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留学生作业代写:Biosynthesis of nano-materials

2017-09-13 来源: 51due教员组 类别: Paper范文

下面为大家整理一篇优秀的paper代写范文- Biosynthesis of nano-materials,供大家参考学习,这篇论文讨论了纳米材料的生物合成。万千生物有不同的生物相貌,通常其生物表面或其提取物中有着参与某些化学反应的天然活性成分。将其与纳米材料制备相结合衍生出纳米材料的生物合成,它相比较传统物理、化学等合成方法具有低毒、环保、低能耗等绿色化学的优点。

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Thousands of organisms have different biological appearance, usually their biological surface or its extracts have a natural active ingredient involved in certain chemical reactions. The biosynthesis of nano-materials is derived from the synthesis of nanometer materials, which has the advantages of low toxicity, environmental protection and low energy consumption compared with traditional synthetic methods such as physics and chemistry. This paper reviews the progress in the research of nano-materials biosynthesis in different organism templates, organism components, biological extracts and typical viruses.

With the development of research in the field of nanometer research, the synthesis method of nanometer materials has been continuously new. The synthetic methods include precipitation method, Sol-gel method, ion Exchange method, chemical method and physical method including ball-milling method, sputtering method and super gravity method. But these traditional methods are generally confronted with pollution environment and high energy consumption problems. The biosynthesis of nanometer materials is a green synthesis method combining nanotechnology and biotechnology. The biological synthesis of nanomaterials is more environmentally friendly than traditional physical and chemical methods in the selection of raw materials, the regulation of reaction conditions and later treatment. Nano-materials with different morphologies and properties were prepared by combining nanotechnology with different organisms, which showed a wider space for development. Some organisms have subtle morphological features, which can be used as templates to produce nano-materials with specific biological morphologies, eliminating the preparation of templates in traditional template method. Some of the components of the organism or its extracts have some active components that are good reductant and stabilizers for some reactions, reducing the use of toxic chemicals. In this paper, the research progress of nano-materials biosynthesis is systematically reviewed based on the different biological templates of Single-cell and multicellular organisms, the composition of organisms, and the different active components and viruses extracted from them.

Green chemistry requires researchers to be able to find reactive precursors or reaction conditions for pollution-free, low toxicity, low energy consumption, green health. The amino and carboxyl groups and specific morphologies of the organism's surface make it a natural reductive ingredient and a ready-made template, which is more suitable for the preparation of nanometer materials than the traditional methods of preparing nanomaterials.

Cells are the basic unit of the structure and function of the organism, while the cell membrane is composed of two layers of phospholipids and proteins embedded therein. Different cells have a unique refinement of the shape and functional surface, with Single-cell as a template to synthesize the morphology of different biological cell nanostructures.

Bacteria and actinomycetes are widely used in the synthesis of metal nanoparticles, and one reason is that they are relatively easy to operate. The JHA, which was first studied, was used to induce the synthesis of TiO2 nanoparticles with 8~35 nm at room temperature, and the mechanism of reaction was proposed. With the development of nano-materials biosynthesis, nano-materials with different morphologies of different microorganisms have been successfully synthesized. Klaus was prepared and found in different binding sites of the cells of Pseudomonas, triangular, hexagonal and spherical ag nanoparticles with a diameter of up to 200nm. The 3~70 nm globular AG nanoparticles were prepared from a type of insect, such as Ahmad. The average pore diameter of 2.5 NM was successfully prepared by using E. coli as template, and the SiO2 was more than that of the table area. 4 m2/g.

