CN114309636A - Chiral gold nano antibacterial material and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of material chemistry, and specifically discloses a chiral gold nanometer antibacterial material and a preparation method thereof. The invention uses gold nano bipyramid as seeds, and obtains chiral gold nano materials with different sea cucumber-like shapes by adding chiral ligands. The invention proves by transmission electron microscope that the prepared nanostructure has good dispersibility and uniformity, the synthesized sea cucumber-like chiral gold nanomaterial has relatively stable structure, and the prepared sample does not change after being placed at room temperature for a long time. At the same time, the product obtained by the present invention has excellent chiral properties and good photothermal effect, and has a remarkable bactericidal effect.

Description

A kind of chiral gold nanometer antibacterial material and preparation method thereof

technical field

The invention belongs to the field of material chemistry, in particular to a chiral gold nanometer antibacterial material and a preparation method thereof.

Background technique

Precious metal nanomaterials (gold, silver) have attracted numerous studies due to their high specific surface area, controllable morphology, and numerous surface binding sites. In recent years, the research on the controllable preparation of metal nanoparticles in size, shape and composition has become a hot topic, and it has also provided more routes and a wide range of applications for the study of their surface plasmonic properties, including photocatalysis, nanobiosensors, Diagnosis and treatment of tumor bioimaging and medicine. Wet chemical synthesis is widely used in the preparation of noble metal nanoparticles due to its low cost and large scale.

Besides gold nanorods, gold nanobicones are another elongated gold nanocrystal with tunable longitudinal plasmon resonance (LSPR). The gold nanobipyramid consists of two pentagonal prisms connected at the bottom and has two sharp vertices. The gold nanobipyramid is more stable than the gold rod. Compared with gold nanorods, gold nanobicones have sharper tips and narrower morphology and size distribution, so the extinction cross-section and local electric field enhancement of gold nanobicones are much stronger than those of gold nanorods.

Sepsis (septicemia) is a life-threatening disease caused by a dysregulated host immune response to infection, leading to tissue damage and organ dysfunction with high mortality. Its etiology mainly involves bacterial (Gram-negative and Gram-positive), viral and fungal pathogens. S. epidermidis is the most common organism in infections associated with foreign implants, such as prosthetic joints, central venous catheters, cerebrospinal fluid shunts, intracardiac devices, artificial heart valves, and vascular grafts. Furthermore, drug-resistant bacteria have become a serious global health problem due to the widespread overuse of antibiotics and the formation of biofilms. Due to their tunable physicochemical properties (e.g., shape, particle size, surface charge, composition, etc.) and easy surface modification, nanomaterials have shown great potential in the treatment of diseases such as sepsis and implantable bacterial infections .

SUMMARY OF THE INVENTION

In order to fight against bacteria and biofilm infections, the present invention specially designs a chiral gold nanomaterial with a controllable plasmon resonance peak and a sea cucumber-like morphology on the basis of gold nanobipyramid, and provides a kind of anti-fatal bacterial infection. , modulating systemic inflammatory responses, preventing multi-organ failure and other promising nanotools to improve the efficacy of sepsis treatment. The preparation method of the chiral gold nanometer antibacterial material of the present invention, the specific steps are as follows:

( ₁ ) add citric acid solution to HAuCl solution, mix homogeneously, add reducing agent, react to obtain gold seed solution;

(2) heat-treating the gold seed solution;

(3) the gold seed solution after heat treatment is added in the water growth solution, obtains gold nano bipyramid solution, and the water growth solution is the mixed solution of CTAB, silver nitrate, hydrochloric acid and ascorbic acid;

(4) adding the chiral dipeptide aqueous solution and the gold nano bipyramid solution into the growth solution, and reacting to obtain the chiral gold nano antibacterial material. _The growth solution is prepared by adding the mixed solution of CTAB and HAuCl to the ascorbic acid solution. have to.

Preferably, in the step (1), the reducing agent is NaBH ₄ and/or KBH ₄ .

