A near-infrared light responsive nanocomposite of halloysite and its preparation method

Abstract

The application discloses a kind of near-infrared light response's halloysite-based nano antibacterial composite material, it includes halloysite nanotube carrier and the polydopamine layer and prussian blue nanoparticle successively coated on its surface, specific preparation steps include: adding dopamine to halloysite nanotube dispersion liquid, rotating mixing is carried out, and HNTs@PDA nanoparticle is prepared;Iron salt-potassium ferricyanide mixed solution is added dropwise to the dispersion liquid of HNTs@PDA nanoparticle under stirring condition, and the halloysite-based nano antibacterial composite material is prepared by avoiding light stirring reaction.The application can realize the efficient loading of prussian blue nanoparticle on the surface of halloysite carrier, and the obtained antibacterial composite material has both photothermal therapy and chemical dynamic therapy two antibacterial mechanisms, with spectral antibacterial property and good biological safety;And the preparation method is simple, the reaction condition is mild, and the cost is low, suitable for popularization and application.

Description

Technical Field

[0001] This invention belongs to the field of antibacterial materials technology, specifically relating to a near-infrared light-excited halloysite-based nanocomposite material with broad-spectrum antibacterial activity and its preparation method. Background Technology

[0002] Bacterial infections have long been a serious threat to human health worldwide. Antibiotics, due to their superior bactericidal ability, low cost, high yield, and relatively few side effects, have become the first choice for clinical treatment of bacterial infections. However, the overuse of antibiotics in the medical and agricultural fields has led to the emergence of a large number of multidrug-resistant (MDR) "superbugs," significantly reducing the bactericidal efficacy of antibiotic-loaded antimicrobial materials. To combat the ever-emerging superbugs, there is an urgent need to further explore and research novel antimicrobial materials that can replace traditional antibiotics.

[0003] Currently, common antibacterial materials mainly include inorganic antibacterial materials such as metal oxides and precious metals, organic antibacterial materials such as natural polymers and hydrogels, and composite antibacterial materials such as polymer-based composite materials and natural silicate clay-based composite materials. Inorganic nano-antibacterial materials such as Prussian blue (PB), iron tetroxide, and copper peroxide can undergo the Fenton reaction to generate reactive oxygen species, which oxidize and destroy cell membranes and cytoplasm, thereby inhibiting bacterial proliferation; however, small-diameter nanoparticles are prone to aggregation, have poor stability, are difficult to recycle, and have significant biotoxic side effects.

[0004] Silicate clay minerals have a large specific surface area and abundant surface hydroxyl groups, making them suitable as carriers for immobilizing and dispersing inorganic antibacterial nanomaterials, thereby enhancing their antibacterial properties. Halloysite nanotubes (HNTs), a naturally occurring clay material, possess characteristics such as a hollow helical nanostructure, high surface area, mechanical and chemical stability, high functionalization potential, good biocompatibility, and low cost. They have already seen numerous applications in the preparation of polymer nanocomposites, drug sustained release, biosafety drug delivery, and chiral drug enantiomer separation. For example, patent CN109619100A provides a method for preparing halloysite-based antibacterial nanocomposite materials incorporating quaternary ammonium salts, demonstrating that these composite antibacterial microparticles exhibit excellent antibacterial activity against various molds, discoloration fungi, decay fungi, and bacteria, showing broad industrial application value in bamboo and wood processing. Patent CN110773002A discloses a halloysite-based antibacterial composite nanofiber membrane with long-lasting antibacterial properties and excellent air filtration performance. However, halloysite-based nanocomposites used for antibacterial purposes currently suffer from drawbacks such as complex preparation methods, limited antibacterial mechanisms, difficulty in achieving broad-spectrum bactericidal effects, and difficulty in maintaining antibacterial efficacy. Summary of the Invention

[0005] The main objective of this invention is to address the problems and shortcomings of existing technologies by providing a halloysite-based nanocomposite material with broad-spectrum antibacterial activity excited by near-infrared light. This is achieved by modifying the surface of halloysite with a polydopamine (PDA) coating and further promoting the in-situ growth of Prussian blue nanoparticles on the PDA coating. The resulting halloysite-based nanocomposite antibacterial material possesses both photothermal therapy (PTT) and chemodynamic therapy (CDT) antibacterial mechanisms, exhibits spectral antibacterial properties, and demonstrates good biocompatibility. Furthermore, the preparation method is simple, the reaction conditions are mild, and the cost is low, making it suitable for widespread application.

