Method for green synthesis of silver nanoparticles using tobacco waste flower extract and application thereof

Abstract

The application discloses a method for green synthesis of silver nanoparticles by using tobacco waste flower extract and application, wherein tobacco waste flower water extract is prepared by grinding tobacco waste flowers, and then is uniformly mixed with AgNO3 solution, centrifuged after water bath reaction, and silver nanoparticles are obtained. The obtained silver nanoparticles are mostly spherical, the particle size is about 15 nm, and the growth of tobacco phytophthora is well inhibited. The application uses natural components in plants (tobacco waste flowers) as reducing agents and sealing agents. The biosynthesis method has the advantages of simplicity, environmental protection, low cost, biocompatibility, large-scale production, degradation and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plant nanoparticle preparation, in particular to a method for green synthesis of silver nanoparticles using tobacco waste flower extract and application. BACKGROUND

[0002] Tobacco is a special economic crop, and high-quality tobacco leaves are used as raw materials to make cigarettes. The roots, stems, branches, tops and unsuitable tobacco leaves are discarded as waste. During the topping period of tobacco, the plant needs to be topped to inhibit the growth of the top auxin and make the plant grow longitudinally. Topping will cause the tobacco flower to be discarded, which not only wastes resources but also pollutes the environment. If the tobacco waste is reused, it can not only reduce the environmental pollution caused by tobacco waste but also effectively utilize resources, ultimately achieving sustainable development of tobacco production and double benefits of ecological environment protection and economic benefits.

[0003] The term "nanomaterial" appeared in the 1980s, which refers to materials that are at least one dimension in the nanometer range (1-100 nm) or are composed of them as basic units. This is approximately equivalent to the scale of 10-1000 atoms arranged closely together. Nanomaterials are divided into zero-dimensional nanomaterials, one-dimensional nanomaterials, two-dimensional nanomaterials and three-dimensional nanomaterials according to structure. Zero-dimensional nanomaterials have nanometer sizes in three dimensions in space, i.e., nanoparticles.

[0004] The synthesis of nanoparticles includes physical, chemical and biological methods. Common physical methods include laser ablation, evaporation condensation and mechanical ball milling. Chemical synthesis methods include co-precipitation, sol-gel, microwave-assisted and microemulsion methods. Physical and chemical methods include hydrogen peroxide, carbon monoxide, hydroxylamine hydrochloride, dimethylformamide, sodium borohydride, hydrazine and other chemicals as reducing agents to synthesize nanoparticles; however, these chemicals are considered dangerous in nature. That is, the existing physical and chemical synthesis methods have disadvantages such as the use of hazardous chemicals, and there is no related technology for green synthesis of nanoparticles using tobacco waste flower extract in biological synthesis methods. SUMMARY

[0005] The present application aims to provide a method for green synthesis of silver nanoparticles using tobacco waste flower extract and application, a method for green synthesis of silver nanoparticles using waste tobacco flower extract, and the application of the green synthesized silver nanoparticles. The utilization value of tobacco waste flowers is also improved to solve the problem of not using tobacco waste flowers for biological synthesis of nanoparticles in the background technology.

[0006] In order to achieve the above object, the present application provides the following technical scheme: a method for green synthesis of silver nanoparticles by using tobacco waste flower extract, comprising the following steps:

[0007] Step one, plant material collection; the collected tobacco waste flowers are washed, then dried after surface moisture, and then frozen with liquid nitrogen for preservation;

[0008] Step two, plant extract; the preserved tobacco waste flowers in step one are ground into homogenate in ultrapure water and heated, then cooled to room temperature and centrifuged, the supernatant is extracted and filtered to obtain the water extract of tobacco waste flowers;

[0009] Step three, synthesis of nanoparticles; the water extract of tobacco waste flowers is mixed with AgNO3 solution, then reacted in a water bath to obtain a brick red solution, which is the synthesized silver nanoparticle suspension;

[0010] Step four, collection of nanoparticles; the brick red solution prepared in step three is precipitated by centrifugation, the precipitate is washed with ultrapure water to remove unreacted reagents, and finally the silver nanoparticles are freeze-dried into powder and stored in a brown bottle.