Preferably, the concentration of the gold seed solution is 0.2-0.3 mM.

Preferably, in the step (2), the heat treatment condition is stirring at 70-90° C. for 60-120 min.

Preferably, in the step (3), the molar ratio of CTAB, silver nitrate, hydrochloric acid and ascorbic acid (AA) in the water growth solution is 1000:1-5:1-5:10-20.

Specifically, the aqueous growth solution can be mixed by 10 mL of CTAB solution (100 mM), 0.1-0.5 mL of silver nitrate aqueous solution (10 mM), 1-5 mL of hydrochloric acid (1 M), 0.1-0.2 mL of AA solution (100 mM) And get.

Preferably, the chiral dipeptide is a dipeptide obtained by condensation of cysteine and phenylalanine, specifically L-CF, D-CF or DL-CF.

Preferably, in the step (4), the molar ratio of Au ³⁺ , CTAB, HAuCl ₄ , ascorbic acid and chiral dipeptide in the gold nanobipyramid solution is 1-25:5-100:1.5-4.5:7.5 -12.5: 0.04-0.12. The concentration of CTAB solution is 5-100 mM, the concentration of HAuCl ₄ aqueous solution is 5-15 mM, the concentration of ascorbic acid solution is 75-125 mM, and the concentration of L/D-CF solution is 0.5-1.5 mM; CTAB solution, HAuCl ₄ aqueous solution, ascorbic acid The volume ratio of the solution and the L/D-CF aqueous solution was 1:0.3:0.1:0.08.

Preferably, in the step (4), the reaction conditions are 25-35° C. for 1.5-2.5 h.

The invention provides a chiral gold nano antibacterial material prepared by the preparation method.

Further, the particle size range of the chiral gold nano antibacterial material is 80-150 nm.

Compared with the prior art, the technical solution of the present invention has the following advantages:

The product has good photothermal effect and chiral properties, and can be targeted to bacteria. It exhibits good performance in killing planktonic bacteria and removing biofilms, and at the same time solves the problem of potential thermal damage to normal tissues that traditional treatments do not target bacteria. The present invention constructs a chiral dipeptide functionalized gold nano bipyramid material for enhancing PTT based on chemical and physical interaction with bacteria, which has a significant bactericidal effect.

Description of drawings

Fig. 1 is the flow chart of the preparation method of the chiral gold nano antibacterial material of the present invention.

Figure 2 is a transmission electron microscope photo and a SEM photo of the chiral gold nano antibacterial material prepared by the present invention.

Figure 3 is a circular dichroism (CD) diagram of the chiral gold nano antibacterial material prepared by the present invention.

Fig. 4 is the ultraviolet image of the chiral gold nanometer antibacterial material prepared by the present invention.

Figure 5 is a graph of temperature changes of S. epidermidis solutions treated with different methods.

Figure 6 is a graph showing the bacterial viability of S. epidermidis treated with different methods.

Figure 7 is a graph of bacterial colonies of Staphylococcus epidermidis treated with different methods.

Figure 8 is a live/dead fluorescence image of bacteria treated with different methods (live/dead bacteria are stained with green/red fluorescence, respectively).

Figure 9 is a SEM image of Staphylococcus epidermidis treated with different methods.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

Example 1

Take 0.025 mL of 100 mM HAuCl ₄ solution, add 3 mL of water and mix to obtain solution A; add 5 mL of 100 mM CTAC (hexadecyl trimethyl ammonium chloride) and 1 mL of 50 mM citric acid solution to solution A, and add 0.625 mL immediately after stirring evenly 100 mM NaBH ₄ solution, stirred for 3 min to obtain solution B. The solution B was stirred in an oil bath at 80° C. for 90 min to obtain a 0.25 mM gold seed solution, which was concentrated to obtain a 100 mM gold seed solution C. At the same time, an aqueous growth solution containing 10 mL of 100 mM cetyltrimethylammonium bromide in water (CTAB), 0.2 mL of 10 mM silver nitrate, 2 mL of 1 M hydrochloric acid, and 0.15 mL of 100 mM ascorbic acid was prepared, to which was added 100 μL of gold seed solution C, 30 Store at ℃ for 2 h, centrifuge, and dissolve the precipitate in 1 mL of 0.1 mol/L CTAB solution to obtain gold nanobipyramid solution D.

