CN105456233B - A kind of long-acting slow-release antibacterial film of high drug load and preparation method thereof - Google Patents

Abstract

The invention relates to a long-acting slow-release antibacterial film with high drug loading and a preparation method thereof, belonging to the technical field of drug carriers. The structure of the antibacterial film is (PO/PAA/peptide-GO/PAA) _n , (peptide-GO/PAA/PO/PAA) _n , (PAA/peptide-GO/PAA/PO) _n or (PAA/PO/ PAA/peptide‑GO) _n ; wherein the PO is a cationic polymer, the PAA is polyacrylic acid, and the peptide‑GO is an antimicrobial peptide/graphene oxide composite hybrid formed by electrostatic binding of antimicrobial peptide molecules and graphene oxide The chemical structure, said n is the number of self-assembled layers; the present invention also provides the preparation method of the long-acting slow-release antibacterial film with high drug loading, adopting the long-acting slow-release antibacterial film with high drug loading obtained in the present invention , its mechanical strength, durability and antibacterial effect are greatly improved, and the loading of drugs in the layer-by-layer assembly film is high.

Description

A long-acting slow-release antibacterial film with high drug loading and preparation method thereof

technical field

The invention relates to a long-acting slow-release antibacterial film with high drug loading and a preparation method thereof, belonging to the technical field of drug carriers.

Background technique

Various medical and sanitary devices are used in medical procedures such as trauma treatment and surgery, and various interventional medical devices are also used in human tissue repair. In the actual operation process, these instruments and devices are inevitably exposed to the air, and their surfaces are easily polluted by harmful bacteria, which further causes bacterial cross-infection of wounds or human tissues. This is one of the main problems of modern medicine, and it is often The main reason restricting the success or failure of treatment. In interventional therapy, large doses of antibiotics are usually used to fight infection, but because the surface of the interventional device is quickly covered by a biofilm formed by various proteins in the human body, it is difficult for the drug to pass through the film, so the effect is minimal, and often even needs to be removed. Implanted devices and reimplantation. Therefore, it is extremely important to adopt a suitable method to prepare long-lasting antibacterial coatings on the surface of these medical devices and interventional devices. On the one hand, it can inhibit the growth of bacteria on the surface, and at the same time reduce the possibility of bacteria developing drug resistance. .

There are several common surface loading methods for antibacterial drugs, including surface adsorption, covalent binding, and blending of drugs and substrates. Wherein (1) the surface adsorption method is to soak the device in a solution of antibacterial drugs so that the surface is adsorbed with drug molecules to prepare an antibacterial surface. This method is simple to operate, but the disadvantage is that drug molecules are easily detached from the surface, and there is only a thin layer of drug on the surface, and the amount of drug loaded is limited. This method is more suitable for the adsorption of drugs with low solubility. For example, silver salts of anionic antibiotics are more difficult to dissolve than sodium salts, and antibacterial surfaces can be prepared by surface adsorption of silver salts. (2) The method of covalent binding is to immobilize the drug on the surface of the device through a covalent bond, so that the drug can continue to function. Compared with the surface adsorption method, the covalent binding method has the advantages of firm drug loading and long action time, but this technology also has its limitations. First, the types of drugs that can be used for covalent binding are limited, and due to the The characteristics determine that the drug cannot be released from the device to the adjacent liquid or tissue, so its antibacterial ability is often limited to the area where the device contacts, and the range of drug action is small. (3) The blending of drugs and substrates is another important method of drug surface loading. This method can greatly increase the loading of drugs, and can provide antibacterial properties on or near the surface of the device. However, if traditional blending It is difficult to achieve controlled release of drugs by means of methods, so this technology still needs to be improved, such as adjusting the force between the substrate and the drug, controlling the blending process, and so on.

