1. Polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions_nThe method is characterized in that: specifically, the polylactic acid nano fiber membrane consists of polylactic acid nano fiber membrane matrix (PLA) and polydopamineTransition layer (PDA) and functional coating (LbL)_nComposition is carried out; wherein: the polydopamine transition layer is arranged between the polylactic acid nanofiber membrane matrix and the functional coating, and the functional coating is an epsilon-polylysine and alginic acid composite coating obtained by electrostatic layer-by-layer self-assembly.

2. The polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions as claimed in claim 1_nThe method is characterized in that: the number n of layers of the functional coating is not more than 10.

3. Polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions as claimed in claim 1_nThe preparation method is characterized by comprising the following steps: the method comprises the following steps:

(1) at normal temperature, placing a polylactic acid nanofiber membrane matrix (PLA) in an alkaline dopamine aqueous solution to be soaked for 8-16h to form a poly-dopamine-coated polylactic acid nanofiber membrane PLA @ PDA;

(2) cleaning the surface of the PLA @ PDA obtained in the step (1), soaking in an epsilon-polylysine aqueous solution for 8-12min, cleaning, soaking in an alginic acid aqueous solution for 8-12min, and cleaning;

(3) repeating the step (2) to obtain polylactic acid nano fiber composite membranes PLA @ PDA @ (LbL) with different epsilon-polylysine and alginic acid contents_nWherein: the number of repetitions is 0 to 10.

4. Polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions as claimed in claim 3_nThe preparation method is characterized by comprising the following steps: the concentration of the dopamine monomer in the alkaline dopamine aqueous solution in the step (1) is 0.1-10 mg/mL.

5. Polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions as claimed in claim 3_nThe preparation method is characterized by comprising the following steps: the alkaline dopamine aqueous solution in the step (1) is preferably a weakly alkaline aqueous solution with excellent pH valueIs selected from 8.0-9.0.

6. Polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions as claimed in claim 3_nThe preparation method is characterized by comprising the following steps: in the step (2), the concentrations of the epsilon-polylysine aqueous solution and the alginic acid aqueous solution are respectively 5-15 mg/mL.

7. Polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions as claimed in claim 1 or 2_nOr the polylactic acid nano-fiber composite membrane PLA @ PDA @ (LbL) with the biomimetic mineralization and antibacterial functions prepared by the method of any one of claims 3-6_nThe material can be used as a bone tissue repair material or a guided bone tissue regeneration membrane.

8. A bone tissue repair material characterized by: polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions as claimed in claim 1 or 2_nOr the polylactic acid nano-fiber composite membrane PLA @ PDA @ (LbL) with the biomimetic mineralization and antibacterial functions prepared by the method of any one of claims 3-6_n。

9. A guided bone tissue regeneration membrane, comprising: polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions as claimed in claim 1 or 2_nOr the polylactic acid nano-fiber composite membrane PLA @ PDA @ (LbL) with the biomimetic mineralization and antibacterial functions prepared by the method of any one of claims 3-6_n。

Background

More and more patients with bone defects and nonunion caused by trauma, bone diseases, tumors and the like. In addition, alveolar bone defects caused by trauma, inflammation, tumor, and the like also become important health problems of social concern. Among the numerous treatment options, bone tissue engineering offers new options for treating bone defects. However, infection caused by bacteria is an important reason for the failure of the implantation of the scaffold material, so that the preparation of the scaffold material with the biomimetic mineralization function and the antibacterial function has important significance.

Polylactic acid is an important renewable biodegradable high polymer material, has good biocompatibility and mechanical strength, is widely used in the fields of packaging materials, fibers, tissue engineering, drug release and the like, and is also deeply researched in the application of medical fields such as orthopedic internal fixation materials, non-dismantling surgical sutures and the like. However, polylactic acid is a hydrophobic material and has no biomimetic mineralization capability, has no function of inducing bone repair when used as an orthopedic fixation material, and also has no antibacterial property, which greatly limits the application of polylactic acid in bone tissue engineering.