Add 1mL 100mM CTAB solution and 0.3mL 10mM HAuCl ₄ solution to 20mL aqueous solution, add 0.1mL 100mM ascorbic acid solution after stirring to obtain growth solution A, add 0.08mL 1mM chiral dipeptide (DL-CF) solution to growth solution A , adding 0.4 mL of gold nanobipyramidal solution D, and standing at 30 °C for 2 h to obtain chiral gold nano antibacterial materials DL-GBPs with sea cucumber-like morphology.

Example 2

Take 0.025mL 100mM HAuCl ₄ solution, add 3mL water and mix to obtain solution A; add 5mL 100mM CTAC and 1mL 50mM citric acid solution to solution A, stir well and immediately add 0.625mL 100mM NaBH ₄ solution, stir for 3min, Solution B was obtained. The solution B was stirred in an oil bath at 80° C. for 90 min to obtain a 0.25 mM gold seed solution, which was concentrated to obtain a 100 mM gold seed solution C. At the same time, an aqueous growth solution containing 10 mL of 100 mM CTAB, 0.2 mL of 10 mM silver nitrate, 2 mL of 1 M hydrochloric acid and 0.15 mL of 100 mM ascorbic acid was prepared, and gold seed solution C was added to it. In mol/L CTAB solution, gold nanobipyramidal solution D was obtained.

Add 1 mL of 95 mM CTAB solution and 0.3 mL of 12 mM HAuCl ₄ solution to 20 mL of aqueous solution, add 0.1 mL of 110 mM ascorbic acid solution after stirring to obtain growth solution A, and add 0.08 mL of 1.0 mM chiral dipeptide (L-CF) to growth solution A solution, add 0.4 mL of gold nano bipyramid solution D, and stand at 30 °C for 2 h to obtain chiral gold nano antibacterial material L-GBPs with sea cucumber-like morphology.

Example 3

Take 0.025mL 100mM HAuCl ₄ solution, add 3mL water and mix to obtain solution A; add 5mL 100mM CTAC and 1mL 50mM citric acid solution to solution A, stir well and immediately add 0.625mL 100mM NaBH ₄ solution, stir for 3min, Solution B was obtained. The solution B was stirred in an oil bath at 80° C. for 90 min to obtain a 0.25 mM gold seed solution, which was concentrated to obtain a 100 mM gold seed solution C. At the same time, an aqueous growth solution containing 10 mL of 100 mM CTAB, 0.2 mL of 10 mM silver nitrate, 2 mL of 1 M hydrochloric acid and 0.15 mL of 100 mM ascorbic acid was prepared, and gold seed solution C was added to it. In mol/L CTAB solution, gold nanobipyramidal solution D was obtained.

Add 1 mL of 100 mM CTAB solution and 0.3 mL of 10 mM HAuCl ₄ solution to 20 mL of aqueous solution, add 0.1 mL of 100 mM ascorbic acid solution after stirring to obtain growth solution A, and add 0.08 mL of 1.0 mM chiral dipeptide (D-CF) to growth solution A solution, add 0.4 mL of gold nanobipyramidal solution D, and stand at 30 °C for 2 h to obtain chiral gold nanomaterials D-GBPs with sea cucumber-like morphology.