[0011] Preferably, the temperature for freezing preservation in step one is -60℃-196℃.

[0012] Preferably, the heating mode in step two is heated in a water bath at 70℃-85℃ for 50min-70min.

[0013] Preferably, the reaction temperature in step three is 80℃-90℃, and the reaction time is 3.5h-5h.

[0014] Preferably, the temperature is kept at 2℃-5℃ during the centrifugation in step two and step four.

[0015] The application of the green synthesis of silver nanoparticles by using tobacco waste flower extract in inhibiting tobacco phytophthora.

[0016] Compared with the prior art, the present application has the beneficial effects that: in the present application, silver nanoparticles for tobacco disease control are prepared by using tobacco waste flowers.

[0017] The main mechanisms of action of Ag nanoparticles are the release of Ag ions, ROS production, interference with energy metabolism and cell wall synthesis, membrane disruption, and interference with DNA, RNA, and other parts of cell metabolism. Ag nanoparticles significantly inhibited the radial growth of F. oxysporum, and higher concentrations (60-140 μg / mL) of Ag nanoparticles inhibited fungal mycelium growth by 79-98%, with less than 50% inhibition observed at lower concentrations (5-40 μg / mL); after treatment with 100 μg / mL and 120 μg / mL Ag nanoparticles, the mycelium showed deformed shapes, wall rupture, and mycelium shrinkage and stacking together, which unbalanced the integrity of the mycelium and eventually inhibited fungal growth. Ag nanoparticles-treated F. oxysporum, most of the conidia were wrinkled, shriveled, and stacked together, forming a concave-convex structure, some large vesicles of ungerminated conidia hindered spore germination, normal cell shape was damaged, and large conidia appeared to be highly damaged. Ag nanoparticles have the ability to cause irreversible damage and disintegration of the cell membrane by changing membrane permeability, ultimately leading to cell death. The effect of Ag nanoparticles on antibacterial and antifungal activity depends on the size and shape of the synthesized nanoparticles. Smaller particle sizes can help nanoparticles easily enter the cell wall of microorganisms and increase the absorption of the load to microbial cells. The pore size of biological membranes such as cell membranes (0.4-1 nm), nuclear membranes (50-70 nm), etc. is mostly at the nanoscale, and the diameter of the cell wall micropore is also between 5-20 nm. In theory, when the particle size of metal-based nanoparticles is smaller than the pore size of the cell wall and the pore size of the biological membrane, metal-based nanoparticles can directly enter the cell and even the organelle. At the same time, the smaller the particle size of metal-based nanoparticles, the easier they are absorbed by living organisms, the more they accumulate in the body, and the greater the potential toxicity.

[0018] Therefore, the silver nanoparticles (spherical, particle size average about 16 nm) obtained by the present application have a great influence on the growth of P. nicotianae, and the present application fills the technical blank of synthesizing silver nanoparticles from tobacco waste flowers, and uses natural ingredients in plants (tobacco waste flowers) as reducing agents and storage agents. The biosynthesis method has the advantages of simplicity, environmental protection, low cost, biocompatibility, large-scale production, degradation, etc.

[0019] At the same time, the present application can utilize the currently discarded tobacco flowers, and the products prepared from the tobacco waste flowers can be directly used for tobacco plants, achieving effective utilization of tobacco waste flowers and reducing environmental pollution. BRIEF DESCRIPTION OF DRAWINGS

[0020] ATTACHMENT Figure 1 The workflow of the present application is shown in the figure;

[0021] ATTACHMENT Figure 2A photograph of the silver nanoparticles produced by the present application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0023] Referring to Figure 1 The present application provides a method for green synthesis of silver nanoparticles by using tobacco waste flower extract.