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

[0007] A near-infrared light-responsive halloysite-based antibacterial nanocomposite material comprises halloysite nanotube carriers and a polydopamine layer and Prussian blue nanoparticles sequentially coated on their surface.

[0008] In the above scheme, the particle size of the Prussian blue nanoparticles is 10-50 nm.

[0009] In the above scheme, the halloysite nanotube carrier has a diameter of 50-100 nm and a length of 1-2 μm.

[0010] The preparation method of the above-mentioned near-infrared light-responsive halloysite-based nano-antibacterial composite material includes the following steps:

[0011] 1) Halloysite nanotubes were dispersed in a buffer solution and subjected to sonication to obtain a halloysite nanotube dispersion; dopamine was added to the dispersion, and the mixture was rotated, centrifuged, washed, and dried to obtain HNTs@PDA nanoparticles.

[0012] 2) Disperse HNTs@PDA nanoparticles in water to obtain suspension I; dissolve iron salt and potassium ferricyanide uniformly in water to obtain mixed solution II;

[0013] 3) Under stirring conditions, mixture II was added dropwise to suspension I, and the mixture was stirred and reacted in the dark. Then, it was centrifuged, washed, and dried to obtain the halloysite-based nano-antibacterial composite material (HNTs@PDA@PB).

[0014] In the above scheme, the buffer solution can be Tris-HCl buffer or the like; the pH value is 8.0 to 9.0.

[0015] In the above scheme, the content of halloysite nanotubes in the halloysite nanotube dispersion is 0.5-2 mg / mL.

[0016] In the above scheme, the ultrasonic treatment time is 5 to 10 minutes.

[0017] In the above scheme, the mass ratio of halloysite nanotubes to dopamine is 1:(1-2).

[0018] In the above scheme, the rotational mixing step is performed at a speed of 40-80 rpm for a time of 4-24 hours.

[0019] In the above scheme, the content of HNTs@PDA nanoparticles in suspension I is 0.5-1 mg / mL.

[0020] In the above scheme, the iron salt can be a soluble iron salt such as ferric chloride.

[0021] In the above scheme, the molar ratio of iron salt to potassium ferricyanide is 1:(1-2); the concentration of potassium ferricyanide in mixed solution II is 0.26-0.52 mM.

[0022] In the above scheme, the mass ratio of iron ions introduced in the mixture II to HNTs@PDA nanoparticles introduced in the suspension I is 1:(25-67).

[0023] In the above scheme, the stirring rate used in the light-protected stirring reaction is 400-600 rpm, and the time is 4-6 h.

[0024] In the above scheme, the drying temperature is 40-60℃.

[0025] The antibacterial application of the halloysite-based nano-antibacterial composite material described above employs conditions including near-infrared light irradiation and the introduction of hydrogen peroxide.

[0026] Furthermore, the antibacterial step includes: adding halloysite-based nano-antibacterial composite material and hydrogen peroxide to the bacterial suspension, and then irradiating it with infrared light.

[0027] Furthermore, the infrared light irradiation uses a power of 1 to 2 W.

[0028] Furthermore, the content of halloysite-based nano-antibacterial composite material in the bacterial suspension is 150–300 μg / mL; the content of hydrogen peroxide is 1–10 mM.

[0029] In the above scheme, the infrared light irradiation time is 7 to 10 minutes.

[0030] In the above scheme, the bacteria include Gram-positive bacteria (such as Staphylococcus) or Gram-negative bacteria (such as Escherichia coli).

[0031] The antibacterial method described above in this invention achieves highly efficient sterilization through the synergistic effect of photothermal and chemical dynamics.

