Broad-spectrum antibacterial carbon quantum dot as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of bacteriostatic nano materials, and particularly provides broad-spectrum bacteriostatic carbon quantum dots as well as a preparation method and application thereof, the broad-spectrum bacteriostatic carbon quantum dots are obtained by performing hydrothermal reaction on common turnip powder or common turnip residues in a water environment; the temperature of the hydrothermal reaction is 120-200 DEG C, and the time is 6-8 hours. The common turnip residues are subjected to polysaccharide extraction. The broad-spectrum antibacterial carbon quantum dots have a good inhibition effect on bacteria and fungi, the whole preparation process is simple and environment-friendly, and the common turnip residue carbon quantum dots have a relatively strong inhibition capability on penicillium expansum.

Description

Technical Field

[0001] The present invention belongs to the technical field of antibacterial nanomaterials, and specifically relates to a broad-spectrum antibacterial carbon quantum dot and a preparation method and application thereof. Background Art

[0002] Bacterial infection has become a major threat to public health, and the widespread use of antibiotics has led to bacterial resistance. As more bacteria show multidrug resistance, it becomes more difficult to treat infections, so it is particularly important to find new methods to inhibit it. Penicillium expansum is a common spoilage fungus in fruits. Its metabolites may remain in processed fruit products, which may cause acute and chronic toxic damage and cytopathic effects after consumption, seriously threatening health. At present, traditional methods mainly use physical and chemical means to inhibit the growth and reproduction of Penicillium expansum. However, physical methods such as low-temperature storage, drying, and irradiation can effectively slow down the growth of fungi, but may increase costs and affect food quality or safety. Chemical methods include the use of chemical preservatives, fumigation, and biological preservatives. Although they can effectively kill bacteria, they also have health risks, environmental impacts, and cost issues, which in turn limit their application in actual production.

[0003] Carbon quantum dots are a new type of nanomaterial with a size of less than 10 nanometers. They have excellent optical properties, good water dispersibility, modifiable surface and good biocompatibility. Carbon quantum dots are widely used in biological and medical fields, such as bioimaging, biosensing, drug delivery, treatment and detection. In recent years, researchers have paid more and more attention to the antibacterial effect of carbon quantum dots. Studies have confirmed that carbon quantum dots have an inhibitory effect on bacteria, but the carbon quantum dots in the existing technology cannot inhibit both bacteria and fungi at the same time. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a broad-spectrum antibacterial carbon quantum dot and a preparation method and application thereof, which can inhibit bacteria and fungi at the same time.

[0005] In order to achieve the above object, the present invention adopts the following technical solution.

[0006] The first aspect of the present invention provides a broad-spectrum antibacterial carbon quantum dot, which is obtained by subjecting genus quahog powder or genus quahog residue to a hydrothermal reaction in a water environment, filtering and discarding the sediment, and concentrating;

[0007] The temperature of the hydrothermal reaction is 120°C to 200°C, and the time is 6h to 8h;

[0008] The mass volume ratio of the genus quahog powder or genus quahog residue to water is 1 g to 1.2 g: 60 mL;

[0009] The genus treotii residue is obtained by subjecting the polysaccharide to ultrasonic-assisted water extraction.

[0010] The genus quahog powder or genus quahog residue of the present invention is subjected to a hydrothermal reaction in a water environment, and the temperature and time of the hydrothermal reaction are controlled so that the obtained broad-spectrum antibacterial carbon quantum dots have a good inhibitory effect on both bacteria and fungi. The genus quahog residue obtained by ultrasonic-assisted water extraction of polysaccharides is selected. This is mainly because different polysaccharide extraction methods may produce different degrees of impurity residues. The presence of these impurities may interfere with the synthesis process of the carbon quantum dots, thereby affecting the performance of the carbon quantum dots. Therefore, the present invention uses the genus quahog residue obtained by extracting polysaccharides by ultrasonic-assisted hot water extraction.

[0011] In another preferred embodiment, the genus trehalose residue is obtained in the following manner:

[0012] Mix the genus darberis with water, perform ultrasonic extraction at 60°C to 65°C for 50min to 55min, filter, dry and crush the precipitate to obtain the genus darberis residue;

[0013] The power of the ultrasound is 350W-360W.