Layer-by-layer self-assembly (Layer-by-layer) technology has also been used in the preparation of antibacterial surfaces in recent years. Chemical reactions, using different modes of action, such as chemical bonds (ionic bonds, covalent bonds, hydrogen bonds, etc.), van der Waals forces, dipole-dipole interactions, etc., to load drug molecules into layer-by-layer assembled films to form surface antibacterial coatings . The layer-by-layer self-assembly technology is simple and low-cost. It can be assembled into a film on the surface of objects of different shapes, and the thickness of the film can be controlled at the molecular level. The layer-by-layer assembly method is convenient for regulating the composition and structure of the film. The slow and controlled release of drugs can be realized, and it is beneficial to realize the preparation of multifunctional integrated property membranes. However, the current layer-by-layer self-assembled antimicrobial films have the following problems: (1) Drugs are generally combined into the layer-by-layer assembly film in a single-molecule state, and the drug loading capacity of a single layer is low. The improvement of the overall drug loading capacity of the assembly film greatly depends on The increase in the number of assembly layers is time-consuming and laborious; (2) the layer-by-layer assembly film is mainly composed of polyelectrolyte molecules, and its mechanical strength is poor; (3) although the layer-by-layer assembly film can be regulated by its composition, such as introducing Degradation of polymer molecules to achieve slow controlled release of the loaded drug, but because the degradation of polymer molecules generally requires specific conditions (such as specific pH, ionic strength, etc.), it is often difficult to achieve in the actual process, so relying solely on the degradation of polymer molecules The slow-release control effect is limited and it is generally difficult to achieve a long sustained-release time.

Contents of the invention

The purpose of the present invention is to provide a long-acting slow-release antibacterial film with high drug loading, which realizes the high drug loading and long-acting slow-release effect of the antibacterial film. The invention also provides a preparation method of the antibacterial film.

Technical scheme of the present invention is:

A long-acting slow-release antibacterial film with high drug loading, its structure is (PO/PAA/peptide-GO/PAA) _n ; wherein the PO is a cationic polymer, the PAA is polyacrylic acid, and the peptide- GO is an antimicrobial peptide/graphene oxide composite hybrid structure formed by electrostatic binding of antimicrobial peptide molecules (peptide) and graphene oxide (GO), and n is the number of self-assembled layers.

The structure of the antibacterial film is realized by layer-by-layer self-assembly. Since the layer-by-layer self-assembly is a cyclic process, in the structural expression, the order of PO and peptide-GO can be exchanged with each other. After the exchange, it is ( peptide-GO/PAA/PO/PAA) _n , similarly its structural expression can also be (PAA/peptide-GO/PAA/PO) _n and (PAA/PO/PAA/peptide-GO) _n .

The antimicrobial peptide molecule (peptide) is a positively charged antimicrobial peptide molecule, preferably G ₄ or Nap-FF-R ₉ , and its molecular structural formulas are respectively:

( ₁ ) Molecular structure of G4:

(2) Molecular structure of Nap-FF-R ₉ :

The number n of self-assembled layers is an integer between 10-100, preferably an integer between 30-60.

The cationic polymer (PO) is selected from poly-β-amino ester (PAE), polyethyleneimine (PEI), polydienyl propylene dimethyl ammonium chloride (PDDA), sodium polystyrene sulfonate (PSS ) in one or more combinations, and the cationic polymer (PO) between the layers is the same or different.

A preparation method of a long-acting slow-release antibacterial film with high drug loading, comprising the following steps:

(1) Prepare an antimicrobial peptide molecular solution with a concentration of 2.0-15.0mmol/L, adjust the pH of the solution to 4-6, and let it stand to make it self-assemble into a nano-short rod-like or fibrous structure;

(2) Prepare a graphene oxide (GO) solution with a concentration of 0.1-1.0 mg/mL, and adjust the pH of the solution to be 7-9;

(3) the antimicrobial peptide molecular solution after step (1) is processed is mixed with the graphene oxide solution that step (2) obtains, and in the mixing ratio, the volume of the antimicrobial peptide solution is 2-2% of the volume of the graphene oxide solution 5 times; ultrasonically mixed to obtain the antimicrobial peptide/graphene oxide complex hybrid structure solution, namely peptide-GO solution;

(4) Prepare a cationic polymer (PO) solution with a concentration of 0.5-2.0 mg/mL, and adjust the pH of the solution to be 4.0-5.0;

(5) prepare polyacrylic acid (PAA) solution, concentration is 0.5-2.0mg/mL, adjust solution pH to be 8.5-9.5;

(6) Select the substrate, immerse the substrate in the solution obtained in any step (3), (4) or (5), soak for 5-10min, then take it out, immerse it in pure water, take it out, and dry it; then immerse it in step (3) ), (4) or (5) obtained in another non-immersed solution for 5-10min for the first time, then take out, immerse in pure water, take out, and dry; when the substrate is repeatedly immersed in the solution for adsorption, the cationic polymer solution and The peptide-GO solution cannot be immersed sequentially, and the polyacrylic acid solution must be used as an interval between the two; each immersion in a cationic polymer solution, a peptide-GO solution, and a polyacrylic acid solution forms a layer, and the above-mentioned immersion The method is repeated n times, and the long-acting slow-release antibacterial film with high drug loading of the present invention is obtained.

