Three-dimensional chiral gold nanoflower for photo-thermal antibiosis as well as preparation method and application of three-dimensional chiral gold nanoflower

Abstract

The invention discloses a three-dimensional chiral gold nanoflower for photo-thermal antibiosis as well as a preparation method and application of the three-dimensional chiral gold nanoflower, and belongs to the technical field of nano materials. According to the method, a gold trioctahedron is used as a chiral evolution starting point, a two-step seed mediated growth method is adopted, D / L-cysteine is used as a chiral inducer, and the chiral gold nanoflower with controllable morphology and optical activity is prepared by regulating and controlling the gold ball seed concentration and the cysteine dosage. After PEG modification, the chiral gold nanoflower shows excellent biocompatibility and photo-thermal conversion efficiency, and has a remarkable photo-thermal antibacterial effect on drug-resistant bacteria. Particularly, different chiral gold nanoflowers show obvious antibacterial difference under the irradiation of chiral near-infrared circularly polarized light, and show good chiral near-infrared light selectivity. According to the method, the structural stability and optical performance of the chiral nano material are effectively improved, and the method has a wide biomedical application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials, and particularly relates to a three-dimensional chiral gold nanoflower for photothermal antibacterial, a preparation method thereof and an application thereof. Background Art

[0002] Chiral molecules play an important role in biological systems, and chiral nanomaterials have become a research hotspot due to their unique optical properties. Especially in the field of biomedicine, chiral plasmonic nanomaterials exhibit significant application potential. However, in the current preparation process of chiral plasmonic nanomaterials, it is difficult to precisely control the morphology and size of nanoparticles, resulting in unstable optical activity and anisotropy factor, and it is difficult to meet the requirements of high efficiency and stability in the fields of biosensing and photothermal therapy. In addition, the currently prepared chiral nanomaterials have limited biocompatibility and cannot be widely applied in medical environments that require long-term action or high biosafety. Especially in the photothermal therapy of drug-resistant bacteria, the photothermal conversion efficiency of traditional chiral nanomaterials is still insufficient, which limits their actual therapeutic effect. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method of a three-dimensional chiral gold nanoflower for photothermal antibacterial. Through a two-step seed-mediated method, using D / L-cysteine as a chiral inducer, by optimizing the concentrations of cysteine and seeds, the morphology, size and optical activity of nanoparticles are precisely controlled, achieving significant chiral optical activity and enhanced photothermal conversion efficiency. Through PEG modification technology, the chiral gold nanoflower is given excellent biocompatibility, making it have broad potential and high efficiency in biomedical applications such as photothermal therapy of drug-resistant bacteria, biosensing and targeted drug delivery.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A preparation method of a three-dimensional chiral gold nanoflower for photothermal antibacterial: This material is prepared by the following method:

[0006] (1) Mix a sodium borohydride solution, a chloroauric acid solution and a cetyltrimethylammonium bromide solution, and let it stand for 2-4 h to obtain a gold cluster solution;

[0007] (2) Mix a chloroauric acid solution, a cetyltrimethylammonium chloride solution and an ascorbic acid solution, then add the gold cluster solution prepared in step (1) and react for 5-30 min. After the reaction is completed, centrifuge to remove the supernatant, and resuspend with water to obtain a gold sphere seed solution;

[0008] (3) Mix the disodium ethylenediaminetetraacetate solution and chloroauric acid solution, then add dilution to obtain the Au-EDTA solution; mix the Au-EDTA solution with cetyltrimethylammonium chloride solution, then add ascorbic acid solution and gold sphere seed solution, quickly shake for 20 - 50 min, centrifuge to remove the supernatant, and resuspend with water to obtain the Au octahedron seed solution;

[0009] (4) Mix water, chloroauric acid solution, cetyltrimethylammonium bromide solution, ascorbic acid solution and cysteine solution, then add the Au octahedron seed solution, and react at 30 - 50 °C for 20 - 40 minutes to obtain a chiral gold nanoflower solution with a concentration of 20 - 40 μg / mL.

[0010] (5) Centrifuge and wash the chiral gold nanoflower solution, then redisperse it in PEG solution, and gently stir at room temperature for 10 - 30 hours, centrifuge to remove the supernatant, and resuspend with water to obtain a PEG-chiral gold nanoflower solution with a concentration of 100 - 150 μg / mL.

