Gamma-polyglutamic acid and hydrophilic polysiloxane composite material and application thereof

Abstract

The invention discloses a gamma-polyglutamic acid and hydrophilic polysiloxane composite material and application thereof, and belongs to the technical field of medical antibacterial coating materials. The gamma-polyglutamic acid and hydrophilic polysiloxane composite material is prepared from a hydrophilic polysiloxane aqueous solution and a gamma-polyglutamic acid aqueous solution through an ionic cross-linking reaction, the hydrophilic polysiloxane is prepared by sequentially carrying out click chemical reaction and ionization modification on polysiloxane with a side chain containing vinyl and a sulfydryl-containing compound; the sulfydryl-containing compound also contains a carboxylic acid group or an amino-terminated group; when the sulfydryl-containing compound further contains carboxylic acid groups, the raw materials of the ionic cross-linking reaction further comprise an aqueous solution containing divalent metal cations. The composite material has low swelling rate and good antibacterial performance, and can be used for long-acting stable antibacterial. As an antibacterial coating, the composite material is suitable for the surfaces of medical apparatuses and instruments made of different materials, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of medical antibacterial coating materials, and particularly relates to a composite material of γ-polyglutamic acid and hydrophilic polysiloxane and its application. Background Art

[0002] The use of medical devices such as medical implant catheters has solved many problems faced in clinical practice. However, the cost caused by the failure of medical devices due to bacterial infection is relatively high. Therefore, there are huge challenges in the antibacterial problem of medical devices.

[0003] Bacteria usually experience adhesion, proliferation and maturation on the surface of the device, and then form a biofilm, which ultimately leads to bacterial infection. In response to this process, constructing an antibacterial coating on the surface of medical devices is an effective way to solve the problem of bacterial infection. By means of blending or chemical grafting, antibacterial components such as silver ions and quaternary ammonium salts are introduced into polymer materials to prepare an antibacterial coating on the surface of medical devices, which can produce an active bactericidal effect. However, this method has cumbersome steps and poor antibacterial sustainability. With the development of strategies for constructing antibacterial coatings, it has been found that using hydrophilic antibacterial polymer materials to construct coatings on the surface of medical devices can effectively reduce the formation of biofilms. However, the hydrophilic antibacterial coating has the problem of easy swelling in the physiological environment, so the long-lasting antibacterial effect of the coating needs to be improved.

[0004] Therefore, it is of great significance to research and develop a new type of hydrophilic antibacterial coating with long-lasting antibacterial performance. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a composite material of γ-polyglutamic acid and hydrophilic polysiloxane and its application. The composite material has both a low swelling rate and good antibacterial performance, and can stably antibacterial for a long time.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a composite material of γ-polyglutamic acid and hydrophilic polysiloxane, which is prepared by an ion cross-linking reaction of an aqueous solution of hydrophilic polysiloxane and an aqueous solution of γ-polyglutamic acid;

[0008] The hydrophilic polysiloxane is prepared by subjecting a polyorganosiloxane with vinyl groups in the side chain and a mercapto compound to a click chemical reaction and an ionization modification in sequence;

[0009] The mercapto compound further contains a carboxylic acid group or a terminal amino group;

[0010] When the mercapto compound further contains a carboxylic acid group, the raw materials for the ion cross-linking reaction further include an aqueous solution containing divalent metal cations.

[0011] The ionization modification refers to using the means of changing pH to make the side groups of the product after the above click chemical reaction become charged hydrophilic groups. For example, changing -COOH to -COO - Na + , changing -NH2 to -NH3 + Cl - , so as to achieve the purpose of hydrophilic modification of polysiloxane.

[0012] When the mercapto-containing compound also contains a carboxylic acid group, the hydrophilic polysiloxane obtained by its ionization modification is electronegative; because changing -COOH to -COO - Na + results in the dissociation of Na + , the hydrophilic polysiloxane is electronegative, and the overall aqueous solution is electrically neutral..

