A multifunctional nacre-like collagen-based supramolecular film and its preparation method

Abstract

The present invention discloses a multifunctional nacre-mimicking collagen-based supramolecular film and a preparation method thereof. The technical solution described in the present invention mainly combines layered zirconium phosphate nanosheets, tannic acid, and type I collagen molecules through a co-assembly strategy. That is, first, the rich surface reactivity of tannic acid molecules is utilized to construct a layered zirconium phosphate nanosheet-tannic acid supramolecular assembly. Then, the supramolecular assembly is utilized to regulate the assembly behavior of collagen molecules and the interfacial interaction between them, thereby preparing a collagen-based supramolecular film with nacre-mimicking properties. The collagen-based supramolecular film prepared by the present invention exhibits excellent thermal stability while maintaining a high degree of transparency. The introduction of the supramolecular assembly not only improves the hydrophobicity of the collagen-based supramolecular film, but also imparts a synergistic antibacterial effect to it, making the film show great application potential in high-barrier food packaging materials and degradable flexible electronic materials.

Description

Technical Field

[0001] The invention belongs to the field of biomacromolecule-based functional materials and relates to a multifunctional nacre-imitation collagen-based supramolecular film and a preparation method thereof. Background Art

[0002] Natural structural materials such as bone, wood, and shells are biocomposites constructed from specific components through a top-down strategy at ambient temperature. They typically consist of a complex, multi-layered structure composed of a large number of ordered "hard phases" and a small number of "soft phases." They not only possess multi-layered structural characteristics from the nanoscale to the macroscale but also exhibit unique strength and toughness, particularly at low densities, where the synergistic coupling of rigidity and toughness is fully realized. Nacreous structures are inspired by the unique layered structure of the nacre of mussels found in nature. For example, nacre is a natural organic-inorganic composite layered structure composed primarily of 95% inorganic calcium carbonate (inorganic phase) and 5% biopolymer matrix (organic phase), separated by biopolymer layers. Due to its highly ordered "brick-and-mortar" microstructure, nacre possesses exceptional strength and toughness. Biomimetic composites inspired by the structure of nacre have garnered considerable research attention in recent years.

[0003] Two-dimensional nanomaterials, with their rich surface functional groups, easy surface chemical modification, and controllable size, can be used as building blocks to construct nacre-like structures. These not only improve the mechanical properties of nacre-like films and impart barrier and antibacterial properties, but also enhance the density of ion migration. Their nanostructured properties allow them to function as nanochannels. Researchers have already incorporated two-dimensional materials such as graphene oxide, MXene, and layered nanoclays into various biomacromolecule matrices to create biomimetic nanocomposites with diverse functional properties. These materials are being applied in a variety of cutting-edge fields, including functional food packaging, flexible wearables, tissue engineering, biomimetic microsensors, membrane separation, and energy conversion.

[0004] Currently, patents have disclosed methods for preparing films with nacre-like structures. For example, patent CN109776829B discloses a method for preparing high-strength, high-toughness layered barrier films. This method primarily utilizes montmorillonite and carboxymethyl cellulose, combined with evaporation-assisted self-assembly and hot-pressing technology, to prepare shell-like binary and ternary layered films. The resulting films exhibit excellent mechanical properties, flame retardancy, and gas barrier properties, improving the hybrid film's oxygen and water vapor barrier properties and flame retardancy. Patent CN115286898A discloses a method for preparing nacre-like MXene / epoxy nanocomposites. This method primarily utilizes in-situ HF-etched MXene solutions and carboxymethyl cellulose, followed by vacuum-assisted infusion of epoxy precursors. After curing, the resulting nacre-like MXene / epoxy nanocomposites exhibit excellent mechanical properties. Furthermore, the nacre-like MXene / epoxy nanocomposites exhibit properties such as crack self-monitoring and electromagnetic shielding. However, there are currently no specific literature or patent reports on the use of tannic acid and layered zirconium phosphate nanosheets to construct supramolecular assemblies for modifying collagen to prepare multifunctional nacre-like collagen-based supramolecular membranes. Summary of the Invention

[0005] The purpose of the present invention is to combine layered zirconium phosphate nanosheets, tannic acid and type I collagen molecules through a co-assembly strategy to prepare a multifunctional collagen-based supramolecular film with a nacre-like layer, providing an important basis for the preparation of new high-barrier food packaging materials and degradable flexible electronic materials.