Compared with the prokaryotic species, the eukaryotic cells are more extensive and more convenient to develop, so the biosynthesis of the template is more studied. The simplest single-celled eukaryotic chlorella can enrich all kinds of heavy metals, such as uranium, copper and nickel. Fayaz AG nanoparticles with $number nm were synthesized under 27 ℃ by fungal trichoderma, and the antibacterial property of penicillin, kanamycin and erythromycin was obviously increased after the ag nanoparticles were added. Lin et HAuCl4 found that the gold ions in the yeast on the surface of the first occurrence of biological adsorption and then biological reduction, thus obtaining au nanoparticles. The study found that the gold ions were first reduced to one valence gold ions by the amino, hydroxyl and other functional groups on the yeast surface, and further reduced to au nanoparticles. Mishra, the AU and AG nanoparticles were synthesized by using high-li false silk yeast as templates, and the two kinds of nanoparticles had high antibacterial activity against Staphylococcus aureus, but the contrast test showed that the two kinds of particles synthesized by chemical method had no antibacterial effect on pathogenic bacteria. The-co3o4 modified hollow structure microspheres of ZnO were synthesized by using yeast as a template. The Fusarium oxysporum can convert the amorphous silicon from rice bran to crystalline SiO2 and form a quasi spherical structure of $number nm on its own surface.

Although the monodisperse of nanoparticles prepared by single cell is better, it involves complex culture process and subsequent treatment, and the preparation method with multicellular organism as template is more convenient and simple.

There are many kinds of plants on the earth, and the biosynthesis of nano-materials with its template is varied. In most cases, the plant body is cultured in a solution containing metal ions, and then the plant body is removed to obtain nano-materials that replicate the microstructure of the plant. Rostami the seeds of rape and alfalfa in a solution containing au3+, the gold ions into nano au particles, the size of 20~128 nm and 8~48 nm respectively. Dwivedi AG and Au nanocrystals with the average grain size of NM and ten nm were prepared by using quinoa as templates, and the natural oxalic acid in the quinoa played an important role in the biological reduction. Cyganiuk, such as Artemisia and metal salts as raw materials for the preparation of carbon-based mixed materials LaMnO3 will be cultivated in a solution containing metal salts, metal salt ions along the plant tissue transmission, and then infiltration. Then calcined carbonization of lignin-rich plant parts in the 600~8000℃ range, the obtained products have good catalytic effect on the conversion of N-butanol into 4-heptane. Huang Baojun, the $literal of micro-nanostructures were synthesized by a series of processes such as impregnation and calcination, and the formation mechanism was preliminarily discussed. Cai, such as the germination of soybeans as a template, prepared at room temperature has a $literal nano-particles, the average size of only 8 nm. The King's Union and so on the Camellia petal as a template the CeO2 layered mesoporous nano-films were prepared by impregnation, and they had good catalytic activity in the visible light band. 1.2.2 Preparation of nano-materials with multicellular animal body as template

The preparation of nanometer material with multicellular animal body as template is relatively few, among which the research of anshup and so on is more prominent. They tested the human body's cancerous cervical epithelial cells, nerve cells and normal human embryonic kidney cells. These human cells are cultured in a test tube simulating the human environment, and the 1mmol/l HAuCl4 in the culture solution eventually obtains the AU nanoparticles of 20~100 nm. Au nanoparticles were deposited in both the nucleus and cytoplasm, and the AU particle size in the nucleus was smaller than that in the cytoplasm.

The organism contains many reductive stability components. If these components are extracted, they can be separated from the original shape of the organism, and the green non-polluting bio-reducing agent is obtained, and then the nanometer materials are prepared. Many carbohydrates, vitamins, cellulose and other biological components have been proved to have a good biological reduction and stability, which makes the nano-materials green biosynthesis more convenient and faster.

Most of the nanomaterials prepared from microbial extracts are nanometer ag and nano-AU, and the two particles have bactericidal effect. Nano-materials prepared by microbial extracts have a smaller particle size, and generally have better germicidal efficacy than those synthesized by general chemical methods. Gholami-shabani, the nitrate reductase was extracted from Fusarium oxysporum, and the spherical nanometer ag particles with the average grain diameter of 50nm were recovered, and the antibacterial effect was good for human pathogenic bacteria and bacteria. The Nano ag particles with different particle sizes and morphologies were successfully synthesized by yeast and Bacillus subtilis extracts, such as Wei et Velmurugan. The reductive enzymes in extracts are important components to promote the reaction. Inbakandan, the HAuCl4 reaction of the extracts from marine sponge and the preparation of the 7~20nm nanoparticles, mainly benefited from the water-soluble organic reduction material. Song, etc, from thermophilic Archaea to extract the high heat-resistant type of tengchong sulfide spindle virus 1 virus protein shell. And it was found that the protein shell can be assembled into the wheel-like nanostructures without genetic material. and TiO2 nanoparticles exhibit good affinity, which will have a wide application prospect in the biosynthesis of nano-materials.