[0013] When the mercapto-containing compound also contains a terminal amino group, the aqueous polysiloxane obtained by its ionization modification is electropositive. Because changing -NH2 to -NH3 + Cl - results in the dissociation of Cl - , the hydrophilic polysiloxane is electropositive, and the overall aqueous solution is electrically neutral.

[0014] Since γ-polyglutamic acid is electronegative, when the hydrophilic polysiloxane is electronegative, in-situ crosslinking needs to be achieved by applying divalent ions such as Ca 2+ or Mg 2+ . When the hydrophilic polysiloxane is electropositive, it directly undergoes ionic crosslinking with electronegative γ-polyglutamic acid through charge interaction. Preferably in the present invention, the mass fraction of γ-polyglutamic acid in the γ-polyglutamic acid aqueous solution is 10% - 20%; more preferably 10%.

[0015] Preferably, the molecular weight of γ-polyglutamic acid is 6000 - 12000 Da; more preferably 6000 - 8000 Da.

[0016] Preferably in the present invention, the mass fraction of the hydrophilic polysiloxane in the hydrophilic polysiloxane aqueous solution is 10% - 60%; more preferably 10% - 30%.

[0017] Preferably in the present invention, the mass ratio of the hydrophilic polysiloxane in the hydrophilic polysiloxane aqueous solution to γ-polyglutamic acid in the γ-polyglutamic acid aqueous solution is (1 - 5):(5 - 9); more preferably (1 - 4):(6 - 9). In some specific embodiments of the present invention, it is preferably 1:9 or 4:6.

[0018] Preferably, the mass ratio of the vinyl group-containing polysiloxane in the side chain to the mercapto compound is 1:(3-8). In some specific embodiments of the present invention, it is preferably 1:3.7.

[0019] Preferably, the click chemical reaction is initiated by a photoinitiator under ultraviolet light irradiation;

[0020] Preferably, the photoinitiator is selected from cleavage-type photoinitiators.

[0021] Preferably, the cleavage-type photoinitiator is selected from α-hydroxy ketone derivative photoinitiator I2959 or benzoin dimethyl ether (BDK).

[0022] Preferably, the molar amount of the photoinitiator is 1%-5% of the molar amount of the mercapto compound; more preferably 1.5%-3%; further preferably 1.9%.

[0023] Preferably, the vinyl group-containing polysiloxane in the side chain is selected from vinyl silicone oil;

[0024] Preferably, the mercapto compound is selected from mercaptopropionic acid or mercaptoethylamine.

[0025] Preferably, the divalent metal cation is selected from calcium ions or magnesium ions.

[0026] The vinyl silicone oil described in the present invention is self-made, and the preparation method includes the following steps:

[0027] Octamethylcyclotetrasiloxane (D4), tetramethyltetravinylcyclotetrasiloxane (D4 Vi ) and a chain stopper are mixed and subjected to anionic ring-opening polymerization under the catalysis of an alkali catalyst to prepare vinyl silicone oil.

[0028] The chain stopper is selected from disiloxanes, including but not limited to bis(chloromethyl)tetramethyldisiloxane, etc.

[0029] The molar amount of the chain stopper is 1%-5% of the sum of the molar amounts of D4 and D4 Vi in terms of molar amount.

[0030] The alkali catalyst is preferably tetramethylammonium hydroxide TMAH.

[0031] The molar amount of the alkali catalyst is 0.1%-0.5% of the sum of the molar amounts of D4 and D4 Vi in terms of molar amount.

[0032] The D4 and D4 Vi molar ratio is (3-6):1.

[0033] The present invention also provides the application of the above composite material of γ-polyglutamic acid and hydrophilic polysiloxane as an antibacterial coating on the surface of medical devices.

[0034] The swelling ratio of the composite material of γ-polyglutamic acid and hydrophilic polysiloxane according to the present invention is 50%-150%. The lower swelling ratio improves the stability of the composite material, effectively reduces the growth of bacteria and microorganisms on the surface of medical devices and has a long-lasting effect, thereby achieving long-term and lasting antibacterial on the surface of medical devices. The antibacterial coating on the surface of the medical device is prepared by mixing the above hydrophilic polysiloxane aqueous solution and γ-polyglutamic acid aqueous solution and then coating them on the surface of the medical device through an ionic cross-linking reaction. And when the hydrophilic polysiloxane is negatively charged, the ionic cross-linking reaction further includes divalent ions such as Ca as raw materials 2+ .