The polylactic acid has the biomimetic mineralization capability and the antibacterial function at the same time by compounding the material with the mineralization induction capability or the antibacterial function with the polylactic acid. For example, titanium metal-based materials, bioactive ceramics, degradable high molecular materials, polypeptides, protein materials and other materials are compounded with a polylactic acid scaffold to enable the polylactic acid scaffold to have biomimetic mineralization capability, and Ag, antibacterial peptides, antibiotics and other materials are compounded to enable the polylactic acid scaffold to have an antibacterial function. However, it is still a challenge to provide a polylactic acid scaffold with both biomimetic mineralization and antibacterial functions by a simple method.

For the above reasons, the present application has been made.

Disclosure of Invention

The epsilon-polylysine (epsilon-PL) is a natural antibacterial agent with cations and has good antibacterial performance. Alginic Acid (ALG) is a natural polysaccharide rich in a large number of hydroxyl and carboxyl groups, which contributes to the deposition of hydroxyapatite. The epsilon-polylysine and the alginic acid are combined by a simple method, so that the scaffold has the biomimetic mineralization function and the antibacterial function and has important significance.

Aiming at the problems or defects in the prior art, the invention aims to provide a polylactic acid nanofiber composite membrane with biomimetic mineralization and antibacterial functions, and a preparation method and application thereof. The invention loads alginic acid and epsilon-polylysine on the surface of the polylactic acid nanofiber by combining biomimetic and layer-by-layer assembly of mussels, and can obtain the polylactic acid nanofiber composite membranes with different mineralization abilities and antibacterial functions by controlling the number of assembly layers.

In order to achieve the first object of the present invention, the present invention adopts the following technical solutions:

polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions_nSpecifically comprises a polylactic acid nanofiber membrane matrix (PLA), a polydopamine transition layer (PDA) and a functional coating (LbL)_nComposition is carried out; wherein: the polydopamine transition layer is arranged between the polylactic acid nanofiber membrane matrix and the functional coating, and the functional coating is an epsilon-polylysine and alginic acid composite coating obtained by electrostatic layer-by-layer self-assembly.

Specifically, according to the technical scheme, the polylactic acid nanofiber membrane matrix provides basic mechanical properties of the composite material; the functional coating has the functions of resisting bacteria and promoting osteogenesis.

Further, in the technical scheme, the number n of layers of the functional coating is not more than 10.

The second purpose of the invention is to provide the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the biomimetic mineralization and antibacterial functions_nThe method comprises the following steps:

(1) at normal temperature, placing a polylactic acid nanofiber membrane matrix (PLA) in an alkaline dopamine aqueous solution to be soaked for 8-16h to form a poly-dopamine-coated polylactic acid nanofiber membrane PLA @ PDA;

(2) cleaning the surface of the PLA @ PDA obtained in the step (1), soaking in an epsilon-polylysine aqueous solution for 8-12min, cleaning, soaking in an alginic acid aqueous solution for 8-12min, and cleaning;

(3) repeating the step (2) to obtain polylactic acid nano fiber composite membranes PLA @ PDA @ (LbL) with different epsilon-polylysine and alginic acid contents_nWherein: the number of repetitions is 0 to 10.

Specifically, in the above technical scheme, the normal temperature refers to a natural room temperature condition in four seasons, no additional cooling or heating treatment is performed, and the normal temperature is generally controlled to be 10-35 ℃.

Further, in the above technical solution, the concentration of the dopamine monomer in the alkaline dopamine aqueous solution in the step (1) is 0.1-10mg/mL, and more preferably 1-3 mg/mL.

Further, in the above technical solution, the alkaline dopamine aqueous solution in step (1) is preferably a weakly alkaline aqueous solution, and the pH value thereof is preferably 8.0-9.0.

Further, in the above technical solution, the soaking reaction time in the step (1) is preferably 12 hours.

Furthermore, in the above technical scheme, the concentrations of the epsilon-polylysine aqueous solution and the alginic acid aqueous solution in the step (2) can be respectively 5-15mg/mL, and more preferably 10mg/mL, which can be the same or different.

The third purpose of the invention is to provide the polylactic acid nano-particles with the biomimetic mineralization and antibacterial functionsFiber composite film PLA @ PDA @ (LbL)_nThe application in bone tissue repair materials or guided bone tissue regeneration membranes.

