Preparation method and application of duck bone-derived blue fluorescent carbon dots

Abstract

The application discloses a preparation method and application of duck bone source blue fluorescent carbon dots, and the preparation method is to take poultry biomass raw material duck bone as a carbon source, to prepare water-soluble carbon dots through one-step hydrothermal reaction of the carbon source raw material after treatment and distilled water. The preparation process is simple, easy to operate, the raw material source is rich and extensive, the cost is low, the efficiency is high, the reaction is completed within 8-12 hours, there is no pollution, and the carbon dots can be used for industrial production and improve the comprehensive utilization rate of byproduct resources. The carbon dots prepared by the application have small size, obvious high-intensity fluorescence effect, good biocompatibility and water solubility, and have a bacteriostatic effect. The carbon dots provided by the application have the characteristics of fluorescence indication and bacteriostasis, can be applied to food production and storage processes to ensure product flavor and product quality, and can prolong the shelf life of products.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials technology, specifically relating to a method for preparing and applying blue fluorescent carbon dots derived from duck bones. Background Technology

[0002] Poultry by-products refer to the waste generated during poultry slaughter, including poultry viscera, fur, bones, etc. Although these by-products cannot be used as food, they still have certain economic and ecological value.

[0003] Ducks are a common type of poultry with a long history and broad cultural significance. They not only provide abundant food but have also become an important part of human life. Duck bones, as part of the duck meat, are often overlooked. Duck bones are rich in various nutrients, including protein, calcium, phosphorus, iron, and other minerals, as well as various vitamins. In addition, duck bones contain various unsaturated fatty acids, which help lower cholesterol and prevent cardiovascular disease. In recent years, the application of biomass materials to synthesize carbon dots has become increasingly widespread, mainly due to the following advantages: First, the precursors for synthesizing biomass carbon dots are mostly renewable, some even being industrial waste. Converting these low-value wastes into high-value carbon dots to reduce resource waste and achieve sustainable development in various research fields is a future trend. Second, some biomass materials contain elements other than carbon, hydrogen, and oxygen, enabling the synthesis of carbon dots doped with different elements without the need for additional heteroatom sources. Third, biomass carbon dots have good biocompatibility and low toxicity, making them better suited for applications in biomedicine and other fields.

[0004] Exploring the use of duck bones, a by-product of poultry, as a carbon source to prepare carbon dot materials can improve the utilization rate of poultry by-products, increase the added value of products, and the resulting carbon dots have excellent physicochemical properties and broad application prospects. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems in the preparation of carbon dots from poultry by-product duck bones, and to provide a one-step method for producing carbon dots using a hydrothermal process.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first objective of this invention is to provide a method for preparing blue fluorescent carbon dots from duck bones, the method comprising the following steps:

[0008] S1: Select the bones from the duck leg, boil them in boiling water, remove the bones, dry them, crush them, and sieve them to obtain duck bone powder;

[0009] S2: Disperse the biomass duck bone powder evenly in distilled water, with a mass-to-volume ratio of duck bone powder to distilled water of 0.5g:(10-20)mL, and stir for 10-20min to form a suspension;

[0010] In a particular embodiment, the mass-to-volume ratio of duck bone powder to distilled water is 0.5g:15mL.

[0011] S3: The obtained suspension is placed in a hydrothermal reactor to carry out a hydrothermal reaction to form a carbon dot solution. After separation and purification, the solution after lyophilization is finally freeze-dried to obtain carbon dot powder.

[0012] Furthermore, the drying conditions described in S1 are drying at 100°C for 2 hours.

[0013] Furthermore, the pulverization rate of the pulverizer described in S1 is 7000 r / min, the pulverization time is 10 s, and the pulverization number is 3 times.

[0014] Furthermore, the sieving described in S1 involves passing the material through a 40-mesh sieve and then a 100-mesh sieve in sequence.

[0015] Furthermore, the hydrothermal reaction conditions described in S3 are: reaction at 180°C for 8–12 hours.

[0016] Furthermore, the separation described in S3 is centrifugation at 10000 r / min for 15 min.