[0032] The principle of this invention is as follows: This invention utilizes the characteristics of catechol groups on the surface of polydopamine to couple and reduce metal ions and their adhesion properties, and further optimizes the reaction conditions and raw material ratios to effectively promote the stable growth of Prussian blue nanoparticles on the polydopamine layer on halloysite surface, thereby achieving effective composite of halloysite and Prussian blue nanoparticles. The resulting halloysite-based nanocomposite antibacterial material has both photothermal therapy (PTT) and chemodynamic therapy (CDT) antibacterial mechanisms, and also has spectral antibacterial properties and good biocompatibility.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1) This invention introduces a polydopamine layer onto the surface of halloysite, then introduces it into a precursor solution for synthesizing Prussian blue, and further optimizes the reaction conditions and ratios to promote a superior synergistic effect between polydopamine and Prussian blue, thereby achieving efficient loading of Prussian blue nanoparticles onto the surface of halloysite. Using a relatively simple method, halloysite nanotubes achieve synergistic antibacterial effects of PTT and CDT while ensuring biosafety.

[0035] 2) This invention utilizes ferric salts and potassium ferricyanide to synthesize Prussian blue nanoparticles under the reducing action of polydopamine. Compared with the common synthesis of Prussian blue using ferrous salts and potassium ferricyanide, this invention reduces the risk that ferrous ions will be oxidized in solution, thus making it difficult for Prussian blue to form; and achieves efficient loading of Prussian blue nanoparticles on halloysite carrier surface.

[0036] 3) The raw materials used in this invention are readily available, environmentally friendly, have lower preparation costs, more stable antibacterial effects, and good biosafety. They have a very obvious competitive advantage in antibacterial materials and are expected to be widely used in antibacterial ceramics, antibacterial dressings, cancer treatment and other fields. Attached Figure Description

[0037] Figure 1 The image shown is a scanning electron microscope image of the HNTs raw material described in Example 1.

[0038] Figure 2 The image shows a scanning electron microscope (SEM) image of the HNTs@PDA obtained in Example 1.

[0039] Figure 3 The image shows a scanning electron microscope (SEM) image of HNTs@PDA@PB obtained in Example 1.

[0040] Figure 4 The ultraviolet absorption spectra of HNTs, HNTs@PDA, and HNTs@PDA@PB as described in Example 1;

[0041] Figure 5The photothermal performance curves of HNTs, HNTs@PDA, and HNTs@PDA@PB described in Example 1 are shown.

[0042] Figure 6 The enzyme activity profiles of HNTs, HNTs@PDA, and HNTs@PDA@PB described in Example 1;

[0043] Figure 7 Enzyme activity profiles of HNTs@PDA@PB obtained under different concentration conditions;

[0044] Figure 8 The in vitro bactericidal effect of HNTs, HNTs@PDA, and HNTs@PDA@PB against Escherichia coli and Staphylococcus aureus is shown in Example 1.

[0045] Figure 9 The results of the biocompatibility test of HNTs@PDA@PB on L929 cells obtained in Example 1 are shown. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0047] In the following embodiments, halloysite nanotubes were provided by Sigma-Aldrich, and their scanning electron microscope images are shown below. Figure 1 .

[0048] Example 1

[0049] A near-infrared light-responsive halloysite-based antibacterial nanocomposite material is prepared by the following steps:

[0050] 1) Synthesis of halloysite-polydopamine nanocomposite material (HNTs@PDA)

[0051] 30 mg HNTs were dispersed in 30 mL of Tris-HCl buffer (10 mM, pH 8.5) and sonicated for 5 min. Then 30 mg DA was added. The resulting mixture was transferred to a rotary mixer and mixed at 40 rpm for 24 h. The solid product was collected by centrifugation (5000 rpm, 10 min) and washed with DI water until the supernatant was clear. Then it was dried at 40 °C to obtain HNTs@PDA.

[0052] 2) Synthesis of halloysite-polydopamine-Prussian blue nanocomposite material (HNTs@PDA@PB)

[0053] Disperse 10 mg HNTs@PDA in 10 mL of distilled water to obtain suspension I;

[0054] Weigh 7.0 mg FeCl3·6H2O and 8.5 mg K3[Fe(CN)6] and dissolve them in 10 mL of distilled water. Then, take 1 mL of the resulting mixture and dilute it with distilled water to 10 mL to obtain mixture II. While the suspension I is being vigorously stirred (600 rpm), mixture II is added dropwise (the mass ratio of iron ions introduced in mixture II to HNTs@PDA nanoparticles introduced in suspension I is 1:34.5). The mixture is then stirred at 600 rpm in the dark for 6 h, centrifuged at 5000 rpm for 10 min, washed three times with distilled water, and dried at 40 °C to obtain the halloysite-based nano-antibacterial composite material (HNTs@PDA@PB).