[0035] The preparation process of the above antibacterial coating on the surface of medical devices is simple and efficient. No organic solvents are used during its forming process, and it has good biocompatibility, which can better meet the industrial production conditions.

[0036] After the ionic cross-linking reaction, it also includes a drying post-treatment.

[0037] The temperature of the drying is preferably 40°C - 50°C.

[0038] The time of the drying is preferably 5 - 10 h.

[0039] The medical devices include but are not limited to medical catheters, medical surgical instruments, in-vivo implants, etc.

[0040] The materials of the medical catheters include but are not limited to polymers such as polyurethane, thermoplastic elastomer, polyethylene, silicone rubber, etc., or inorganic materials such as glass, ceramics, and metal materials.

[0041] Compared with the prior art, the composite material of γ-polyglutamic acid and hydrophilic polysiloxane provided by the present invention is prepared by an ionic cross-linking reaction of a hydrophilic polysiloxane aqueous solution and a γ-polyglutamic acid aqueous solution; the hydrophilic polysiloxane is prepared by a click chemical reaction and an ionization modification of a polysiloxane with vinyl groups in the side chain and a mercapto compound in sequence; the mercapto compound also contains a carboxylic acid group or a terminal amino group; when the mercapto compound also contains a carboxylic acid group, the raw materials of the ionic cross-linking reaction further include an aqueous solution containing divalent metal cations. The composite material has both a low swelling ratio and good antibacterial properties, and can antibacterial for a long time and stably. The composite material as an antibacterial coating is applicable to the surfaces of medical devices made of different materials and has broad application prospects. Description of the Drawings

[0042] Figure 1Dissolution of hydrophilic modified polysiloxane aqueous solutions with different mass fractions in Example 2;

[0043] Figure 2 Swelling rate test results of the thin films (Film 1, Film 2, Film 3) prepared in Example 5 from Examples 1, 2, and 3 respectively;

[0044] Figure 3 Antibacterial test results of the coatings prepared from the solutions of the comparative example and Examples 1, 2, and 3. Detailed implementation mode

[0045] To further illustrate the present invention, the γ-polyglutamic acid and aqueous polysiloxane composite material and its application provided by the present invention will be described in detail below in conjunction with examples.

[0046] Example 1

[0047] The γ-polyglutamic acid powder (molecular weight 6000 Da) was dissolved in deionized water at room temperature to prepare a polyanion solution (γ-polyglutamic acid solution) with a mass fraction of 10%.

[0048] Example 2

[0049] (1) Add tetramethylammonium hydroxide (TMAH) (56 μL, 0.048 g, 0.13 mmol) to the reaction flask, maintain under vacuum for 30 min to remove methanol, and then add octamethylcyclotetrasiloxane (D4) (8.41 g, 28.36 mmol), tetramethyltetravinylcyclotetrasiloxane (D4 Vi )(2.44 g, 7.09 mmol) and the chain terminator 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane (0.11 g, 0.47 mmol), react at 80 °C for 10 h under nitrogen, after the reaction, dissolve in chloroform, and then precipitate in methanol, and obtain a colorless viscous liquid (9.2 g) after centrifugation, which is vinyl silicone oil, and its structure is as follows:

[0050]

[0051] (2) Dissolve the vinyl silicone oil (2.0 g, in which the vinyl group is 6.1 mmol) synthesized in the above step (1) in 20 ml of tetrahydrofuran, add the initiator I 2959 (0.023 g, 0.1 mmol) and mercaptopropionic acid (0.54 g, 5.08 mmol), stir evenly and then react under a 365 nm ultraviolet environment for 40 min; after the reaction, precipitate the reaction mixture in water, and obtain a colorless viscous product (2.4 g) after centrifugation and concentration, which is side-chain functionalized vinyl silicone oil, and its structure is as follows:

[0052] where r + p = m.