[0017] Furthermore, the purification described in S3 involves sequentially filtering through 0.45μm and 0.22μm aqueous filter membranes and then dialyzing in a dialysis bag with a molecular weight of 500Da for 48 hours.

[0018] Furthermore, the dialysis time described in S3 is 48 hours, with the water changed every 24 hours.

[0019] The preparation method described above yielded micron-sized biomass raw materials with a particle size of less than 0.150 mm, which provides a feasibility for enhancing the preparation yield of carbon dots.

[0020] The second objective of this invention is to provide a blue fluorescent carbon dot derived from duck bones, which is prepared using the aforementioned preparation method.

[0021] Blue-green fluorescent carbon dots were prepared according to the above preparation method, exhibiting strong fluorescence properties and good water solubility. In Examples 2 and 3, the maximum excitation wavelength of the duck bone-derived blue fluorescent carbon dots was 340 nm, and the maximum emission wavelength was 425 nm, demonstrating broad application prospects.

[0022] The third objective of this invention is to provide the application of the aforementioned duck bone-derived blue fluorescent carbon dots in the preparation of antibacterial agents.

[0023] Furthermore, the bacteria in question is Escherichia coli.

[0024] In a specific embodiment, the aforementioned blue fluorescent carbon dots from duck bones were prepared into a carbon dot solution with a concentration of 1 mg / mL. The bacteria in question was Escherichia coli. It was found that the prepared carbon dot solution had a certain antibacterial effect against Escherichia coli.

[0025] The technical solution of this invention has the following advantages over the prior art:

[0026] (1) Compared with traditional petroleum-based carbon materials, this invention uses green and pollution-free biomass material duck bones as raw materials for synthesizing carbon dots and prepares carbon dots through a one-step hydrothermal reaction using distilled water as a solvent. The raw materials are widely available, inexpensive and environmentally friendly, which can promote the integrated utilization of by-product resources and generate higher economic added value.

[0027] (2) The process of this invention is simple to operate and relatively easy to prepare. The hydrothermal reaction is completed within 8-12 hours. The one-step method at ambient temperature can achieve large-scale production and is expected to be industrialized in the future. Moreover, the prepared biomass carbon dots have strong fluorescence characteristics and good water solubility, which can be developed for various applications and solve practical production and application problems.

[0028] (3) The carbon dot material of the present invention can be used in the food field for food preservation and to extend the shelf life of products. The prepared blue-green duck bone-derived fluorescent carbon dots have certain antibacterial properties and can be used as an additive in food packaging materials. In addition, the strong fluorescence properties of the carbon dots can be further developed for traceability management in the food circulation process; in the field of biotherapy, they can also be used for early diagnosis of diseases and for developing applications such as cell imaging, molecular imaging, and drug imaging. Attached Figure Description

[0029] Figure 1 Flowchart of the preparation process of duck bones, a biomass byproduct

[0030] Figure 2 Flowchart of preparation of duck bone-derived carbon dots

[0031] Figure 3 Appearance of distilled water (A) and carbon dot solution at 395 nm (B)

[0032] Figure 4 Example 1: Appearance of duck bone-derived carbon dot solutions of different concentrations under sunlight.

[0033] Figure 5 Example 1: Appearance of duck bone-derived carbon dot solutions of different concentrations under 395nm ultraviolet light irradiation.

[0034] Figure 6 Example 1: Ultraviolet absorption spectra of duck bone-derived carbon dot solutions at different concentrations

[0035] Figure 7 Example 1: Fluorescence spectra of duck bone-derived carbon dot solutions at different concentrations

[0036] Figure 8 Example 2: Appearance of duck bone-derived carbon dot solutions of different concentrations under sunlight.

[0037] Figure 9 Example 2: Appearance of duck bone-derived carbon dot solutions of different concentrations under 395nm ultraviolet light irradiation.

[0038] Figure 10 Example 2: Ultraviolet absorption spectra of duck bone-derived carbon dot solutions at different concentrations

[0039] Figure 11 Example 2: Fluorescence spectra of duck bone-derived carbon dot solutions at different concentrations

[0040] Figure 12 Example 3: Antibacterial effect of duck bone carbon dots Detailed Implementation

[0041] The present invention will be further explained below with reference to the embodiments, but the embodiments do not limit the present invention in any way.

