CN116327640A - Bioadhesive hydrotalcite-polydopamine skin composite light shielding agent and preparation method thereof - Google Patents

Abstract

The invention discloses a bioadhesive hydrotalcite-polydopamine skin composite light-shielding agent and a preparation method thereof. Under the condition of avoiding light, different proportions of zinc-titanium-cerium hydrotalcite, dopamine and an oxidant are added to a weak alkaline buffer solution at room temperature. React for 3-72h, post-process, and vacuum-dry to obtain a bioadhesive hydrotalcite-polydopamine composite light-shielding agent. In terms of weight ratio, zinc-titanium-cerium hydrotalcite: dopamine=100:1-1:1; oxidant: dopamine=50:1-1:1, reacted at 10-40°C for 3-72h; the product is 5000-11000r/ Centrifuge at a speed of 1-15 min, wash 3-8 times, and vacuum-dry at 40-70°C for 8-72 hours to prepare ZnTiCe-LDH@PDA nanocomposites. The invention provides the ZnTiCe‑LDH@PDA nanocomposite material obtained by the above preparation method, which has good light shielding property, light stability, free radical resistance, skin adhesion and water resistance.

Description

Bioadhesive hydrotalcite-polydopamine skin composite light shielding agent and its preparation method

technical field

The invention relates to a light shielding agent, in particular to a hydrotalcite-polydopamine composite ultra-broad-spectrum light shielding agent and a preparation method thereof, belonging to the field of functional composite materials.

Background technique

It is well known that long-term excessive ultraviolet radiation is the culprit of skin phototoxicity, skin photoaging and even skin cancer. As people learned about photodamage to the skin caused by sunlight, it was discovered that visible light can also have an effect on the skin. It can cause skin pigmentation, erythema, aggravate conditions such as melasma or cause conditions such as solar urticaria. Therefore, using sunscreen products to resist the sun's rays is very important to our life safety and health. However, the current sunscreen products are not ideal. This is because sunscreens have poor water resistance, insufficient protection breadth, and active oxygen will be generated when exposed to strong sunlight, which will cause damage to the skin and be easily absorbed by the skin, bringing safety hazards and other problems. .

In order to solve these deficiencies of sunscreens, the current relevant research (Journal of cosmeticdermatology, 2019, 18 (1): 315-321; Nature Materials, 2015, 14 (12): 1278-85; CN113061256 A; CN112225894 B) proposed the main The solution is to encapsulate the sunscreen into nanomaterials to improve the sunscreen performance and waterproof performance of the sunscreen and avoid direct contact between the sunscreen and the skin, thereby avoiding its burden on the skin. Although the results of related research show that this method can effectively improve the above problems, there are still problems such as limited ultraviolet protection area and no protection against visible light. Therefore, combining nanomaterial packaging with materials with a wide range of UV protection and blocking visible light is one of the methods to break the bottleneck of current light shielding materials.

Hydrotalcite is a class of supramolecular compounds composed of negatively charged interlayer anions and positively charged host laminates. It has low cost, good biocompatibility, UV resistance and excellent metal ion and anion exchange capacity. It has a wide range of applications in the fields of flame retardancy, medicine, catalysis and sun protection. Inorganic sunscreens zinc oxide and titanium dioxide have excellent UV blocking properties and are widely used in the field of sun protection; while zinc-titanium hydrotalcite can achieve the combined effect of the two, and has excellent UV blocking capabilities. In the research of other inorganic materials as sunscreens, cerium-containing materials also showed good UV absorption. Akemi Yasukawa et al first reported hydroxyapatite containing titanium and cerium, and found that hydroxyapatite containing titanium and cerium has better ultraviolet absorption performance in the UVA band than titanium alone (Colloids and SurfacesA, 2021, 609:125705). Polydopamine is a biomimetic material of mussel protein, which has the ability to absorb visible light, bioadhesion, good biocompatibility and eumelanin-like properties - to resist UV damage by scavenging free radicals. Tang Zuwu and others prepared a hydrogel containing polydopamine, and found that after polydopamine modification, the hydrogel can adhere to the skin and has good ultraviolet shielding ability, waterproof ability and biocompatibility (Cellulose, 2021, 28 :1527–1540). Modification of zinc-titanium-cerium hydrotalcite by polydopamine can make use of their respective advantages to prepare a light-shielding agent with better performance.