The bone tissue repair material comprises the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with the biomimetic mineralization and antibacterial functions_n。

The membrane for guiding bone tissue regeneration comprises the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with the biomimetic mineralization and antibacterial functions_n。

The invention relates to a polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions_nThe preparation principle is as follows:

the dopamine can oxidize and self-polymerize under the alkalescent condition and can adhere to the surface of a matrix. In order to successfully adhere epsilon-polylysine to a hydrophobic polylactic acid nano fiber membrane substrate, dopamine is selected to carry out surface treatment on the polylactic acid nano fiber membrane to form a polydopamine transition layer.

The invention adopts a layer-by-layer self-assembly technology of polymer electrolytes with opposite charges, and deposits on the surface of PLA @ PDA in a mode of dip coating in an alternating sequence of positive and negative charge materials according to different charged performances.

Compared with the prior art, the polylactic acid nanofiber composite membrane with the biomimetic mineralization and antibacterial functions, the preparation method and the application thereof have the following beneficial effects:

(1) the composite material with the biomimetic mineralization function and the antibacterial function is obtained by loading epsilon-polylysine and alginic acid on the surface of the polylactic acid nanofiber membrane, has good biomimetic mineralization capability, good antibacterial performance and good biocompatibility, and has good application prospects in biomedical fields such as bone tissue repair, guided bone tissue regeneration membranes and the like.

(2) The preparation method is simple and environment-friendly, the adopted raw materials have no toxic or side effect, and the obtained polylactic acid nanofiber composite membrane has excellent mechanical properties.

(3) Aiming at the characteristics of the adopted high molecular polyelectrolyte material with positive and negative charges, the invention adopts a polyelectrolyte layer-by-layer self-assembly method (LBL) to alternately deposit epsilon-polylysine and alginic acid on the surface of the polydopamine transition layer, so that the polydopamine transition layer-by-layer self-assembly material is more in line with the requirements of biomedical implant materials.

Drawings

FIG. 1 is a flow chart of a preparation process of the polylactic acid nanofiber composite membrane with biomimetic mineralization and antibacterial functions;

FIG. 2 is a scanning electron microscope (PLA) image of polylactic acid nanofiber (PLA) film stock used in various embodiments of the present invention;

a, B, C, D in FIG. 3 are PLA @ PDA prepared in comparative example 1, PLA @ PDA @ (LbL) prepared in example 2, in that order₂PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀A Scanning Electron Microscope (SEM) image of (a);

FIG. 4 shows PLA film stock used in the present invention, PLA @ PDA prepared in comparative example 1, and PLA @ PDA @ (LbL) prepared in example 2₂PLA @ PDA @ (LbL) prepared in example 3₄A water contact angle test result graph of (1);

a, B, C, D, E in FIG. 5 are sequentially the PLA film stock used in the present invention, PLA @ PDA prepared in comparative example 1, PLA @ PDA @ (LbL) prepared in example 2₂PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀Scanning Electron Microscope (SEM) images of seven days of immersion in 1.5 xSBF; (F) PLA @ PDA @ (LbL) prepared for example 6₁₀Scanning Electron Microscope (SEM) images of four days soaking in 1.5 xSBF;

a, B in FIG. 6 is the PLA film stock used in the present invention, PLA @ PDA prepared in comparative example 1, PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀A result chart of antibacterial performance test of staphylococcus aureus and escherichia coli; C. d is PLA film material used in the present invention, PLA @ PDA prepared in comparative example 1, PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀A histogram of antibacterial performance against staphylococcus aureus and escherichia coli;

a, B in FIG. 7 are in turn embodiments of the present inventionPLA film stock used, PLA @ PDA as prepared in comparative example 1, PLA @ PDA as prepared in example 2 (LbL)₂PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀Graph of results of biocompatibility test on L929 cells and MC3T3-E1 cells;

FIG. 8 shows PLA film stock used in the present invention, PLA @ PDA prepared in comparative example 1, and PLA @ PDA @ (LbL) prepared in example 2₂PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀The tensile property test result chart of (1).

