Green synthesis of nanoparticles

TERMINOLOGIES

• NanoparticlesParticles having atleast one dimension in the range of 1-100nm

• Green ChemistryUtilization of a set of principles that reduces or eliminatesthe use or generation of hazardous substances in thedesign, manufacture, and application of chemical products

• Green Synthesis of NanoparticlesUse of biological routes such as those involvingmicroorganisms, plants etc. for the synthesis ofnanoparticles.

PRINCIPLES OF GREEN CHEMISTRY

1. Prevent Waste2. Atom Economy3. Less Hazardous Chemical Synthesis4. Designing Safer Chemicals5. Safer Solvents6. Design for Energy Efficiency7. Use of Renewable Feedstock8. Reduce Derivatives9. Catalysis10. Design for Degradation11. Real Time Analysis for Pollution Prevention12. Inherently Safer Chemistry for Accident Prevention

DIFFERENT APPROACHES TO NANOFABRICATION

2) TOP-DOWN APPROACH1) Material is fragmented to yield a nanoparticle

2) Long Execution Time

1) BOTTOM-UP APPROACH1) Assembling individual atoms and molecules to

form nanoparticle

2) Short Execution Time

SYNTHESIS METHODS

PHYSICAL METHOD CHEMICAL METHOD BIOLOGICAL METHOD

MECHANICAL METHODS CO-PRECIPITATION METHODSYNTHESIS USING PLANT

EXTRACTS

VAPOUR DEPOSITION SOL-GEL METHOD SYNTHESIS USING ENZYMES

SPUTTER DEPOSITION MICROEMULSIONSSYNTHESIS USING

AGRICULTURAL WASTE

ELECTRIC ARC DEPOSITION HYDROTHERMAL SYNTHESIS

ION BEAM TECHNIQUE SONOCHEMICAL SYNTHESIS

MOLECULAR BEAM EPITAXY MICROWAVE SYNTHESIS

GREEN SYNTHESIS OF NANOMATERIALS

• Physical Method – time and energy consuming, synthesis at high temp. and pressure

• Chemical Method – simple, inexpensive and low temp. synthesis method, use of toxic reducing and stabilizing agents makes it harmful

• Green Method – easy, efficient, and eco-friendly. Eliminates the use of toxic chemicals, consume less energy and produce safer products and by products

• Example – bacteria for Au, Ag, Zn and Fe NPs; yeasts for Ag and Pb NPs; plants for Au, Ag, Pd and Pt NPs

BIOLOGICAL METHODS

• Used for synthesis of highly stable and well-characterized NPs

• Rapid Synthesis, controlled toxicity and size characteristics, economical and eco-friendly

• Sizes and morphologies controlled by altering conditions such as pH, substrate concentration, temperature, mixing speed and exposure time.

• Different Synthesis Methods– Use of plant extracts

– Use of waste

– Use of enzymes and microorganisms

1. SYNTHESIS USING PLANT EXTRACTS

ADVANTAGES

• Environmental friendly

• Easily scaled up for large synthesis of nanoparticles

• No need of high temperature, pressure, energy and toxic chemicals

• More advantageous over use of micro-organisms by less elaborate process of maintaining cultures

• Reduces cost of micro-organism isolation and their culture media

DISADVANTAGES

• Plants cannot be manipulated as the choice of nanoparticles through optimized synthesis through genetic engineering

• Plant produce low yield of secreted proteins which decreases the synthesis rate

2. SYNTHESIS USING WASTE

ADVANTAGES

• Easily available and does not require rigorous processing

• Directly used for NP synthesis

• Option for waste management

• Leads to fast and cost effective approach

• Does not induce toxic NP

3. SYNTHESIS USING ENZYMES/MICROORGANISMS

• Microbial synthesis of nanoparticles is a green chemistry approach that interconnects the fields of nanotechnology and microbial biotechnology.

• A bottom-up approach used.

