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The green synthesis of silver nanoparticles (AgNPs) is a good approach to avoiding the drawbacks associated with by-products formed in chemical synthesis. The present investigation was intended to synthesize AgNPs using gallnut extract as reducing agent and evaluate their potential biomedical applications. The ultraviolet-visible spectroscopy provided a preliminary indication of AgNP synthesis. Changing the pH of the reaction mixture from pH 3 to 10 revealed a significant impact of pH on the synthesis of AgNPs with the wavelength shift from red to blue. Transmission electron microscope characterizations showed that the synthesized AgNPs at pH 3-10 were spherical with average sizes of 51, 27, 18, 30, 10, 8, 5 and 4nm. The synthesized AgNPs were further characterized by different techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray photoelectron spectroscopy and powder X-ray diffraction. The AgNPs biosynthesized using gallnut extract showed higher antioxidant activity (81%) than AgNPs chemically synthesized using sodium borohydride (56%), indicating that AgNP-capping molecules such as tannic acid play an important role in antioxidant function. The biosynthesized AgNPs showed potent anticancer activity on four cervical cancer cell lines, namely, ME180, SiHa, HeLa and CaSki.
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Biomedical potential of silver nanoparticles
biosynthesized using gallnut extract
1Ezhaveni Sathiyamoorthi MTech
PhD scholar, Department of Chemical Engineering, Chungbuk
National University, Cheongju, Republic of Korea
2Bilal Iskandarani MSc
PhD scholar, Department of Chemical Engineering, Chungbuk
National University, Cheongju, Republic of Korea
3Bipinchandra K. Salunke PhD
Postdoctoral Fellow, Department of Chemical Engineering, Chungbuk
National University, Cheongju, Republic of Korea
4Beom Soo Kim PhD
Professor, Department of Chemical Engineering, Chungbuk National
University, Cheongju, Republic of Korea (corresponding author:
1 2 3 4
The green synthesis of silver nanoparticles (AgNPs) is a goodapproachtoavoidingthedrawbacksassociatedwithby-
products formed in chemical synthesis. The present investigation was intended to synthesize AgNPs using gallnut extract
as reducing agent and evaluate their potential biomedical applications. The ultravioletvisible spectroscopy provided a
preliminary indication of AgNP synthesis. Changing the pH of the reaction mixture from pH 3 to 10 revealed a signicant
impact of pH on the synthesis of AgNPs with the wavelength shift from red to blue. Transmission electron microscope
characterizations showed that the synthesized AgNPs at pH 310 were spherical with average sizes of 51, 27, 18,
30, 10, 8, 5 and 4 nm. The synthesized AgNPs were further characterized by different techniques such as Fourier
transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray photoelectron
spectroscopy and powder X-ray diffraction. The AgNPs biosynthesized using gallnut extract showed higher antioxidant
activity (81%) than AgNPs chemically synthesized using sodium borohydride (56%), indicating that AgNP-capping
molecules such as tannic acid play an important role in antioxidant function. The biosynthesized AgNPs showed potent
anticancer activity on four cervical cancer cell lines, namely, ME180, SiHa, HeLa and CaSki.
1. Introduction
Developments of eco-friendly nanoparticle synthesis approaches
devoid of lethal chemicals in synthesis protocols are urgently needed.
Plant extracts,
and fungi
are recommended as potential
environmentally friendly substitutes for the physical and chemical
syntheses of metal nanoparticles. In particular, metal nanoparticles
such as silver, gold and platinum can be manufactured through
reduction by means of biological methods. This offers numerous
benets such as cost-effective production and suitability for
biomedical applications. The approach of using medicinal plants for
silver nanoparticle (AgNP) synthesis is eco-friendly, and the
synthesized AgNPs display virtuous antimicrobial efcacy.
are valuable due to their utility in applications such as antibacterial
products, anticancer agents, air puriers, imaging, sensors and
AgNPs are also treasured for diagnostics of disease and
drug delivery treatments.
Different parameters such as temperature,
pH and reaction time can inuence the characteristic of AgNPs in
plant extract-mediated synthesis. Biomolecules present in plant
extracts have a signicant share for nanoparticle synthesis.
the selection of plant type and quality of extract is very important.
Some AgNPs synthesized using plant extracts showed biological
activities such as antimicrobial, antioxidant and anticancer
activities. Cassia stula leaf extract-mediated biogenic-synthesized
AgNPs showed good cytotoxicity against skin cancer cells (A-431
cell line).
Enhanced antibacterial effects were detected for AgNPs
synthesized using the Aloe vera plant compared with antibiotic
The free radical scavenging potential of Pongamia
pinnata-synthesized AgNPs was evaluated in vitro by using ve
different assays.
Pimpinella anisum seed extract-synthesized
AgNPs were evaluated for toxicological effects on colon cancer
cells (HT115) against human neonatal skin stromal cells.
synthesized using the seed-based extract of P. pinnata showed
antibacterial property and interacted with human serum albumin.
The antifungal effectiveness of fungal species Neofusicoccum
parvum and Rhizoctonia solani was found for AgNPs synthesized
by Trifolium resupinatum seed extract.
AgNPs synthesized using
the leaf extracts of the species of the Kalopanax plant showed
antimicrobial activity.
Plant extract-synthesized AgNPs were
advocated to display a variety of biological activities.
As the particles with uniform shape demonstrate good functional
properties, increasing research interest has been generated in the
control of the size and shape of AgNPs.
Tannic acid carrying
numerous phenolic groups is a virtuous reducing agent for AgNP
size control in the range 1830 nm.
Monodispersed spherical
Cite this article
Sathiyamoorthi E, Iskandarani B, Salunke BK and Kim BS (2018)
Biomedical potential of silver nanoparticles biosynthesized using gallnut extract.
Green Materials,
Research Article
Paper 1700032
Received 27/10/2017; Accepted 02/03/2018
ICE Publishing: All rights reserved
Keywords: green chemistry/
Green Materials
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AgNPs of controlled size in the range 766 nm were formed
utilizing tannic acid as reductant and stabilizer by changing the pH
and molar ratio of tannic acid to silver nitrate (AgNO
Tan nic
acid can effectively promote the equilibrium in nucleation and
growth processes, thereby tuning AgNP size.