[0011] In the above preparation method: in step (1), the volume ratio of sodium borohydride solution, chloroauric acid solution and cetyltrimethylammonium bromide solution is 0.2 - 1:1 - 10:1 - 10;

[0012] And the molar concentration of sodium borohydride solution is 5 - 20 mmol / L; the molar concentration of chloroauric acid solution is 0.1 - 1 mmol / L; the molar concentration of cetyltrimethylammonium bromide solution is 50 - 200 mmol / L.

[0013] In the above preparation method: in step (2), the volume ratio of chloroauric acid solution, cetyltrimethylammonium chloride solution, ascorbic acid solution and gold cluster solution is 1 - 5:1 - 5:0.5 - 5:0.05 - 0.3;

[0014] And the molar concentration of chloroauric acid solution is 0.1 - 5 mmol / L; the molar concentration of cetyltrimethylammonium chloride solution is 100 - 300 mmol / L; the molar concentration of ascorbic acid solution is 50 - 200 mmol / L;

[0015] Preferably: the molar concentration of chloroauric acid solution is 0.1 - 1 mmol / L; the molar concentration of cetyltrimethylammonium chloride solution is 180 - 220 mmol / L; the molar concentration of ascorbic acid solution is 80 - 120 mmol / L.

[0016] In the above preparation method: the concentration of the gold sphere seed solution in step (2) is 10 - 100 μg / mL; preferably: the concentration of the gold seed solution is 10 - 50 μg / mL;

[0017] The particle size of the gold particles in the gold sphere seed solution is 5 - 15 nm.

[0018] In the above preparation method: in the Au-EDTA solution in step (3), the concentration of disodium ethylenediaminetetraacetate is 0.1 to 1 mmol / L, and the concentration of chloroauric acid is 0.1 to 1 mmol / L;

[0019] The volume ratio of the Au-EDTA solution, cetyltrimethylammonium chloride solution, ascorbic acid solution, and gold nanoparticle seed solution is 1 to 5:1 to 5:0.1 to 0.5:0.01 to 0.1;

[0020] And the molar concentration of the cetyltrimethylammonium chloride solution is 50 to 200 mmol / L; the molar concentration of the ascorbic acid solution is 50 to 200 mmol / L;

[0021] In the above preparation method: in the Au octahedron seed solution in step (3), the particle size of the Au octahedron nanoparticles is 30 to 100 nm; the concentration of the Au octahedron solution is 0.1 to 1 mg / mL.

[0022] In the above preparation method: in step (4), the volume ratio of water, chloroauric acid solution, cetyltrimethylammonium bromide solution, ascorbic acid solution, and cysteine solution is 5 to 10:0.1 to 1:0.5 to 5:0.5 to 5:0.01 to 0.1;

[0023] And the molar concentration of the cysteine solution is 75 to 100 nmol / L; the molar concentration of the chloroauric acid solution is 5 to 15 mmol / L; the molar concentration of the cetyltrimethylammonium bromide solution is 5 to 15 mmol / L; the molar concentration of the ascorbic acid solution is 5 to 15 mmol / L;

[0024] Preferably: in step (4), cysteine is selected from D-cysteine or L-cysteine.

[0025] In the above preparation method: in step (5), the volume ratio of the chiral gold nanoflower solution to the PEG solution is 5 to 15:1;

[0026] And the concentration of the PEG solution is 0.5 to 3 mg / mL.

[0027] A chiral gold nanoflower for photothermal antibacterial, which is prepared by the above method.

[0028] In the technical solution of the present invention, the application of the three-dimensional chiral gold nanoflower prepared by the above method in antibacterial or cancer treatment.

[0029] In the technical solution of the present invention, the chiral gold nanorose nanoparticles prepared by the above method can achieve precise control of morphology, size and optical activity, have a high anisotropy factor, and exhibit excellent biocompatibility and photothermal properties, and are particularly suitable for photothermal therapy of drug-resistant bacteria. The unique advantages of this material endow it with great application potential in the biomedical field and are expected to provide new and efficient solutions for antibacterial therapy, cancer therapy, etc.