Detailed Description

The invention provides the following technical scheme: polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions_nSpecifically comprises a polylactic acid nanofiber membrane matrix (PLA), a polydopamine transition layer (PDA) and a functional coating (LbL)_nComposition is carried out; wherein: the polydopamine transition layer is arranged between the polylactic acid nanofiber membrane matrix and the functional coating, and the functional coating is an epsilon-polylysine and alginic acid composite coating obtained by electrostatic layer-by-layer self-assembly.

The polylactic acid nano fiber membrane is used as a matrix, and is sequentially and alternately soaked and cleaned by an epsilon-PL aqueous solution and an ALG aqueous solution after being treated and cleaned by an alkaline dopamine aqueous solution.

In the invention, the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with the biomimetic mineralization and antibacterial functions_nThe specific preparation method comprises the following steps:

(1) at normal temperature, placing a polylactic acid nanofiber membrane matrix (PLA) in an alkaline dopamine aqueous solution for soaking for 8-16h to enable dopamine to undergo self-polymerization to form a polydopamine-coated polylactic acid nanofiber membrane PLA @ PDA;

(2) cleaning the surface of the PLA @ PDA obtained in the step (1), soaking in an epsilon-polylysine aqueous solution for 8-12min, cleaning, soaking in an alginic acid aqueous solution for 8-12min, and cleaning;

(3) repeating the step (2) to obtain the polylactic acid nano fibers with different epsilon-polylysine and alginic acid contentsComposite film PLA @ PDA @ (LbL)_nWherein: the number of repetitions is 0 to 10.

The present invention will be described in further detail below with reference to examples. The present invention is implemented on the premise of the technology of the present invention, and the detailed embodiments and specific procedures are given to illustrate the inventive aspects of the present invention, but the scope of the present invention is not limited to the following embodiments.

Various modifications to the precise description of the invention will be readily apparent to those skilled in the art from the information contained herein without departing from the spirit and scope of the appended claims. It is to be understood that the scope of the invention is not limited to the procedures, properties, or components defined, as these embodiments, as well as others described, are intended to be merely illustrative of particular aspects of the invention. Indeed, various modifications of the embodiments of the invention which are obvious to those skilled in the art or related fields are intended to be covered by the scope of the appended claims.

For a better understanding of the invention, and not as a limitation on the scope thereof, all numbers expressing quantities, percentages, and other numerical values used in this application are to be understood as being modified in all instances by the term "about". At the very least, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

The test methods used in the following examples are all conventional methods unless otherwise specified; the raw materials and reagents used are, unless otherwise specified, those commercially available from ordinary commercial sources.

Example 1

The polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions of the embodiment₁Specifically comprises a polylactic acid nanofiber membrane matrix (PLA), a polydopamine transition layer (PDA) and a functional coating (LbL)₁Composition is carried out; wherein: the polydopamine transition layer is arranged between the polylactic acid nanofiber membrane substrate and the functional coating, and the functional coating is epsilon-polylysine and functional coating obtained by electrostatic layer-by-layer self-assemblyAlginic acid composite coating.

In this embodiment, the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions is described above₁The preparation method comprises the following steps:

A. uniformly immersing a polylactic acid nanofiber membrane matrix (the size is 5cm in length and 5cm in width) into 2mg/ml dopamine aqueous solution with the pH value equal to 8.5 for 12 hours; forming a polydopamine layer on the surface of the polylactic acid film due to dopamine self-polymerization to obtain a polydopamine-coated polylactic acid nanofiber film (PLA @ PDA);

B. washing the PLA @ PDA obtained in the step A with deionized water to remove impurities physically adsorbed on the surface;

C. soaking the PLA @ PDA obtained in the step B into an epsilon-PL water solution with the concentration of 10mg/mL for 10 min;

D. cleaning the surface of the modified fiber membrane obtained after soaking in the step C with deionized water;

E. d, soaking the modified fiber membrane obtained in the step D in an ALG aqueous solution with the concentration of 10mg/mL for 10 min;

F. and E, cleaning the surface of the modified fiber membrane obtained after soaking in the step E with deionized water to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the functions of biomimetic mineralization and antibiosis₁。

Example 2

The polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions of the embodiment₂Specifically comprises a polylactic acid nanofiber membrane matrix (PLA), a polydopamine transition layer (PDA) and a functional coating (LbL)₂Composition is carried out; wherein: the polydopamine transition layer is arranged between the polylactic acid nanofiber membrane matrix and the functional coating, and the functional coating is an epsilon-polylysine and alginic acid composite coating obtained by electrostatic layer-by-layer self-assembly.