Moreover, size- and
shape-controlled AgNPs are valuable in plasmonics, catalysts,
bactericides, electronics and optical materials.
controlled AgNP synthesis is achieved by selecting a reductant with
appropriate reactivity to facilitate processes of nucleation and
Some researchers tried to control the shape and size of
AgNPs by varying the ratio of silver nitrate and the reducing agent
such as sodium borohydride (NaBH
), tannic acid and plant
Research has also been carried out by some
researchers into the size and shape control of AgNPs using plant
extracts exclusively without additional reducing agents in the
reaction mixture. However, the production of AgNPs with
controlled shape and size had minimal success. More research
efforts are needed to screen different plants and reaction conditions
for the size and shape control of particles.
Gallnut is an outgrowth of plant tissues released by the larva of
gall insects such as the Cynipidae family, the gall wasps. As a
result of the unique advantage and market demand, they are
widely used in different industries.
The components of gallnut
(Galla chinensis) are 69% gallotannin, 25·7% gallic acid and
5·3% methyl gallate.
It also exhibits medicinal properties
such as antiallergic, anticancer, antimicrobial, antidiabetic and
antioxidant activities.
Due to their biological compatibility
and biological activities, AgNPs are important for antioxidant and
antimicrobial agents and treating various cancers.
some AgNPs have been found to have antioxidant activity, no
research has been conducted to determine the cause of antioxidant
activity. Herein, the potential of gallnut extract containing high
amounts of tannic acid was investigated in the synthesis of
AgNPs and to nd conditions for controlling the size of particles.
The antioxidant activity to scavenge 2,2-diphenyl-1-
picrylhydrazyl (DPPH) free radicals of AgNPs biosynthesized
using gallnut extract and AgNPs chemically synthesized using
sodium borohydride was compared for the rst time. The
anticancer potential of the synthesized AgNPs was also assessed
using four cervical cancer cell lines (ME180, SiHa, HeLa and
CaSki), with a view to biomedical applications.
2. Materials and methods
2.1 Materials
Gallnut powder was purchased from Jecheon Dongsan Medicinal
Herb (Jecheon, Korea). Silver nitrate (Junsei Chemicals),
potassium carbonate, dimethyl sulfoxide, l-glutamine, fetal bovine
serum (FBS), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide (MTT) and Dulbeccos modied Eagles medium
(DMEM) were procured from Sigma-Aldrich. The rest of the
chemicals used were of analytical reagent grade, and experiments
were carried out using deionized water. All glassware was rst
rinsed with acetone and then with Millipore water before use.
2.2 Preparation of gallnut extract
The gallnut extract was prepared by boiling 1·7 g of gallnut powder
in sterile distilled water (100 ml) for 1 h. After cooling at room
temperature, the extract was ltered using lter paper (Whatman
number 1) to remove insoluble residues. The ltered gallnut extract
was stored at 4°C and used for further experiments.
2.3 Synthesis of AgNPs
For the biological synthesis of AgNPs, 1 ml gallnut extract solution
was diluted with 99 ml of distilled water in a 100 ml round-bottomed
ask, under constant stirring of 400 revolutions per minute (rpm) at
30°C. After that, 1 ml of 0·1 M silver nitrate was added slowly. The
effect of pH was investigated by adjusting pH in the range 310 by
using 0·5 M potassium carbonate. The mixture was stirred for 15 min
and the color change was monitored. Due to the photoactivation of
silver nitrate, the reactions were carried out in darkness. After the
reaction, the purication of AgNPs was carried out by centrifuging at
15 000 rpm for 20 min at room temperature and redispersing pellets
in deionized water. The puried nanoparticles were lyophilized
overnight. For the chemical synthesis of AgNPs, 0·5 ml of a 0·1 M
sodium borohydride solution was added dropwise to 100 ml of
0·05 M aqueous silver nitrate solution at room temperature. The color
change was observed immediately and the solution was stirred at
room temperature for 10 min.
2.4 Characterization of AgNPs
The synthesis of AgNPs was observed by taking the ultraviolet
(UV)visible spectrum between 200 and 800 nm wavelengths of the
reaction medium using a UVvisible spectrophotometer (UV-1601,
Shimadzu, Japan). Fourier transform infrared (FTIR) spectroscopy
spectra were obtained on a Nicolet IR 200 instrument in the range
between 4000 and 400 cm
. The pellet was prepared by mixing
puried AgNP powder and potassium bromide (KBr) and spectra
were recorded against a potassium bromide reference blank. The
puried AgNP powder was coated on the glass substrate to record X-
ray diffraction (XRD; Rigaku, Ultima IV, Japan) spectra using copper
(Cu) Karadiation (l= 1·5418 Å) monochromatic lter in the range
1080°. X-ray photoelectron spectroscopy (XPS) of AgNPs was
examined using a PHI quantera-II, ulvac-PHI. The morphology of
the AgNPs was investigated using a scanning electron microscope
(SEM; Leo-1530). Energy-dispersive X-ray (EDX) spectra were
obtained from a Leo-1530 instrument coupled with an EDX detector
(Carl Zeiss, Oberkochen, Germany). The morphology and size of
AgNPs were visualized using an energy-ltering transmission
electron microscope (EF-TEM; Libra 120, Carl Zeiss). Before that,
AgNPs were dispersed in 1 ml of ethanol on a hydrophilic carbon-
coated copper grid and then dried under ambient conditions.
2.5 Antioxidant activity assay
The DPPH scavenging assay was performed according to the
modied method described by Clarke et al.
In this method, a
96-well plate was used where the synthesized AgNP solution was
diluted from 10 to 100% in a total sample volume of 60 ml. DPPH
ethanol solution (20 ml of 0·2 mM) was added, and the mixture
was shaken and incubated in the dark for 30 min. Absorbance was
Green Materials Biomedical potential of silver
nanoparticles biosynthesized using
gallnut extract
Sathiyamoorthi, Iskandarani, Salunke and Kim
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measured at 517 nm against blank ethanol. The DPPH scavenging
potential was compared for gallnut extract and for chemically
synthesized AgNPs. A similar procedure was also performed for
nanoparticles biosynthesized at various pH values.