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

[0007] A method for preparing a multifunctional nacreous collagen-based supramolecular film comprises the following steps:

[0008] (1) First, the layered zirconium phosphate nanosheets were ultrasonically dispersed in deionized water. Then, a 0.1 mol / L exfoliant was slowly added dropwise to the dispersion and magnetic stirring was continued at room temperature for 6 h to obtain an exfoliated layered zirconium phosphate nanodispersion. Then, a 1.0 mg / mL tannic acid solution was slowly added to the nanodispersion and the reaction was continued for 2 h to obtain a layered zirconium phosphate nanosheet-tannic acid supramolecular assembly.

[0009] (2) The freeze-dried collagen was fully dissolved in 0.5 mol / L acetic acid solution to obtain a collagen acetic acid solution with a concentration of 10 mg / mL. Then, equal volumes of the supramolecular assembly dispersion were mixed with the collagen acetic acid solution and stirred at room temperature for 2 h to obtain a film-forming solution. The film-forming solution was then coated on the surface of a silicon wafer substrate and dried in an oven at 30°C for 12 h to obtain a multifunctional nacre-like collagen-based supramolecular film.

[0010] The diameter of the layered zirconium phosphate nanosheets is 50-100 nm.

[0011] The stripping agent is one of tetrabutylammonium hydroxide, triethanolamine and tris(hydroxymethyl)aminomethane, and the molar ratio of the nanosheet to the stripping agent is 1:(0.4-2.0).

[0012] The mass ratio of the tannic acid to the layered zirconium phosphate nanosheets is (0.0025-0.04):1.

[0013] The mass ratio of the layered zirconium phosphate nanosheets to collagen is (0.1-0.5):1.

[0014] A multifunctional nacreous collagen-based supramolecular film is prepared by the above-mentioned preparation method.

[0015] Compared with the prior art, the advantages and effects of the present invention are as follows:

[0016] (1) The preparation method used is simple and easy to operate, and the raw materials are abundant and environmentally friendly;

[0017] (2) The prepared collagen-based supramolecular film exhibits nacre-like structural characteristics;

[0018] (3) The prepared collagen-based supramolecular films exhibited excellent thermal stability while maintaining high transparency;

[0019] (4) The introduction of supramolecular assemblies not only improves the hydrophobicity of the film but also imparts a synergistic antibacterial effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a scanning electron micrograph of a cross section of the multifunctional nacre-like collagen-based supramolecular film prepared in Example 3;

[0021] Figure 2 IR spectra of the multifunctional nacre-like collagen-based supramolecular film prepared in Example and a control collagen film;

[0022] Figure 3 The differential scanning calorimetry analysis spectra of the multifunctional nacre-like collagen-based supramolecular film prepared in Example and the control collagen film;

[0023] Figure 4 Digital photos of the multifunctional nacre-like collagen-based supramolecular film prepared in Example and a control collagen film;

[0024] Figure 5 The transmittance test results of the multifunctional nacre-like collagen-based supramolecular film prepared in Example and the control collagen film are shown;

[0025] Figure 6The contact angle test results of the multifunctional nacre-like collagen-based supramolecular film prepared in Example and the control collagen film;

[0026] Figure 7 The antibacterial effects of the multifunctional nacre-like collagen-based supramolecular film prepared in the example and the control collagen film on Escherichia coli and Staphylococcus aureus, respectively. DETAILED DESCRIPTION

[0027] The following examples illustrate the collagen-based supramolecular film with nacre-like properties described herein. The layered zirconium phosphate nanosheets were prepared using ZrOCl2·8H2O as a raw material by refluxing at 100°C for 24 hours. It should be noted that this example is intended only to further illustrate the present invention and is not to be construed as limiting its scope. Persons skilled in the art may make non-essential improvements and adjustments based on the above disclosure.