In this embodiment, the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions is described above₂The preparation method comprises the following steps:

A. uniformly immersing a polylactic acid nanofiber membrane matrix (the size is 5cm in length and 5cm in width) into 2mg/ml dopamine aqueous solution with the pH value equal to 8.5 for 12 hours; forming a polydopamine layer on the surface of the polylactic acid film due to dopamine self-polymerization to obtain a polydopamine-coated polylactic acid nanofiber film (PLA @ PDA);

B. washing the PLA @ PDA obtained in the step A with deionized water to remove impurities physically adsorbed on the surface;

C. soaking the PLA @ PDA obtained in the step B into an epsilon-PL water solution with the concentration of 10mg/mL for 10 min;

D. cleaning the surface of the modified fiber membrane obtained after soaking in the step C with deionized water;

E. d, soaking the modified fiber membrane obtained in the step D in an ALG aqueous solution with the concentration of 10mg/mL for 10min, and further adhering the alginic acid with negative electricity to the surface of the epsilon-polylysine functional coating with positive electricity through electrostatic adsorption;

F. and E, cleaning the surface of the modified fiber membrane obtained after soaking in the step E with deionized water to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the functions of biomimetic mineralization and antibiosis₁。

G. Utilizing the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) obtained in the step F₁The step C, D, E, F is repeated for 1 time in sequence to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the biomimetic mineralization function and the antibacterial function₂。

Example 3

The polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions of the embodiment₄Specifically comprises a polylactic acid nanofiber membrane matrix (PLA), a polydopamine transition layer (PDA) and a functional coating (LbL)₄Composition is carried out; wherein: the polydopamine transition layer is arranged between the polylactic acid nanofiber membrane matrix and the functional coating, and the functional coating is an epsilon-polylysine and alginic acid composite coating obtained by electrostatic layer-by-layer self-assembly.

In this embodiment, the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions is described above₄The preparation method comprises the following steps:

A. uniformly immersing a polylactic acid nanofiber membrane matrix (the size is 5cm in length and 5cm in width) into 2mg/ml dopamine aqueous solution with the pH value equal to 8.5 for 12 hours; forming a polydopamine layer on the surface of polylactic acid due to dopamine self-polymerization to obtain a polydopamine-coated polylactic acid nanofiber membrane (PLA @ PDA);

B. washing the PLA @ PDA obtained in the step A with deionized water to remove impurities physically adsorbed on the surface;

C. soaking the PLA @ PDA obtained in the step B into an epsilon-PL water solution with the concentration of 10mg/mL for 10 min;

D. cleaning the surface of the modified fiber membrane obtained after soaking in the step C with deionized water;

E. d, soaking the modified fiber membrane obtained in the step D in an ALG aqueous solution with the concentration of 10mg/mL for 10 min;

F. and E, cleaning the surface of the modified fiber membrane obtained after soaking in the step E with deionized water to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the functions of biomimetic mineralization and antibiosis₁。

G. Utilizing the polylactic acid nanofiber membrane PLA @ PDA @ (LbL) obtained in the step F₁The step C, D, E, F is repeated for 3 times in sequence to obtain the polylactic acid nanofiber membrane PLA @ PDA @ (LbL) with the biomimetic mineralization function and the antibacterial function₄。

Example 4

The polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions of the embodiment₆Specifically comprises a polylactic acid nanofiber membrane matrix (PLA), a polydopamine transition layer (PDA) and a functional coating (LbL)₆Composition is carried out; wherein: the polydopamine transition layer is arranged between the polylactic acid nanofiber membrane matrix and the functional coating, and the functional coating is an epsilon-polylysine and alginic acid composite coating obtained by electrostatic layer-by-layer self-assembly.