2.6 Cell viability assay
The MTT assay was used to test cell viability using cervical cancer
cell lines. Briey, ME180, SiHa, HeLa and CaSki cells were grown
in DMEM medium augmented with 1 mM l-glutamine and 10%
FBS. The seeding of cells was done in 96-well plates composed of
100 mlmediaat1×10
cells/ml density, and culturing was done at
37°C overnight in a humidied incubator with 5% carbon dioxide
). The anticancer efcacy of the AgNPs was evaluated by
treating the cultured cells at various doses of AgNPs (10, 25, 50 and
100 mg/ml) for different time periods (24 and 48 h). A microplate
reader was used to record absorbance at 450 nm. For each toxicity,
three end point independent experiments were carried out. For the
determination of cell viability, the ratio of absorbance values for each
treatment was recorded. The inverted microscope images were
captured to monitor cell viability.
3. Results and discussion
3.1 Synthesis of AgNPs and UVvisible absorption
Gallnut extracts were prepared and used for the synthesis of
AgNPs under facile conditions (Figure 1(a)). The color of the
solution changed within a few seconds from yellow to reddish
brown after the addition of aqueous silver nitrate into the gallnut
extract, giving the preliminary indication of AgNP synthesis. This
is due to the excitation of free electrons in AgNPs. The observed
result is similar to that for AgNPs synthesized using Acalypha
indica leaf extract, which exhibits different colors in the
The UVvisible absorption spectra of AgNPs are
sensitive to various factors including size, shape and interactions
between particles.
Gallnut-extract-synthesized AgNPs showed
characteristic UVvisible absorption spectra at 428 nm. This
observation is similar to characteristics of plant-synthesized
AgNPs reported by other researchers.
The bioreduction of silver was postulated as the trapping of silver
ions (Ag
) on protein surface due to electrostatic interactions
between Ag
and proteins in plant extract.
Proteins reduce silver
ions, leading to their secondary structure change and formation of
silver nuclei. The formed silver nuclei successively grow with the
further reduction of silver ions and their build-up in the nuclei,
leading to the formation AgNPs.
It has been reported that the
key mechanism behind the plant-mediated synthesis of AgNPs is
a plant-assisted reduction due to phytochemicals. The primary
phytochemicals are ketones, terpenoids, amides, avones,
carboxylic acids and aldehydes.
Water-soluble phytochemicals,
including organic acids, quinones and avones, are responsible
for the instantaneous reduction in silver ions in the reaction
Absorbance: arbitrary units
200 300 400 500 600 700 800
Wavelength: nm
pH3 (426 nm)
pH4 (420 nm)
pH5 (418 nm)
pH6 (416 nm)
pH7 (414 nm)
pH8 (413 nm)
pH8 (410 nm)
pH10 (409 nm)
200 300 400 500 600 700 800
Wavelength: nm
Tannic acid
Absorbance: arbitrary units
Figure 1. (a) Photographic representation of gallnut dried fruit, gallnut powder and gallnut extract; (b) UVvisible spectra for the
synthesized AgNPs from gallnut extract at pH 310; and (c) UVvisible spectra for gallnut extract and tannic acid
Green Materials Biomedical potential of silver
nanoparticles biosynthesized using
gallnut extract
Sathiyamoorthi, Iskandarani, Salunke and Kim
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In the majority of cases, reducing agents in plant
extracts also serve as capping and stabilizing agents, thereby
eliminating the need for external capping and stabilizing agents.
The reduction of silver ions has been found to depend on the type
of plant extract used as a reducing agent.
3.2 Effect of pH
pH plays a signicant role in the synthesis and stability of
AgNPs. The pH of the solution affects the formation rate of
nanoparticles and therefore their nal size. Furthermore, AgNPs
along with other metal nanoparticles are unique by having surface
plasmon resonance (SPR). The absorption peak detected in
UVvisible absorption spectra allows approximate particle size
estimation. This is due to the direct proportionality between the
wavelength of maximum absorption of AgNPs and their size.
Figure 1(b) displays the UVvisible absorption spectra of AgNPs
in the range 200800 nm. The maximum absorption peaks for
AgNPs synthesized at pH 310 occurred at 426, 420, 418, 416,
414, 413, 410 and 409 nm, respectively, and the wavelength
shifted from red to blue.
The absorbance of AgNPs increased
with increasing pH from 3 to 10 probably due to the increase of
particle numbers in the solution. The absorption spectrum is due
to strong SPR, the resonance absorption of photons by AgNPs.
Since the SPR band depends on the size and refractive index of
the solution, the observed absorption band is dependent on size.
The shift in peak wavelength indicates that the size of the
particles decreases as the pH of the solution increases. As
the diameter of the particles increases, the energy required
for excitation of the surface plasmon electrons decreases, and
as a result, the absorption maximum shifts toward the
longer-wavelength region. In the UVvisible spectroscopy of
gallnut extract and tannic acid, similar peaks at the wavelength
around 271276 nm were observed (Figure 1(c)). Peak intensity
suggests that gallnut contains a higher amount of tannic acid.
Tannic acid has been reported to synthesize different types of
metal nanoparticles.
Tannic acid present in gallnut can play an
important role in the synthesis of AgNPs.
3.3 Transmission electron microscopy
Transmission electron microscopy (TEM) micrographs suggest
that at pH 36, the size and shape of AgNPs are irregular
(Figures 2(a)2(d)) compared to pH 710 (Figures 2(e)2(h)). This
indicates the poor balance between nucleation and growth processes
in acidic conditions compared to neutral and basic conditions. The
low formation rate of AgNPs was also observed at acidic pH
compared to neutral and basic conditions. It was reported that the
formation of AgNPs using Solanum xanthocarpum berry methanol
extract was lower in acidic conditions and higher in basic
Larger particles were formed at pH 5, while highly
dispersed and smaller nanoparticles were formed at pH 9.