[0042] Example 1

[0043] (1) Raw materials: Six fresh duck legs were selected for the experiment. The samples were purchased from Nanjing Suguo Supermarket.

[0044] (2) Reagents: All reagents were domestically produced analytical grade.

[0045] (3) Sample processing: Fresh duck leg bones were used as raw material. Fresh duck legs were boiled in boiling water for 25 minutes until the duck meat and bones could be completely separated. The duck meat was removed, leaving only the bones. The resulting duck bones were wiped dry with filter paper and then dried in a 100℃ oven for 2 hours to remove internal moisture, improving subsequent crushing. The dried duck bones were brittle. (35-45)g of the dried duck bones were weighed and placed in a grinder, and crushed three times at 7000r / min, each time for 10s, with a 15s interval. The crushed duck bones were first filtered through a 40-mesh sieve, and then the duck bone powder was filtered through a 100-mesh sieve to obtain the biomass raw material for subsequent preparation of fluorescent carbon dots. Figure 1 ).

[0046] (4) Instruments and equipment

[0047]

[0048] (5) Preparation of fluorescent carbon dots from duck bone source under hydrothermal reaction conditions of 8 h

[0049] Weigh 0.5g of dried duck bone powder and evenly disperse it in 15ml of distilled water. Stir for 15min at room temperature, then place the suspension in a 25ml hydrothermal reactor and react in an oven at 180℃ for 8h to form a carbon dot solution. After cooling the formed carbon dot solution to room temperature, centrifuge at 10000r / min for 15min to remove impurities. The supernatant after centrifugation is then filtered using an aqueous microporous membrane and dialyzed using a dialysis bag. First, the centrifuged carbon dot solution is passed through a 0.45μm aqueous microporous membrane using a syringe, then through an aqueous microporous membrane with a pore size of 0.22μm. The collected carbon dot solution is then dialyzed in a dialysis bag for 48h. The molecular weight of the dialysis bag is 500Da, and the water is changed every 24h during dialysis. The solution is then freeze-dried for 48h to obtain carbon dot powder, which is stored at 4℃ for use. Figure 2 ).

[0050] The prepared fluorescent carbon dot powder was redissolved in deionized water to prepare seven different concentrations of carbon dot solutions: 1 mg / mL, 0.8 mg / mL, 0.6 mg / mL, 0.4 mg / mL, 0.2 mg / mL, 0.1 mg / mL, and 0.01 mg / mL. The appearance of the carbon dot solutions was then tested under sunlight and at 395 nm.

[0051] 1. Appearance images of distilled water and 1 mg / mL carbon dot solution at 395 nm are shown below. Figure 3 As shown in the results, the distilled aqueous solution under ultraviolet light irradiation did not produce fluorescence. However, the carbon dot solution emitted a blue-green fluorescence under ultraviolet light excitation, with a significant fluorescence effect.

[0052] 2. Appearance of duck bone source carbon dot solutions of different concentrations under sunlight (see figures). Figure 4 As shown, the results indicate that under illumination, the carbon dot solution appears pale yellow, and the color gradually deepens with increasing carbon dot concentration. Furthermore, the solution is clear and uniform at all concentrations, demonstrating that the carbon dots of this invention have good water solubility.

[0053] 3. Appearance images of duck bone-derived carbon dot solutions of different concentrations under 395nm ultraviolet light irradiation are shown below. Figure 5 The results show that, compared with the aqueous solution, the carbon dot solution under ultraviolet light exhibits a significant photoluminescence effect, displaying blue-green fluorescence. Furthermore, the fluorescence intensity increases with increasing carbon dot concentration, and the solution is clear and uniform at all concentrations, indicating that the carbon dots of this invention have good water solubility.

[0054] (6) Ultraviolet-Vis absorption spectrum of duck bone-derived fluorescent carbon dot solution

[0055] The UV-Vis absorption spectra of seven carbon dot solutions with different concentrations were determined using a UV-Vis spectrophotometer. Spectral scanning was performed in the range of 200–700 nm. Distilled water was used as a blank control. The sample volume was increased to more than two-thirds of the cuvette volume each time. Samples were rinsed repeatedly with deionized water between tests, and each sample was tested three times.