In this embodiment, the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions is described above₆The preparation method comprises the following steps:

A. uniformly immersing a polylactic acid nanofiber membrane matrix (the size is 5cm in length and 5cm in width) into 2mg/ml dopamine aqueous solution with the pH value equal to 8.5 for 12 hours; forming a polydopamine layer on the surface of polylactic acid due to dopamine self-polymerization to obtain a polydopamine-coated polylactic acid nanofiber membrane (PLA @ PDA);

B. washing the PLA @ PDA obtained in the step A with deionized water to remove impurities physically adsorbed on the surface;

C. soaking the PLA @ PDA obtained in the step B into an epsilon-PL water solution with the concentration of 10mg/mL for 10 min;

D. cleaning the surface of the modified fiber membrane obtained after soaking in the step C with deionized water;

E. d, soaking the modified fiber membrane obtained in the step D in an ALG aqueous solution with the concentration of 10mg/mL for 10 min;

F. and E, cleaning the surface of the modified fiber membrane obtained after soaking in the step E with deionized water to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the functions of biomimetic mineralization and antibiosis₁。

G. Utilizing the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) obtained in the step F₁The step C, D, E, F is repeated for 5 times in sequence to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the functions of biomimetic mineralization and antibiosis₆。

Example 5

The polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions of the embodiment₈Specifically comprises a polylactic acid nanofiber membrane matrix (PLA), a polydopamine transition layer (PDA) and a functional coating (LbL)₈Composition is carried out; wherein: the polydopamine transition layer is arranged between the polylactic acid nanofiber membrane matrix and the functional coating, and the functional coating is an epsilon-polylysine and alginic acid composite coating obtained by electrostatic layer-by-layer self-assembly.

In this embodiment, the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions is described above₈The preparation method comprises the following steps:

A. uniformly immersing a polylactic acid nanofiber membrane matrix (the size is 5cm in length and 5cm in width) into 2mg/ml dopamine aqueous solution with the pH value equal to 8.5 for 12 hours; forming a polydopamine layer on the surface of the polylactic acid film due to dopamine self-polymerization to obtain a polydopamine-coated polylactic acid nanofiber film (PLA @ PDA);

B. washing the PLA @ PDA obtained in the step A with deionized water to remove impurities physically adsorbed on the surface;

C. soaking the PLA @ PDA obtained in the step B into an epsilon-PL water solution with the concentration of 10mg/mL for 10 min;

D. cleaning the surface of the modified fiber membrane obtained after soaking in the step C with deionized water;

E. d, soaking the modified fiber membrane obtained in the step D in an ALG aqueous solution with the concentration of 10mg/mL for 10 min;

F. and E, cleaning the surface of the modified fiber membrane obtained after soaking in the step E with deionized water to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the functions of biomimetic mineralization and antibiosis₁。

G. Utilizing the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) obtained in the step F₁The step C, D, E, F is repeated for 7 times in sequence to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the functions of biomimetic mineralization and antibiosis₈。

Example 6

The polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions of the embodiment₁₀Specifically comprises a polylactic acid nanofiber membrane matrix (PLA), a polydopamine transition layer (PDA) and a functional coating (LbL)₁₀Composition is carried out; wherein: the polydopamine transition layer is arranged between the polylactic acid nanofiber membrane matrix and the functional coating, and the functional coating is an epsilon-polylysine and alginic acid composite coating obtained by electrostatic layer-by-layer self-assembly.

In this embodiment, the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions is described above₁₀The preparation method comprises the following steps:

A. uniformly immersing a polylactic acid nanofiber membrane matrix (the size is 5cm in length and 5cm in width) into 2mg/ml dopamine aqueous solution with the pH value equal to 8.5 for 12 hours; forming a polydopamine layer on the surface of the polylactic acid film due to dopamine self-polymerization to obtain a polydopamine-coated polylactic acid nanofiber film (PLA @ PDA);

B. washing the PLA @ PDA obtained in the step A with deionized water to remove impurities physically adsorbed on the surface;

C. soaking the PLA @ PDA obtained in the step B into an epsilon-PL water solution with the concentration of 10mg/mL for 10 min;