Example 4

Take 0.025 mL of 100 mM HAuCl ₄ solution, add 4 mL of water and mix to obtain solution A; add 5 mL of 100 mM CTAC and 1 mL of 50 mM citric acid solution to solution A, stir evenly and immediately add 0.625 mL of 100 mM NaBH ₄ solution, stir for 4 min, Solution B was obtained. The solution B was stirred in an oil bath at 70° C. for 120 min to obtain a 0.25 mM gold seed solution, which was concentrated to obtain a 100 mM gold seed solution C. At the same time, an aqueous growth solution containing 10 mL of 100 mM CTAB, 0.2 mL of 10 mM silver nitrate, 1 mL of 1 M hydrochloric acid and 0.15 mL of 100 mM ascorbic acid was prepared, and gold seed solution C was added to it. In 1 mL of 0.1 mol/L CTAB solution, gold nano bipyramid solution D was obtained.

Add 1 mL of 100 mM CTAB solution and 0.3 mL of 10 mM HAuCl ₄ solution to 20 mL of aqueous solution, add 0.1 mL of 100 mM ascorbic acid solution after stirring to obtain growth solution A, and add 0.08 mL of 1.0 mM chiral dipeptide (D-CF) to growth solution A solution, add 0.4 mL of gold nanobipyramidal solution D, and stand at 30 °C for 2 h to obtain chiral gold nanomaterials D-GBPs with sea cucumber-like morphology.

Example 5

Take 0.025 mL of 100 mM HAuCl ₄ solution, add 4 mL of water and mix to obtain solution A; add 5 mL of 100 mM CTAC and 1 mL of 50 mM citric acid solution to solution A, and immediately add 0.625 mL of 100 mM NaBH ₄ solution after stirring, and stir for 4 min to obtain solution B. The solution B was stirred in an oil bath at 90° C. for 60 min to obtain a 0.25 mM gold seed solution, which was concentrated to obtain a 100 mM gold seed solution C. At the same time, an aqueous growth solution containing 10 mL of 100 mM CTAB, 0.2 mL of 10 mM silver nitrate, 1 mL of 1 M hydrochloric acid and 0.15 mL of 100 mM ascorbic acid was prepared, and gold seed solution C was added to it. In 0.1mol/L CTAB solution, gold nanobipyramidal solution D was obtained.

Add 1 mL of 100 mM CTAB solution and 0.3 mL of 10 mM HAuCl ₄ solution to 20 mL of aqueous solution, add 0.1 mL of 100 mM ascorbic acid solution after stirring to obtain growth solution A, and add 0.08 mL of 1.0 mM chiral dipeptide (D-CF) to growth solution A solution, add 0.4 mL of gold nanobipyramidal solution D, and stand at 30 °C for 2 h to obtain chiral gold nanomaterials D-GBPs with sea cucumber-like morphology.

Effect evaluation 1

Antibacterial testing was performed on PBS, PEG-Au NBP, Examples 1, 2 and 3, 100 μL of bacterial suspension (S. epidermidis in 2×10 ⁴ (CFU)/mL (TSB)) and 100 μL of 0.01M PBS, PEG-Au NBPs, DL-GBPs, D-GBPs, and L-GBPs were added to the wells of 96-well plates, respectively. The mixture was vortexed for 3 min, then placed in the incubator for another 3 h, and then irradiated with an 808 nm laser for 5 min (0.8 W/cm ² ). After irradiation, the mixture was incubated at 37°C for an additional 12h. Finally, the value of optical density was measured at 600 nm using a microplate reader. The results are shown in Figure 6 using bacterial suspensions grown from unirradiated samples as controls.

In the standard plate count assay, bacterial suspensions were serially diluted in 0.01 M sterile PBS, and 100 μL of each diluted sample was plated on tryptic soy agar plates. After 12h incubation at 37°C, the colonies formed on the surface of the plate were counted to evaluate the bacterial concentration. The results are shown in Figure 7.

Effect evaluation 2

Bacteria live/dead staining assay was performed on PBS, PEG-Au NBP and Examples 1, 2, 3, treated bacteria were stained with LIVE/DEAD BacLight Bacterial Viability Kit and visualized by Axio Vert.A1 Fluorescence Microscope Imaging System . The results are shown in Figure 8.