[0055] The HNTs, HNTs@PDA, and HNTs@PDA@PB nanocomposites described in this embodiment were dispersed on different silicon wafers, sputtered with gold, and analyzed by scanning electron microscopy. The results are as follows: Figure 1-3 As shown: Figure 1 and Figure 2 The scanning electron microscope images of HNTs and HNTs@PDA show that both exhibit smooth nanotube structures. Figure 3 The scanning electron microscope image of HNTs@PDA@PB obtained in step 2) shows that Prussian blue nanoparticles grown on the surface of the nanotubes can be further observed; wherein, the particle size of the Prussian blue nanoparticles is 10-50 nm, the diameter of the halloysite nanotube carrier is 50-100 nm, and the length is 1-2 μm.

[0056] The HNTs, HNTs@PDA, and HNTs@PDA@PB nanocomposites described in this embodiment were subjected to ultraviolet spectroscopy tests, as follows: 200 μg of each HNTs, HNTs@PDA, and HNTs@PDA@PB nanocomposites were dispersed in 1 mL of distilled water and ultrasonically dispersed to obtain a uniformly dispersed suspension. The spectra at 400-900 nm were measured using a microplate reader (Multiskan GO, Thermo Scientific, USA) (see...). Figure 4 The results showed that the HNTs@PDA@PB obtained in Example 1 exhibited a characteristic Prussian blue absorption peak at 700 nm.

[0057] Example 2

[0058] A near-infrared light-responsive halloysite-based antibacterial nanocomposite material is prepared in a manner largely the same as in Example 1, except that the synthesis steps of the halloysite-polydopamine nanocomposite material (HNTs@PDA) in step 1) include: dispersing 15 mg of HNTs in 30 mL of Tris-HCl buffer (10 mM, pH 8.5), sonicating for 5 min, and then adding 30 mg of DA; transferring the resulting mixture to a rotary mixer and mixing at 40 rpm for 8 h, collecting the solid product by centrifugation (5000 rpm, 10 min), washing with DI water until the supernatant is clear, and then drying at 40 °C to obtain HNTs@PDA.

[0059] Example 3

[0060] A near-infrared light-responsive halloysite-based antibacterial nanocomposite material is prepared using a method largely the same as in Example 1, except that step 2) of the synthesis of the halloysite-polydopamine-Prussian blue nanocomposite material (HNTs@PDA@PB) includes the following steps:

[0061] Disperse 10 mg HNTs@PDA in 10 mL of distilled water to obtain suspension I;

[0062] Weigh 7.0 mg FeCl3·H2O and 12.75 mg K3[Fe(CN)6] and dissolve them in 10 mL of distilled water. Then, take 1 mL of the resulting mixture and dilute it with distilled water to 10 mL to obtain mixture II. While the suspension I is being vigorously stirred (600 rpm), mixture II is added dropwise. The mixture is then stirred at 600 rpm in the dark for 6 h, centrifuged at 5000 rpm for 10 min, washed three times with distilled water, and dried at 40 °C to obtain the halloysite-based nano-antibacterial composite material (HNTs@PDA@PB).

[0063] Comparative Example 1

[0064] A halloysite-based nano-antibacterial composite material, the preparation method of which includes the following steps:

[0065] Disperse 10 mg of HNTs in 10 mL of distilled water to obtain suspension I;

[0066] Weigh 7.0 mg FeCl3·H2O and 8.5 mg K3[Fe(CN)6] and dissolve them in 10 mL of distilled water. Then take 1 mL of the solution and dilute it with distilled water to 10 mL to obtain mixture II. While the suspension I is being vigorously stirred (600 rpm), mixture II is added dropwise. The mixture is then stirred at 600 rpm in the dark for 6 h. After centrifugation at 5000 rpm for 10 min, the mixture is washed three times with distilled water and dried at 40 °C to obtain the halloysite-based nano-antibacterial composite material.