D. cleaning the surface of the modified fiber membrane obtained after soaking in the step C with deionized water;

E. d, soaking the modified fiber membrane obtained in the step D in an ALG aqueous solution with the concentration of 10mg/mL for 10 min;

F. and E, cleaning the surface of the modified fiber membrane obtained after soaking in the step E with deionized water to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the functions of biomimetic mineralization and antibiosis₁。

G. Utilizing the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) obtained in the step F₁The step C, D, E, F is repeated for 9 times in sequence to obtain the polylactic acid nano fiber composite membrane PLA @ PDA @ (LbL) with the functions of biomimetic mineralization and antibiosis₁₀。

Example 7

The polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions of the embodiment₁The preparation method is basically the same as that of example 1, and the difference is only that: in step a of this example, the concentration of dopamine monomer in the dopamine aqueous solution is 0.1mg/mL, and the pH of the dopamine aqueous solution is 8.0.

Example 8

The polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions of the embodiment₁The preparation method is basically the same as that of example 1, and the difference is only that: in this example, the concentration of dopamine monomer in the dopamine aqueous solution in step a is 1mg/mL, and the pH value of the dopamine aqueous solution is 9.0.

Comparative example 1

A method of making a polydopamine coated polylactic acid nanofiber membrane (PLA @ PDA) of this comparative example, the method comprising the steps of:

A. soaking polylactic acid nanofiber membrane (size: 5cm long × 5cm wide) in dopamine aqueous solution with pH value of 8.5 for 12h, wherein: the concentration of the dopamine monomer in the dopamine aqueous solution is 2 mg/mL;

B. and D, washing the PLA @ PDA obtained in the step A by using deionized water, and removing impurities such as unreacted dopamine monomers and the like physically adsorbed on the surface of polydopamine to obtain the polydopamine-coated polylactic acid nanofiber membrane PLA @ PDA.

Structural analysis:

a, B, C, D in FIG. 3 are PLA @ PDA prepared in comparative example 1, PLA @ PDA @ (LbL) prepared in example 2, in that order₂PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀Scanning Electron Microscope (SEM) images of (a). As can be seen from fig. 3, compared with the polylactic acid fiber membrane raw material of fig. 1, the fiber membrane surfaces treated by the comparative example and the example become rough, which indicates that the polydopamine transition layer, the epsilon-polylysine and the alginic acid are successfully adhered to the surfaces of the products prepared by the comparative example and the example.

FIG. 4 shows PLA film stock used in the present invention, PLA @ PDA prepared in comparative example 1, and PLA @ PDA @ (LbL) prepared in example 2₂PLA @ PDA @ (LbL) prepared in example 3₄A water contact angle test result graph of (1); wherein the water contact angle of PLA is 115 degrees, and PLA @ PDA @ (LbL)₂The contact angle of the polylactic acid fiber membrane is 36 degrees, and the result shows that the invention effectively improves the hydrophobicity of the polylactic acid fiber membrane by a layer-by-layer dip coating mode.

Performance testing

(1) In vitro mineralization Capacity test

Preparing 1.5xSBF simulated body fluid, and shearing the sample into 1cm²The small blocks are put into 10mL of simulated body fluid to be soaked for 24h, and the simulated body fluid is replaced every 24 h. And observing the deposition condition of hydroxyapatite on the surface of the sample film by a scanning electron microscope after soaking for seven days. FIG. 5 shows that the polylactic acid nanofiber composite membrane PLA @ PDA @ (LbL) with biomimetic mineralization and antibacterial functions prepared by the invention_nHas good capability of inducing the deposition of hydroxyapatite.

(2) Test of antibacterial Property

PLA used as the raw material of the polylactic acid nanofiber membrane, PLA @ PDA obtained in comparative example 1, and PLA @ PDA @ (LbL) obtained in example 4 were mixed₆PLA @ PDA @ (LbL) obtained in example 6₁₀The antibacterial performance of the sample on escherichia coli is tested, and the specific test method comprises the following steps:

shearing the sample into 1cm × 1cm, ultraviolet irradiating for 30min, dripping 50uL of bacteria on the membrane surface, and culturing in a thermostat for 6 h. And (3) washing bacteria loosely attached to the surface of the membrane by using phosphoric acid buffer solution, then putting the membrane into 2mL of phosphoric acid buffer solution, fully shaking to obtain bacterial liquid, taking 100uL of shaking solution for gradient dilution, and finally taking 10uL of dilution solution to culture in a culture dish for 24h to obtain the number of bacterial colonies.