[0028] Example 1

[0029] First, 1.6 g of layered zirconium phosphate nanosheets were ultrasonically dispersed in 100 mL of deionized water. Then, 45 mL of 0.1 mol / L tetrabutylammonium hydroxide solution was slowly added dropwise to the dispersion and magnetically stirred at room temperature for 6 h to obtain an exfoliated layered zirconium phosphate nanodispersion. Then, 0.445 mL of tannic acid solution was slowly added to the nanodispersion and the reaction continued for 2 h to obtain a layered zirconium phosphate nanosheet-tannic acid supramolecular assembly. Freeze-dried collagen was fully dissolved in 0.5 mol / L acetic acid solution to obtain a 10 mg / mL collagen acetic acid solution. Then, equal volumes of the supramolecular assembly dispersion were mixed with the collagen acetic acid solution, maintaining a mass ratio of layered zirconium phosphate nanosheets to collagen of 0.1:1. The mixture was stirred at room temperature for 2 h to obtain a film-forming solution. The film-forming solution was then coated on a silicon wafer substrate and dried in a 30°C oven for 12 h to obtain a multifunctional nacre-mimicking collagen-based supramolecular film.

[0030] Example 2

[0031] First, 1.6 g of layered zirconium phosphate nanosheets were ultrasonically dispersed in deionized water. Then, 45 mL of 0.1 mol / L tetrabutylammonium hydroxide solution was slowly added dropwise to the dispersion and magnetic stirring was continued at room temperature for 6 h to obtain an exfoliated layered zirconium phosphate nanodispersion. Then, 0.445 mL of tannic acid solution was slowly added to the nanodispersion and the reaction was continued for 2 h to obtain a layered zirconium phosphate nanosheet-tannic acid supramolecular assembly. Freeze-dried collagen was fully dissolved in 0.5 mol / L acetic acid solution to obtain a 10 mg / mL collagen acetic acid solution. Then, equal volumes of the supramolecular assembly dispersion were mixed with the collagen acetic acid solution, maintaining a mass ratio of layered zirconium phosphate nanosheets to collagen of 0.2:1. The mixture was stirred at room temperature for 2 h to obtain a film-forming solution. The film-forming solution was then coated on the surface of a silicon wafer substrate and dried in a 30°C oven for 12 h to obtain a multifunctional nacre-like collagen-based supramolecular film.

[0032] Example 3

[0033] First, 1.6 g of layered zirconium phosphate nanosheets were ultrasonically dispersed in deionized water. Then, 45 mL of 0.1 mol / L tetrabutylammonium hydroxide solution was slowly added dropwise to the dispersion and magnetic stirring was continued at room temperature for 6 h to obtain an exfoliated layered zirconium phosphate nanodispersion. Then, 0.445 mL of tannic acid solution was slowly added to the nanodispersion and the reaction was continued for 2 h to obtain a layered zirconium phosphate nanosheet-tannic acid supramolecular assembly. Freeze-dried collagen was fully dissolved in 0.5 mol / L acetic acid solution to obtain a 10 mg / mL collagen acetic acid solution. Then, equal volumes of the supramolecular assembly dispersion were mixed with the collagen acetic acid solution, maintaining a mass ratio of layered zirconium phosphate nanosheets to collagen of 0.3:1. The mixture was stirred at room temperature for 2 h to obtain a film-forming solution. The film-forming solution was then coated on the surface of a silicon wafer substrate and dried in a 30°C oven for 12 h to obtain a multifunctional nacre-like collagen-based supramolecular film.