[0067] Testing revealed that the resulting composite material did not exhibit the Prussian blue absorption peak at 700 nm in the ultraviolet-visible absorption spectrum; and it also showed an absorption peak in the near-infrared spectrum (808 nm, 1.5 W / cm²). 2 After irradiation for 7 minutes, the temperature was 30℃, with almost no photothermal effect.

[0068] Comparative Example 2

[0069] A halloysite-based antibacterial nanocomposite material is prepared using a method largely the same as in Example 1, except that step 2) of the synthesis of the halloysite-polydopamine-Prussian blue nanocomposite material (HNTs@PDA@PB) includes the following steps:

[0070] Disperse 10 mg HNTs@PDA in 10 mL of distilled water to obtain suspension I;

[0071] Weigh 7.0 mg FeCl3·H2O and 8.5 mg K3[Fe(CN)6] and dissolve them in 10 mL of distillation to obtain mixture II. Add mixture II dropwise while stirring suspension I vigorously (600 rpm). Then stir the mixture at 600 rpm in the dark for 6 h, centrifuge at 5000 rpm for 10 min, wash three times with distilled water, and dry at 40 °C to obtain the halloysite-based nano-antibacterial composite material (HNTs@PDA@PB).

[0072] Testing revealed that the obtained composite material exhibited a very weak Prussian blue absorption peak at 700 nm in the ultraviolet-visible absorption spectrum; and a similar absorption peak in the near-infrared spectrum (808 nm, 1.5 W / cm²). 2 After irradiation for 7 minutes, the temperature only reached 49℃, which did not reach the effective sterilization temperature.

[0073] The photothermal properties and peroxidase-like activities of the HNTs, HNTs@PDA, and HNTs@PDA@PB nanocomposites described in Example 1 were tested, as follows:

[0074] 1) Photothermal performance test

[0075] The obtained HNTs@PDA and HNTs@PDA@PB nanocomposites can convert light energy into heat energy under near-infrared light irradiation at 808 nm. Their photothermal effects were detected by measuring the temperature changes of the HNTs, HNTs@PDA, and HNTs@PDA@PB nanocomposites. The specific detection steps are as follows: First, suspensions of 200 μg / mL HNTs, HNTs@PDA, and HNTs@PDA@PB were prepared and ultrasonically dispersed for 5 minutes. Then, 200 μL of each suspension was placed in a 96-well plate and irradiated with an 808 nm laser (1.5 W / cm²). 2Irradiate for 7 minutes, and use an infrared thermometer to measure and record the temperature every minute.

[0076] Test results are as follows Figure 5 As shown, since HNTs do not have photoresponsiveness, their temperature change is small; the temperature of HNTs@PDA nanocomposite material can reach 45℃ under near-infrared light irradiation; HNTs@PDA@PB can further reach 61℃.

[0077] 2) Peroxidase-like activity test

[0078] The HNTs@PDA@PB nanocomposite material can catalyze the production of ROS from hydrogen peroxide (H2O2) solution, which then reacts with 3,3',5,5'-tetramethylbenzidine (TMB) to generate TMB oxide. The TMB oxide product has a characteristic peak at 652 nm. This invention utilizes a microplate reader (Multiskan GO, Thermo Scientific, USA) to measure the UV-Vis absorption spectrum, obtaining the enzyme activities of HNTs, HNTs@PDA, and HNTs@PDA@PB nanocomposite materials, as well as the relationship between the enzyme activity and concentration of the HNTs@PDA@PB nanocomposite material: 900 μL of acetate-sodium acetate (NaOAc·HOAc, pH 5, 0.2 M) buffer was added to a 5 mL centrifuge tube, followed by 10 μL of 20 mM TMB solution, 10 μL of 20 mM H2O2, and 80 μL of... Different HNTs, HNTs@PDA, and HNTs@PDA@PB suspensions were prepared at 5 mg / mL (20, 40, 60, 80, and 120 μL of 5 mg / mL HNTs@PDA@PB suspension were added when testing different concentrations); the control group centrifuge tubes contained 1000 μL of buffer solution, without the material solution, and all other components were the same. Results are as follows. Figure 6-7 As shown, the Control, HNTs, and HNTs@PDA groups showed no color change and no absorption peak at 650 nm, indicating that these materials do not possess catalase activity. After in-situ growth of Prussian blue, the HNTs@PDA@PB group exhibited a UV absorption peak at 650 nm, indicating the presence of catalase activity. Figure 7 As shown, the catalytic performance gradually increases with increasing concentration.