[0030] Advantages of the present invention:

[0031] (1) Precise regulation of structure and optical properties: By adjusting the synthesis conditions, the morphology, size and optical activity of chiral gold nanoroses can be realized, with high stability and repeatability.

[0032] (2) Excellent biocompatibility: Through PEG modification, replacing traditional surfactants, chiral gold nanoroses have excellent biocompatibility. This is not only suitable for long-term use in the biomedical field but also reduces the risk of possible cytotoxicity.

[0033] (3) Efficient photothermal conversion and antibacterial properties: By precisely controlling the morphology and size of chiral gold nanoroses, the photothermal conversion efficiency is greatly improved, making it have excellent performance in photothermal antibacterial therapy, especially suitable for the treatment of drug-resistant bacterial infections. Description of the drawings

[0034] Figure 1 SEM images of different chiral gold nanoroses. Note: (a) D-Cys-gold nanoroses (Example 5); (b) L-Cys-gold nanoroses (Example 11).

[0035] Figure 2 g-factor spectra of chiral gold nanoroses synthesized with different concentrations of gold sphere seeds. Note: (a) D-Cys-gold nanoroses (Examples 1-6); (b) L-Cys-gold nanoroses (Examples 7-12).

[0036] Figure 3 Curves of the change of solution temperature with time under 808 nm laser irradiation for different concentrations of D-Cys-gold nanoroses (Example 5).

[0037] Figure 4 Antibacterial rates of chiral gold nanoroses against methicillin-resistant Staphylococcus aureus under different conditions. Detailed implementation manners

[0038] The following further illustrates the present invention with reference to examples, but the protection scope of the present invention is not limited thereto: Example 1

[0039] (1) Preparation of gold nanosphere seed solution: Mix 0.6 mL of 10 mM sodium borohydride solution prepared with cold water, 5 mL of 0.25 mM chloroauric acid solution, and 5 mL of 100 mM cetyltrimethylammonium bromide solution, and keep at 37 °C for 3 hours to obtain a gold cluster solution.

[0040] (2) Mix 2 mL of 0.5 mM chloroauric acid solution, 2 mL of 200 mM cetyltrimethylammonium chloride solution, and 1.5 mL of 100 mM ascorbic acid solution, then introduce 100 μL of the gold cluster solution, and synthesize at room temperature for 10 min to obtain a 9 nm gold nanosphere seed solution. After the reaction, centrifuge at 15000 rpm / min for 15 min to remove the supernatant, and add 0.8 mL of ultrapure water to resuspend, so that the final concentration of the gold nanosphere seed suspension is 38.8 μg / mL.

[0041] (3) Preparation of Au octahedron seed solution: Mix sodium ethylenediaminetetraacetate solution and chloroauric acid solution and dilute with water to obtain an Au-EDTA solution. The concentration of sodium ethylenediaminetetraacetate in the Au-EDTA solution is 0.5 mM, and the concentration of chloroauric acid is 0.5 mM to obtain an Au-EDTA solution.

[0042] Mix 4 mL of 100 mM cetyltrimethylammonium chloride solution and 3 mL of Au-EDTA solution at room temperature. Then, add 260 μL of 100 mM ascorbic acid solution and 25 μL of the gold nanosphere seed suspension obtained in step (2), and the reaction is carried out on a shaker at 10 °C and 250 rpm for 30 min. Centrifuge at 5000 rpm / min for 5 min, remove the supernatant, and resuspend with ultrapure water to obtain an Au octahedron seed solution with a particle size of about 40 nm and a concentration of 400 μg / mL.

[0043] (4) Preparation of D-Cys-gold nanoflowers: Mix 0.1 mL of 10 mM chloroauric acid solution, 1.6 mL of 10 mM cetyltrimethylammonium bromide solution, and 7.9 mL of ultrapure water, then add 0.95 mL of 10 mM ascorbic acid solution and 30 μL of 75 nM D-Cys solution. Finally, add 0.1 mL of the Au octahedron seed solution obtained in step (3), and react in a 37 °C water bath for 30 min to obtain a 38.8-D-Cys-gold nanoflower solution with a concentration of 30 μg / mL.

