M.R S New 123
M.R S New 123
M.R S New 123
1. INTRODUCTION
1.1 INTRODUCTION
Nanoparticles, generally considered as particles with a size up to 100 nm,
exhibit completely new or improved properties as compared to the bulk
material that they are collected based on particular characteristics such as
size, distribution, and morphology . Nanoparticles of noble metals, such as
gold, silver and platinum are broadly applied in many fields and also directly
come in contact with the human body, such as shampoos, soaps, detergents,
shoes, cosmetic products, and tooth paste, besides medical and
pharmaceutical applications .
volume ratio. Nanoparticles are made from noble metals; in particular Ag, Pt.,
Au, and Pd. Metal nanoparticles have marvelous applications in the area of
catalysis, optoelectronics, diagnostic biological probes, and display devices.
Among the above four silver nanoparticles play a major role in the field of
biology and medicine 3 . Silver has been describing as an ‘oligodynamic.
Classification
Common Name : Curry Leaves
Family : Rutaceae
Plant part taken : Leaves
Genus : Murraya
Species : koenigii
Botanical name : Murraya koenigii
Fig. 1 Murray koenigii leaf
Description :
2. REVIEW OF
LITERATURE
2.1 Nanoparticles:
Use of biological systems for the synthesis of nanometal is rapidly
gaining importance due to their anomalous optical (Iravani et al., 2011),
chemical (Krolikowska et al., 2003), photo electrochemical (Kumar et al.,
2003) and electronic (Chandrasekharan et al., 2000) properties. There is a
need for an eco-friendly method of nanoparticle synthesis.
Apart from physical and chemical methods, biological systems are found to be
efficient Nano-factories for nanoparticle synthesis since they possess reducing
agents such as enzymes, which can reduce metals. The nanoparticles
synthesized by various living systems have been shown to be coated with
peptides or proteins. This leads to a similar charge distribution all over the
surface of nanometal which results in repulsion between them. These inter
particle repulsive forces prevent aggregation and so, nano metal solutions
synthesized by microbes and algae have been shown to be extremely stable
even after a period of six months.
Extracts from natural sources are suitably scaled up for large scale
biosynthesis of AgNPs in a controlled manner according to their shape, size
and sensitivity (Kruis et al., 2000, Magnusson et al., 1999 and Jung et al.,
2006).The aim of this chapter is, therefore, to reflect on the current state and
future prospects, especially the potentials and limitations of the above
mentioned techniques for industries.
The evaporated vapor can cool at a suitable rapid rate, because the
temperature gradient in the vicinity of the heater surface is very steep in
comparison with that of a tube furnace. This makes possible the formation of
small nanoparticles in high concentration. This physical method can be useful
The aforementioned reducing agents reduce silver ions (Ag+) and lead to the
formation of metallic silver (AgO), which is followed by agglomeration into
oligomeric clusters. These clusters eventually lead to formation of metallic
colloidal silver particles (Tsuji et al., 2002 and Merga et al., 2007). It is
important to use protective agents to stabilize dispersive nanoparticles during
the course of metal nanoparticle preparation, and protect the nanoparticles
that can be absorbed on or bind onto nanoparticle surfaces, avoiding their
agglomeration (Evanoff et al., 2004). The presence of surfactants
comprising functionalities (e.g., thiols, amines, acids, and alcohols ) for
interactions with particle surfaces can stabilize particle growth, and protect
particles from sedimentation, agglomeration, or losing their surface
properties. Recently, a simple one-step process, Tollens method, has been
used for the synthesis of silver nanoparticles with a controlled size. In the
modified Tollens procedure, silver ions are reduced by saccharides in the
presence of ammonia, yielding silver nanoparticle films (50-200 nm), silver
hydrosols (20-50 nm) and silver nanoparticles of different shapes Oliveira et
al., 2005).
Ag+ ions and accumulates silver nanoparticles, the size of such nanoparticles
being in the range 16–40 nm, with the average diameter of 27 nm (Mann,
1996).).
The examples also include magneto tactic bacteria which produce magnetite
(Fe3O4) or greigite (Fe3S4) and diatoms which produce siliceous material
(Klaus-Joerger T.et al., 2001).
The intracellular methods need special ion transportation system into the
microbial cell. Formation of magnetite particles proceeds through a sequence
of events: reduction of Fe (III) to Fe (II), precipitation of amorphous oxide and
subsequent transformation to magnetite (Klaus et al., 2001),). Gold
nanoparticles have also been synthesized in human cells, both in cancer and
non-cancer ones (Mann, 2001); the scanning microscopic images confirmed
that their morphologies differed significantly.