Figure 2(i) shows the graphical representation of average particle
size with pH. The average sizes were 51, 27, 18, 30, 10, 8, 5 and
4 nm, respectively, for AgNPs synthesized at pH 310. Although
particle sizes were lower at higher pH at 810, more evenly
dispersed particles were observed at pH 7 in the study. Almost
70% of particles were in similar size and shape at pH 7 compared
to other pH conditions. The spherical shape of AgNPs at pH 7
can be attributed to the balance between the nucleation and
growth processes as well as to the silver precursor (silver ions)
reduction rate increase.
AgNPs formed at pH 7 were further
characterized by other techniques.
The previous analysis and other references indicate the formation
of a good crystalline structure of the synthesized nanoparticles,
with a distance of 0·23 nm between the lattice planes matching
the (111) lattice of the face-centered cubic silver (Ag).
crystal structure of the NPs was further demonstrated by the
selected area (electron) diffraction pattern with bright circular
rings corresponding to the (111), (200), (220) and (311) Braggs
reection planes.
3.4 FTIR spectroscopy
FTIR spectrum peaks for gallnut extract occurred in 2345, 1613,
1535, 1448, 1321 and 1201 cm
. For tannic acid, the peaks were
Average particle size: nm
(a) (b) (c) (d)
(e) (f) (g) (h)
pH 3
pH 7 pH 8 pH 9 pH 10
pH 4 pH 5 pH 6
50 nm 50 nm 50 nm
50 nm
50 nm
50 nm50 nm
50 nm
Figure 2. (ah) TEM images of AgNPs synthesized at different pH
(pH 310); (i) graphical representation of AgNPs synthesized at
different pH values against average particle size (nm)
Green Materials Biomedical potential of silver
nanoparticles biosynthesized using
gallnut extract
Sathiyamoorthi, Iskandarani, Salunke and Kim
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found at 2377, 1612, 1535, 1448, 1322 and 1202 cm
. The peaks
for silver nitrate were at 2305, 1634, 1357 and 828 cm
. AgNPs
biosynthesized by using gallnut extract showed peaks at 2373,
1634, 1545, 1460, 1365 and 1224 cm
(Figure 3). The peaks
presented in gallnut extract (2345 cm
) and AgNPs (2373 cm
represent the CH asymmetric stretching. The bands at 1613 and
1535 cm
are due to the C=C stretching and protein secondary
amine bending vibration. The band at 1321 cm
carboxylate group symmetrical stretch. The broad band at
1201 cm
is due to CH and CO stretching modes. The peak at
1634 cm
suggests that the OH and C=O groups were adsorbed
on the surface of AgNPs and involved in the reduction process.
The band at 1364 cm
suggests the silver ion binding to
carboxylate and hydroxyl groups, respectively. The peak at
1224 cm
signies the polyol CO group, demonstrating the role
of polyols in the reduction of AgNPs. FTIR studies reveal that the
carbonyl groups of amino acid, peptides and proteins can bind to
metal and coat the particles and stabilize the AgNPs against
agglomeration. This demonstrates that the proteins and tannins
from the gallnut extract similar to phytochemicals present in gum
kondagogu may be involved in the formation of AgNPs.
3.5 SEM, EDX, XPS and XRD
The morphology of AgNPs was analyzed by SEM, which revealed
the presence of spherical particles (Figure 4(a)). EDX measurement
(Figure (4b)) showed the presence of silver, conrming the synthesis
of AgNPs. The composition analysis indicated the presence of 93·85
weight% and 71·82 atom% of silver. Figure 4(c) shows the XPS
spectrum of the capped AgNPs with gallnut. The characteristic
feature showed the silver electron valence state Ag
The XRD of
the AgNPs suggested that sharp peaks were observed in the silver
region (Figure 4(d)).
As per the powder diffraction card of the Joint
Committee on Powder Diffraction Standards silver le number 04-
0783, the high intense peak was observed in (111) reection. The
majorfourstrongBraggreections at 38·199, 44·379, 64·657 and
77·584° correspond to the planes of (111), (200), (220) and (311),
respectively, which can be indexed according to the facets of the
face-centered cubic crystal structure of silver.
The average
crystallite size Dof AgNPs was estimated from the diffractogram
using the DebyeScherrer formula, D=0·94l/bcos q, where lis the
wavelength of the X-ray used in the diffraction and bis the full
width at half maximum of a peak.
The calculated average
crystallite of AgNPs from the four peaks is 11·8 nm. The value of
the interplanar spacing between atoms dwas calculated using
Braggslaw,2dsin q=nl, where nis the order of the diffraction
pattern (n= 1 in this case). The calculated dvalues are 2·356, 2·041,
1·442 and 1·230 Å for the (111), (200), (220) and (311) planes,
respectively, and matched with standard silver values. The lattice
constant was estimated using the formula a=d(h
where h,kand lare Miller index parameters. The average value of
the four avalues calculated from the four dvalues obtained from the
data for four peaks is 4·0804 Å. This is in good agreement with the
standard value for silver, 4·0857 Å.
Thus, XRD analysis showed
that AgNPs with well-dened dimensions can be synthesized by the
reduction of silver ions using gallnut extracts.
3.6 Antioxidant activity
The DPPH scavenging results showed an effective free radical
scavenging potential independent of the nanoparticle solution
dose and nanoparticle size (Figures 5(a) and 5(b)). The typical
scavenging activity of biosynthesized AgNPs is 81%, similar to
73% of gallnut plant extract. AgNPs chemically synthesized using
sodium borohydride showed a much lower scavenging activity of
56%. This indicates that AgNP-capping molecules such as tannic
acid play an important role in antioxidant function. Other plant
extracts showed different DPPH scavenging potential, where
59·3% was reported for AgNPs synthesized using Bergenia ciliate
plant extract,
and about 70% for AgNPs synthesized using
Iresine herbstii leaf aqueous extract.
Therefore, AgNPs
synthesized using gallnut extract showed clear superiority as an
antioxidant to remove DPPH free radicals, which can be attributed
to AgNP-capping molecules such as tannic acid, which improves
the free radical scavenging ability of AgNPs.