The most research on the preparation of nanomaterials from biological extracts is the utilization of plant extracts, because there are many kinds of plants on Earth, which provide many possibilities for the biosynthesis of nanometer materials. The 22~35nm of AU nanoparticles was obtained by reducing the extract solution of sea lotus seed plant. The prepared samples have a great antibacterial effect on pathogenic bacteria, and can catalyze the reduction of sodium borohydride 4-nitrophenol to 4-aminophenol, and can also catalyze methylene blue into colorless methylene blue. Velmurugan and Kulkarni respectively with cashew nut shell extract and sugarcane juice to successfully prepare the Cashier Rice AG and nano-AG/AGCL composite particles, both have good bactericidal effect. Sivaraj the spherical cuo nanoparticles, which had inhibitory effect on the Escherichia coli of urinary pathogens, were prepared by the extracts of a medicinal plant leaf.

Carbohydrate is the most abundant organic compound in organism, it is divided into monosaccharide, starch, cellulose and so on. Its unique structure and composition can be used to synthesize nanostructured materials of various structures. Panacek and so on, tested two kinds of monosaccharide and two kinds of two sugars on [ag2]+ 's reduction effect, the average particle size of ag nanoparticles prepared by maltose reduction is 25nm, and it has good inhibitory effect on Gram-positive bacteria and gram-negative bacteria including Staphylococcus aureus resistant to various antibiotics. The Abdel Halim, such as Gao, and so on, respectively, were prepared by reducing silver nitrate particles with different diameters with starch and cellulose, and had good antibacterial effect on some bacteria.

Vitamin is the human body indispensable ingredient, in the human body's metabolic process plays an important role, is very good stabilizer and reducing agent. The Hui of ag nanoparticles modified by vitamin C reduction were prepared by the method of AgNO3 and oxidized graphene with vitamin C, the average particle size of ag nanoparticles was 15nm and attached to the surface of graphene nano-flake. The nano-PD with different morphologies was synthesized at room temperature with vitamin B2 as reductive active ingredient by Nadagouda. It was found that the morphologies and sizes of nanomaterials prepared in different solvents were different.

The virus itself is not biologically active and can be hosted in other host cells to replicate itself, which is actually a protective shell of DNA or RNA fragments, the size of which is usually between 20~450 nm, the size of its nano-scale makes it easier to prepare nano-materials for the template. Shenton $literal nanotubes were prepared by using tobacco mosaic virus as template. Because the tobacco mosaic virus is composed of a spiral-shaped protein unit, the internal formation of hollow tube. $literal, which is made from this template, also replicates this structural feature and presents a tubular structure. Because the tobacco mosaic virus is small in size but high in stability, it is frequently used as the skeleton of nano-material biosynthesis. Dang, the single walled carbon nanotubes-tio2 crystal core-shell composite nanomaterials were prepared by using transgenic M13 virus as template. It is found that the energy conversion efficiency of dye-sensitized solar cells with this as a light anode is 10.6%.

The biosynthesis of nanometer materials belongs to the marginal discipline, which not only integrates the rigor and diversity of biotechnology, but also preserves the advanced and practicability of nanotechnology, and is superior to other physical and chemical nanomaterials by its non-toxic, environmental protection and low energy consumption. With the increasingly close combination of nano-synthesis and biotechnology, the biosynthesis of nano-materials will not only stay in the phase of biological morphology, but the synthesis of novel bio-nanomaterials guided by biological extracts or bioactive components will be a great research hotspot in the future. The biosynthesis of nanomaterials will also play an important role in the preparation of new materials in the future.

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