[0014] The second aspect of the present invention provides a method for preparing the broad-spectrum antibacterial carbon quantum dots, comprising the following steps:

[0015] The genus quahog powder or genus quahog residue is mixed with water, subjected to hydrothermal reaction at 120°C to 200°C for 6h to 8h, filtered, allowed to stand and cool to 20°C to 24°C, the sediment is discarded to obtain a solution, the solution is filtered through a filter membrane to obtain a filtrate, and the filtrate is concentrated to obtain the broad-spectrum antibacterial carbon quantum dots.

[0016] In another preferred embodiment, the filter membrane is a 0.45 μm water ultrafiltration membrane.

[0017] The third aspect of the present invention provides the use of the broad-spectrum antibacterial carbon quantum dots in the preparation of antifungal products.

[0018] In another preferred embodiment, the fungus is Penicillium expansum.

[0019] The fourth aspect of the present invention provides the use of the broad-spectrum antibacterial carbon quantum dots in the preparation of products that inhibit bacteria.

[0020] In another preferred embodiment, the bacteria is one or both of Escherichia coli and Staphylococcus aureus.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention controls the hydrothermal reaction temperature at 120°C to 200°C for 6h to 8h in a water environment to obtain broad-spectrum antibacterial carbon quantum dots that have good antibacterial effects on both bacteria and fungi. The genus genus residue in the present invention is obtained by ultrasonic-assisted water extraction of polysaccharides, which can reduce impurities in the genus genus residue and avoid interference in the synthesis process of carbon quantum dots. The genus genus in the present invention is both a medicine and a food, and the entire preparation process is simple and environmentally friendly. In addition, the carbon quantum dots of the genus genus residue show a strong inhibitory ability against Penicillium expansum.

[0023] (2) The present invention effectively utilizes the medicinal and edible plant genus larkspur and develops a new type of green and environmentally friendly antibacterial material with good biocompatibility and environmental friendliness. The inhibitory effect of carbon quantum dots on Penicillium expansum was explored, providing a new prevention and control method for the field of food processing and preservation, which is expected to improve the safety and quality of food. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The Fourier transform infrared spectroscopy characterization and analysis diagram of the carbon quantum dots of genkwa powder and genkwa residue powder in Examples 1 to 6 of the present invention.

[0025] Figure 2 This is a diagram showing the inhibitory effects of the six types of genus quatrain carbon dots on Escherichia coli in Examples 1 to 6 of the present invention.

[0026] Figure 3 This is a diagram showing the inhibitory effects of the six types of genus genus carbon dots on Escherichia coli in Examples 1 to 6 of the present invention.

[0027] Figure 4 This is a graph showing the inhibitory effects of the six types of Gentiana raphani carbon dots on Staphylococcus aureus in Examples 1 to 6 of the present invention.

[0028] Figure 5 This is a graph showing the inhibitory effects of the six types of genus genus carbon dots on Staphylococcus aureus in Examples 1 to 6 of the present invention.

[0029] Figure 6 This is a graph showing the inhibitory effects of six types of genkwa residue carbon dots on Penicillium expansum in Examples 1 to 6 of the present invention.

[0030] Figure 7 Figure 1 is a graph showing the inhibitory effect of different concentrations of Z160 / 12 on Penicillium expansum in Example 1 of the present invention, wherein A is a graph showing the inhibitory effect of the blank control group, B is a graph showing the inhibitory effect of 4.76 mg / mL Z160 / 12 on Penicillium expansum, and C is a graph showing the inhibitory effect of 0.48 mg / mL Z160 / 12 on Penicillium expansum. DETAILED DESCRIPTION

[0031] The technical solutions in the present invention will be described clearly and completely below in conjunction with the specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The methods described in the embodiments of the present invention are conventional methods unless otherwise specified. The materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0033] Preparation of coriander root powder: Dry fresh coriander root slices at 60°C for 12 hours, grind into powder and set aside.

[0034] Preparation of genus quail residue powder: Mix genus quail with water in a solid-liquid ratio of 1 g:43 mL, perform ultrasonic extraction at 60°C for 55 min, wherein the ultrasonic power is 360 W, filter out the precipitate, dry the precipitate at 60°C for 12 h, and then crush to obtain genus quail residue powder.

[0035] The present invention does not limit the particle size of the genus corydalis powder and the genus corydalis residue powder, and they can be crushed by conventional technology.