[0056] The ultraviolet absorption spectra of duck bone carbon dot solutions of different concentrations are shown below. Figure 6 The results showed that the synthesized carbon dots had ultraviolet absorption peaks at 220 and 280 nm, and the ultraviolet absorbance value gradually increased with the increase of carbon dot solution concentration.

[0057] (7) Fluorescence spectrum of duck bone-derived fluorescent carbon dot solution

[0058] The fluorescence spectra of carbon dot solutions at a concentration of 1 mg / mL were measured using a fluorescence spectrometer, and the variation of emission wavelength with excitation wavelength was observed. Measurement conditions: excitation slit width: 5.0 nm; emission slit width: 5.0 nm; voltage: 400 V; excitation wavelengths: 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, 400 nm, 410 nm, 420 nm; acquisition wavelength: 2 nm.

[0059] The fluorescence spectra of duck bone-derived carbon dot solutions under different excitation wavelengths are shown below. Figure 7 The results show that the maximum emission intensity and position of the carbon dots depend on the excitation wavelength. When the excitation wavelength changes, the emission peak shifts, and the intensity also changes accordingly. Fluorescence emission spectra at different excitation wavelengths (280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420 nm) show that when the excitation wavelength increases from 320 nm to 420 nm, the maximum emission wavelength shifts, and the emission intensity first increases and then gradually decreases.

[0060] Example 2

[0061] (1) Raw materials: Six fresh duck legs were selected for the experiment. The samples were purchased from Nanjing Suguo Supermarket.

[0062] (2) Reagents: All reagents were domestically produced analytical grade.

[0063] (3) Sample processing: Fresh duck leg bones were used as raw materials. The fresh duck legs were boiled in boiling water for 25 minutes until the duck meat and bones could be completely separated. The duck meat was removed, leaving only the bones. The resulting duck bones were wiped dry with filter paper and then placed in a 100℃ oven for 2 hours to remove internal moisture, improving subsequent crushing. The dried duck bones were brittle. (35-45)g of the dried duck bones were weighed and placed in a grinder, and ground three times at 7000r / min, each time for 10s, with a 15s interval. The ground duck bones were first filtered through a 40-mesh sieve, and then the duck bone powder was filtered through a 100-mesh sieve to obtain the biomass raw material for subsequent preparation of fluorescent carbon dots.

[0064] (4) Instruments and equipment

[0065]

[0066]

[0067] (5) Preparation of fluorescent carbon dots from duck bone source under hydrothermal reaction conditions of 12 h

[0068] Weigh 0.5g of dried duck bone powder and disperse it evenly in 15ml of distilled water. Stir for 15min at room temperature, then place the suspension in a 25ml hydrothermal reactor and react in an oven at 180℃ for 12h to form a carbon dot solution. After cooling the carbon dot solution to room temperature, centrifuge at 10000r / min for 15min to remove impurities. The supernatant after centrifugation is then filtered using an aqueous microporous membrane and dialyzed using a dialysis bag. First, the centrifuged carbon dot solution is passed through a 0.45μm aqueous microporous membrane using a syringe, then through a 0.22μm aqueous microporous membrane. The collected carbon dot solution is then dialyzed in a dialysis bag for 48h. The dialysis bag has a molecular weight of 500Da, and the water is changed every 24h during dialysis. The resulting carbon dot powder is then dried in a freeze dryer for 48h and stored at 4℃ for use.

[0069] The prepared fluorescent carbon dot powder was redissolved in deionized water to prepare seven different concentrations of carbon dot solutions: 1 mg / mL, 0.8 mg / mL, 0.6 mg / mL, 0.4 mg / mL, 0.2 mg / mL, 0.1 mg / mL, and 0.01 mg / mL.

[0070] Images of duck bone-derived carbon dot solutions of different concentrations under sunlight are shown below. Figure 8 As shown, the results indicate that adding less carbon dot powder has little effect on the solution color. Compared with distilled water, the carbon dot solution with higher concentration is pale yellow, and the solution is clear and uniform at all concentrations, indicating that the carbon dots of the present invention have good water solubility.