Effect evaluation 3

SEM images were taken to observe the morphology of PBS, PEG-AuNBP, Examples 1, 2, 3 in irradiated and non-irradiated bacteria.

Differently treated S. epidermidis solutions were dropped onto silicon wafers and then fixed with 2% glutaraldehyde for 3 h at room temperature, followed by gradients of a series of ethanol solutions (50%, 70%, 90%, 95% and 100%) Dehydration, 10min each step.

After drying under nitrogen flow, the wafers were sputtered with an ultrathin gold coating and imaged at 3.0 kV using a Hitachi Su8010 instrument. The results are shown in Figure 9.

After a series of material performance characterization comparisons, it can be seen that the present invention successfully prepares a sea cucumber-like chiral gold nanometer antibacterial material. Tests such as photothermal effect and bacterial survival performance show that the chiral gold nanomaterial with sea cucumber-like morphology can be sterilized by targeting bacteria and enhancing PTT effect, and the sterilization effect is remarkable.

Therefore, the sea cucumber-like chiral gold nano-antibacterial material prepared by the present invention provides a promising nano-tool for improving the therapeutic effect of sepsis, such as fighting against lethal bacterial infection, regulating systemic inflammatory response, preventing multiple organ failure, etc.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, other different forms of changes or modifications can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. However, the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (10)

1. A preparation method of a chiral gold nano antibacterial material is characterized by comprising the following steps:

(1) to HAuCl₄Adding a citric acid solution into the solution, uniformly mixing, adding a reducing agent, and reacting to obtain a gold seed solution;

(2) carrying out heat treatment on the gold seed solution;

(3) adding the gold seed solution after heat treatment into a gold nano bipyramid solution to obtain a gold nano bipyramid solution, wherein the gold nano bipyramid solution is a mixed solution of CTAB, silver nitrate, hydrochloric acid and ascorbic acid;

(4) adding a chiral dipeptide aqueous solution and the gold nanometer bipyramid solution into a growth solution to react to prepare the chiral gold nanometer antibacterial material, wherein the growth solution is prepared from CTAB and HAuCl₄Adding ascorbic acid solution into the mixed solution to obtain the final product.

2. The method for preparing chiral gold nano antibacterial material according to claim 1, wherein in the step (1), the reducing agent is NaBH₄And/or KBH₄。

3. The method for preparing the chiral gold nano antibacterial material according to claim 1, wherein the concentration of the gold seed solution is 0.2-0.3 mM.

4. The method for preparing the chiral gold nano antibacterial material according to claim 1, wherein in the step (2), the heat treatment condition is stirring at 70-90 ℃ for 60-120 min.

5. The method for preparing chiral gold nano antibacterial material according to claim 1, characterized in that in the step (3), the molar ratio of CTAB, silver nitrate, hydrochloric acid and ascorbic acid in the water growth solution is 1000:1-5:1-5: 10-20.

6. The method for preparing chiral gold nano-antibacterial material according to claim 1, wherein the chiral dipeptide is L-CF, D-CF or DL-CF.

7. The method for preparing chiral gold nano antibacterial material according to claim 1, wherein in the step (4), Au is contained in the gold nano bipyramid solution³⁺、CTAB、HAuCl₄Ascorbic acid and chiral dipeptide in a molar ratio of 1-25: 5-100: 1.5-4.5: 7.5-12.5: 0.04-0.12.

8. The method for preparing the chiral gold nano antibacterial material according to claim 1, wherein in the step (4), the reaction is carried out at 25-35 ℃ for 1.5-2.5 h.

9. A chiral gold nano antibacterial material prepared by the preparation method of any one of claims 1-8.

10. The chiral gold nano-antibacterial material according to claim 9, wherein the particle size of the chiral gold nano-antibacterial material is in the range of 80-150 nm.

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