[0044] (5) Preparation of PEG-D-Cys-gold nanoflowers: Centrifuge the 10 mL of D-Cys-gold nanoflower solution obtained in step (4) at 4000 rpm for 3 min, discard the supernatant, wash the precipitate with ultrapure water by centrifugation 3 times, then resuspend it in 1 mL of PEG solution with a concentration of 1 mg / mL and stir overnight at room temperature. Centrifuge at 4000 rpm for 3 min, discard the supernatant, and resuspend the precipitate in 0.45 mL of ultrapure water to obtain a 38.8-PEG-D-Cys-gold nanoflower solution with a concentration of 120 μg / mL.

[0045] Example 2

[0046] (1) The preparation of the gold cluster solution is the same as in Example 1.

[0047] (2) Mix 2 mL of 0.5 mM chloroauric acid solution, 2 mL of 200 mM cetyltrimethylammonium chloride solution, and 1.5 mL of 100 mM ascorbic acid solution, then introduce 100 μL of the gold cluster solution, and synthesize at room temperature for 10 min to obtain a gold ball seed solution. After the reaction, centrifuge at 15000 rpm for 15 min to discard the supernatant, add 1 mL of ultrapure water to resuspend, so that the final concentration of the gold ball seed suspension is 31.4 μg / mL.

[0048] (3) The preparation of the Au octahedron seed solution is the same as in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 43 nm.

[0049] (4) The preparation of D-Cys-gold nanoflowers is the same as in Example 1 to obtain a 31.4-D-Cys-gold nanoflower solution.

[0050] (5) The preparation of PEG-D-Cys-gold nanoflowers is the same as in Example 1 to obtain a 31.4-PEG-D-Cys-gold nanoflower solution with a concentration of 120 μg / mL.

[0051] Example 3

[0052] (1) The preparation of the gold cluster solution is the same as in Example 1.

[0053] (2) Mix 2 mL of 0.5 mM chloroauric acid solution, 2 mL of 200 mM cetyltrimethylammonium chloride solution, and 1.5 mL of 100 mM ascorbic acid solution, then introduce 100 μL of the gold cluster solution, and synthesize at room temperature for 10 min to obtain a gold ball seed solution. After the reaction, centrifuge at 15000 rpm for 15 min to discard the supernatant, add 1.2 mL of ultrapure water to resuspend, so that the final concentration of the gold ball seed suspension is 26.4 μg / mL.

[0054] (3) The preparation of the Au octahedron seed solution was the same as in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 52 nm.

[0055] (4) The preparation of D-Cys-gold nanorods was the same as in Example 1 to obtain a 26.4-D-Cys-gold nanorods solution.

[0056] (5) The preparation of PEG-D-Cys-gold nanorods was the same as in Example 1 to obtain a 26.4-PEG-D-Cys-gold nanorods solution with a concentration of 120 μg / mL.

[0057] Example 4

[0058] (1) The preparation of the gold cluster solution was the same as in Example 1.

[0059] (2) Mix 2 mL of 0.5 mM chloroauric acid solution, 2 mL of 200 mM cetyltrimethylammonium chloride solution and 1.5 mL of 100 mM ascorbic acid solution, then introduce 100 μL of the gold cluster solution, synthesize at room temperature for 10 min to obtain a gold ball seed solution. After the reaction, centrifuge at 15000 rpm / min for 15 min to remove the supernatant, and add 1.4 mL of ultrapure water to resuspend, so that the final concentration of the gold ball seed suspension is 22.8 μg / mL.

[0060] (3) The preparation of the Au octahedron seed solution was the same as in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 58 nm.

[0061] (4) The preparation of D-Cys-gold nanorods was the same as in Example 1 to obtain a 22.8-D-Cys-gold nanorods solution.

[0062] (5) The preparation of PEG-D-Cys-gold nanorods was the same as in Example 1 to obtain a 22.8-PEG-D-Cys-gold nanorods solution with a concentration of 120 μg / mL.

[0063] Example 5

[0064] (1) The preparation of the gold cluster solution was the same as in Example 1.