3.7 Cell viability of cervical cancer cell lines
The cytotoxic activity effects of AgNPs biosynthesized using gallnut
extract on four cervical cancer cell lines are depicted in
Figures 6(a)6(d). The dose-dependent reduction in cell viability was
observed. The photomicrographic images (Figures S1S4 in the
online supplementary material) reveal cell morphological changes.
Membrane lyses of cancer cells and nuclear damage in all four
cervical cancer cell lines were observed. In comparison to the
controls, the cell number reduction was witnessed for high doses of
AgNPs (25, 50 and 100 mg/ml). From observations, a heterogeneous
model of cell toxicity with the inclusion of a combination of different
death modes depending on various parameters such as cell line,
exposure time, AgNP concentration and capping agents can be
Silver nitrate
Tannic acid
4000 3500 3000 2500 2000 1500 1000 500
th: nm
Figure 3. FTIR spectra of gallnut, tannic acid, silver nitrate and
AgNPs synthesized at pH 7
Green Materials Biomedical potential of silver
nanoparticles biosynthesized using
gallnut extract
Sathiyamoorthi, Iskandarani, Salunke and Kim
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Mag - 100·00 K X 100 nm
80 000
60 000
40 000
20 000
Element Wt% Atom%
Al K
Si K
Ag L
100 100
1·84 4·28
385 380 375 370 365 360
Intensity: arbitrary units
Binding energy: eV
Intensity: arbitrary units
(122) (210)
10 20 30 40 50 60 70 80 90
2θ: °
Figure 4. (a) SEM image, (b) EDX, (c) XPS and (d) XRD for AgNPs synthesized at pH 7
DPPH scavenging potential: %
DPPH scavenging potential: %
Figure 5. (a) DPPH radical scavenging percentage for AgNPs biosynthesized using gallnut extract, gallnut extract alone and AgNPs
chemically synthesized using sodium borohydride; (b) DPPH radical scavenging percentage for biosynthesized AgNPs at different pH values
Green Materials Biomedical potential of silver
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gallnut extract
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suggested. Similar kinds of anticancer potential of AgNPs were
reported by other researchers.
A suitable complex antioxidant enzyme network may be involved
according to the hypothetical mechanism of AgNP biosynthesis.
Current research on the antioxidant potential of gallnut provides a
hypothesis that antioxidant molecules in the gallnut extract are
involved in the biological synthesis of AgNPs. Previous studies have
shown that plants containing phenols and avonoids have high
antioxidant capacity and therefore biosynthesis of nanoparticles.
Electrostatic interactions between positively charged nanomaterials
and target cancer cells are described in the literature. Cancer cells
usually exhibit a high concentration of anionic phospholipids on their
outer leaet, compared to normal cells that exhibit zwitterionic
This condition plays an important role in the cellular
uptake of positively charged nanoparticles in cancer cells compared
to normal cells. Because AgNPs are positively charged (+20·1 mV
zeta potential), it is expected that they are more toxic to cancer cells
than to normal cells.
4. Conclusion
The economical, simple and green biosynthesis of AgNPs was
studied using gallnut extract for the rst time. Color change from
light yellow to dark brown indicated the reduction of silver ions to
and spectra at 426409 nm in UVvisible spectroscopy
conrmed the synthesis of AgNPs at different pH values. Out of the
different pH values tested, pH 7 was found to be good for the
synthesis of AgNPs with uniformity. FTIR studies indicated the role
of plant tannins and polyphenolic compounds in the metal reduction
and capping of AgNPs. The XRD results suggested the crystalline
nature of the biosynthesized AgNPs. The antioxidant activity to
remove DPPH free radicals was compared between biosynthesized
and chemically synthesized AgNPs. AgNPs biosynthesized using
gallnut extract showed a higher antioxidant activity than AgNPs
chemically synthesized using sodium borohydride, indicating that
gallnut extract plays an important role in improving antioxidant
ability. Cell viability analysis showed potent anticancer effects of
gallnut-synthesized AgNPs on different cancer cell lines depending
on dose, exposure time and cell line. Due to the high antioxidant and
anticancer activities of gallnut extract-synthesized AgNPs, this study
opens opportunities for further research into the exciting use of
gallnut extract for AgNP synthesis toward potential applications in
the eld of biomedical nanotechnology.
This research was supported by the Small and Medium Business
Administration (C0505005 and S2492537).
1. Salunke BK, Sawant SS, Kang TK et al. (2015) Potential of
biosynthesized silver nanoparticles as nanocatalyst for enhanced
degradation of cellulose by cellulose. Journal of Nanomaterials 2015:
(a) (b)
(c) (d)
Per cent cell viability
Per cent cell viability
Per cent cell viability Per cent cell viability
control 10 25 50 100 10 25 50 100
10 25 50 100
10 25 50 100
24 h
48 h
24 h
48 h
24 h
48 h
24 h
48 h
Concentration: µg/ml Concentration: µg/ml
Concentration: µg/mlConcentration: µg/ml
control CaSki
Figure 6. Cell viability percentage for (a) ME180, (b) SiHa, (c) HeLa and (d) CaSki cells after incubation with 24 and 48 h with different
concentrations of AgNPs synthesized at pH 7
Green Materials Biomedical potential of silver
nanoparticles biosynthesized using
gallnut extract
Sathiyamoorthi, Iskandarani, Salunke and Kim
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2. Salunke BK, Sawant SS, Lee SI and Kim BS (2015) Comparative study
of MnO
nanoparticle synthesis by marine bacterium Saccharophagus
degradans and yeast Saccharomyces cerevisiae.Applied Microbiology
and Biotechnology 99(13): 54195427.
3. Bhainsa KC and Souza SFD (2006) Extracellular biosynthesis of silver
nanoparticles using the fungus Aspergillus fumigates.Colloids and
Surfaces B: Biointerfaces 47(2): 160164.
4. Philip D (2010) Honey mediated green synthesis of silver
nanoparticles. Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy 75(3): 10781081.