For example: immerse the substrate in the PO solution obtained in step (4) for 5-10 minutes, take it out, immerse it in pure water for 5-10s, take it out, blow the surface with nitrogen to dry; then put it into the PAA solution obtained in step (5) Soak for 5-10min, take it out, immerse in pure water for 5-10s, take it out, blow the surface with nitrogen to dry; then put it into the peptide-GO composite hybrid structure solution obtained in step (3) and soak for 5-10min, take it out, Immerse in pure water for 5-10s, take it out, purge the surface with nitrogen to dry; finally put it into the PAA solution obtained in step (5) and soak for 5-10min, take it out, immerse in pure water for 5-10s, take it out, and purge the surface with nitrogen to dry Drying; this is a layer group, and the above-mentioned soaking step is used to cycle n times, and the long-acting slow-release antibacterial film with high drug loading of the present invention can be obtained.

In the step (1), the concentration of the prepared antimicrobial peptide molecule solution is above its self-assembly concentration.

In the step (1), after the pH is adjusted, the solution is left at room temperature for 1-5 days, and the solution can self-assemble into a nano-short rod-like or fibrous structure.

In the step (3), when the antimicrobial peptide molecular solution is mixed with the GO solution, the ratio of the two will be different according to the concentration change of the antimicrobial peptide solution. It greatly exceeds the number of negative charges on the surface of GO, so as to ensure the stable dispersion of the peptide/GO mixed solution without precipitation, and the surface of the peptide-GO hybrid has positive charges.

In the step (3), the ultrasonic conditions are as follows: the ultrasonic power is 90-110W, and the ultrasonic time is 10-20min.

In the step (6), the substrate is preferably a silicon dioxide substrate as a model.

In the step (6), it is preferable to use the same solution soaking sequence for each layer group soaking.

The present invention selects a positively charged antimicrobial peptide molecule with strong self-assembly ability, makes it self-assemble into a nano-assembly in the form of a supramolecular aggregate above its critical self-assembly concentration, and then mixes it with graphene oxide sheets form a complex hybrid structure. Selecting specific antimicrobial peptide molecules and carrying out drug loading through supramolecular nano-assemblies is the key to increasing the drug loading capacity, and the structure of the assembly can ensure that the positive charges of the peptide molecules are exposed on the surface of the assembly, resulting in hybridization with graphene oxide The charge reversal on the surface of the hybrid ensures the combination of the peptide/graphene oxide complex hybrid with the negatively charged polymer molecules during the layer-by-layer assembly process to form a multilayer film smoothly.

In addition, the peptide/graphene oxide composite hybrid structure is easy to precipitate in the solution due to the interaction between colloidal particles. When preparing the layer-by-layer assembly film, ultrasonic treatment should be performed in advance to make it uniformly dispersed and suspended in the solution, so as to ensure A multilayer film with uniform thickness and controllable properties is prepared.

Compared with prior art, the beneficial effect of the present invention is:

(1) the graphene oxide lamellar structure adopted in the present invention can greatly improve the mechanical strength of surface coating, improve its durability;

(2) The selected antimicrobial peptide molecules can be self-assembled into supramolecular nanoassemblies, which can be combined into layer-by-layer assembly membranes in the form of molecular aggregates. load within;

(3) The antimicrobial peptide molecular assembly is combined with the surface of graphene oxide through non-covalent bonds such as electrostatic/hydrophobic interactions, which is conducive to the release of active substances from the surface;

(4) In the layer-by-layer assembly process, the PO layer can be selected to add a degradable polymer molecule according to actual needs, which can ensure its degradation under suitable conditions (such as poly β-amino ester (PAE) can be used at pH>7.0 Under hydrolysis), the encapsulated surface active substance is exposed to the solution for release;

(5) Self-assembled antimicrobial peptides are used for hybrid construction, which can take advantage of the aggregation and dissociation balance between the peptide assembly and its single-molecule form to slowly release antimicrobial peptide molecules, which has a very long-term antibacterial effect.