[0024] Step 1: Collection of plant material

[0025] The collected fresh tobacco waste flowers (derived from Solanaceae-Nicotiana-Red Flower Tobacco-Nicotiana tabacum cv. Yunyan 87) were washed, then surface moisture was dried, then frozen with liquid nitrogen, and then stored in a-80℃ refrigerator.

[0026] Step 2: Plant extract

[0027] First, 1g of tobacco flowers was added to 10mL of ultrapure water in a mortar and ground into a homogenate, then heated in a 80℃ water bath for 1h, then cooled to room temperature, centrifuged at 10000rpm 4℃ for 10min, and the supernatant was filtered, and finally the tobacco flower water extract was obtained.

[0028] Step 3: Synthesis of nanoparticles

[0029] 10mL of tobacco flower extract was mixed with 10mL of 2.5mM AgNO3 solution, then reacted in a 90℃ water bath for 4h, and finally a brick red solution was obtained, which was the synthesized silver nanoparticle suspension.

[0030] Step 4: Collection of nanoparticles

[0031] The synthesized silver nanoparticles were centrifuged at 1000rpm 4℃ for 10min, the precipitate was washed with ultrapure water to remove unreacted reagents, and finally the silver nanoparticles were freeze-dried into powder and stored in a brown bottle.

[0032] Reference Figure 2 and Table 1, SEM analysis showed that the silver nanoparticles synthesized by tobacco waste flower extract were mostly spherical, and the obtained silver nanoparticles had a great inhibitory effect on the growth of Phytophthora nicotianae.

[0033] Table 1 Effect of silver nanoparticles synthesized by tobacco waste flower extract on Phytophthora nicotianae

[0034] Concentration of AgNPs (mg / L) P. nicotianae growth (mm) Inhibition rate (%) 0 (CK) 82.00±0.00a — 30 27.67±1.01b 71.49 60 18.25±0.43c 83.88 90 15.17±1.38d 87.94 120 12.08±0.52e 92.00

[0035] Although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can be modified, or some of the technical features can be replaced by equivalent features, by those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for green synthesis of silver nanoparticles using tobacco waste flower extract, the method comprising: a) providing a tobacco waste flower extract; b) adding silver nitrate to the tobacco waste flower extract; c) adding a reducing agent to the tobacco waste flower extract; and d) allowing the silver nanoparticles to form. It comprises the following steps: Step one, plant material collection; the collected tobacco waste flowers are washed, then dried after surface water, and then frozen with liquid nitrogen for preservation; Step two, plant extract; the tobacco waste flowers preserved in step one are grinded into homogenate in ultrapure water, heated, then cooled to room temperature and centrifuged, the supernatant is filtered to obtain the water extract of tobacco waste flowers; Step three, synthesis of nanoparticles; the water extract of tobacco waste flowers is mixed with AgNO3 solution, then reacted in water bath to obtain a brick red solution, which is the synthesized silver nanoparticle suspension; Step four, collection of nanoparticles; the brick red solution prepared in step three is precipitated by centrifugation, the precipitate is washed with ultrapure water to remove unreacted reagents, finally the silver nanoparticles are freeze-dried into powder and stored in a brown bottle; The heating method in step two is heated in a water bath at 70-85℃ for 50-70min; The reaction temperature in step three is 80-90℃, and the reaction time is 3.5-5h; The silver nanoparticles are spherical with an average particle size of about 16nm.

2. The method for green synthesis of silver nanoparticles using tobacco waste flower extract according to claim 1, characterized in that: The freezing temperature in step one is-60--196℃.

3. The method for green synthesis of silver nanoparticles using tobacco waste flower extract according to claim 1, characterized in that: The temperature during centrifugation in steps two and four is kept at 2-5℃.

4. The application of the synthesized silver nanoparticles according to the method of any one of claims 1-3 in inhibiting tobacco Phytophthora.

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