[0065] (2) Mix 2 mL of 0.5 mM chloroauric acid solution, 2 mL of 200 mM cetyltrimethylammonium chloride solution and 1.5 mL of 100 mM ascorbic acid solution, then introduce 100 μL of the gold cluster solution, synthesize at room temperature for 10 min to obtain a gold ball seed solution. After the reaction, centrifuge at 15000 rpm / min for 15 min to remove the supernatant, and add 1.6 mL of ultrapure water to resuspend, so that the final concentration of the gold ball seed suspension is 20.0 μg / mL.

[0066] (3) The preparation of the Au octahedron seed solution was the same as that in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 61 nm.

[0067] (4) The preparation of D-Cys-gold nanoflowers was the same as that in Example 1 to obtain a 20.0-D-Cys-gold nanoflower solution.

[0068] (5) The preparation of PEG-D-Cys-gold nanoflowers was the same as that in Example 1 to obtain a 120 μg / mL 20.0-PEG-D-Cys-gold nanoflower solution.

[0069] Example 6

[0070] (1) The preparation of the gold cluster solution was the same as that in Example 1.

[0071] (2) Mix 2 mL of 0.5 mM chloroauric acid solution, 2 mL of 200 mM cetyltrimethylammonium chloride solution, and 1.5 mL of 100 mM ascorbic acid solution, then introduce 100 μL of the gold cluster solution, synthesize at room temperature for 10 min to obtain a gold ball seed solution. After the reaction, centrifuge at 15000 rpm / min for 15 min to remove the supernatant, and add 1.8 mL of ultrapure water to resuspend, so that the final concentration of the gold ball seed suspension is 17.8 μg / mL.

[0072] (3) The preparation of the Au octahedron seed solution was the same as that in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 64 nm.

[0073] (4) The preparation of D-Cys-gold nanoflowers was the same as that in Example 1 to obtain a 17.8-D-Cys-gold nanoflower solution.

[0074] (5) The preparation of PEG-D-Cys-gold nanoflowers was the same as that in Example 1 to obtain a 120 μg / mL 17.8-PEG-D-Cys-gold nanoflower solution.

[0075] Example 7

[0076] (1) The preparation of the gold cluster solution was the same as that in Example 1.

[0077] (2) The preparation of the gold ball seed suspension was the same as that in Example 1.

[0078] (3) The preparation of the Au octahedron seed solution was the same as that in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 40 nm.

[0079] (4) Except that D-Cys was replaced with L-Cys, other conditions were the same as those in Example 1.

[0080] (5) Preparation of PEG-L-Cys-gold nanoflowers: Centrifuge the 10 mL of L-Cys-gold nanoflower solution obtained in step (4) at 4000 rpm for 3 min, discard the supernatant, wash the precipitate with ultrapure water by centrifugation 3 times, then resuspend it in 1 mL of PEG solution with a concentration of 1 mg / mL and stir overnight at room temperature. Centrifuge at 4000 rpm for 3 min, discard the supernatant, and resuspend the precipitate in 0.45 mL of ultrapure water to obtain a 38.8-PEG-L-Cys-gold nanoflower solution with a concentration of 120 μg / mL.

[0081] Example 8

[0082] (1) The preparation of the gold cluster solution is the same as in Example 1.

[0083] (2) The preparation of the gold ball seed suspension is the same as in Example 2.

[0084] (3) The preparation of the Au octahedron seed solution is the same as in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 43 nm.

[0085] (4) The preparation of L-Cys-gold nanoflowers is the same as in Example 7 to obtain a 31.4-L-Cys-gold nanoflower solution.

[0086] (5) The preparation of PEG-L-Cys-gold nanoflowers is the same as in Example 7 to obtain a 31.4-PEG-L-Cys-gold nanoflower solution with a concentration of 120 μg / mL.

[0087] Example 9

[0088] (1) The preparation of the gold cluster solution is the same as in Example 1.

[0089] (2) The preparation of the gold ball seed suspension is the same as in Example 3.

[0090] (3) The preparation of the Au octahedron seed solution is the same as in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 52 nm.

[0091] (4) The preparation of L-Cys-gold nanoflowers is the same as in Example 7 to obtain a 26.4-L-Cys-gold nanoflower solution.