Contents of the invention

In order to solve the problems of existing sunscreen agents such as poor waterproof ability, single protection range, and potential safety hazards, the present invention proposes a new type of bioadhesive hydrotalcite-polydopamine composite light shielding agent (ZnTiCe-LDH@PDA), and A preparation method of the light shielding agent is provided. The present invention utilizes the characteristic that dopamine is easily oxidized and self-polymerized by oxidants in an alkaline environment, and adopts a one-pot method to modify the surface of zinc-titanium-cerium hydrotalcite to form a polydopamine coating on the surface to obtain a ZnTiCe-LDH@PDA nanocomposite material. The material has good light-shielding performance, shows strong absorption to UVB, UVA and visible light regions, and does not generate active oxygen under ultraviolet light irradiation, has good photostability, and can resist free radicals at the same time. Certain protective effect. In addition, it is not washed away by water after a short incubation on the skin, indicating that it is skin-adhesive and the interaction with the skin is waterproof.

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

A preparation method of a bioadhesive hydrotalcite-polydopamine composite light shielding agent, under the condition of avoiding light, adding different proportions of zinc-titanium-cerium hydrotalcite, dopamine and an oxidant to a weak alkaline buffer solution, and reacting at room temperature for 3- After 72 hours, it was post-treated and vacuum-dried to obtain a bioadhesive hydrotalcite-polydopamine composite light-shielding agent.

The present invention provides a preparation method of the above-mentioned bioadhesive hydrotalcite-polydopamine composite light shielding agent. Under the condition of avoiding light, different proportions of zinc-titanium-cerium hydrotalcite, dopamine and oxidant are added to the weak alkaline buffer solution to react at room temperature for 3 -72h, post-treatment, and vacuum drying to obtain a bioadhesive hydrotalcite-polydopamine composite light shielding agent.

Further, in the above technical scheme, by weight ratio, zinc-titanium-cerium hydrotalcite: dopamine=100:1-1:1; oxidizing agent: dopamine=50:1-1:1, react at 10-40°C for 3 -72h; the product was centrifuged at a speed of 5000-11000r/min for 1-15min, washed 3-8 times, and vacuum-dried at 40-70°C for 8-72h to obtain a ZnTiCe-LDH@PDA nanocomposite material. The invention provides the ZnTiCe-LDH@PDA nanocomposite material obtained by the above preparation method, which has good light shielding property, light stability, free radical resistance, skin adhesion and water resistance.

Further, in the above technical scheme, the chemical formula of zinc-titanium-cerium hydrotalcite is [Zn ²⁺ _1-xy Ti ⁴⁺ _x Ce ³⁺ _y (OH) ₂ ] ^(y+2x)+ (CO ₃ ^2- ) _{( y+2x)/2} mH ₂ O, where x is the amount ratio of Ti ⁴⁺ /(Zn ²⁺ +Ti ⁴⁺ +Ce ³⁺ ); y is Ce ³⁺ /(Zn ²⁺ +Ti ⁴⁺ +Ce ³⁺ ) substance ratio; (Ti ⁴⁺ +Ce ³⁺ )/(Zn ²⁺ +Ti ⁴⁺ +Ce ³⁺ ) substance ratio is x+y, 0.12≤x+ y≤0.65; the amount ratio of Ti ⁴⁺ /Ce ³⁺ is x/y, 1≤x/y≤20; m is the number of crystal water molecules, 0.5≤m≤2.

Further, in the above technical solution, the oxidizing agent is one or more combinations of sodium periodate, ammonium persulfate, copper sulfate, hydrogen peroxide, potassium permanganate and potassium dichromate.

Further, in the above technical scheme, the buffer solution is N-tris(hydroxymethyl)methylglycine buffer solution, triethanolamine buffer solution, tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution, disodium hydrogen phosphate-lemon One of acid buffer solution, borax-sodium hydroxide buffer solution, disodium hydrogen phosphate-sodium hydroxide buffer solution, pH is 7.5-12.0.

Further, in the above technical scheme, the dosage ratio of the zinc-titanium-cerium hydrotalcite to the buffer solution is 0.5-5g:100mL.

ZnTiCe-LDH@PDA nanocomposite is characterized by wide absorption range, can absorb light in UVB, UVA and visible light regions, can provide good protection against sunlight, and also has photostability, anti-free radical ability, Excellent properties such as skin adhesion and water resistance.