Description of drawings

Figure 1: Atomic force microscope (AFM) image of the composite structure formed by the antimicrobial peptide molecule G ₄ and graphene oxide (GO),

Figure 2: SEM images of (PAE/PAA/G ₄ -GO/PAA) ₅₀ -layer assembled film on a silica substrate,

Fig. 3: Tensile modulus test curve of (PAE/PAA/G ₄ -GO/PAA) ₅₀ -layer assembled film (treated with 0.05% sodium hydroxide solution) on a silica substrate.

Detailed ways

The technical content of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

1. A long-acting slow-release antibacterial film with high drug loading, the structure is (PO/PAA/peptide-GO/PAA) ₅₀ , wherein the PO is selected from poly β-amino ester (PAE), and the PAA is poly Acrylic acid, peptide _- GO is an antimicrobial peptide/graphene oxide complex hybrid structure formed by electrostatic binding of antimicrobial peptide molecule G4 and GO.

2. The preparation method of the long-acting slow-release antibacterial film with high drug loading is:

( ₁ ) prepare G4 solution, concentration is 4.0mmol/L, (this concentration is above its self-assembly concentration), adopt the NaOH solution of 1.0mol/L to adjust solution pH to be 4.5, place 3 days, make it self-assemble into Nano short rod-like structure;

(2) prepare the graphene oxide (GO) solution that concentration is 1.0mg/mL, adopt the NaOH solution of 1.0mol/L to adjust the solution pH to be 8;

(3) Mix the G ₄ solution obtained in step (1) with the GO solution obtained in step (2) according to the volume ratio of 3:1, and ultrasonically mix, the ultrasonic power is 100W, and the ultrasonic time is 15min to obtain G ₄ -GO composite Hybrid structure solution, as shown in Figure 1;

(4) prepare poly-β-amino ester (PAE) solution, concentration is 1.0mg/mL, adopts the HCl solution of 1.0mol/L to adjust pH to be 4.5;

(5) prepare polyacrylic acid (PAA) solution, concentration is 1.0mg/mL, adopts the NaOH solution of 1.0mol/L to adjust pH to be 9;

(6) Select the silicon dioxide substrate, immerse the silicon dioxide substrate in the PAE solution obtained in step (4) for 10 minutes, take it out, immerse it in pure water for 5 seconds, take out the nitrogen gas and purge the surface for drying; then put it into step (5) Soak in the obtained PAA solution for 10min, take it out, immerse in pure water for 5s, take out the nitrogen gas to blow the surface and dry it; Water for 5s, take out nitrogen to blow the surface to dry; finally put it into the PAA solution obtained in step (5) and soak for 10min, take it out, immerse in pure water for 5s, take out nitrogen to blow the surface to dry; this is a layer group, use the above The soaking sequence was cycled 50 times to obtain the long-acting slow-release antibacterial film (PAE/PAA/G ₄ -GO/PAA) ₅₀ with high drug loading according to the present invention, which is referred to as a layer-by-layer assembly film, and its cross-sectional appearance is shown in Figure 2 shown.

Figure 1 is an atomic force microscope (AFM) picture of the composite structure formed by the antimicrobial peptide molecule G ₄ and graphene oxide (GO); it can be seen from the figure that G ₄ is assembled into nano-short rod-like structures, and these structures are combined into GO sheets A G ₄ -GO complex hybrid structure is formed on the surface.

Fig. 2 is a scanning electron microscope image of a ₅₀ -layer (PAE/PAA/G ₄ -GO/PAA) assembled film on a silicon dioxide substrate obtained in this example. The picture shows that the above species can effectively form a film on the surface of the solid substrate after 50 cycles of layer-by-layer assembly, forming a film layer with a thickness of about 2 μm, with a certain layered structure.

Fig. 3 is a tensile modulus test curve of (PAE/PAA/G ₄ -GO/PAA) ₅₀ -layer assembled film (treated with 0.05% sodium hydroxide solution) on a silica substrate. The long-acting slow-release antibacterial film with high drug loading obtained in this example, through the mechanical tensile test, has a tensile elastic modulus of 8-10 Gpa and a vertical elastic modulus of 1.5-4 Gpa.

The long-acting slow-release antibacterial film with high drug loading obtained in this embodiment is measured by the thermogravimetric method, and the content of the antibacterial active ingredient (G ₄ ) in the multilayer film is 23.2wt%; Effective sustained release for more than 45 days.

3. Antibacterial experiment:

Add 40 μL of bacterial species (Escherichia coli, Escherichia coli) to 2 mL of medium (LB) solution, shake and culture overnight at 37°C, centrifuge to remove the lower layer, wash with PBS buffer, repeat 3 times, and adjust the OD value to about 0.2.