[0079] The HNTs, HNTs@PDA, and HNTs@PDA@PB nanocomposites described in the examples were subjected to in vitro antibacterial experiments:

[0080] HNTs@PDA@PB nanocomposites exhibit synergistic antibacterial activity through both chemical kinetics and photothermal action. The photothermal synergistic in vitro antibacterial effect of HNTs@PDA@PB nanocomposites was verified using Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The specific steps were as follows:

[0081] Add 100 μL of bacterial stock solution to 50 mL of LB nutrient broth, place in a constant temperature shaker, and activate at 200 rpm and 37 °C for 18 h to obtain a bacterial stock solution in the stable phase (OD). 600 ≈1.0-1.1). The activated bacterial stock solution has a high bacterial concentration. In order to facilitate plate counting later, the bacterial stock solution needs to be diluted. Use a pipette to aspirate 50 μL of bacterial stock solution into a 10 mL centrifuge tube, and then aspirate 4.95 mL of PBS buffer into the centrifuge tube. Shake well and dilute the bacterial stock solution 100 times. Take 100 μL of the diluted solution and incubate it with 100 μL of material in a 96-well plate. After sealing, place it in an incubator and co-culture at 37°C for 2 h. Set the bacterial experiment as follows: (1) Bacteria + PBS; (2) Bacteria + PBS + near-infrared light (808 nm, 1 W / cm). 2 (3) Bacteria + PBS + H2O2, wherein the H2O2 content is 1mM; (4) Bacteria + PBS + H2O2 + near-infrared light (808nm, 1W / cm) 2 (5) Bacteria + HNTs, where the HNT content is 200 μg / mL; (6) Bacteria + HNTs + near-infrared light (808 nm, 1 W / cm²) 2 (7) Bacteria + HNTs@PDA, wherein the content of HNTs@PDA is 200 μg / mL; (8) Bacteria + HNTs@PDA + near-infrared light (808 nm, 1 W / cm²) 2 (9) Bacteria + HNTs@PDA@PB, wherein the content of HNTs@PDA@PB is 200 μg / mL; (10) Bacteria + HNTs@PDA@PB + near-infrared light (808 nm, 1 W / cm²) 2 (11) Bacteria + HNTs@PDA@PB + H2O2, wherein the content of HNTs@PDA@PB is 200 μg / mL and the content of H2O2 is 1 mM; (12) Bacteria + HNTs@PDA@PB + H2O2 + near-infrared light (808 nm, 1 W / cm) 2The medium was irradiated with HNTs@PDA@PB at a concentration of 200 μg / mL and H2O2 at a concentration of 1 mM. Since the bacterial count was still relatively high after co-culturing, 50 μL was pipetted from each well into a 10 mL centrifuge tube, followed by another 4.95 mL. The mixture was shaken well and repeated once, resulting in a 10,000-fold dilution of the bacteria. 200 μL was then dropped onto the surface of LB solid medium, spread evenly with a spreader, and incubated at 37°C for 24 hours. Three parallel plates were prepared from each different co-culture solution to minimize error.

[0082] The results are as follows Figure 8 As shown in the plate experiment diagrams for *E. coli* and *Staphylococcus aureus*, it can be seen that even without the addition of hydrogen peroxide, a small number of bacteria remained after 10 minutes of near-infrared light irradiation by HNTs@PDA@PB, indicating that photothermal alone cannot kill all bacteria. With the addition of hydrogen peroxide, HNTs@PDA@PB converts hydrogen peroxide into reactive oxygen species (ROS), further enhancing its antibacterial properties; after 10 minutes of near-infrared light irradiation, all bacteria were killed. This demonstrates that HNTs@PDA@PB can achieve highly efficient sterilization through the synergistic effect of photothermal and chemodynamic processes.

