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Green synthesis of gold nano particles
- 1. Green Synthesis of Gold Nano Particles Arpit Modh 16BCH035 Vishal Naidu 16BCH016
- 2. Green Synthesis • Nanotechnology to enhance the environmental sustainability • Development of products • Green Innovation targets
- 4. Detrimental Effects of Nano Particles
- 7. Mechanisms of Toxicity • Oxidative Stress • Cytotoxicity • Genotoxicity
- 14. Gold Nano Particles by Plant Extracts • Size : 5 nm to 300 nm • Morphology : Spherical, FCC, Triangular, Hexagonal, Nano prisms, Nano rods etc. • Effect of microwave assisted method
- 16. Gold Nano Particles by Microorganisms • Who? • How? • Microbial reduction : Extracellular or Intracellular
- 20. Gold Nano Particles by Plant Gums • Non toxic, non mutagenic, biodegradable in nature • Greater stability to low pH, electrolyte addition & high pressure treatment • Metal bio sorption properties
- 24. References • C. M and V. D. Lingen, "E. Catalytic Gold Nano Particles," Mater Forum, 2002. • M. C. Alkilany AM, "Toxicity and cellular uptake of gold nanoparticles: what we have learned so far?," Journal of Nanoparticle Research., vol. 12, no. 7, p. 2313–2333, 2010. • S. Kanchi and S. Ahmed, Green Metal Nanoparticles: Synthesis, Charecterization and their applications, Chennai, India: Scrivener Published LLC, USA, 1989.
- 25. Thank You
Editor's Notes
- The frame wrok of nanotechnology involves the production and processes to make nanomaterials, green chemistry, green engineering, direct and indirect environmental applications; and also encompasses the production of nanomembranes(can help separate desired chemical reaction products from waste materials.), nanocatalysts(can make chemical reactions more efficient and less wasteful.) and the greater emancipation of harnessed energy. It also encompasses the use of products of nanotechnology to enhance sustainability. 2) Encompasses the use of products of nanotechnology to enhance sustainability. Nanomaterials or products directly can clean hazardous waste sites, desalinate water, treat pollutants, or sense and monitor environmental pollutants. Indirectly, lightweight nanocomposites for automobiles and other means of transportation could save fuel and reduce materials used for production; nanotechnology-enabled fuel cells and light-emitting diodes (LEDs) could reduce pollution from energy generation and help conserve fossil fuels; self-cleaning nanoscale surface coatings could reduce or eliminate many cleaning chemicals used in regular maintenance routines. 3) The global demand for energy is expected to increase by more than 30% between 2010 and 2035. More than 800 million people throughout the world are currently without proper access to drinking water. Green innovation targets the reduction of environmental impacts by increasing energy efficiency, reducing waste or greenhouse gas emissions and by minimizing the consumption of non renewable raw materials.
- The extremely small size of nanomaterials also means that they much more readily gain entry into the human body than larger sized particles. How these nanoparticles behave inside the body is still a major question that needs to be resolved. The behavior of nanoparticles is a function of their size, shape and surface reactivity with the surrounding tissue. In principle, a large number of particles could overload the body's phagocytes, cells that ingest and destroy foreign matter, thereby triggering stress reactions that lead to inflammation and weaken the body’s defense against other pathogens. In addition to questions about what happens if non-degradable or slowly degradable nanoparticles accumulate in bodily organs, another concern is their potential interaction or interference with biological processes inside the body. Because of their large surface area, nanoparticles will, on exposure to tissue and fluids, immediately adsorb onto their surface some of the macromolecules they encounter. This may, for instance, affect the regulatory mechanisms of enzymes and other proteins. Nanomaterials are able to cross biological membranes and access cells, tissues and organs that larger-sized particles normally cannot.[19] Nanomaterials can gain access to the blood stream via inhalation[4] or ingestion.[5] Broken skin is an ineffective particle barrier, suggesting that acne, eczema, shaving wounds or severe sunburn may accelerate skin uptake of nanomaterials. Then, once in the blood stream, nanomaterials can be transported around the body and be taken up by organs and tissues, including the brain, heart, liver, kidneys, spleen, bone marrow and nervous system.[6] Nanomaterials have proved toxic to human tissue and cell cultures, resulting in increased oxidative stress, inflammatory cytokine production and cell death.