The Neem (Azadirachta indica) leaf broth and aqueous solution of silver
nitrate or chloroauric acid were used for the extracellular synthesis of pure
metallic silver and gold particles (Shankar et al., 2004). The time required for
Ag+ and Au3+ ions to reduce was 4 h and 2 h, respectively, being extremely
short compared to both bacteria and fungi (24 h and 120 h). Surface active
constituents of the leaf broth stabilize nanoparticle suspensions – an aqueous
suspension showed stability even after 4 weeks.
However, Huang et al., 2007; synthesized silver and gold nanoparticles using
the sundried Cinnamomum camphora leaf extract (Singaravelu et al., 2007). A
simple green synthesis method for production of well-defined silver
nanowires was reported recently by Lin et al, 2008. The method involves
reduction of silver nitrate with the broth of sundried Cassia fistula leaf at
room temperature without using any additive.
Fungi in Nanoparticle Synthesis: The fungi taking the center stage of studies
on biological generation of nanoparticles because of the tolerance and
bioaccumulation (Loveley et al., 1987). The advantages of using fungi in their
scale up process (e.g., using a thin solid substrate fermentation method) is
that they are efficient secretor of extra cellular enzymes; it can easily obtain
large scale production of enzymes. Further advantages of using fungal
mediated green approach for synthesis of metallic nanoparticles include
economic viability and ease in handling biomass. The main drawback of
biosynthesis of nanoparticles synthesis in eukaryotic organisms lies in the
problem of genetic manipulation of the organism as a mean to over express
the enzymes which is relatively much more difficult in eukaryotes than that in
prokaryotes. Mukherjee et al. demonstrated “green synthesis” of highly
stabilized nanocrystalline silver particles by a nonpathogenic and
agriculturally important fungus, Trichoderma asperellum (Slawson et al.,
1992).
The left side of the figure shows the possible mechanism of silver
nanoparticle synthesis at lower concentration which may involve nitrate
reductase enzyme. B- The right side of the figure shows the possible
mechanism for the induction of apopt Possible mechanisms of the duality in
functions of silver nitrate in bacteria.
03 OBJECTIVES
Green synthesis of silver nanoparticle
Characterization of silver nanoparticle
Atimicrobial activity of synthesized silver nanoparticle
04 MATERIALS AND
METHOD
4.2 METHODOLOGY :
The 25g of plant powder was taken along with 500 ml of distilled water in a
round bottom flask and then allowed to boil at 60°C for 30 min under reflux
condition, then it was cooled down to room temperature. Thus the prepared
solution was initially filtered through normal filter paper there by powdered
leafy. Materials will be filtered out, the filtrate was again filtered through
Whatman No.1 filter paper to get clear solution. The filtrate was then stored at
4°C which is to be used for further characterization and future works.
Fig.4
After 24, 48 and 72 hours of time interval colour changed from pale yellow to
reddish brown colour due to reduction of Silver nitrate to Silver ions which
indicates formation of silver nanoparticles.
Then the solution was centrifuged at10,000 rpm for 15 min , consequently
dispersed in double distilled water to remove any heavy-handed biological
materials .
Fig. 6 Fig. 7
XRD study
Powdered sample was used for X-ray diffraction; analysis for silver nanoparticles
was performed by using monochromatic Cu kα radiation (λ=1.5406 A°) operated
at 40 kV and 30 mA at 2θ angle pattern.The Coherently diffracting
Crystallography domain size of the Silver nano particle was calculated from the
width of the XRD peaks using scherrer formula.
Antimicrobial activity
The bacterial sensitivity of pathogens were tested using Well diffusion method
[28].The antimicrobial study of AgNPs was estimated against pathogenic bacteria
such as E-coli, Pseudomonas aeruginosa and Staphylococcus aureus. Nutrient agar
was used to cultivate the bacteria. Medium was sterilized by using autoclave then
poured into petriplates. After solidification of medium the holes were punched on
the solidified medium by using stainless steel cylinder.
The prepared Silver nanoparticles were added into the holes with different
concentrations like 25 µl, 50µl and 100 µl. Plates were incubated for 24 hr. at
37°C. After incubation period zone of inhibition was measured around the well.
5. RESULT AND
DISCUSSION
Table 1: UV-VIS Spectrum analysis shows time interval for changing color of plant
extracts.
Fig. 10
The average particle size was (example 30-35 nm.) XRD analysis, peaks assigned
to the corresponding diffraction signals ( examples (111), (200), (220), and (311)
)facets of Silver. The mean particle diameter of silver nanoparticles was calculated
from the XRD pattern according to the line width.
image of TEM
Fig. 12
The well diffusion method was used to analyze the antimicrobial study of
pathogens such as E-coli, Pseudomonas aeruginosa (gram negative) and
Staphylococcus aureus (gram negative). The zone of inhibition (ZOI) was
increased when increasing the concentration of Silver nanoparticles. However the
zone of inhibition. Maximum zone of inhibition and Minimum ZOI was observed
from bacteria, when compared to other pathogens.
6 CONCLUSION
7. REFERENCES
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