• Nanoparticle formation occurs due to the reduction/oxidation of metallic ions.

• Nanoparticle formation can be either extracellular or intracellular depending on the microorganism.

• Many bacteria, fungi and plants have the ability to synthesize metallic nanoparticles and all have their own advantages and disadvantages.

Example: Synthesis of Silver nanoparticle by bacteria.

• Ag nanoparticles have been synthesized using Pseudomonas stutzeri AG259 bacterium.

• Mechanism:

NADH

NAD+ e-

NADH dependent reductase enzyme

Ag +

Ag nanoparticle

• Ag nanoparticles prepared were accumulated in periplasmic space of bacteria and were 36-45 nanometer size.

• This bacteria in conc. aqueous solution of silver nitrate produce nanoparticles upto 200 nm in size.

• Similarly, many other bacterial species are used like Escherichia coli, Klebsiella pneumonia, Lactobacillus spp., Bacillus cereus, Corynebacterium sp., and Pseudomonas sp., etc.

• Other microorganisms like actinomycetes, viruses, fungi, algae, yeasts, are also used for nanomaterial synthesis.

• Advantages:

1. Clean, non-toxic, biocompatible and eco-friendly method for synthesis of nanoparticles.

2. Cost effective, safe and sustainable.

3. Bacteria are easy to handle and can be easily manipulated.

• Disadvantages:

1. Culturing of micro-organisms is time-consuming.

2. Difficult to have control over size, shape and crystallinity.

3. Particles are not mono-dispersed and rate of production is slow.

CONCLUSION

• Different methods (physical, chemical and biological) have been developed to obtain NPs of various shapes and sizes.

• Biological method of NPs is economically and environmentally friendly alternative to chemical and physical approaches.

• It provide a new possibility of synthesizing NPs using natural reducing and stabilizing agents.

• It has faster synthesis rates, controlled toxicity and well-characterized NPs.

• This method is used in various areas such as pharmaceuticals, cosmetics, foods and medical applications.

REFERENCES

• Ahmed, S., Ahmad, M., Swami, B.L., Ikram, S., 2016. A review on plants extract mediated synthesis of silver nanoparticles for antimicrobial applications: A green expertise. J. Adv. Res. 7, 17–28. doi:10.1016/j.jare.2015.02.007

• Kalishwaralal, K., Deepak, V., Ram Kumar Pandian, S., Kottaisamy, M., BarathManiKanth, S., Kartikeyan, B., Gurunathan, S., 2010. Biosynthesis of silver and gold nanoparticlesusing Brevibacterium casei. Colloids Surfaces B Biointerfaces 77, 257–262. doi:10.1016/j.colsurfb.2010.02.007

• Makarov, V. V., Love, A.J., Sinitsyna, O. V., Makarova, S.S., Yaminsky, I. V., Taliansky, M.E., Kalinina, N.O., 2014. “Green” nanotechnologies: Synthesis of metal nanoparticles using plants. Acta Naturae 6, 35–44. doi:10.1039/c1gc15386b

• Shah, M., Fawcett, D., Sharma, S., Tripathy, S.K., Poinern, G.E.J., 2015. Green synthesis of metallic nanoparticles via biological entities, Materials. doi:10.3390/ma8115377

• Sharma, D., Kanchi, S., Bisetty, K., 2015. Biogenic synthesis of nanoparticles: A review. Arab. J. Chem. doi:10.1016/j.arabjc.2015.11.002

• N.Pantidos and L. E Horsfall, ‘Biological Synthesis of Metallic Nanoparticles by Bacteria, Fungi and Plants’; Nanomedicine & Nanotechnology ,2014 (vol 5).

• Monaliben Shah , Derek Fawcett , Shashi Sharma , Suraj Kumar Tripathy and Gérrard Eddy Jai Poinern: a review on Green Synthesis of Metallic Nanoparticles via Biological Entities,Materials 2015.(7278-7308)