- 1) Oxidative stress For some types of particles, the smaller they are, the greater their surface area to volume ratio and the higher their chemical reactivity and biological activity. The greater chemical reactivity of nanomaterials can result in increased production of reactive oxygen species (ROS), including free radicals. ROS production has been found in a diverse range of nanomaterials including carbon fullerenes, carbon nanotubes and nanoparticle metal oxides. ROS and free radical production is one of the primary mechanisms of nanoparticle toxicity; it may result in oxidative stress, inflammation, and consequent damage to proteins, membranes and DNA.[8] 2)Cytotoxicity A primary marker for the damaging effects of NPs has been cell viability as determined by state and exposed surface area of the cell membrane. Cells exposed to metallic NPs have, in the case of copper oxide, had up to 60% of their cells rendered unviable. When diluted, the positively charged metal ions often experience an electrostatic attraction to the cell membrane of nearby cells, covering the membrane and preventing it from permeating the necessary fuels and wastes.[9] With less exposed membrane for transportation and communication, the cells are often rendered inactive. NPs have been found to induce apoptosis in certain cells primarily due to the mitochondrial damage and oxidative stress brought on by the foreign NPs electrostatic reactions.[9] 3) Genotoxicity Metal Oxides such as copper oxide, uraninite, and cobalt oxide have also been found to exert significant stress on exposed DNA.[9] The damage done to the DNA will often result in mutated cells and colonies as found with the HPRT gene test.
- 3 stages: Activation phase: The primary stage in which the metal ions are recuperated from their salt precursors through the plant metabolites. They reduces and then nucleates. growth phases: the seceded metal atoms coalesce to form metal NPs though more biological reduction of metal ions. If the growth stage rises in enhanced thermodynamic stability of NP wheresas extensive nucleation may result in aggregation, altering their morphologies. Termination: NPs ultimately get their most keenly promising and stable morphology when capped by plant metabolites.
- Green synthesised NP are employed in areas: nanomedicine, DDS, antimicrobial agents, DNA investigations, biosensors, catalysts, separation science, cancer treatment, gene treatment and magnetic resonance imaging.
- Microwave-assisted method found to be rapid & thus reduced aggregation.
- Green plants (have shown competency to soak up, hyper accumulate and reduce inorganic metallic ions from their surroundings. Amalgamations of molecules found in plant extracts can behave as both reducing and stabilizing(caping) agents. Working process is simple. Reaction fullfills within few minutes. Salt+extract reduces and forms nano particles
- Algae, viruses, bacteria, yeast, fungi are used. They reduce metal ions to form water soluble complexes to defend them from their toxicity. Not confirm but though in common, Various cell activities generate biopolymers in them which can detoxify the mettle ions in such a nice ordered structure and size of both organic & inorganic.
- Microbial reduction happens through bioaccumulation, precipitation, biomineralization or biosorption. Extracellular: occurs on the surface of the microbial cell. Electrostatic interaction causes metal cations to attach with negatively charged enzymatic groups present at the cell wall where reduction takes place. Intracellular: Involves the trapping of metal ion on the microbial cell and then reducing it in the presence of enzymes.
- A highly effective microorganism, Stenotrophomonas maltophilia, has been described for synthesis of gold nanoparticles of desired size and shape. The results confirmed that a specific NADPH-dependent enzyme existing in the isolated strain reduces Au3+ to Au0 through an electron traveling mechanism. The flavanone and terpenoid components of the leaf broth of neem extract are thought to be the surface active molecules stabilizing the nanoparticles. The formation of pure metallic and bimetallic nanoparticles by reduction of the metal ions may be enabled by reducing sugars and/or terpenoids present in Neem leaf broth.
- The synthesis is carried out in environmentally benign aqueous-solvent medium without the requirement of any added external chemicals. As the plant gums are soluble in water, the use of Organic solvents could be avoided. In comparison with conventional solvents, water is preferred for reactions because it exhibits unequaled and unique physical properties. Besides, it is Nontoxic, cost-effective and nonhazardous while handling. Being natural polymers, the gums are also amenable for biodegradation. By virtue of being biogenic and encapsulated with proteins, these surface-functionalized nanoparticles could be easily integrated for various biological, pharmaceutical and medical applications. The use of environmentally benign, inexpensive and renew- able materials and benign solvent medium offers several benefits, including one-pot synthesis, catalyst free, simple yet clean reaction conditions, no waste generation and environmental safety.
- an electron shuttling mechanism related to NADH-dependent reductase. The first step includes the reduction of Au3+ from AuCl4- ionic system to Au+, and it is reduced again to gold nanoparticles