[0071] The appearance of duck bone-derived carbon dot solutions of different concentrations under 395nm ultraviolet light irradiation is shown in the following figures. Figure 9 As shown, the results indicate that the fluorescence intensity gradually increases with increasing carbon dot solution concentration. Compared to distilled water, it emits a distinct blue-green fluorescence under ultraviolet light excitation, and the solution is clear and homogeneous at all concentrations, demonstrating that the carbon dots of this invention have good water solubility.

[0072] (6) Ultraviolet-Vis absorption spectrum of duck bone-derived fluorescent carbon dot solution

[0073] The experimental method was the same as in Example 1. The ultraviolet absorption spectra of duck bone carbon dot solutions of different concentrations are shown below. Figure 10 As shown, the results indicate that the UV absorbance gradually increases with the increase of carbon dot solution concentration, with obvious absorption peaks at 230 and 270 nm.

[0074] (7) Fluorescence spectrum of duck bone-derived fluorescent carbon dot solution

[0075] The experimental method was the same as in Example 1. The fluorescence spectrum of the 1 mg / mL duck bone carbon dot solution is shown below. Figure 11 As shown, the results indicate that increasing the hydrothermal reaction time improves the fluorescence intensity of the duck bone-derived carbon dots, and the emission wavelength red-shifts with increasing excitation wavelength, which is a typical carbon dot photoluminescence phenomenon.

[0076] Example 3

[0077] (1) Preparation of bacterial suspension

[0078] The *E. coli* strain was activated in a clean bench. The strain was inoculated onto nutrient agar slants and incubated at 37°C for 24 h. After two activations, the colonies were inoculated into LB medium and incubated at 37°C for 24 h. Before use, the bacterial suspension was centrifuged at 6000 rpm for 10 min. The precipitate was collected, washed twice with sterile physiological saline, and resuspended in physiological saline. The final concentration of the *E. coli* suspension was 10. 7 -10 8 CFU / mL.

[0079] (2) Antibacterial properties of duck bone-derived fluorescent carbon dot solution

[0080] Carbon dot powder was dissolved in deionized water to prepare a 1 mg / mL carbon dot aqueous solution. 1 mL of the carbon dot solution was added dropwise to a culture medium, and its antibacterial properties were observed.

[0081] The antibacterial effect of duck bone-derived carbon dots is shown in the figure below. Figure 12 As shown in the figure, the Escherichia coli grew well on the culture medium, but a clear inhibition zone was observed at the point where the carbon dot solution was added, indicating that the prepared duck bone-derived carbon dot solution has a certain antibacterial effect.

[0082] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of duck bone-derived blue fluorescent carbon dots in the preparation of antibacterial agents, characterized in that, The blue fluorescent carbon dots derived from duck bones were prepared using the following method: S1: Select the bones from the duck leg, boil them in boiling water, remove the bones, dry them, crush them, and sieve them to obtain duck bone powder; S2: Disperse the biomass duck bone powder evenly in distilled water, with a mass-to-volume ratio of duck bone powder to distilled water of 0.5g:(10-20)mL, and stir for 10-20min to form a suspension; S3: The obtained suspension is placed in a hydrothermal reactor to carry out a hydrothermal reaction to form a carbon dot solution. After separation and purification, the solution after lyophilization is finally freeze-dried to obtain carbon dot powder. The drying conditions described in S1 are drying at 100°C for 2 hours; The hydrothermal reaction conditions described in S3 are: reaction at 180°C for 8–12 hours.

2. The application according to claim 1, characterized in that, The pulverization rate of S1 is 7000 r / min, the pulverization time is 10 s, and the pulverization number is 3 times.

3. The application according to claim 1, characterized in that, The sieving process described in S1 involves passing the material through a 40-mesh sieve and then a 100-mesh sieve in sequence.

4. The application according to claim 1, characterized in that, The separation described in S3 involves centrifugation at 10000 r / min for 15 min.

5. The application according to claim 1, characterized in that, The purification process described in S3 involved sequential filtration through 0.45μm and 0.22μm aqueous membranes followed by dialyzing in a dialysis bag with a molecular weight of 500 Da for 48 hours.

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