Photonic crystals in biology

Poster Session, Tuesday, June 15
Theme A1 - B702
Biological and Green Synthesis of Silver Nanoparticles
Mehrdad Forough 1 and Khalil Farhadi 2 *
1 Department of Chemistry, Faculty of Science, Payam-e-Noor University, Khoy, Iran
2 Department of Chemistry, Faculty of Science, Urmia University, Urmia, Iran
Abstract -The synthesis of stable silver nanoparticles by bio-reduction method , using aqueous extract of Manna of hedysarum plant
as reducing agent of Ag + to Ag 0 , and Soap-root (Acanthe phyllum bracteatum) plant extract as a stabilizing agent has been
investigated. Various spectroscopic methods such as X – ray diffraction Analysis (XRD) , energy – dispersive spectroscopy (EDX) ,scanning
electron microscopy (SEM) and UV-Vis spectroscopy were used to characterize the nanoparticles obtained. The energy dispersive
spectroscopy (EDX) of the nanoparticles dispersion confirmed the presence of element silver signal no peaks of the impurity were
detected. Comparison of experimental results showed that the diameter of prepared nanoparticles in solution is about 29-68 nm.
In recent years noble metal nanoparticles have been the
subject of focused researches due to their unique optical,
electronic, mechanical, magnetic and chemical properties that
are significantly different from those of bulk materials [1].
These special and unique properties could be attributed to
their small sizes and large surface area. Many techniques of
synthesizing silver nanoparticles have been reported, such
as chemical reduction of silver ions in aqueous solutions,
with or without stabilizing[2], chemical and photo reduction
in reverse micelles[3]. Since noble metal nanoparticles, are
widely applied to human contacting area[4] there is a growing
need to develop environmentally friendly processes of
nanoparticles synthesis that do not use toxic chemicals.
Biological methods of nanoparticles synthesis using
microorganism[5-6], have been suggested as possible ecofriendly
alternatives to chemical and physical methods.
Sometimes , the synthesis of nanoparticles using plants or
parts of plants could prove advantageous over other biological
processes by eliminating the elaborate processes of
maintaining the microbial cultures [7].
In the present work, we investigate the synthesis of stable
silver nanoparticles with bio-reduction method using two
plants that, one of them acts as a reducing agent and the
other acts as a stabilizing agent. Aqueous extract of Soaproot
( Acanthe phylum bracteatum ) was employed as a
stabilizer and aqueous extract of Manna of hedysarum was
employed as a reductant. In this work we also compared
the synthesis of silver nanoparticles by monitoring the
conversion using UV – Vis spectroscopy.
First, the aqueous extracts of plants were prepared by simple
physicochemical methods, purified and then filtered. For
preparation of silver nanoparticles, 10 ml of prepared
extract of Soap-root ( Acanthe phylum bracteatum) plant as
a stabilizing agent was added to 100 ml of 0.003 M
aqueous AgNO 3 solution and after 5 min, 15 ml of
aqueous extract of manna of Hedysarum was added to
mixture for reduction of Ag + ions. The silver nanoparticles
solution thus obtained was purified by several centrifugation.
After freeze drying of the purified silver nanoparticles ,the
structure, composition and average size of the synthesized
silver nanoparticles were analyzed by scanning electron
microscopy (SEM), X-ray diffraction spectroscopy (XRD) and
energy dispersive X-ray microanalysis spectroscopy (EDX).
Also the purified powders of silver nanoparticles were
subjected to FT-IR spectroscopy measurement. It is well
known that silver nanoparticles exhibit yellowish – brown
color in aqueous solution due to excitation of surface
plasmon vibrations in silver nanoparticles. Figure (a ) shows
the photographs of samples .The silver containing solution
(left flask) is colorless but changes to brownish color on
completion of the reaction with manna of hedysarum
extract (right flask).
(a)
Figure 1. ( a). Solution of silver nitrate (3 mM) before (left) and
after (right) addition plant extract.(b) Scanning electron
micrograph of the silver nanoparticles obtained.
The energy dispersive spectroscopy (EDX)of the
nanoparticles dispersion confirmed the presence of element
silver signal and no peaks of the impurity were detected.
Scanning electron microscopy has provided further insight
into the morphology and size details of the silver
nanoparticles. Comparison of experimental results, showed
that the diameter of prepared nanoparticles in solution is
about 29-68 nm.Figure (b) shows the scanning electron
micrograph of the of silver nanoparticles that obtained with
treated 3.0 mM silver nitrate solution with plant extract in
86 °C for 13 min.
*Corresponding author: 1Tkhalil.farhadi@yahoo.com1T
[1] Mazur M. Electrochemistry Communications 6, 400 (2004).
[2] Liz-Marzan LM, Lado-Tourino . Langmuir 12, 3585 (1996).
[3] Pileni MP, Pure Appl Chem 72, 53 (2000).
[4] Jae YS, BEAM SK, Bioprocess Biosyst Eng 32, 79 (2009).
[5] Klaus T ,Joerger R, Olsson E, Granqvist C-G, Proc Nalt Acad Sci
crystalline USA 96, 13611(1999).
[6] Konishi Y , Uruga T,J Biotechnol 128, :648 (2007).
[7] Shankar SS, Rai A, Ahmad A, Sastry M, J Colloid Interface Sci
275, 496 (2004).
(b)
6th Nanoscience and Nanotechnology Conference, zmir, 2010 286