5. Salunke BK, Sawant SS and Kim BS (2016) Enhancement of
antibacterial effect by biosynthesized silver nanoparticles with
antibiotics. Journal of Nanoscience and Nanotechnology 16(7):
6. Salunke BK, Sathiyamoorthi E, Tran TK and Kim BS (2017) Phyto-
synthesized silver nanoparticles for biological applications. Korean
Journal of Chemical Engineering 34(4): 943951.
7. Dar MA, Ingle A and Rai M (2013) Enhanced antimicrobial activity
of silver nanoparticles synthesized by Cryphonectria sp. evaluated
singly and in combination with antibiotics. Nanomedicine 9(1):
8. El-Rae MH, Shaheen TI, Mohamed AA and Hebeish A (2012)
Biosynthesis and applications of silver nanoparticles onto cotton
fabrics. Carbohydrate Polymers 90(2): 915920.
9. Song JY and Kim BS (2009) Rapid biological synthesis of silver
nanoparticles using plant leaf extracts. Bioprocess and Biosystems
Engineering 32(1):7984.
10. Song JY, Kwon EY and Kim BS (2012) Antibacterial latex foams
coated with biologically synthesized silver nanoparticles using
Magnolia kobus leaf extract. Korean Journal of Chemical
Engineering 29(12): 17711775.
11. Mohanta YK, Panda SK, Biswas K et al. (2016) Biogenic synthesis of
silver nanoparticles from Cassia stula (Linn.): in vitro assessment of
their antioxidant, antimicrobial and cytotoxic activities. IET
Nanobiotechnology 10(6): 438444.
12. Logaranjan K, Raiza AJ, Gopinath SC, Chen Y and Pandian K (2016)
Shape- and size-controlled synthesis of silver nanoparticles using Aloe
vera plant extract and their antimicrobial activity. Nanoscale Research
Letters 11: 520.
13. Priya RS, Geetha D and Ramesh PS (2016) Antioxidant activity of
chemically synthesized AgNPs and biosynthesized Pongamia pinnata
leaf extract mediated AgNPs a comparative study. Ecotoxicology
and Environmental Safety 134(Pt 2): 308318.
14. Alsalhi MS, Devanesan S, Alfuraydi AA et al. (2016) Green synthesis
of silver nanoparticles using Pimpinella anisum seeds: antimicrobial
activity and cytotoxicity on human neonatal skin stromal cells and
colon cancer cells. International Journal of Nanomedicine
11: 44394449.
15. Beg M, Maji A, Mandal AK et al. (2017) Green synthesis of silver
nanoparticles using Pongamia pinnata seed: characterization,
antibacterial property, and spectroscopic investigation of interaction
with human serum albumin. Journal of Molecular Recognition
30(1): e2565.
16. Khatami M, Nejad MS, Salari S and Almani PG (2016) Plant-mediated
green synthesis of silver nanoparticles using Trifolium resupinatum
seed exudate and their antifungal efcacy on Neofusicoccum parvum
and Rhizoctonia solani.IET Nanobiotechnology 10(4): 237243.
17. Salunke BK, Shin J, Sawant SS et al. (2014) Rapid biological synthesis
of silver nanoparticles using Kalopanax pictus plant extract and their
antimicrobial activity. Korean Journal of Chemical Engineering
31(11): 20352040.
18. Salunke BK, Sawant SS and Kim BS (2014) Potential of Kalopanax
septemlobus leaf extract in synthesis of silver nanoparticles for
selective inhibition of specic bacterial strain in mixed culture.
Applied Biochemistry and Biotechnology 174(2): 587601.
19. Borase HP, Salunke BK, Salunkhe RB et al. (2014) Plant extract:
a promising biomatrix for ecofriendly, controlled synthesis of
silver nanoparticles. Applied Biochemistry and Biotechnology
20. Lee SH, Salunke BK and Kim BS (2014) Sucrose density gradient
centrifugation separation of gold and silver nanoparticles synthesized
using Magnolia kobus plant leaf extracts. Biotechnology and
Bioprocess Engineering 19(1): 169174.
21. Dadosh T (2009) Synthesis of uniform silver nanoparticles with a
controllable size. Materials Letters 63(26): 22362238.
22. Yanzhen C, Rongfeng Z, Xiaohui J et al. (2014) Syntheses and
characterization of nearly monodispersed, size tunable silver
nanoparticles over a wide size range of 7200 nm by tannic acid
reduction. Langmuir 30(13): 38763882.
23. Haes J, Haynes CL, McFarland AD et al. (2005) Plasmonic materials
for surface-enhanced sensing and spectroscopy. MRS Bulletin
30(5): 368375.
24. Elechiguerra JL, Burt JL, Morones JR et al. (2005) Interaction of silver
nanoparticles with HIV-1. Journal of Nanobiotechnology 3:6.
25. Morones R, Elechiguerra JL, Camacho A et al. (2005) The
bactericidal effect of silver nanoparticles. Nanotechnology
16(10): 23462353.
26. Prabhu S and Poulose EK (2015) Silver nanoparticles: mechanism of
antimicrobial action, synthesis, medical applications, and toxicity
effects. International Nano Letters 2: 32.
27. Ajitha B, Ashok Kumar Reddy Y and Sreedhara Reddy P (2015)
Enhanced antimicrobial activity of silver nanoparticles with
controlled particle size by pH variation. Powder Technology
28. Cataldo F, Ursini O and Angelini G (2013) A green synthesis of
colloidal silver nanoparticles and their reaction with ozone. European
Chemical Bulletin 2(10): 700705.
29. Sivaraman SK, Elango I, Kumar S and Santhanam V (2009) A green
protocol for room temperature synthesis of silver nanoparticles in
seconds. Current Science 97(7): 10551059.
30. Guo XY, Shao HQ, Hu WL, Gao W and Chen X (2010) Tannin and
polyacrylic acid polarity and structure inuence on the performance of
polyvinylchloride ultraltration membrane. Desalination 250(2):
31. Tian F, Li B, Ji B, Zhang G and Luo Y (2009) Identication
and structureactivity relationship of gallotannins separated from
Galla chinensis.LWT Food Science and Technology 42(7):
32. Lee YH, Hwang EK, Baek YM and Kim HD (2015) Deodorizing
function and antibacterial activity of fabrics dyed with gallnut
(Galla chinensis) extract. Textile Research Journal 85(10):
33. Tian F, Li B, Ji B et al. (2009) Antioxidant and antimicrobial activities
of consecutive extracts from Galla chinensis: the polarity affects the
bioactivities. Food Chemistry 113(1): 173179.
