving dopamine in aqueous sodium hydroxide (pH = 9) and self-polymerized for 1 day with stirring. Then purifying by an acetone precipitation method: taking 2mL of dispersion, slowly dripping acetone (16 mL) under the condition of rapid stirring, standing and settling after dripping, collecting precipitate after settling for 10min, centrifuging at low speed (500 r/min,5 min), removing supernatant, washing the precipitate for 3 times by using acetone, naturally drying, weighing 0.1g of polydopamine, and re-dispersing in 2mL of sodium hydroxide aqueous solution (pH = 9) for storage.

(3) Preparing a medical patch material (PALA-PDA-HPAE-Ag) comprising the following components:

2.0g of lipoic acid monomer is added into a 50mL centrifuge tube, and then 2mL of polydopamine solution and 0.3g of synthesized hyperbranched polymer are sequentially added, wherein the mass ratio of dopamine to lipoic acid is 5%, and the mass ratio of hyperbranched poly-beta-amino ester HPAE1 to lipoic acid is 15%. Then, the mixture was heated and stirred in an oil bath at 80 ℃ for 20min, and a silver nitrate aqueous solution (12.5 g/L, 400. Mu.L) was added so that the mass fraction of silver ions in the whole system was 0.1%. Heating and stirring for 10min, cooling to room temperature to obtain patch material, and placing in oven at 60 deg.C for balancing for 3 days.

Example 2

(1) Preparation of hyperbranched poly-beta-amino ester HPAE 2:

polyethylene glycol diacrylate 700 (PEGDA 700,11.025g, 15.75mmol) and histamine dihydrochloride (HIS, 1.900g, 10mmol) were added to 30mL of n, n-dimethylformamide to be sufficiently dissolved in a round-bottom flask, wherein the molar ratio of double bonds to amino active hydrogens was 1.05. And adding triethylamine into the mixed solution to adjust the pH value to 8, and then placing the mixed solution in an oil bath at 60 ℃ to be heated and react for 6 hours in a dark place. And naturally cooling to room temperature after the reaction is finished. Filtering the reaction mixed solution to remove salt precipitate generated in the reaction process; then, the reaction mixture was sufficiently washed with 5 times the amount of diethyl ether as the product to remove the solvent and unreacted monomers, and the polymer was vacuum-dried to remove the excess purifying agent. The purified HPAE2 was stored in a refrigerator at-20 ℃.

(2) Preparation of polydopamine:

polydopamine was prepared by dissolving dopamine in aqueous sodium hydroxide (pH = 9) and autopolymerized for 1 day under stirring. Then purifying by an acetone precipitation method: taking 2mL of dispersion, slowly dripping acetone (16 mL) under the condition of rapid stirring, standing and settling after dripping, collecting precipitate after settling for 10min, centrifuging at low speed (500 r/min,5 min), removing supernatant, washing the precipitate for 3 times by using acetone, naturally drying, weighing 0.1g of polydopamine, and re-dispersing in 2mL of sodium hydroxide aqueous solution (pH = 9) for storage.

(3) Preparing a medical patch material (PALA-PDA-HPAE-Ag) of poly lipoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver:

2.0g of lipoic acid monomer is added into a 50mL centrifuge tube, and then 2mL of polydopamine solution and 0.3g of synthesized hyperbranched polymer are sequentially added, wherein the mass ratio of dopamine to lipoic acid is 5%, and the mass ratio of hyperbranched poly beta amino ester HPAE2 to lipoic acid is 15%. Then, the mixture was stirred in an oil bath at 80 ℃ for 20 minutes, and an ethanol solution (29.9 g/L, 400. Mu.L) of silver methanesulfonate was added so that the mass fraction of silver ions in the whole system was 0.2%. Heating and stirring for 10min, cooling to room temperature to obtain patch material, and placing in oven at 60 deg.C for balancing for 3 days.

Effect verification:

experimental example 1: the chemical structure of the medical patch material (PALA-PDA-HPAE-Ag) of the polythiooctanoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver is characterized in that:

the invention summarizes the synthesis principle of each step in the examples, and the specific results are shown in figures 1-3.

Fig. 1 is a schematic diagram of the synthesis of hyperbranched poly β amino ester HPAE1 in example 1, which is prepared by reacting Methylenebisacrylamide (MBA) and histamine dihydrochloride (HIS) under certain conditions to form hyperbranched poly β amino ester HPAE1. Wherein dimethyl sulfoxide (DMSO) is used as solvent, and Triethylamine (TEA) is used as catalyst.