Take 8 μL of bacterial liquid and drop them on the surface of ₅₀ multilayer films of (PAE/PAA/G ₄ -GO/PAA) loaded on the silica substrate of 3 groups respectively, incubate in a constant temperature room at 37°C for 1 hour, and then put 3 pieces of two The silicon oxide substrate was washed and centrifuged with PBS, and the volume was adjusted to 200 μL, and 100 μL was taken and spread on the LB solid culture plate, and each sample was measured 3 times in parallel, and the average value was obtained. After each antibacterial experiment, the layer-by-layer assembly film loaded on the silica substrate was soaked in the aqueous solution for a certain period of time, and the antibacterial test was carried out again to investigate the long-term drug sustained release and antibacterial effect of the layer-by-layer assembly film.

The results showed that the survival rate of Escherichia coli on the surface of the freshly prepared layer-by-layer assembly membrane was less than 5%. The total time of intermittent soaking in water was 72 hours, and the antibacterial activity was reduced to about half of the initial value, while the total soaking time was as long as 192 hours. The survival rate of E. coli bacteria on its surface is still less than 15%.

Example 2:

1. A long-acting slow-release antibacterial film with high drug loading, the structure is (PO/PAA/peptide-GO/PAA) ₅₀ , wherein the PO is polyethyleneimine (PEI), and the PAA is polyacrylic acid , peptide-GO is a peptide/graphene oxide complex hybrid structure formed by the antibacterial peptide molecule Nap-FF-R ₉ through electrostatic binding and GO.

2. The preparation method of the long-acting slow-release antibacterial film with high drug loading is:

(1) prepare Nap-FF-R ₉ solution, the concentration is 4.0mmol/L, (this concentration is above its self-assembly concentration), adopt the NaOH solution of 1.0mol/L to adjust the solution pH to be 5, place 3 days, make It self-assembles into a nano-short rod-like structure;

(2) prepare the graphene oxide (GO) solution that concentration is 0.5mg/mL, adopt the NaOH solution of 1.0mol/L to adjust the solution pH to be 7;

(3) Mix the Nap-FF-R ₉ solution obtained in step (1) with the GO solution obtained in step (2) according to the volume ratio of 2:1, and ultrasonically mix, the ultrasonic power is 100W, and the ultrasonic time is 20min to obtain Nap -FF-R ₉ -GO complex hybrid structure solution;

(4) prepare polyethyleneimine (PEI) solution, concentration is 1.0mg/mL, adopts the HCl solution of 1.0mol/L to adjust pH to be 4;

(5) prepare polyacrylic acid (PAA) solution, concentration is 1.0mg/mL, adopts the NaOH solution of 1.0mol/L to adjust pH to be 9;

(6) Select the silicon dioxide substrate, immerse the silicon dioxide substrate in the PEI solution obtained in step (4) for 10 minutes, take it out, immerse it in pure water for 8 seconds, take out the nitrogen gas to purge the surface for drying; then put it into step (5) Soak in the obtained PAA solution for 10min, take it out, immerse it in pure water for 8s, take out the nitrogen gas and blow the surface to dry; then put it into the Nap-FF- _R9 -GO composite hybrid structure solution obtained in step (3) and soak for 10min , take it out, immerse in pure water for 8s, take out the nitrogen to blow the surface to dry; finally put it into the PAA solution obtained in step (5) and soak for 10min, take it out, immerse in pure water for 8s, take out the nitrogen to blow the surface to dry; Layer group, using the above soaking steps to cycle 50 times to obtain the long-acting slow-release antibacterial film with high drug loading according to the present invention (PEI/PAA/Nap-FF-R ₉ -GO/PAA) ₅₀ , referred to as layer-by-layer assembly membrane.

The (PEI/PAA/Nap-FF-R ₉ -GO/PAA) ₅₀ long-acting slow-release antibacterial film with high drug loading obtained in this example passed the mechanical tensile test, and its tensile elastic modulus was 9～12Gpa , and its vertical modulus of elasticity is 2-4Gpa.

The long-acting slow-release antibacterial film with high drug loading obtained in this embodiment is measured by the thermogravimetric method, and the content of the antibacterial active ingredient (Nap-FF-R ₉ ) in the multilayer film is 25.7wt%; the antibacterial film Long-acting sustained release in aqueous solution for more than 60 days.