(3) Evaluation of biocompatibility

The biocompatibility test of the present invention is determined by the MTT method. Cutting the sample into small discs with diameter of 3mm, sterilizing by ultraviolet irradiation for 2h, washing with phosphate buffer, placing in 96-well plate, and placing 100 μ L of the cell with density of 8 × 10⁴cell/ml MC3T3-E1 cell suspension was added to the well plate and incubated in a 37 ℃ incubator for 48 h. Testing was performed using MTT kit.

(4) Tensile Property test

The sample was cut into strips of 8mm in width and 4cm in length, and the test was carried out at room temperature using a universal drawing machine at a drawing rate of 5 mm/min.

A, B, C, D, E in FIG. 5 are sequentially the PLA film stock used in the present invention, PLA @ PDA prepared in comparative example 1, PLA @ PDA @ (LbL) prepared in example 2₂PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀Scanning Electron Microscope (SEM) images of seven days of immersion in 1.5 xSBF; (F) PLA @ PDA @ (LbL) prepared for example 6₁₀Scanning Electron Microscope (SEM) images of four days soaking in 1.5 xSBF; the result shows that the polylactic acid fiber membrane modified by layer-by-layer dip coating can form a large amount of hydroxyapatite on the surface after being soaked in simulated body fluid for 7 days, and the surface hydroxyapatite is increased along with the increase of the number of the assembling layers. The polylactic acid nanofiber membrane prepared by the layer-by-layer dip coating modification can promote the rapid deposition of hydroxyapatite.

A, B in FIG. 6 is the PLA film stock used in the present invention, PLA @ PDA prepared in comparative example 1, PLA @ PDA @ (LbL) prepared in example 4₆P prepared in example [email protected]@(LbL)₁₀The antibacterial performance test result chart of staphylococcus aureus and escherichia coli shows that the number of the colonies in the test group of the sample containing the layer-by-layer assembled functional coating is the least under the same condition; C. d is PLA film material used in the present invention, PLA @ PDA prepared in comparative example 1, PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀A histogram of antibacterial properties of Staphylococcus aureus and Escherichia coli, using PLA group as control, and a sample PLA @ PDA @ (LbL) with layer-by-layer assembled functional coating on the surface₆And PLA @ PDA @ (LbL)₁₀The survival rates of staphylococcus aureus and escherichia coli in the experimental groups are 22% and 21% and 24.5% and 13.5% respectively. Experimental results show that the polylactic acid nanofiber membrane prepared by the method through layer-by-layer dip coating modification has good antibacterial performance.

A, B in FIG. 7 are sequentially the PLA film stock used in the present invention, PLA @ PDA as prepared in comparative example 1, PLA @ PDA @ (LbL) as prepared in example 2₂PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀The results of the biocompatibility test on the MC3T3-E1 cells correspond to the following cell survival rates in sequence: 92.7%, 87.9%, 101.9%, 104.1%, 93.7%; the result shows that the polylactic acid nanofiber membrane prepared by the layer-by-layer dip coating modification has good biocompatibility, and the biological toxicity of the PLA @ PDA prepared by the method is reduced compared with that of the PLA @ PDA prepared by the comparative example 1.

FIG. 8 shows PLA film stock used in the present invention, PLA @ PDA prepared in comparative example 1, and PLA @ PDA @ (LbL) prepared in example 2₂PLA @ PDA @ (LbL) prepared in example 4₆PLA @ PDA @ (LbL) prepared in example 6₁₀The tensile strength of the tensile property test result chart is respectively as follows: 1.16MPa, 1.69MPa, 2.86MPa, 3.42MPa and 3.78MPa, which shows that the mechanical property of the polylactic acid fiber membrane can be improved by layer-by-layer dip coating modification.