Fig. 2 is a schematic diagram of the synthesis of hyperbranched poly β -amino ester HPAE2 in example 2, which is prepared by reacting polyethylene glycol diacrylate 700 (PEGDA 700) and histamine dihydrochloride (HIS) as raw materials under certain conditions to form hyperbranched poly β -amino ester HPAE2. Wherein N, N-Dimethylformamide (DMF) is used as a solvent, and Triethylamine (TEA) is used as a catalyst.

Fig. 3 is a synthetic principle diagram of polydopamine in step (2) of the present invention, which is prepared by reacting Dopamine (DA) as a raw material under a certain condition to generate Polydopamine (PDA).

Further, in order to verify the interaction within the patch material, use is made of ¹ The raw materials in the examples and the obtained patch materials were subjected to structural characterization by characterization means such as H-NMR, raman, XPS, etc., and the specific results are shown in FIGS. 4 to 6.

FIG. 4 is a drawing of hyperbranched poly β amino ester HPAE1 of example 1 ¹ From the H-NMR spectrum, it is apparent that new peaks H (4.30 ppm) and i (2.93 ppm) were produced, indicating that the double bond reacted with the amino active hydrogen and that the Michael addition proceeded successfully. No amino group was foundThe peak of active hydrogen, and the related peaks d (6.38 ppm), e (5.91 ppm) and f (5.81 ppm) of the double bond remain, demonstrating that the product was successfully capped with double bonds and that further modification reactions can be carried out. Thus proving the successful synthesis of the terminal double-bond hyperbranched poly-beta-amino ester.

FIG. 5 is a Raman spectrum of the patch material obtained in example 2, and shows a peak (510 cm) of the disulfide bond of protooctanoic acid in the PALA-PDA-HPAE-Ag material ^-1 ) Apparently split into two peaks (508 cm) ^-1 And 525cm ^-1 ) This confirmed ring-opening polymerization of lipoic acid at 673cm ^-1 The C-S bond peak is more pronounced, indicating successful covalent crosslinking between ALA and HPAE.

FIG. 6 is an XPS spectrum of the patch materials obtained in examples 1 and 2, and it can be observed that the Ag 3d orbital peak of the PALA-PDA-HPAE-Ag sample is significantly asymmetric and contains many sub-peaks, such as Ag 0 (Ag and Ag-S, peaks 373.5EV and 367.3 EV) and Ag 1 (Ag ⁺ And Ag ₂ O, peaks at 372.8EV and 366.7 EV), indicating the presence of various forms of elemental silver in the system, demonstrating that the transition from silver ions to nanosilver is achieved by the reduction of the polythiooctanoic acid. Meanwhile, in the Ag-containing sample, the new peak binding energy of the S element moves to a high position, which shows that the S element is coordinated with the Ag element with larger binding energy.

Experimental example 2: the mechanical property and self-repairing characteristics of the medical patch material (PALA-PDA-HPAE-Ag) of the polythiooctanoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver are as follows:

fig. 7 is a photograph of a manual tensile test of the medical patch material obtained in example 2. The elongation of the PALA-PDA-HPAE-Ag patch was over 500%, and even the elongation of the notch sample was over 300%.

In order to characterize the mechanical strength of the obtained medical patch material, a rectangular sample is subjected to tensile test on a tensile machine, the tensile rate is 50mm/min, a stress-strain curve is recorded, and the Young modulus of each sample is calculated according to the slope of the stress-strain curve.

Further, in order to study the self-repairing capability of the obtained medical patch material, the sample is contacted and recovered at room temperature for different times after being out of service, and then the tensile test is carried out by the same method.

Fig. 8 shows the stress-strain curve and the elastic modulus statistics of the medical patch material obtained in example 1. Comparing stress strain curves of three PALA-based patch samples obtained in the preparation process, the elastic modulus of the PALA-PDA sample is about 27kPa, and the elongation at break exceeds 650%; the elastic modulus of the sample is obviously reduced after the HPAE is added, which is probably because the glass transition temperature of the whole patch material is reduced and the curing time is prolonged and weakened due to the addition of the HPAE; when Ag is present ⁺ After introduction, the cohesive strength of the system is obviously increased, the elastic modulus is increased to 69kPa, and the elongation is slightly reduced to about 560%. The patch material obtained by the invention has good elasticity and also has the elastic modulus (dozens of kPa) matched with human soft tissues.

Fig. 9 shows the self-repairing stress-strain curve and the self-repairing efficiency statistics of the PALA-PDA-HPAE-Ag medical patch material obtained in example 1. At room temperature, the damaged sample is contacted again under the condition of not applying any external stimulus, and the elastic modulus can recover to 85.6 percent after 5min, thereby proving that the PALA-PDA-HPAE-Ag patch material has excellent self-repairing performance.