Since zinc-titanium-cerium hydrotalcite has three elements of zinc, titanium, and cerium, it can absorb ultraviolet rays in the UVB and UVA regions. Due to its benzene ring, catechol and quinone structure, polydopamine has both light absorption capacity, free radical resistance, skin adhesion and water resistance.

The light-shielding performance evaluation, photostability evaluation, anti-free radical ability evaluation and skin adhesion and waterproof performance evaluation experiments of ZnTiCe-LDH@PDA nanocomposites show that the material of the present invention has excellent light-shielding ability and skin-friendly features.

Compared with traditional sunscreen materials, the present invention is characterized by:

(1) Zinc-titanium-cerium hydrotalcite has a wide absorption range and has good absorption capacity for ultraviolet rays in the UVB and UVA regions.

(2) Compared with the traditional method for preparing the surface of polydopamine-modified materials, the present invention triggers the self-polymerization of dopamine through an oxidizing agent, and the preparation method has the advantages of simplicity, high efficiency, and low cost.

(3) After the zinc-titanium-cerium hydrotalcite is modified by polydopamine, the light shielding property, the ability to resist free radicals, skin adhesion and water resistance are significantly improved.

Description of drawings

(a) in Figure 1 is the transmission electron microscope image of samples PL0-4, and (b) in Figure 1 is the XRD image of samples PL0-4;

Fig. 2 is the solid ultraviolet-visible diffuse reflectance spectrogram of sample PL0～4;

Figure 3 shows the photostability of samples PL0-4; the order from left to right in the histogram is the order of icons from left to right;

Figure 4 is the anti-free radical ability of samples PL0-4;

Figure 5 shows the skin adhesion and water resistance of Z samples PL0-4;

PL0-4 in the figure represent the ZnTiCe hydrotalcite prepared in the comparative example and the ZnTiCe-LDH@PDA nanocomposite material produced in Examples 1-4, respectively.

Specific implementation method

The method of the present invention will be further described below in conjunction with the examples, but the present invention is not limited.

(1) Example of ZnTiCe-LDH@PDA nanocomposite preparation

comparative example

Dissolve 0.32g ZnCl ₂ , 0.17g TiCl ₄ , 0.042g CeCl ₃ .7H ₂ O and 1.08g urea in a 50mL beaker, sonicate until the solution is clear, transfer to a hydrothermal kettle, and crystallize at 150°C 48h. After the hydrothermal kettle was cooled to room temperature, the slurry in the kettle was taken out, washed several times after centrifugation, and dried in a vacuum drying oven to obtain zinc-titanium-cerium hydrotalcite PL0. It can be seen from the transmission electron microscope image of Fig. 1(a) PL0 and the XRD pattern of Fig. 1(b) PL0 that zinc-titanium-cerium hydrotalcite was prepared.

Example 1

In 200mL of N-tris(hydroxymethyl)methylglycine buffer solution or triethanolamine buffer solution of pH=8, add 4.00g of zinc titanium cerium hydrotalcite ([Zn ²⁺ _0.700 Ti ⁴⁺ _0.267 Ce ³⁺ _0.033 (OH) ₂ ] ^0.567+ (CO ₃ ^2- ) _0.284 H ₂ O), 0.08g dopamine and 0.16g ammonium persulfate, sonicate for 30min, react at room temperature for 5h; centrifuge the product at 6000r/min for 3min, After washing three times, vacuum drying at 40°C for 10 h, the ZnTiCe-LDH@PDA nanocomposite was prepared. From the TEM image of PL1 in Fig. 1(a) and the XRD pattern of PL1 in Fig. 1(b), it can be seen that the ZnTiCe-LDH@PDA nanocomposite material was prepared.

Example 2

In the tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution or disodium hydrogen phosphate-citric acid buffer solution of 200mL pH=9, add the zinc titanium cerium hydrotalcite ([Zn ²⁺ _0.700 Ti ⁴⁺ _0.267 Ce ³⁺ _0.033 (OH) ₂ ] ^0.567+ (CO ₃ ^2- ) _0.284 H ₂ O), 0.20g dopamine and 0.40g sodium periodate, ultrasonic 30min, room temperature reaction 10h; product at 7000r/min Centrifuge at a high speed for 6 min, wash 4 times, and dry in vacuum at 50 °C for 15 h to prepare ZnTiCe-LDH@PDA nanocomposites. From the transmission electron microscope image of PL2 in Fig. 1(a) and the XRD pattern of PL2 in Fig. 1(b), it can be seen that the ZnTiCe-LDH@PDA nanocomposite material was prepared.