[0036] Staphylococcus aureus (ATCC25923) and Escherichia coli (ATCC25922) were purchased from Qingdao Hi-Tech Industrial Park Haibo Biotechnology Co., Ltd. Penicillium expansum was donated by Tian Shiping, a researcher at the Institute of Botany, Chinese Academy of Sciences, and stored at -80°C.

[0037] Example 1

[0038] A method for preparing carbon quantum dots from genus quahog, comprising the following steps:

[0039] S1. Take 1g of genus corydalis powder and 1g of genus corydalis residue powder, add 60mL of distilled water respectively, stir magnetically for 10min, then transfer to a high-pressure reactor, place at 120℃ for hydrothermal reaction for 6h, filter and discard the sediment to obtain a solution, and let the solution stand to cool to 24℃.

[0040] S2. Ultrafilter the solution through a 0.45 μm water ultrafiltration membrane to obtain a filtrate, and concentrate the filtrate at 80° C. for 12 h to obtain carbon quantum dots of genkwa powder and carbon quantum dots of genkwa residue powder, respectively.

[0041] Among them, the carbon quantum dots from genus yantra powder are denoted as Y120 / 6, and the carbon quantum dots from genus yantra slag powder are denoted as Z120 / 6.

[0042] Example 2

[0043] A method for preparing carbon quantum dots from genus quahog, comprising the following steps:

[0044] S1. Take 1g of genus corydalis powder and 1g of genus corydalis residue powder, add 60mL of distilled water respectively, stir magnetically for 10min, then transfer to a high-pressure reactor, place at 120℃ for hydrothermal reaction for 12h, filter and discard the sediment to obtain a solution, and let the solution stand to cool to 20℃.

[0045] S2. The solution was ultrafiltered through a 0.45 μm water ultrafiltration membrane to obtain a filtrate. The filtrate was concentrated at 80° C. for 12 h to obtain carbon quantum dots of genkwa powder and carbon quantum dots of genkwa residue powder, respectively.

[0046] Among them, the carbon quantum dots from genus yantra powder are denoted as Y120 / 12, and the carbon quantum dots from genus yantra slag powder are denoted as Z120 / 12.

[0047] Example 3

[0048] A method for preparing carbon quantum dots from genus quahog, comprising the following steps:

[0049] S1. Take 1g of genus corydalis powder and 1g of genus corydalis residue powder, add 60mL of distilled water respectively, stir magnetically for 10min, then transfer to a high-pressure reactor, place at 160℃ for hydrothermal reaction for 6h, filter and discard the sediment to obtain a solution, and let the solution stand to cool to 23℃.

[0050] S2. The solution was ultrafiltered through a 0.45 μm water ultrafiltration membrane to obtain a filtrate. The filtrate was concentrated at 80° C. for 12 h to obtain carbon quantum dots of genkwa powder and carbon quantum dots of genkwa residue powder, respectively.

[0051] Among them, the carbon quantum dots from genus yantra powder are denoted as Y160 / 6, and the carbon quantum dots from genus yantra slag powder are denoted as Z160 / 6.

[0052] Example 4

[0053] A method for preparing carbon quantum dots from genus quahog, comprising the following steps:

[0054] S1. Take 1g of genus corydalis powder and 1g of genus corydalis residue powder, add them into 60mL of distilled water respectively, stir them magnetically for 10min, then transfer them into a high-pressure reactor, place them at 160℃, perform hydrothermal reaction for 12h, filter and discard the sediment to obtain a solution, and let the solution stand to cool to 22℃.

[0055] S2. The solution was ultrafiltered through a 0.45 μm water ultrafiltration membrane to obtain a filtrate. The filtrate was concentrated at 80° C. for 12 h to obtain carbon quantum dots of genkwa powder and carbon quantum dots of genkwa residue powder, respectively.

[0056] Among them, the carbon quantum dots from genus yantra powder are denoted as Y160 / 12, and the carbon quantum dots from genus yantra slag powder are denoted as Z160 / 12.

[0057] Example 5

[0058] A method for preparing carbon quantum dots from genus quahog, comprising the following steps:

[0059] S1. Take 1g of genus corydalis powder and 1g of genus corydalis residue powder, add them into 60mL of distilled water respectively, stir them magnetically for 10min, then transfer them into a high-pressure reactor, place them at 200℃, perform hydrothermal reaction for 6h, filter and discard the sediment to obtain a solution, and let the solution stand to cool to 24℃.