[0092] (5) The preparation of PEG-L-Cys-gold nanoflowers is the same as in Example 7 to obtain a 26.4-PEG-L-Cys-gold nanoflower solution with a concentration of 120 μg / mL.

[0093] Example 10

[0094] (1) The preparation of the gold cluster solution is the same as in Example 1.

[0095] (2) The preparation of the gold ball seed suspension is the same as that in Example 4.

[0096] (3) The preparation of the Au octahedron seed solution is the same as that in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 58 nm.

[0097] (4) The preparation of the L-Cys-gold nanoflower is the same as that in Example 7 to obtain a 22.8-L-Cys-gold nanoflower solution.

[0098] (5) The preparation of the PEG-L-Cys-gold nanoflower is the same as that in Example 7 to obtain a 22.8-PEG-L-Cys-gold nanoflower solution with a concentration of 120 μg / mL.

[0099] Example 11

[0100] (1) The preparation of the gold cluster solution is the same as that in Example 1.

[0101] (2) The preparation of the gold ball seed suspension is the same as that in Example 5.

[0102] (3) The preparation of the Au octahedron seed solution is the same as that in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 61 nm.

[0103] (4) The preparation of the L-Cys-gold nanoflower is the same as that in Example 7 to obtain a 20.0-L-Cys-gold nanoflower solution.

[0104] (5) The preparation of the PEG-L-Cys-gold nanoflower is the same as that in Example 7 to obtain a 20.0-PEG-L-Cys-gold nanoflower solution with a concentration of 120 μg / mL.

[0105] Example 12

[0106] (1) The preparation of the gold cluster solution is the same as that in Example 1.

[0107] (2) The preparation of the gold ball seed suspension is the same as that in Example 6.

[0108] (3) The preparation of the Au octahedron seed solution is the same as that in Example 1 to obtain a 400 μg / mL Au octahedron seed solution with a particle size of about 64 nm.

[0109] (4) The preparation of the L-Cys-gold nanoflower is the same as that in Example 7 to obtain a 17.8-L-Cys-gold nanoflower solution.

[0110] (5) The preparation of the PEG-L-Cys-gold nanoflower is the same as that in Example 7 to obtain a 17.8-PEG-L-Cys-gold nanoflower solution with a concentration of 120 μg / mL.

[0111] Performance detection:

[0112] (1) Scanning electron microscope (SEM) test

[0113] The SEM images of the chiral gold nanoflowers prepared in Example 5 and Example 11 are as Figure 1 shown. As can be seen from Figure 1 it, the chiral nanoparticles are of uniform size, forming an obviously curved petal-like surface. The D-Cys-gold nanoflowers (D-Au NFs) and L-Cys-gold nanoflowers (L-Au NFs) show counterclockwise and clockwise rotation respectively.

[0114] (2) Circular dichroism spectroscopy (CD) measurement

[0115] The CD spectra of the chiral gold nanoflowers prepared in Examples 1-12 are as Figure 2 shown. As can be seen from Figure 2 it, with the decrease of the concentration of gold nanoparticle seeds, the CD peak first increases and then decreases, reaching the maximum value at 20.0 μg / mL (Example 5, Example 11).

[0116] (3) Photothermal performance measurement

[0117] The chiral gold nanoflowers prepared in Example 5 were diluted to different concentrations (15 μg / mL, 30 μg / mL, 60 μg / mL, 120 μg / mL, 240 μg / mL), and irradiated with an 808 nm laser (1.5 W / cm 2 ) for 10 min to measure their photothermal performance. The results are as Figure 3 shown. After irradiation with near-infrared light, the solution temperature was significantly increased within 10 min. At the lowest concentration (15 μg / mL), the solution temperature also rapidly exceeded 50 °C within 5 min. In addition, the solution temperature was positively correlated with the material concentration, indicating that the chiral gold nanoflower solution has excellent photothermal effect.

[0118] 2. Photothermal antibacterial performance measurement of chiral gold nanoflowers

[0119] Example 13

[0120] After mixing Example 5 with a methicillin-resistant Staphylococcus aureus solution, it was irradiated with left-handed circularly polarized light from an 808 nm laser (1.5 W / cm 2 ) for 10 min. After irradiation, the mixture was cultured at 37 °C for 12 h.