Example 3

In 200mL of N-tris(hydroxymethyl)methylglycine buffer solution or borax-sodium hydroxide buffer solution of pH=10, add the zinc titanium cerium hydrotalcite ([Zn ²⁺ _0.700 Ti ^{4 +} _0.267 Ce ³⁺ _0.033 (OH) ₂ ] ^0.567+ (CO ₃ ^2- ) _0.284 H ₂ O), 0.40g dopamine and 0.80g copper sulfate, sonicate for 30min, react at room temperature for 15h; the product is centrifuged at 6000r/min 9min, washed 5 times, and vacuum dried at 60°C for 20h to prepare the ZnTiCe-LDH@PDA nanocomposite. From the transmission electron microscope image of PL3 in Fig. 1(a) and the XRD pattern of PL3 in Fig. 1(b), it can be seen that the ZnTiCe-LDH@PDA nanocomposite material was prepared.

Example 4

In 200mL disodium hydrogen phosphate-citric acid buffer solution or disodium hydrogen phosphate-sodium hydroxide buffer solution with pH=12.0, add 4.00g nano-hydroxyapatite, 0.80g dopamine and 1.60g copper sulfate, sonicate for 30min, room temperature Reacted for 20 hours; the product was centrifuged at 10000r/min for 12 minutes, washed 6 times, and vacuum-dried at 70°C for 24 hours to prepare the ZnTiCe-LDH@PDA nanocomposite. From the transmission electron microscope image of PL4 in Fig. 1(a) and the XRD pattern of PL4 in Fig. 1(b), it can be seen that the ZnTiCe-LDH@PDA nanocomposite material was prepared.

(2) Performance examples of ZnTiCe-LDH@PDA nanocomposites

Embodiment 5 (light shielding performance test)

Adopt ultraviolet/visible light/near-infrared spectrophotometer to test the light-shielding property of material of the present invention: use the Lambda 1050+ type spectrophotometer equipped with integrating sphere attachment to record its solid ultraviolet-visible diffuse reflectance spectrogram at room temperature, use BaSO _as background. The results are shown in Figure 2, which shows that the reflectivity of ZnTiCe-LDH@PDA is low in the range of 280–780nm, which means that it has strong absorption in this range.

Embodiment 6 (photostable performance test)

At room temperature, 6 mg of each sample was weighed, added to 75 mL of methylene blue solution (5 mg/L), and then stirred in the dark for 30 min to achieve adsorption-desorption equilibrium. Then, photodegradation reactions were carried out under ultraviolet light with wavelengths of 365 nm and 254 nm, respectively, and 3 mL of the suspension was taken out from each beaker at predetermined intervals. Finally, the remaining methylene blue content in the solution was measured at the maximum absorption point (664nm) of methylene blue by UV-visible spectroscopy. The test results were compared with those of rutile titanium dioxide commonly used in commerce and believed to have good photostability and zinc-titanium-cerium hydrotalcite without polydopamine modification (Figure 3). It can be seen from Figure 3 that ZnTiCe-LDH@PDA hardly degrades methylene blue, indicating that it has good photostability.

Embodiment 7 (anti-free radical ability test)

2 mg of the prepared materials were added to 4 mL of 1,1-diphenyl-2-picrylhydrazine (DPPH) solution, and then reacted at ambient temperature for 30 min in the dark. Finally, the absorbance of each sample was measured at the DPPH absorption maximum (517 nm) using an ultraviolet-visible spectrometer. Antioxidant activity is represented by the percentage of inhibiting DPPH free radicals, and the calculation formula is as follows:

Wherein, Abs ₀ and Abs _i represent the absorbance values of the negative control (100% free radical) and the tested sample respectively. The antioxidant activity of ZnTiCe-LDH@PDA was calculated, as shown in Figure 4, compared with zinc-titanium-cerium hydrotalcite without polydopamine coating, the antioxidant capacity of ZnTiCe-LDH@PDA was significantly improved.