[0060] S2. The solution was ultrafiltered through a 0.45 μm water ultrafiltration membrane to obtain a filtrate. The filtrate was concentrated at 80° C. for 12 h to obtain carbon quantum dots of genkwa powder and carbon quantum dots of genkwa residue powder, respectively.

[0061] Among them, the carbon quantum dots from genus yantra powder are denoted as Y200 / 6, and the carbon quantum dots from genus yantra slag powder are denoted as Z200 / 6.

[0062] Example 6

[0063] A method for preparing carbon quantum dots from genus quahog, comprising the following steps:

[0064] S1. Take 1g of genus corydalis powder and 1g of genus corydalis residue powder, add them into 60mL of distilled water respectively, stir them magnetically for 10min, then transfer them into a high pressure reactor, place them at 200℃, perform hydrothermal reaction for 12h, filter and discard the sediment to obtain a solution, and let the solution stand to cool to 20℃.

[0065] S2. The solution was ultrafiltered through a 0.45 μm water ultrafiltration membrane to obtain a filtrate. The filtrate was concentrated at 80° C. for 12 h to obtain carbon quantum dots of genkwa powder and carbon quantum dots of genkwa residue powder, respectively.

[0066] Among them, the carbon quantum dots from yantra powder are denoted as Y200 / 12, and the carbon quantum dots from yantra residue powder are denoted as Z200 / 12.

[0067] The carbon quantum dots of genkwa powder and genkwa residue powder in Examples 1 to 6 were characterized by infrared spectroscopy. The results are as follows: Figure 1 As shown. Figure 1 It can be seen that the Fourier transform infrared spectra of genus aralia powder carbon quantum dots and genus aralia slag powder carbon quantum dots are at 3390 cm -1 The peaks near 2939cm show OH / NH stretching vibration, indicating the presence of hydroxyl and amine groups in the series of carbon quantum dots. -1 、1624cm -1 、1413cm -1 、1249cm -1 、1083cm -1 The peaks at are attributed to CH, C=O, CN, COC and CO stretching vibrations, respectively.

[0068] 1. Study on the inhibitory activity of bacteria

[0069] 1) Inhibition of bacteria

[0070] Staphylococcus aureus and Escherichia coli were selected as representatives of Gram-positive and Gram-negative bacteria, respectively.

[0071] The prepared genus genus powder carbon quantum dots and genus genus residue powder carbon quantum dots in Examples 1 to 6 were mixed with water to prepare carbon dot solutions with different concentrations of 3.125 mg / L, 6.25 mg / L and 12.5 mg / L, and then mixed with Staphylococcus aureus and Escherichia coli, respectively, wherein the concentrations of Staphylococcus aureus and Escherichia coli were both 1×10 6 CFU / mL, the carbon dot solution and bacterial solution were mixed in a volume ratio of 1:1, and co-cultured at 37°C for 12 hours to obtain the culture solution; then 50 μL of the culture solution was inoculated into the agar medium and cultured at 37°C for 24 hours to observe the results. Figure 2 to Figure 5 As shown. Figure 2 to Figure 5 It can be seen that the six genus spatholobi carbon dots and the six genus spatholobi carbon dots all showed inhibitory ability against Escherichia coli and Staphylococcus aureus. The higher the temperature and the longer the time of the hydrothermal reaction, the better the antibacterial effect. The results are also related to the concentration of the carbon dot solution. The higher the concentration, the more obvious the antibacterial effect. Overall, the genus spatholobi carbon has a better inhibitory effect on Escherichia coli, and the genus spatholobi carbon dots have a better inhibitory effect on Staphylococcus aureus.

