nanoparticle synthesis

1. SYNTHESIS AND CHARACTERIZATION OF
NANOPARTICLES FROM BIOLOGICAL SOURCES

2. SYNTHESIS OF NANOPARTICLES FROM BACTERIA
⮚ Bacteria have been most extensively researched for synthesis of
nanoparticles because of their fast growth and relative ease of genetic
manipulation.

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 is used.
⮚ Nanoparticle formation occurs due to the reduction/ oxidation of metallic ions.
⮚ Nanoparticle formation can be either extracellular or intracellular depending upon the
microorganism.
⮚ Many bacteria , fungi and plants have the ability to synthesize the metallic nanoparticles
and all have their own advantages and disadvantages.

5. GREEN SYNTHESIS OF NANOPARTICLES AND
ADVANTAGES
❖ Different biological routes such as those involving microorganisms, plants etc
for the synthesis of nanoparticles.
⮚ Easy
⮚ Efficient
⮚ Eco-Friendly
⮚ Eliminates use of toxic chemicals
⮚ Consume less energy
⮚ Produce safer products and by products
⮚ Does not impart any hazardous effect on environment

7. METHODS OF SYNTHESIS
❖ INTRACELLULAR ;
Inside the cell, in cytoplasm or cytosol.
❖ EXTRACELLULAR ;
Outside the cell ,on the surface or between the cells
inside a colony.

8. INTRACELLULAR SYNTHESIS OF NANOPARTICLES BY
BACTERIA
⮚Bioaccumulation
⮚In order to release the intracellular synthesized nanoparticles,
additional processing steps such as ultrasound treatment or
reaction with suitable detergents are required.

9. INNN
Intracellular
biosynthesis
i
Entrapment of
positively charged
metal ions within
negatively
charged cell wall
en
Enzymatic bio
reduction of metal
ions within cell
wall
Formation of
nano clusters
Nanoparticles
diffuse out of cell
wall

10. Synthesis of silver nanoparticles by bacteria
⮚ Culture supernatants of bacteria
can be used for synthesis of Ag
NPs.
⮚ Such as culture supernatants of E.
coli, Klebsiella pneumonia, B.
subtilis, Enterobacter cloacae and
Bacillus Licheniformis.
⮚ Also, Lactobacillus strains can be
used for synthesis of Ag NPs.

11. EXTRACELLULAR SYNTHESIS OF NANOPARTICLES BY BACTERIA
⮚ It occurs due to extracellular bio mineralization, biosorption, complexation or precipitation.
⮚ With the change in pH of the solution, various shapes and sizes were formed.
Production of
extracellular reductase in
cell free supernatant.
Enzymatic bioreduction of
metal ions within cell free
supernatant.
Formation of
nanoparticles within
cell free supernatant

12. SYNTHESIS OF NANOPARTICLES BY FUNGI AND YEAST
⮚ Fungi and yeast are very effective secretors of extracellular enzymes and numbers of species
grow fast and therefore culturing keeping them in the laboratory is very simple.
⮚ They are able to produce metal nanoparticles and nanostructure via reducing enzyme
extracellularly.

13. EXAMPLES OF FUNGI PRODUCING NANOPARTICLES
⮚ Synthesis of silver nanoparticles has been investigated utilizing
many ubiquitious fungal species including Trichoderma, Fusarium,
Pencillium, Rhizoctonia, Pleurotus and Aspergillus.
⮚ Extracellular synthesis has been demonstrated by Trichoderma
virde, T. reesei, Fusarium oxysporm, F. semitectum, Aspergillus
niger, A. flavus, A. fumigatus etc.
⮚ Synthesis of gold nanoparticles has been investigated utilizing
Fusarium, Neurospora, Verticillium

15. PLANTS AND PLANT EXTRACTS AS A TOOL FOR NANOPARTICLES
⮚ Provides single step biosynthesis process.
⮚ Protocols involving free from toxicants and natural capping agents.
⮚ Can generate bimetallic silver and gold shell nanoparticles.
⮚ Excellent stability and size control.
⮚ Cost-effective large scale production of metallic, semiconductor and metal oxide
nanoparticle.

18. CHARACTERIZATION OF
NANOPARTICLES
⮚ It refers to the study of materials features such as its composition, structure,
and various properties like physical, electrical, magnetic etc.
⮚ Properties of nanoparticles vary with size and shape. So accurate
measurement of nanoparticles size and shape is therefore critical to its
applications.
⮚ Nanofluids are characterized by the techniques; SEM, TEM,XRD, FT-IR, DLS,
TGA and zeta potential analysis.
⮚ DLS analysis: estimate the average dispersive size of nanoparticles in the
base liquid media and
⮚ TGA: study the influence of heating and melting on the thermal stabilities of
nanoparticles.
⮚ Zeta potential value is related to the stability of nanoparticle dispersion in
base fluid.

19. ADVANTAGE
S
1. Bulk samples can be observed and larger sample area can be viewed.
2. Generates photo-like images.
3. Very high resolution images are possible.
4. SEM can yield valuable information regarding the purity as well as degree of
aggregation.
DISADVANTAGE
S
1. Samples must have surface electrical conductivity.
2. Non-conductive samples need to be coated with a conductive layer.
3. Time consuming and expensive.
4. Sometimes it is not possible to clearly differentiate nanoparticle from the substrate.
5. SEM can’t resolve the internal structure of these domains.

23. THANK YOU…….