Spectrochimica Acta Part A 78 (2011) 899–904
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Murraya Koenigii leaf-assisted rapid green synthesis of silver and gold
nanoparticles
Daizy Philip
a,∗
, C. Unni
b
, S. Aswathy Aromal
a
, V.K. Vidhu
a
a
Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, India
b
Department of Electronics and Communication, T.K.M. College of Engineering, Kollam 691 005, India
article info
Article history:
Received 13 September 2010
Received in revised form 9 December 2010
Accepted 14 December 2010
Keywords:
Gold nanoparticles
Silver nanoparticles
Biosynthesis
Murraya Koenigii
Surface plasmon resonance
abstract
A facile bottom-up ‘green’ and rapid synthetic route using Murraya Koenigii leaf extract as reducing
and stabilizing agent produced silver nanoparticles at ambient conditions and gold nanoparticles at
373 K. The nanoparticles were characterized using UV–vis, transmission electron microscopy (TEM), X-
ray diffraction (XRD) and FTIR analysis. This method allows the synthesis of well-dispersed silver and
gold nanoparticles having size ∼10 nm and ∼20 nm, respectively. Silver nanoparticles with size ∼10 nm
having symmetric SPR band centered at 411 nm is obtained within 5 min of addition of the extract to the
solution of AgNO
3
at room temperature. Nearly spherical gold nanoparticles having size ∼20 nm with
SPR at 532 nm is obtained on adding the leaf extract to the boiling solution of HAuCl
4
. Crystallinity of
the nanoparticles is confirmed from the high-resolution TEM images, selected area electron diffraction
(SAED) and XRD patterns. From the FTIR spectra it is found that the biomolecules responsible for capping
are different in gold and silver nanoparticles. A comparison of the present work with the author’s earlier
reports on biosynthesis is also included.
© 2010 Elsevier B.V. All rights reserved.
1. Introduction
Recent interest in the development of new and novel strate-
gies for the generation of gold and silver nanoparticles stems from
their potential applications in the fields of physics, chemistry, biol-
ogy, medicine and materials science [1–3]. Nanosize metals such
as silver and gold have been shown to exhibit size-dependent opti-
cal properties. It is also well-known that metal nanoparticles with
anisotropic shapes provide enhanced optical properties, which lend
the candidates for the spectroscopic techniques like SERS. Gold
nanoparticle based fluorescent probes have been used in the iden-
tification of pathogenic bacteria in DNA micro-array technology.
The use of gold nanoparticles is advantageous in biological label-
ing as visible light can be used to observe a colour shift from
red to blue when it forms aggregates. Very small nanoparticles
are essential for biological labeling while for SERS studies using
gold, multi-branched particles are preferred [4]. Now-a-days silver
nanoparticles have received greater attention due to antimicrobial
properties [5]. The application of colloidal nanomaterials in medical
science gives a new scope for detecting diseases. Anisotropic gold
and silver nanoparticles having longitudinal plasmon band find
applications in SERS studies using NIR laser excitation. Controlling
∗
Corresponding author. Tel.: +91 471 2530887.
E-mail addresses: philipdaizy@yahoo.co.in, daizyp@rediffmai.com (D. Philip).
size, shape and structure of metal nanoparticles is technologically
important because of the strong correlation between these param-
eters and optical, electrical and catalytic properties.
Physical and chemical methods of nanoparticle synthesis [6–15]
are not environmentally friendly. Our environment is a rich source
of plants, marine organisms and micro-organisms. Biosynthe-
sis of nanoparticles is now established as an emerging area of
nanoscience research. Gold nanoparticles have been considered as
important area of research due to their unique and tunable surface
plasmon resonance (SPR) and their applications in biomedical sci-
ence including drug delivery, tissue/tumor imaging, photothermal
therapy and immunochromatographic identification of pathogens
in clinical specimens [16]. Biosynthesized silver nanoparticles have
large number of applications such as in nonlinear optics, spectrally
selective coating for solar energy absorption, bio-labeling, interca-
lation materials for electrical batteries, as optical receptors, catalyst
in chemical reactions and as antibacterial capacities [17]. Nanopar-
ticles of noble metals are even used for the purification of water
which is one of the essential enablers of life on earth [18]. There
are several reports on the use of natural materials sources like
plants, bacteria, fungi, yeast and honey for synthesizing gold and sil-
ver nanoparticles [19–52]. Plants like Aloe barbadensis, Azadirachta
indica, Camellia sinensis, Cinnamomum camphora, Cinnamom zey-
lanicum, Carica papaya, Capsicum annum, Coriandrum sativum,
Coleus amboinicus, Jatropha curcas Cymbopogon flexuosus, Diopyros
kaki, Emblica officianalis, Gliricidia sepium, natural rubber, Pelargo-
nium graveolens, Psidium guajava, Tamarindus indica, Hibiscus rosa
1386-1425/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2010.12.060