Bio synthesis of nano particles using bacteria
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Bacteria can be used to biosynthesize nanoparticles through intracellular and extracellular methods. Intracellular synthesis occurs inside the cell, where bacteria reduce metal ions and deposit nanoparticles in locations like the periplasmic space. Extracellular synthesis involves enzymes secreted by bacteria reducing metal ions outside the cell and precipitating nanoparticles. Examples are given of bacteria producing silver, titanium, zinc sulfide and lead sulfide nanoparticles through extracellular and intracellular pathways. While a green approach, bacterial nanoparticle synthesis can be slow with difficulty controlling size, shape and crystallinity of particles.
![• Titanium nanoparticles of spherical aggregates of 40–60 nm were
produced extracellularly using the culture filtrate of Lactobacillus
sp. at room temperature. These titanium nanoparticles were
lighter in weight and high resistance to corrosion and have
enormous applications in
automobiles, missiles, airplanes, submarines, cathode ray tubes
and in desalting plants and has promising future role in cancer
chemotherapy and gene delivery.
• Immobilized Rhodobacter sphaeroides extracellularly produced
spherical shaped zinc sulfide (ZnS) semiconductor nanoparticles of
8 nm in size [88]. In analogous, immobilized purple, nonsulfur
photosynthetic bacterium, R. sphaeroides produced extracellularly
fcc structured lead sulfide (PbS) nanoparticles of size 10.5± 0.15
nm with monodispersed spherical morphology.
• The extracellular production of nanoparticles has wider
applications in optoelectronics, electronics, bioimaging and in
sensor technology than intracellular accumulation.](https://image.slidesharecdn.com/biosynthesisofnanoparticlesusingbacteria-131010085607-phpapp01/85/Bio-synthesis-of-nano-particles-using-bacteria-14-320.jpg)
Bio synthesis of nano particles using bacteria
- 1. BIO SYNTHESIS OF NANOPARTICLES BY BACTERIA PRESENTED BY ROOPAVATH UDAY KIRAN M.Tech 1st year Centre for Nano science and Technology Course: Synthesis & Characterization of Nano structured materials Code : NST 616 Course instructor : Associate professor Dr. A. Vadivel Murugan .
- 2. OVERVIEW • INTRODUCTION • GENERAL STRUCTURE OF BACTERIA • METHODS OF SYNTHESIS IN BACTERIA • EXAMPLES
- 3. INTRODUCTION • Microbial synthesis of nanoparticles is a green chemistry approach that interconnects nanotechnology and microbial biotechnology. • Although ultraviolet irradiation, aerosol, lithography, laser ablation, ultrasonic fields & photochemical synthesis are successful in synthesis of many nanoparticles they involve use of HAZARDOUS CHEMICALS. • Biological nanoparticles are not mono dispersed and the rate of synthesis is slow. • To overcome above, microbial cultivation methods, extraction techniques & combinatorial approach such as photo biological methods are used.
- 4. • Microbes are regarded as POTENT ECO- FRIENDLY GREEN FACTORIES. • Drawbacks of bio synthesis : • Time consuming – Rate of production is slow • Difficulty in control over size distribution, shape and crystallinity. • The nanoparticles are also not mono dispersed.
- 5. Microbial resistance to most toxic heavy metals is due to: • Chemical detoxification • Ion efflux from cell by membrane proteins • Alteration in solubility Interaction b/w metals n microbes for ?: • Bio remediation • Bio mineralization • Bio leaching • Bio corrosion
- 8. METHODS OF SYNTHESIS Intracellular: Inside the cell, in cytoplasm or cytosol. Extracellular : Out side the cell on the surface or between the cells inside a colony.
- 9. Intracellular synthesis of nanoparticles by bacteria
- 11. Crystal topologies by P. stutzeri AG259. (a, b) Triangular, hexagonal, and spheroidal Ag-NPs found at different cellular binding sites ( with permission from National Academy of Sciences, U.S.A.) Dark-field TEM image of S. algae cells showing the presence of platinum nanoparticles deposited in periplasmic space ( with permission from Elsevier publishers).
- 12. TEMof negatively stained cells of M. gryphiswaldense displaying themagnetosome chain and isolated magnetosomes. (a). Enlarged view of the magnetosome chain within M. gryphiswaldense. The bar denotes 0.1 μm. (b) Isolated magnetosome particles with intact magnetosome membranes. Magnetosome membrane is indicated by arrows TEMimage of flocculated UO2 nanoparticles associatedwith Desulfosporosinus spp. bacteria (arrow). Inset, high-resolution TEMimage of isolated particles
- 13. Extracellular synthesis of nanoparticles by bacteria • Extracellular bio mineralization, biosorption, complexation or precipitation. When the cell wall reductive enzymes or soluble secreted enzymes are involved in the reductive process of metal ions then it is obvious to find the metal nanoparticles extracellularly. • With the change in pH of the solution, various shapes and sizes were formed. • The culture supernatants of Enterobacteriaceae (Klebsiella pneumonia, E. coli andEnterobacter cloacae) also rapidly synthesized silver nanoparticles by reducing Ag+ to Ag0. These particles ranged in size from 28.2 nm to 122 nm with an average size of 52.5 nm. With the addition of piperitone, silver ion reduction was partially inhibited, which showed the involvement of nitroreductase enzymes in the reduction process.
- 14. • Titanium nanoparticles of spherical aggregates of 40–60 nm were produced extracellularly using the culture filtrate of Lactobacillus sp. at room temperature. These titanium nanoparticles were lighter in weight and high resistance to corrosion and have enormous applications in automobiles, missiles, airplanes, submarines, cathode ray tubes and in desalting plants and has promising future role in cancer chemotherapy and gene delivery. • Immobilized Rhodobacter sphaeroides extracellularly produced spherical shaped zinc sulfide (ZnS) semiconductor nanoparticles of 8 nm in size [88]. In analogous, immobilized purple, nonsulfur photosynthetic bacterium, R. sphaeroides produced extracellularly fcc structured lead sulfide (PbS) nanoparticles of size 10.5± 0.15 nm with monodispersed spherical morphology. • The extracellular production of nanoparticles has wider applications in optoelectronics, electronics, bioimaging and in sensor technology than intracellular accumulation.
- 15. Characterization of PbS nanoparticles synthesized by immobilized R. sphaeroides (a) TEM image (b) HRTEM image (c) (200) lattice fringes of denoted area (d) corresponding SAED pattern