The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention. For those skilled in the art, any obvious changes made to it without departing from the essence and spirit of the present invention will constitute an infringement of the patent right of the present invention and will bear corresponding legal responsibilities.

Claims (8)

1. the long-acting slow-release antibacterial film of a kind of high drug load, it is characterised in that the antibacterial film structure is (PO/PAA/ peptide-GO/PAA)_n、(peptide-GO/PAA/PO/PAA)_n、(PAA/peptide-GO/PAA/PO)_nOr (PAA/PO/ PAA/peptide-GO)_n；Wherein described PO is cationic polymer, and the PAA is polyacrylic acid, and the peptide-GO is Antibacterial peptide/graphene oxide composite hybridization body structure that antibacterial peptide molecule is formed with graphene oxide by electrostatical binding, the n For the self assembly number of plies；

The antibacterial peptide molecule is positively charged antibacterial peptide molecule；

The antibacterial peptide molecule selects G₄Or Nap-FF-R₉, its molecular structural formula is respectively：

(1)G₄Molecular structure：

(2)Nap-FF-R₉Molecular structure：

2. the long-acting slow-release antibacterial film of high drug load according to claim 1, it is characterised in that the self assembly number of plies N chooses the integer between 10-100.

3. the long-acting slow-release antibacterial film of high drug load according to claim 1, it is characterised in that the cationic polymerization One kind in poly- beta-amino ester, polyethyleneimine, the third alkyl dimethyl ammonium chloride of polydiene base, kayexalate of thing or A variety of combinations, cationic polymer between layers are identical or different.

4. a kind of preparation method of the long-acting slow-release antibacterial film of high drug load, is used to prepare described in claim any one of 1-3 Long-acting slow-release antibacterial film, it is characterised in that comprise the following steps：

(1) compound concentration is the antibacterial peptide molecular solution of 2.0-15.0mmol/L, and adjusting pH value of solution is 4-6, stands, makes it from group Fill as nanometer corynebacterium or filamentary structure；

(2) compound concentration is the graphene oxide solution of 0.1-1.0mg/mL, and adjusting pH value of solution is 7-9；

(3) the antibacterial peptide molecular solution after step (1) processing is mixed with the graphene oxide solution that step (2) obtains, mixed In proportioning, the antibacterial peptide liquor capacity is 2-5 times of the graphene oxide solution volume；Ultrasound mix, obtain antibacterial peptide/ Graphene oxide composite hybridization body structure-solution, i.e. peptide-GO solution；

(4) cationic polymer solution is prepared, concentration 0.5-2.0mg/mL, adjusting pH value of solution is 4.0-5.0；

(5) polyacrylic acid solution is prepared, concentration 0.5-2.0mg/mL, adjusting pH value of solution is 8.5-9.5；

(6) substrate is selected, substrate is immersed in step (3), (4) or (5) either step resulting solution, soaks 5-10min, with Take out afterwards, immerse pure water, taking-up, drying；It is then immersed in the solution that another non-first time obtained by step (3), (4) or (5) immerses Middle 5-10min, then takes out, immerses pure water, taking-up, drying；When substrate is adsorbed in immersion solution repeatedly, cation gathers Polymer solution and peptide-GO solution are unable to tandem immersion, it is necessary between using polyacrylic acid solution interval； Often immerse 1 cationic polymer solution, 1 peptide-GO solution and 2 polyacrylic acid solutions and form a group layer, use Above-mentioned immersion process moves in circles n times, that is, obtains the long-acting slow-release antibacterial film of the high drug load.

5. the preparation method of the long-acting slow-release antibacterial film of high drug load according to claim 4, it is characterised in that the step Suddenly in (1), adjust pH after, placed 1-5 days under room temperature, the solution can self assembly be nanometer corynebacterium or filamentary structure.

6. the preparation method of the long-acting slow-release antibacterial film of high drug load according to claim 4, it is characterised in that the step Suddenly in (3), the ultrasonic condition is：Ultrasonic power is 90-110W, ultrasonic time 10-20min.

7. the preparation method of the long-acting slow-release antibacterial film of high drug load according to claim 4, it is characterised in that the step Suddenly in (6), the substrate selects silicon dioxide substrate.

8. the preparation method of the long-acting slow-release antibacterial film of high drug load according to claim 4, it is characterised in that the step Suddenly in (6), using identical solution immersion order when each layer of group is soaked.