[0034] Example 4

[0035] First, 1.6 g of layered zirconium phosphate nanosheets were ultrasonically dispersed in deionized water. Then, 45 mL of 0.1 mol / L triethanolamine solution was slowly added dropwise to the dispersion and magnetic stirring was continued at room temperature for 6 h to obtain an exfoliated layered zirconium phosphate nanodispersion. Then, 0.445 mL of tannic acid solution was slowly added to the nanodispersion and the reaction was continued for 2 h to obtain a layered zirconium phosphate nanosheet-tannic acid supramolecular assembly. Freeze-dried collagen was fully dissolved in 0.5 mol / L acetic acid solution to obtain a 10 mg / mL collagen acetic acid solution. Then, equal volumes of the supramolecular assembly dispersion were mixed with the collagen acetic acid solution, maintaining a mass ratio of layered zirconium phosphate nanosheets to collagen of 0.3:1. The mixture was stirred at room temperature for 2 h to obtain a film-forming solution. The film-forming solution was then coated on the surface of a silicon wafer substrate and dried in a 30°C oven for 12 h to obtain a multifunctional nacre-mimicking collagen-based supramolecular film.

[0036] Example 5

[0037] First, 1.6 g of layered zirconium phosphate nanosheets were ultrasonically dispersed in deionized water. Then, 45 mL of 0.1 mol / L tris(hydroxymethyl)aminomethane) solution was slowly added dropwise to the dispersion and magnetically stirred at room temperature for 6 h to obtain an exfoliated layered zirconium phosphate nanodispersion. Then, 0.445 mL of tannic acid solution was slowly added to the nanodispersion and the reaction continued for 2 h to obtain a layered zirconium phosphate nanosheet-tannic acid supramolecular assembly. Freeze-dried collagen was fully dissolved in 0.5 mol / L acetic acid solution to obtain a 10 mg / mL collagen acetic acid solution. Then, equal volumes of the supramolecular assembly dispersion were mixed with the collagen acetic acid solution, maintaining a mass ratio of layered zirconium phosphate nanosheets to collagen of 0.2:1. The mixture was stirred at room temperature for 2 h to obtain a film-forming solution. The film-forming solution was then coated on a silicon wafer substrate and dried in a 30°C oven for 12 h to obtain a multifunctional nacre-mimicking collagen-based supramolecular film.

[0038] Control

[0039] A 10 mg / mL collagen acetic acid solution was directly coated on the surface of the silicon wafer base as control sample 1; an equal volume of layered zirconium phosphate nanodispersion was mixed with the collagen acetic acid solution, maintaining a mass ratio of layered zirconium phosphate nanosheets to collagen at 0.3:1. The mixture was stirred at room temperature for 2 hours to obtain a film-forming solution, which was then coated on the surface of the silicon wafer base and dried in a 30°C oven for 12 hours to prepare a collagen / 30% layered zirconium phosphate nanosheet composite film as control sample 2.

[0040] Figure 1This is a cross-sectional scanning electron micrograph of the multifunctional nacre-mimicking collagen-based supramolecular film prepared in Example 3. The SEM image clearly shows that the layered zirconium phosphate nanosheets-tannic acid supramolecular assemblies are uniformly dispersed within the collagen matrix, and the prepared collagen-based supramolecular film exhibits nacre-mimicking structural characteristics.

[0041] Figure 2 The infrared spectra of the multifunctional nacre-like collagen-based supramolecular film prepared in Example 1 and the control collagen film are shown. The infrared spectra show that the position of the characteristic peak of collagen does not change before and after the addition of the layered zirconium phosphate nanosheet-tannic acid supramolecular assembly. -1 The characteristic peak of zirconium phosphate appeared at , proving that the addition of the assembly would not change the triple helical structure of collagen and was successfully dispersed in the collagen matrix.

[0042] Figure 3 Differential scanning calorimetry (DSC) spectra of the multifunctional nacre-like collagen-based supramolecular film prepared in Example 1 and a control collagen film. The addition of the layered zirconium phosphate nanosheet-tannic acid supramolecular assembly increased the heat deformation temperature of the collagen film from 80°C to 120°C, demonstrating that the prepared nacre-like collagen-based supramolecular film exhibits excellent thermal stability.