[0121] Example 14

[0122] After mixing Example 5 with a methicillin-resistant Staphylococcus aureus solution, it was irradiated with right-handed circularly polarized light from an 808 nm laser (1.5 W / cm 2 ) for 10 min. After irradiation, the mixture was cultured at 37 °C for 12 h.

[0123] Example 15

[0124] After mixing Example 11 with the methicillin-resistant Staphylococcus aureus solution, irradiate it with 808 nm laser (1.5 W / cm 2 ) left-handed circularly polarized light for 10 min. After irradiation, incubate the mixture at 37 °C for 12 hours.

[0125] Example 16

[0126] After mixing Example 11 with the methicillin-resistant Staphylococcus aureus solution, irradiate it with 808 nm laser (1.5 W / cm 2 ) right-handed circularly polarized light for 10 min. After irradiation, incubate the mixture at 37 °C for 12 hours.

[0127] Comparative Example 1

[0128] After mixing Example 5 with the methicillin-resistant Staphylococcus aureus solution, incubate it at 37 °C for 12 hours.

[0129] Comparative Example 2

[0130] After mixing Example 11 with the methicillin-resistant Staphylococcus aureus solution, incubate it at 37 °C for 12 hours.

[0131] Blank group

[0132] After mixing 0.9% normal saline with the methicillin-resistant Staphylococcus aureus solution, incubate it at 37 °C for 12 hours.

[0133] After gradient dilution of all samples, determine the colony growth by standard plate counting to evaluate the photothermal antibacterial performance of chiral gold nanoflowers. The results are as Figure 4 shown. It can be seen from Figure 4 that the antibacterial effect of chiral gold nanoflowers without near-infrared circularly polarized light irradiation is poor. The antibacterial rate of D-Au NFs (Comparative Example 1) is 56%, and the antibacterial rate of L-Au NFs (Comparative Example 2) is 45%. After irradiation, the antibacterial rate of chiral gold nanoflowers (Examples 13-16) against methicillin-resistant Staphylococcus aureus is significantly higher than that of the comparative examples, and shows a strong chiral near-infrared light selectivity:

[0134] The antibacterial rate of D-Au NFs under right-handed circularly polarized light is 93.7% (Example 14);

[0135] The antibacterial rate of D-Au NFs under left-handed circularly polarized light is 85% (Example 13);

[0136] The antibacterial rate of L-Au NFs under left-handed circularly polarized light is 93% (Example 15),

[0137] The antibacterial rate of L-Au NFs against right-handed circularly polarized light was 76.3% (Example 16).

[0138] Therefore, chiral gold nanoflowers have excellent photothermal antibacterial properties under near-infrared circularly polarized light.

Claims

1. A method for preparing three-dimensional chiral gold nanoflowers for photothermal antibacterial, characterized in that: The material is prepared by the following method: (1) mixing sodium borohydride solution, chloroauric acid solution and hexadecyltrimethylammonium bromide solution and letting it stand for 2 to 4 hours to obtain a gold cluster solution; (2) mixing the chloroauric acid solution, the hexadecyltrimethylammonium chloride solution and the ascorbic acid solution, and then adding the gold cluster solution prepared in step (1) to react for 5 to 30 minutes. After the reaction is completed, centrifuging to remove the supernatant, adding water to resuspend, and obtaining a gold ball seed solution; (3) mixing the disodium ethylenediaminetetraacetic acid solution and the chloroauric acid solution and then adding the diluted solution to obtain an Au-EDTA solution; The Au-EDTA solution and the hexadecyltrimethylammonium chloride solution were mixed, and then the ascorbic acid solution and the gold ball seed solution were added, and the mixture was rapidly shaken for 20 to 50 minutes, and the supernatant was removed by centrifugation, and the mixture was resuspended in water to obtain the Au trioctahedral seed solution; (4) Mix water, chloroauric acid solution, hexadecyltrimethylammonium bromide solution, ascorbic acid solution and cysteine ​​solution, then add Au trioctahedral seed solution, react at 30-50° C. for 20-40 minutes, and obtain a gold nanoflower solution with a chiral concentration of 20-40 μg / mL. (5) After washing the chiral gold nanoflower solution by centrifugation, the solution was redispersed in a PEG solution and gently stirred at room temperature for 10 to 30 hours. The supernatant was removed by centrifugation and resuspended in water to obtain a PEG-chiral gold nanoflower solution with a concentration of 100 to 150 μg / mL.