[0053] (3) Dissolve the side-chain functionalized vinyl silicone oil (2.4 g) synthesized in step (2) above in 20 mL of tetrahydrofuran, and gradually add dropwise 10 mL of an aqueous solution of Na2CO3 (0.26 g). Gas is slowly released from the system. After no more bubbles emerge, end the reaction. Most of the tetrahydrofuran is removed by vacuum pumping. Add 20 mL of deionized water and stir until the system becomes clear. Adjust to neutral with dilute hydrochloric acid (0.01 M), and then remove most of the water by rotary evaporation to obtain aqueous solutions of hydrophilically modified polysiloxane with mass fractions of 10%, 20%, and 30% respectively; the structure of the hydrophilically modified polysiloxane is as follows:

[0054] where r + p = m.

[0055] The dispersion and dissolution conditions of the aqueous solutions of hydrophilically modified polysiloxane with mass fractions of 10%, 20%, and 30% are as Figure 1 shown;

[0056] (4) Mix the aqueous solution of hydrophilically modified polysiloxane (mass fraction 20%) prepared in step (3) above with the γ-polyglutamic acid solution prepared in Example 1 in a ratio of 1:9 by mass of pure polymers to obtain a homogeneous mixture.

[0057] Example 3

[0058] Mix the aqueous solution of hydrophilically modified polysiloxane (mass fraction 20%) prepared in step (3) of Example 2 with the γ-polyglutamic acid solution prepared in Example 1 in a ratio of 4:6 by mass of pure polymers to obtain a homogeneous mixture.

[0059] Example 4

[0060] Heat and concentrate the homogeneous mixtures prepared in Example 2 and Example 3 to a mass fraction of 13% - 17%, and then carry out ionic crosslinking with CaCl2 solution respectively to obtain composite materials 2 and 3 of γ-polyglutamic acid and hydrophilic polysiloxane.

[0061] Example 5

[0062] Heat and concentrate the homogeneous mixtures prepared in Example 2 and Example 3 to a mass fraction of 13% - 17% respectively, and uniformly coat them on glass plates with a coating amount of 0.03 - 0.06 g / cm 2 . Then carry out ionic crosslinking with CaCl2 solution. After the water volatilizes at room temperature, films are formed to obtain Film 2 and Film 3; similarly, uniformly coat the polyanion solution (γ-polyglutamic acid solution) prepared in Example 1 on glass plates with the same coating amount, and after the water volatilizes at room temperature, a film is formed to obtain Film 1.

[0063] Performance test

[0064] (1) Swelling ratio test

[0065] Weigh each group of samples (Composite Material 2, Composite Material 3, Membrane 1, Membrane 2, Membrane 3) (3 cm × 0.5 cm) prepared in Examples 4 and 5 above, record the initial mass as mi (g), immerse each group of samples in phosphate buffer solution respectively, and weigh the mass after swelling equilibrium as ms (g). Then the calculation formula for the swelling ratio (SR) is: SR = (ms - mi) / mi × 100%.

[0066] Among them, the swelling ratio test results of the films prepared from the solutions of Examples 1, 2, and 3 in Example 5 are as Figure 2 shown. The results show that the swelling ratio of Example 3 (Membrane 3) < Example 2 (Membrane 2) < Example 1 (Membrane 1).

[0067] The swelling ratio results of the composite materials prepared in Example 4 are still Composite Material 3 < Composite Material 2.

[0068] (2) Antibacterial performance test

[0069] First, coat the solutions prepared in Examples 1, 2, and 3 above on the surface of a commercial medical polyethylene sheet, and perform ionic cross-linking on the sheets after coating in Examples 2 and 3 with CaCl2 solution. Also, coat Composite Material 2 and Composite Material 3 prepared in Example 4 on the surface of a commercial medical polyethylene sheet. Secondly, dry all the coated sheets to obtain polyethylene implants with a uniformly coated medical antibacterial coating on the surface.