[0043] Figure 4 Digital photos of the multifunctional nacre-like collagen-based supramolecular film prepared in Example 1 and the collagen film of control sample 1;

[0044] Figure 5 The light transmittance test results for the multifunctional nacre-like collagen-based supramolecular film prepared in Example 1 and the collagen film of Control Sample 1 are shown. UV-visible spectroscopy analysis shows that the addition of the layered zirconium phosphate nanosheet-tannic acid supramolecular assembly does not reduce the light transmittance of the collagen film, maintaining a transmittance of 80%.

[0045] Figure 6 The contact angle test results of the multifunctional nacre-like collagen-based supramolecular film prepared in Example 1 and the collagen film of control sample 1 are shown. The introduction of the layered zirconium phosphate nanosheet-tannic acid supramolecular assembly improves the hydrophobicity of the film.

[0046] Figure 7Figure 3 shows the antibacterial effects of collagen / layered zirconium phosphate nanosheets-tannic acid supramolecular films against (a) Escherichia coli and (b) Staphylococcus aureus (Control 1: collagen film; Control 2: collagen / 30% layered zirconium phosphate nanosheet composite film; Example 3: collagen / 30% layered zirconium phosphate nanosheets-tannic acid supramolecular film). Compared to Control 1, the antibacterial results of Control 2 demonstrate that the introduction of layered zirconium phosphate imparts a certain antibacterial effect to the collagen film. The antibacterial results of Example 3 demonstrate that the introduction of the layered zirconium phosphate nanosheets-tannic acid supramolecular assembly further enhances the antibacterial effect, demonstrating a synergistic antibacterial effect.

Claims

1. A method for preparing a multifunctional nacreous collagen-based supramolecular film, characterized in that: The specific steps include: Step 1: Preparation of supramolecular assembly: Layered zirconium phosphate nanosheets were ultrasonically dispersed in deionized water. A 0.1 mol / L exfoliant was then slowly added dropwise to the dispersion and magnetically stirred for 6 h at room temperature to obtain an exfoliated layered zirconium phosphate nanodispersion. A 1.0 mg / mL tannic acid solution was then slowly added to the nanodispersion and the reaction continued for 2 h to obtain a layered zirconium phosphate nanosheet-tannic acid supramolecular assembly. Step 2: Preparation of collagen-based supramolecular film: The freeze-dried collagen was fully dissolved in 0.5 mol / L acetic acid solution to obtain a collagen acetic acid solution with a concentration of 10 mg / mL. Then, equal volumes of the above supramolecular assembly dispersion were mixed with the collagen acetic acid solution and stirred at room temperature for 2 h to obtain a film-forming solution. The film-forming solution was then coated on the surface of a silicon wafer substrate and dried in an oven at 30°C for 12 h to obtain a multifunctional nacre-like collagen-based supramolecular film.

2. The method for preparing a multifunctional nacreous collagen-based supramolecular film according to claim 1, characterized in that: In step 1, the diameter of the layered zirconium phosphate nanosheets is 50-100 nm.

3. The method for preparing a multifunctional nacreous collagen-based supramolecular film according to claim 2, characterized in that: In step 1, the stripping agent is one of tetrabutylammonium hydroxide, triethanolamine, and tris(hydroxymethyl)aminomethane, and the molar ratio of the nanosheets to the stripping agent is 1:(0.4-2.0).

4. The method for preparing a multifunctional nacreous collagen-based supramolecular film according to claim 3, wherein: In step 1, the mass ratio of the solute in the tannic acid solution to the layered zirconium phosphate nanosheets is (0.0025-0.04):

1.

5. The method for preparing a multifunctional nacreous collagen-based supramolecular film according to claim 4, characterized in that: In step 2, the mass ratio of the layered zirconium phosphate nanosheets to collagen is (0.1-0.5):

1.

6. A multifunctional nacreous collagen-based supramolecular film prepared by the preparation method according to any one of claims 1 to 5.

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