2. The method for preparing chiral gold nanoflowers according to claim 1, characterized in that: In step (1), the volume ratio of the sodium borohydride solution, the chloroauric acid solution and the hexadecyltrimethylammonium bromide solution is 0.2-1:1-10:1-10; The molar concentration of the sodium borohydride solution is 5-20 mmol / L; the molar concentration of the chloroauric acid solution is 0.1-1 mmol / L; and the molar concentration of the hexadecyltrimethylammonium bromide solution is 50-200 mmol / L.

3. The method for preparing chiral gold nanoflowers according to claim 1, characterized in that: In step (2), the volume ratio of the chloroauric acid solution, the hexadecyltrimethylammonium chloride solution, the ascorbic acid solution and the gold cluster solution is 1-5:1-5:0.5-5:0.05-0.3; The molar concentration of the chloroauric acid solution is 0.1 to 5 mmol / L; the molar concentration of the hexadecyltrimethylammonium chloride solution is 100 to 300 mmol / L; and the molar concentration of the ascorbic acid solution is 50 to 200 mmol / L; Preferably: the molar concentration of chloroauric acid solution is 0.1-1 mmol / L; hexadecyltrimethylammonium chloride solution The molar concentration of ascorbic acid solution is 180-220 mmol / L; the molar concentration of ascorbic acid solution is 80-120 mmol / L.

4. The method for preparing chiral gold nanoflowers according to claim 1, characterized in that: The concentration of the gold ball seed solution in step (2) is 10 to 100 μg / mL; preferably, the concentration of the gold seed solution is 10 to 50 μg / mL; The particle size of the gold particles in the gold ball seed solution is 5 to 15 nm.

5. The method for preparing chiral gold nanoflowers according to claim 1, characterized in that: In the Au-EDTA solution of step (3), the concentration of disodium ethylenediaminetetraacetate is 0.1 to 1 mmol / L, and the concentration of chloroauric acid is 0.1 to 1 mmol / L; The volume ratio of Au-EDTA solution, hexadecyltrimethylammonium chloride solution, ascorbic acid solution and gold ball seed solution is 1-5:1-5:0.1-0.5:0.01-0.1; The molar concentration of the hexadecyltrimethylammonium chloride solution is 50 to 200 mmol / L; and the molar concentration of the ascorbic acid solution is 50 to 200 mmol / L.

6. The method for preparing chiral gold nanoflowers according to claim 1, characterized in that: The particle size of the Au trioctahedral nanoparticles in the Au trioctahedral seed solution in step (3) is 30 to 100 nm; the concentration of the Au trioctahedral solution is 0.1 to 1 mg / mL.

7. The method for preparing chiral gold nanoflowers according to claim 1, characterized in that: The volume ratio of water, chloroauric acid solution, hexadecyltrimethylammonium bromide solution, ascorbic acid solution and cysteine ​​solution in step (4) is 5-10:0.1-1:0.5-5:0.5-5:0.01-0.1; The molar concentration of the cysteine ​​solution is 75-100 nmol / L; the molar concentration of the chloroauric acid solution is 5-15 mmol / L; the molar concentration of the hexadecyltrimethylammonium bromide solution is 5-15 mmol / L; and the molar concentration of the ascorbic acid solution is 5-15 mmol / L. Preferably, the cysteine ​​in step (4) is D-cysteine ​​or L-cysteine.

8. The method for preparing chiral gold nanoflowers according to claim 1, characterized in that: In step (5), the volume ratio of the chiral gold nanoflower solution to the PEG solution is 5 to 15:1; The concentration of the PEG solution is 0.5-3 mg / mL.

9. A chiral gold nanoflower for photothermal antibacterial, characterized in that: The nano material is prepared by the method described in any one of claims 1 to 8.

10. Application of the photothermal antibacterial three-dimensional chiral gold nanoflowers prepared by the method of claim 1 in antibacterial or cancer treatment.

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