34. Lee HA, Hong SH, Han SJ and Kim OJ (2011) Antimicrobial effects of
the extract of Galla rhois on the long-term swine clinical trial.
Journal of Veterinary Clinics 28(1):16.
35. Zhang J, Li L, Kim SH, Hagerman AE and Lu J (2009) Anti-cancer,
anti-diabetic and other pharmacologic and biological activities of
penta-galloyl-glucose. Pharmaceutical Research 26(9): 20662080.
36. Yang H, Zheng S, Meijer L et al. (2005) Screening the active
constituents of Chinese medicinal herbs as potent inhibitors of
Cdc25 tyrosine phosphatase, an activator of the mitosis-inducing
p34cdc2 kinase. Journal of Zhejiang University Science B 6(7):
37. Kim SH, Park HH, Lee S et al. (2005) The anti-anaphylactic effect of
the gall of Rhusjavanica is mediated through inhibition of histamine
release and inammatory cytokine secretion. International
Immunopharmacology 5(1314): 18201829.
Green Materials Biomedical potential of silver
nanoparticles biosynthesized using
gallnut extract
Sathiyamoorthi, Iskandarani, Salunke and Kim
Downloaded by [ UNIVERSITY OF EXETER] on [14/06/18]. Copyright © ICE Publishing, all rights reserved.
38. Abdel-Aziz MS, Shaheen MS, El-Nekeety AA and Abdel-Wahhab
MA (2014) Antioxidant and antibacterial activity of silver
nanoparticles biosynthesized using Chenopodium murale leaf extract.
Journal of Saudi Chemical Society 18(4): 356363.
39. Austin LA, Mackey MA, Dreaden EC and El-Sayed MA (2014) The
optical, photo thermal and facile surface chemical properties of gold
and silver nanoparticles in biodiagnostics, therapy, and drug delivery.
Archives of Toxicology 88(7): 13911417.
40. Dos Santos CA, Seckler MM, Ingle AP et al. (2014) Silver
nanoparticles: therapeutical uses, toxicity, and safety issues. Journal
of Pharmaceutical Sciences 103(7): 19311944.
41. Majdalawieh A, Kanan MC, El-Kadri O and Kanan SM (2014) Recent
advances in gold and silver nanoparticles: synthesis and applications.
Journal of Nanoscience and Nanotechnology 14(7): 47574780.
42. Mher FP, Khanjani M and Vatani P (2015) Synthesis of nano-Ag
particles using sodium borohydride. Oriental Journal of Chemistry
31(3): 18311833.
43. Clarke G, Ting KN, Wiart C and Fry J (2013) High correlation of
2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric
reducing activity potential and total phenolics content indicates
redundancy in use of all three assays to screen for antioxidant
activity of extracts of plants from the Malaysian rainforest.
Antioxidants 2(1):110.
44. Krishnaraj C, Jagan EG, Rajasekar S et al. (2010) Synthesis of silver
nanoparticles using Acalypha indica leaf extracts and its antibacterial
activity against water borne pathogens. Colloids and Surfaces B:
Biointerfaces 76(1):5056.
45. Amaladhas TP, Sivagami S, Devi TA, Ananthi N and Velammal
SP (2012) Biogenic synthesis of silver nanoparticles by leaf extract of
Cassia angustifolia.Advances in Natural Sciences: Nanoscience and
Nanotechnology 3(4): 045006.
46. Li S (2007) Green synthesis of silver nanoparticles using Capsicum
annuum L. extract. Green Chemistry 9(8): 852858.
47. Pohlit AM, Rezende AR, Lopes Baldin EL, Lopes NP and Neto
VF (2011) Plant extracts, isolated phytochemicals, and plant-derived
agents which are lethal to arthropod vectors of human tropical
diseases a review. Planta Medica 77(6): 618630.
48. Doughari JH (2012) Phytochemicals: extraction methods, basic
structures and mode of action as potential chemotherapeutic agents.
In Phytochemicals a Global Perspective of Their Role in Nutrition
and Health (Rao V (ed.)). InTech, Rijeka, Croatia, pp. 132.
49. Sathishkumar M, Sneha K, Won SW et al. (2009) Cinnamon
zeylanicum bark extract and powder mediated green synthesis of
nanocrystalline silver particles and its bactericidal activity. Colloids
and Surfaces B: Biointerfaces 73(2): 332338.
50. Ahmed S, Ahmad M, Swami BL and Ikram S (2016) A review on
plants extract mediated synthesis of silver nanoparticles for
antimicrobial applications: a green expertise. Journal of Advanced
Research 7(1):1728.
51. Lee KS and El-Sayed MA (2006) Gold and silver nanoparticles in
sensing and imaging: sensitivity of plasmon response to size, shape,
and metal composition. Journal of Physical Chemistry B 110(39):
52. Ahmad T (2014) Reviewing the tannic acid mediated synthesis of
metal nanoparticles. Journal of Nanotechnology 2014: 954206.
53. Amendola V, Bakr OM and Stellacci F (2010) A study of the surface
plasmon resonance of silver nanoparticles by the discrete dipole
approximation method: effect of shape, size, structure, and assembly.
Plasmonics 5(1):8597.
54. Alqadi MK, Abo Noqtah OA, Alzoubi FY, Alzouby J and Aljarrah K
(2014) pH effect on the aggregation of silver nanoparticles
synthesized by chemical reduction. Materials Science Poland
32(1): 107111.