[0070] Then, use S. aureus and E. coli as representative strains of Gram-positive and Gram-negative bacteria respectively to conduct antibacterial performance tests on the surface coatings of medical devices. Referring to JIS Z2801, cut the above-prepared polyethylene sheets with antibacterial coatings and the control (the control is a polyethylene sheet ultrasonically rinsed 3 times with absolute ethanol and deionized water in sequence and completely dried) into 1.5 cm × 1.5 cm, drop 25 μL (10 6 CFU / mL) of bacterial solution on them, and incubate at 37°C for 24 h. Subsequently, immerse the incubated samples in 2 mL of phosphate buffer solution and ultrasonically treat for 3 min. Finally, dilute the bacterial suspension, perform plating, incubate the prepared solid culture plates at 37°C for 24 h, count the colonies, and calculate the number of colonies on each petri dish.

[0071] The antibacterial performance tests of the control and the coatings formed from the solutions prepared in Examples 1, 2, and 3 are as Figure 3As shown, the results indicate that for S. aureus, the antibacterial performance of Example 1 > Example 2 > Example 3 > Comparative Example; for E. coli, the antibacterial performance of Example 1 > Example 3 > Example 2 > Comparative Example.

[0072] Moreover, the antibacterial performance test results of the composite materials prepared in Examples 2 and 3 in the comparative example and Example 4 show that for S. aureus, the antibacterial performance is still Composite Material 2 > Composite Material 3 > Comparative Example; for E. coli, the antibacterial performance is still Composite Material 3 > Composite Material 2 > Comparative Example.

[0073] The description of the above examples is only used to help understand the method of the present invention and its core idea. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A composite material of γ-polyglutamic acid and hydrophilic polysiloxane, characterized in that, It is prepared by an ionic cross-linking reaction of a hydrophilic polysiloxane aqueous solution and a γ-polyglutamic acid aqueous solution; The hydrophilic polysiloxane is prepared by subjecting a polysiloxane with vinyl groups in the side chain and a mercapto compound to a click chemical reaction and an ionization modification in sequence; The mercapto compound further contains a carboxylic acid group or a terminal amino group; When the mercapto compound further contains a carboxylic acid group, the raw materials for the ionic cross-linking reaction further include an aqueous solution containing divalent metal cations.

2. The composite material according to claim 1, wherein, The mass fraction of γ-polyglutamic acid in the γ-polyglutamic acid aqueous solution is 10%-20%; The molecular weight of the γ-polyglutamic acid is 6000-12000 Da.

3. The composite material according to claim 1, characterized in that, The mass fraction of the hydrophilic polysiloxane in the hydrophilic polysiloxane aqueous solution is 10%-60%.

4. The composite material according to claim 1, characterized in that, The mass ratio of the hydrophilic polysiloxane in the hydrophilic polysiloxane aqueous solution to the γ-polyglutamic acid in the γ-polyglutamic acid aqueous solution is (1-5):(5-9).

5. The composite material according to claim 1, wherein, The mass ratio of the polysiloxane with vinyl groups in the side chain to the mercapto compound is 1:(3-8).

6. The composite material according to claim 1, wherein The click chemical reaction is carried out by the initiation of a photoinitiator under ultraviolet light irradiation; The photoinitiator is selected from cleavage-type photoinitiators.

7. The composite material according to claim 1, wherein The cleavage-type photoinitiator is selected from the α-hydroxy ketone derivative photoinitiator I2959 or benzoin dimethyl ether.

8. The composite material according to claim 1, wherein, The molar amount of the photoinitiator is 1%-5% of the molar amount of the mercapto compound.

9. The composite material according to claim 1, characterized in that, The polysiloxane with vinyl groups in the side chain is selected from vinyl silicone oil; The mercapto compound is selected from mercaptopropionic acid or mercaptoethylamine; The divalent metal cation is selected from calcium ions or magnesium ions.

10. Use of the composite material of γ-polyglutamic acid and hydrophilic polysiloxane according to any one of claims 1-9 as an antibacterial coating on the surface of a medical device.

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