Experimental example 3: the adhesion performance characterization of the polythiooctanoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material (PALA-PDA-HPAE-Ag) is as follows:

fig. 10 shows the tissue adhesion of the medical patch material obtained in example 1. The PDA-PALA-HPAE-Ag patch can be firmly adhered to the surface of the pigskin, and can not fall off when the pigskin is stretched, twisted and impacted by strong water flow, thereby showing high adaptability to the shape of the adhered surface and water resistance.

Fig. 11 shows the tissue adhesion of the medical patch material obtained in example 2. The patch can be adhered to the surface of pig skin, muscle, heart, liver, stomach, etc., and bear its weight.

Further, in order to quantitatively study the adhesion property of the obtained medical patch material, a lap shear test was performed on the medical patch material using a stretching assembly of a universal tensile machine to measure the adhesion strength thereof.

The base materials used for the test are Ti sheets, al sheets, ni sheets, stainless steel sheets, ceramic sheets, glass sheets, PE sheets, PET sheets, PTFE sheets and pigskin. Cutting the elastomer into rectangular sheets, uniformly adhering the rectangular sheets on the surface of one substrate, then contacting the rectangular sheets with the other substrate, recording the area of an adhesion area, and carrying out a lap shear test after all samples are placed at room temperature for 2 hours; the bond strength was calculated as F/S (F is the maximum load and S is the adhesion area).

FIG. 12 shows the results of the lap shear test of the adhesion of the medical patch material obtained in example 1 to various kinds of substrates. It was found that if no PDA was added to the system, the strength of adhesion of the cured patch material to the animal skin was almost negligible, and therefore a great gain in tissue adhesion of the PDA to the patch material was observed. The comparison shows that the relationship of the adhesive strength of the three PALA-PDA based patches obtained in the preparation process is consistent with the relationship of the mechanical strength measured in the experimental example 2. The PDA-PALA-HPAE-Ag patch material has wide and excellent adhesiveness to metal substrates, inorganic non-metal substrates, resin substrates and animal tissues, the adhesive strength to stainless steel exceeds 100kPa, the adhesive strength to PTFE with extremely low surface energy and difficult adhesion generally reaches 30kPa, and the adhesive strength to pigskin is about 26kPa.

Experimental example 4: the biocompatibility characterization of the polythiooctanoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material (PALA-PDA-HPAE-Ag) comprises the following steps:

in order to investigate the biocompatibility of the resulting medical patch material, an in vitro cytotoxicity test was performed thereon using the MTT method and the survival rate of cells was calculated.

First, the samples were sterilized by immersion in 75% ethanol for 24h, and then immersed in PBS buffer to displace the remaining ethanol. At the same time, the L929 cells were treated at 37 ℃ with 5% CO ₂ In a 96-well plate in a humid environment for 24h. The old medium in the well plate was then removed and 200 μ Ι _ of material leach solution was added to each well. After 24h and 48h incubation, the matrix in the wells was replaced by 180. Mu.L of fresh medium and 20. Mu. LMTT, wrapped with tinfoil, mixed thoroughly, and placed into a 37 ℃ incubator in the dark for 4h. All matrices were then removed, 150 μ L of DMSO was added to each well and the well plates were shaken well. Make itThe absorbance of the solution at 570nm in each well was measured with a microplate reader, and the results obtained with untreated cells served as a control. Cell viability was calculated according to the following formula:

wherein, abs _extract And Abs _control Represents the absorbance of the cells cultured in the material extract and the cell culture medium, respectively.

FIG. 13 shows the cell viability of the PALA-PDA-HPAE-Ag medical patch material of examples 1 and 2 measured by the MTT method. The survival rate of the L929 cells after being incubated with the leaching solution of the patch for 24 hours and 48 hours is more than 80 percent, which indicates good biocompatibility.

Experimental example 5: the antibacterial and antioxidant performance of the polythiooctanoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material (PALA-PDA-HPAE-Ag) is characterized in that:

in order to research the antibacterial performance of the obtained medical patch material, bacterial suspension bacteriostasis experiments of escherichia coli and staphylococcus aureus are carried out on the medical patch material.

Firstly, 50mg of each group of samples are respectively packed in a 96-well plate, and the samples are sterilized; then preparing a liquid culture medium and sterilizing for 1.5h by using an autoclave; meanwhile, the bacteria liquid is prepared into 10 by an ultraviolet spectrophotometer ⁷ CFU/ml, corresponding to an absorbance value of 0.01; and finally, adding 200 mul of prepared bacterial liquid into each group, incubating for 24h in a constant-temperature incubator at 37 ℃, measuring the OD value of the bacterial suspension at 600nm by using a microplate reader at 0h, 3h, 6h, 9h, 12h and 24h, and calculating the relative activity of the final bacteria so as to judge the antibacterial effect of the material. The relative activity of the bacteria was calculated by the following formula:

wherein, OD _sample And OD _control Respectively represent a bacterial culture solution and a control group bacterial culture solution which are co-cultured with the materialAbsorbance of (b).