[0072] 2) Fungal inhibition

[0073] Penicillium expansum was selected as a representative of plant pathogenic fungi, and the genus yantra carbon dots Z200 / 12 and genus yantra carbon dots Y200 / 12 with good antibacterial effects were selected as examples. They were respectively prepared into carbon dot solutions with a concentration of 60 mg / mL. 15 mL of the two carbon dot solutions were taken and added to 135 mL of PDA culture medium cooled to 60 ° C. The final concentration of the two carbon dot solutions was 6 mg / mL. After mixing thoroughly, pour it into the culture dish. After the culture medium solidifies, a pathogenic fungus cake is inoculated in the center of each culture dish, and it is cultured at 25 ° C to observe the diameter of the hyphae. Each treatment was repeated 3 times, and the control group without carbon dot solution was recorded as CK. The results are shown in the figure. Figure 6As shown. It can be seen from the figure that both the genus yantra carbon quantum dots and the genus yantra residue carbon quantum dots have an inhibitory effect on Penicillium expansum. Under the same synthesis conditions and the same concentration conditions, the inhibitory ability of the genus yantra residue carbon quantum dots is stronger than that of the genus yantra carbon quantum dots. This may be due to the different functional groups on the surface of the two carbon quantum dots, resulting in different inhibitory abilities. By comparing the Fourier transform infrared spectra of the genus yantra residue carbon dots Z 200 / 12 and the genus yantra carbon dots Y200 / 12, it can be found that the C=O peak intensity of the genus yantra residue carbon dots Z 200 / 12 is higher than that of the genus yantra carbon dots Y200 / 12, and the presence of C=O has a positive effect on the antibacterial effect. The carbonyl group has a high reactivity, which can react with biomacromolecules in microbial cells, such as binding with proteins, nucleic acids, etc., interfering with the normal metabolism and physiological functions of microorganisms, thereby producing an antibacterial or bactericidal effect.

[0074] Select the best antibacterial effect of genus yantra carbon quantum Z200 / 12, prepare the carbon dot solution with the concentration of 100mg / mL and 10mg / mL, take 5mL of the above two concentrations of carbon dot solution and add them to 100mL PDA culture medium cooled to 60℃, the final concentrations of the two concentrations of carbon dot solution are 4.76mg / mL and 0.48mg / mL respectively. After mixing thoroughly, pour into the culture dish, inoculate a pathogenic fungus cake in the center of each culture dish after the culture medium solidifies, place it at 25℃, observe the mycelium diameter, the results are as follows Figure 7 As shown, it can be seen that the carbon quantum dots from the root of genus Atractylodes showed a strong inhibitory ability on Penicillium expansum. The higher the content of carbon quantum dots in the culture medium, the better the inhibitory effect on the growth of Penicillium expansum hyphae. When the concentration was as low as 0.48 mg / mL, it still had an inhibitory effect.

[0075] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0076] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A broad-spectrum antibacterial carbon quantum dot, characterized in that: The broad-spectrum antibacterial carbon quantum dots are obtained by subjecting radix quatica powder or radix quatica residue to a hydrothermal reaction in a water environment, filtering and discarding the sediment, and concentrating the residue. The temperature of the hydrothermal reaction is 120°C to 200°C, and the time is 6h to 8h; The mass volume ratio of the genus quahog powder or genus quahog residue to water is 1 g to 1.2 g: 60 mL; The genus treotii residue is obtained by subjecting the polysaccharide to ultrasonic-assisted water extraction.

2. The broad-spectrum antibacterial carbon quantum dots according to claim 1, characterized in that The specific method of obtaining the genus bream residue is as follows: Mixing the radix dahuricae with water, extracting by ultrasonic at 60°C to 65°C for 50min to 55min, filtering, drying and crushing the precipitate to obtain the radix dahuricae residue; The power of the ultrasound is 350W-360W.

3. A method for preparing broad-spectrum antibacterial carbon quantum dots according to any one of claims 1 or 2, characterized in that: The steps include: The genus quahog powder or genus quahog residue is mixed with water, subjected to hydrothermal reaction at 120°C to 200°C for 6h to 8h, filtered and discarded to obtain a solution, the solution is allowed to stand and cool to 20°C to 24°C, the solution is filtered through a filter membrane to obtain a filtrate, and the filtrate is concentrated to obtain the broad-spectrum antibacterial carbon quantum dots.

4. The method for preparing broad-spectrum antibacterial carbon quantum dots according to claim 3, characterized in that: The filter membrane is a 0.45 μm water system ultrafiltration membrane.

5. Use of the broad-spectrum antibacterial carbon quantum dots according to any one of claims 1 or 2 in the preparation of antifungal products.

6. The use according to claim 5, characterized in that: The fungus is Penicillium expansum.

7. Use of the broad-spectrum antibacterial carbon quantum dots described in any one of claims 1 or 2 in the preparation of products that inhibit bacteria.

8. The use according to claim 7, characterized in that: The bacteria are one or both of Escherichia coli and Staphylococcus aureus.

Images