Embodiment 8 (skin adhesion and water resistance test)

Fresh pigskins are first carefully de-haired to avoid damaging the skin. The cleaned pigskins were then stored at -20°C and thawed with saline before use. Cut the thawed pigskin into 1×1cm squares, and then take 2mg of each sample and spread it evenly on the pigskin, incubate at room temperature for 30min, and then clean the skin by simple rinsing, cleaning and wiping. sex was assessed. The results before and after clearing are shown in Fig. 5, indicating that ZnTiCe-LDH@PDA has excellent skin adhesion and water resistance compared with ZnTiCe hydrotalcite without polydopamine modification.

Claims (10)

1. A preparation method of a bioadhesive hydrotalcite-polydopamine composite light shielding agent is characterized by comprising the following steps: under the condition of avoiding light, zinc-titanium-cerium hydrotalcite, dopamine and oxidant in different proportions are added into weak alkaline buffer solution, the mixture is reacted for 3 to 72 hours at room temperature, the post-treatment is carried out, and the bioadhesive hydrotalcite-polydopamine composite light shielding agent is obtained through vacuum drying.

2. The method for preparing the bioadhesive hydrotalcite-polydopamine composite light shielding agent according to claim 1, wherein the method comprises the following steps: the chemical formula of the zinc-titanium-cerium hydrotalcite is [ Zn ] ²⁺ _1-x-y Ti ⁴⁺ _x Ce ³⁺ _y (OH) ₂ ] ^(y+2x)+ (CO ₃ ^2- ) _(y+2x)/2 ·mH ₂ O, wherein x is Ti ⁴⁺ /(Zn ²⁺ +Ti ⁴⁺ +Ce ³⁺ ) The mass ratio of the substances; y is Ce ³⁺ /(Zn ²⁺ +Ti ⁴⁺ +Ce ³⁺ ) The mass ratio of the substances; (Ti) ⁴⁺ +Ce ³⁺ )/(Zn ²⁺ +Ti ⁴⁺ +Ce ³⁺ ) The mass ratio of the substances is x+y, and x+y is more than or equal to 0.12 and less than or equal to 0.65; ti (Ti) ⁴⁺ /Ce ³⁺ The mass ratio of the substances is x/y, and x/y is more than or equal to 1 and less than or equal to 20; m is the number of crystal water molecules, and m is more than or equal to 0.5 and less than or equal to 2.

3. The method for preparing the bioadhesive hydrotalcite-polydopamine composite light shielding agent according to claim 1, wherein the method comprises the following steps: the oxidant is one or more than two of sodium periodate, ammonium persulfate, copper sulfate, hydrogen peroxide, potassium permanganate and potassium dichromate, and the mass ratio of the oxidant to the dopamine is 50:1-1:1.

4. The method for preparing the bioadhesive hydrotalcite-polydopamine composite light shielding agent according to claim 1, wherein the method comprises the following steps: the weight ratio of the zinc-titanium-cerium hydrotalcite to the dopamine is 100:1-1:1.

5. The method for preparing the bioadhesive hydrotalcite-polydopamine composite light shielding agent according to claim 1, wherein the method comprises the following steps: the buffer solution is N-tris (hydroxymethyl) methylglycine buffer solution, triethanolamine buffer solution, tris (hydroxymethyl) aminomethane-hydrochloric acid buffer solution, disodium hydrogen phosphate-citric acid buffer solution, borax-sodium hydroxide buffer solution, disodium hydrogen phosphate-sodium hydroxide buffer solution, and pH is 7.5-12.0.

6. The method for preparing the bioadhesive hydrotalcite-polydopamine composite light shielding agent according to claim 1, wherein the method comprises the following steps: the dosage ratio of the zinc-titanium-cerium hydrotalcite to the buffer solution is 0.5-5 g/100 mL.

7. The method for preparing the bioadhesive hydrotalcite-polydopamine composite light shielding agent according to claim 1, wherein the method comprises the following steps: the post-treatment is centrifugation and washing for 3-8 times.

8. The method for preparing the bioadhesive hydrotalcite-polydopamine composite light shielding agent according to claim 7, wherein the method comprises the following steps: during centrifugal separation, the rotation speed is 5000-11000 r/min, and the centrifugal time is 1-15 min.

9. The method for preparing the bioadhesive hydrotalcite-polydopamine composite light shielding agent according to claim 1, wherein the method comprises the following steps: the temperature of vacuum drying is 40-70 ℃ and the time is 8-72h.

10. The bioadhesive hydrotalcite-polydopamine composite light shielding agent obtained by the preparation method according to any one of claims 1 to 9 is applied to the field of sun protection.

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