FIG. 14 shows the relative activities of bacteria measured by the bacterial suspension test of the medical patch materials obtained in examples 1 and 2. The PALA-based copolymer material has certain antibacterial effect, which is probably due to the action of disulfide bond and sulfide, wherein the sulfide is the key for adhering to the growth of bacteria, and Ag is introduced ⁺ The antibacterial effect on escherichia coli and staphylococcus aureus is better. In Ag ⁺ In example 1 with a mass fraction of 0.1%, after 24h of culture, the relative activity of escherichia coli is only 4.95%, and the relative activity of staphylococcus aureus is only 9.18%. In Ag ⁺ In example 2 with the mass fraction of 0.2%, after 24 hours of culture, the relative activity of escherichia coli is only 1.03%, and the relative activity of staphylococcus aureus is only 1.95%. The potential application of the PALA-PDA-HPAE-Ag medical patch material prepared by the preparation method disclosed by the patent as an antibacterial material is verified.

In order to investigate the antioxidant property of the obtained medical patch material, the DPPH scavenging ability thereof was evaluated by UV-Vis. The absorbance at 516nm of DPPH/PBS, DPPH/sample in methanol was measured and its ROS capture efficiency was calculated according to the following formula:

wherein, abs _sample And Abs _control Represent absorbance of the methanol solutions of DPPH/sample and DPPH/PBS, respectively.

FIG. 15 shows ROS capturing efficiency of the medical patch materials obtained in examples 1 and 2 measured by DPPH method. The ROS scavenging efficiency of two PALA-PDA-HPAE-Ag patch materials is more than 90%, and the PALA-PDA-HPAE-Ag patch materials show excellent antioxidant performance.

The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.

Claims

1. A preparation method of a biomedical patch material based on polythiooctanoic acid is characterized by comprising the following steps:

(1) Adding double-end double-bond monomer and histamine dihydrochloride into an organic solvent to dissolve to form a mixed solution; adding organic base into the mixed solution to adjust the pH, and then heating the mixed solution for reaction to obtain hyperbranched poly-beta-amino ester; the molar ratio of the double bonds in the double-ended double bond monomer to the amino active hydrogen in the histamine dihydrochloride is 3:1-1.05;

(3) Sequentially adding the polydopamine alkaline solution and the hyperbranched poly beta-amino ester into a lipoic acid monomer, heating and stirring; and then adding a silver ion solution, continuously heating, and cooling to room temperature to obtain the poly lipoic acid-polydopamine-hyperbranched poly beta amino ester-nano silver medical patch material PALA-PDA-HPAE-Ag.

2. A method for preparing a biomedical patch material based on polythiooctanoic acid according to claim 1, characterized in that, in step (1), the double-terminal double bond monomer comprises methylene bisacrylamide or polyethylene glycol diacrylate.

3. The method for preparing a biomedical patch material based on polythiooctanoic acid according to claim 1, wherein in step (1), an organic base is added to adjust the pH to 8 to 11; reacting for 1-10h under the condition of oil bath at 50-100 ℃ and avoiding light.

4. The method for preparing a biomedical patch material based on polythiooctanoic acid according to claim 1, wherein, in step (2), the pH of the aqueous alkaline solution is 8 to 10.

5. The method for preparing a biomedical patch material based on polythiooctanoic acid according to claim 1, wherein in step (3), the ratio of dopamine PDA to lipoic acid is in the range of 5-10% by mass.

6. The method for preparing a biomedical patch material based on polythiooctanoic acid according to claim 1, characterized in that, in step (3), the mass ratio of hyperbranched poly β amino ester HPAE to lipoic acid is in the range of 10-20%.

7. The method for preparing a biomedical patch material based on polythiooctanoic acid according to claim 1, wherein in step (3), the heating conditions are: the oil bath heating temperature is 60-120 ℃.

8. The method for preparing a biomedical patch material based on polythiooctanoic acid according to claim 1, wherein in step (3), the silver ion solution includes but is not limited to silver nitrate aqueous solution or ethanol solution of silver methylsulfonate, and the mass fraction of silver ion in the whole system is in the range of 0.05-0.5%.

9. A biomedical patch material based on polythiooctanoic acid prepared by the preparation method as set forth in any one of claims 1 to 8.