[0083] The cytotoxicity test of the HNTs@PDA@PB nanocomposite obtained in this embodiment is as follows:

[0084] L929 cells were subjected to cytotoxicity assay using CCK-8. 8 × 10⁸ cells were used per well. 3 L929 cells were seeded into 96-well plates at a density of [number] cells per well. Cell suspension was added, and the plates were incubated at 37°C for 24 hours. After discarding the supernatant, different concentrations (0, 50, 100, 150, 200, and 300 μg / mL) of HNTs@PDA@PB suspension were added to each well containing cells. After further incubation for 24 hours, the cell culture medium was aspirated from the wells, and 10% CCK-8 solution was added simultaneously. The plates were then incubated at 37°C for 2 hours. The absorbance at 450 nm was measured using a microplate reader. Results are as follows: Figure 9 As shown, 88.1% of the cells in a group containing 300 μg / mL HNTs@PDA@PB still survived. Therefore, HNTs@PDA@PB has good biosafety at concentrations below 300 μg / mL, and has greater advantages in the biomedical field compared to general antibacterial agents.

[0085] Obviously, the above preferred embodiments are merely examples for clear illustration and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A near-infrared light-responsive halloysite-based nano-antibacterial composite material, characterized in that, It includes halloysite nanotube carriers and a polydopamine layer and Prussian blue nanoparticles sequentially coated on its surface; The preparation method of the near-infrared light-responsive halloysite-based nano-antibacterial composite material includes the following steps: 1) Halloysite nanotubes were dispersed in a buffer solution and subjected to sonication to obtain a halloysite nanotube dispersion; dopamine was added to the dispersion, and the mixture was rotated, centrifuged, washed, and dried to obtain HNTs@PDA nanoparticles. 2) Disperse HNTs@PDA nanoparticles in water to obtain suspension I; dissolve iron salt and potassium ferricyanide uniformly in water to obtain mixed solution II; 3) Under stirring conditions, mixture II was added dropwise to suspension I, stirred and reacted in the dark, and then centrifuged, washed and dried to obtain the halloysite-based nano antibacterial composite material; The mass ratio of halloysite nanotubes to dopamine is 1:(1~2); The content of HNTs@PDA nanoparticles in suspension I is 0.5~1 mg / mL; The molar ratio of the iron salt to potassium ferricyanide is 1:(1~2); the concentration of potassium ferricyanide in mixture II is 0.26~0.52mM; The mass ratio of iron ions introduced in the mixture II to HNTs@PDA nanoparticles introduced in the suspension I is 1:(25~67); The reaction time, involving stirring in the dark, is 4-6 hours.

2. The halloysite-based nano-antibacterial composite material according to claim 1, characterized in that, The Prussian blue nanoparticles have a particle size of 10~50 nm.

3. The halloysite-based nano-antibacterial composite material according to claim 1, characterized in that, The halloysite nanotube carrier has a diameter of 50~100 nm and a length of 1~2 μm.

4. The method for preparing the halloysite-based nano-antibacterial composite material according to any one of claims 1 to 3, comprising the following steps: 1) Halloysite nanotubes were dispersed in a buffer solution and subjected to sonication to obtain a halloysite nanotube dispersion; dopamine was added to the dispersion, and the mixture was rotated, centrifuged, washed, and dried to obtain HNTs@PDA nanoparticles. 2) Disperse HNTs@PDA nanoparticles in water to obtain suspension I; dissolve iron salt and potassium ferricyanide uniformly in water to obtain mixed solution II; 3) Under stirring conditions, mixture II was added dropwise to suspension I, stirred and reacted in the dark, and then centrifuged, washed and dried to obtain the halloysite-based nano antibacterial composite material; The mass ratio of halloysite nanotubes to dopamine is 1:(1~2); The content of HNTs@PDA nanoparticles in suspension I is 0.5~1 mg / mL; The molar ratio of the iron salt to potassium ferricyanide is 1:(1~2); the concentration of potassium ferricyanide in mixture II is 0.26~0.52mM; The mass ratio of iron ions introduced in the mixture II to HNTs@PDA nanoparticles introduced in the suspension I is 1:(25~67); The reaction time, involving stirring in the dark, is 4-6 hours.

5. The preparation method according to claim 4, characterized in that, The rotational mixing step is performed at a speed of 40-80 rpm for a time of 4-24 h.

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