55. Amin M, Anwar F, Janjua MRSA, Iqbal MA and Rashid U (2012)
Green synthesis of silver nanoparticles through reduction with
Solanum xanthocarpum L. berry extract: characterization,
antimicrobial and urease inhibitory activities against Helicobacter
pylori.International Journal of Molecular Sciences 13(8):
56. Vinod VTP, Saravanan P, Sreedhar B, Devi DK and Sashidhar
RB (2011) A facile synthesis and characterization of Ag, Au and Pt
nanoparticles using a natural hydrocolloid gum kondagogu
(Cochlospermum gossypium). Colloids and Surfaces B: Biointerfaces
83(2): 291298.
57. He S, Yao J, Xie S, Pang S and Gao H (2001) Investigation of
passivated silver nanoparticles. Chemical Physics Letters 343(12):
58. Philip D and Unni C (2011) Extracellular biosynthesis of gold and
silver nanoparticles using Krishna tulsi (Ocimum sanctum) leaf.
Physica E: Low-dimensional Systems and Nanostructures 43(7):
59. Abdul Razack V, Duraiarasan S and Mani V (2016) Biosynthesis of
silver nanoparticle and its application in cell wall disruption to release
carbohydrate and lipid from C. vulgaris for biofuel production.
Biotechnology Reports 11:7076.
60. Vijayan SR, Santhiyagu P, Singamuthu M et al. (2014) Synthesis and
characterization of silver and gold nanoparticles using aqueous extract
of seaweed, Turbinaria conoides, and their antimicrofouling activity.
Scientic World Journal 2014: e938272.
61. Patel V, Berthold D, Puranik P and Gantar M (2015) Screening of
cyanobacteria and microalgae for their ability to synthesize silver
nanoparticles with antibacterial activity. Biotechnology Reports
62. Shankar SS, Ahmad A, Pasricha R and Sastry M (2003) Bioreduction
of chloroaurate ions by geranium leaves and its endophytic fungus
yields gold nanoparticles of different shapes. Journal of Materials
Chemistry 13(7): 18221826.
63. Smitha SL, Nissamuddin KM, Philip D and Gopchandran KG (2008)
Studies on surface plasmon resonance and photoluminescence of
silver nanoparticles. Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy 71(1): 186190.
64. Amaladhas TP, Sivagami S, Devi TA, Ananthi N and Velammal
SP (2012) Biogenic synthesis of silver nanoparticles by leaf extract of
Cassia angustifolia.Advances in Natural Sciences: Nanoscience and
Nanotechnology 3(4): 045006.
65. Prakash P, Gnanaprakasam P, Emmanuel R, Arokiyaraj S and
Saravanan M (2013) Green synthesis of silver nanoparticles from leaf
extract of Mimusops elengi, Linn. for enhanced antibacterial activity
against multi drug resistant clinical isolates. Colloids and Surfaces B:
Biointerfaces 108: 255259.
66. Dubey SP, Lahtinen M and Sillanpaa M (2010) Tansy fruit mediated
greener synthesis of silver and gold nanoparticles. Process
Biochemistry 45(7): 10651071.
67. Mehta BK, Chhajlani M and Shrivastava BD (2017) Green synthesis of
silver nanoparticles and their characterization by XRD. Journal of
Physics: Conference Series 836(1): 012050.
68. Phull AR, Abbas Q, Ali A et al. (2016) Antioxidant, cytotoxic and
antimicrobial activities of green synthesized silver nanoparticles from
crude extract of Bergenia ciliate.Future Journal of Pharmaceutical
Sciences 2(1):3136.
69. Dipankar C and Murugan S (2012) The green synthesis,
characterization and evaluation of the biological activities of silver
nanoparticles synthesized from Iresine herbstii leaf aqueous extracts.
Colloids and Surfaces B: Biointerfaces 98:112119.
70. Karunamoorthy V, Kaliappan I, Ramasamy MK, Agrawal A and Dubey
GP (2014) Anticancer activity of Moringa oleifera mediated silver
nanoparticles on human cervical carcinoma cells by apoptosis
induction. Colloids and Surfaces B: Biointerfaces 117 : 354359.
71. Prabu D, Arunvasu C, Babu G, Manikandan R and Srinivasan P (2013)
Biologically synthesized green silver nanoparticles from leaf extract
Green Materials Biomedical potential of silver
nanoparticles biosynthesized using
gallnut extract
Sathiyamoorthi, Iskandarani, Salunke and Kim
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of Vitex negundo L. induce growthinhibitory effect on human colon
cancer cell HCT15. Process Biochemistry 48(2): 317324.
72. Prasad R (2014) Synthesis of silver nanoparticles in photosynthetic
plants. Journal of Nanoparticles 2014: 963961.
73. Mohanta YK, Panda SK, Biswas K et al. (2016) Biogenic synthesis of
silver nanoparticles from Cassia stula (Linn.): in vitro assessment
of their antioxidant, antimicrobial and cytotoxic activities.
IET Nanobiotechnology 10(6): 438444.
74. Papo N, Shahar M, Eisenbach L and Shai Y (2003) A novel lytic
peptide composed of DL-amino acids selectively kills cancer cells in
culture and in mice. Journal of Biological Chemistry 278(23):
75. Ohgaki M, Kizuki T, Katsura M and Yamashita K (2001) Manipulation
of selective cell adhesion and growth by surface charges of electrically
polarized hydroxyapatite. Journal of Biomedical Materials Research
57(3): 366373.
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Green Materials Biomedical potential of silver
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Sathiyamoorthi, Iskandarani, Salunke and Kim
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... The produced Au-BNNs nanohybrid was centrifuged at 13,000 rpm for 30 min before being redispersed in 20 mL of distilled water for further use. The experimental procedure used for the in situ growth of nanoparticles onto BNNs surface is presented in Fig. 1. 0.1 mM AgNO 3 was used for Ag-BNNs nanohybrid, and the BNNs dispersion pH was adjusted to 8.0 using 0.5 N K 2 CO 3 (Sathiyamoorthi et al., 2018). The obtained nanohybrids were centrifuged and freeze dried for characterization and experiments. ...
... AuNPs and AgNPs were prepared by mixing 1 mL of GNE with 50 mL of either HAuCl 4 or AgNO 3 solution (0.1 mM) at pH 8.0. The resulting mixtures were subjected to a continuous stirring for 30 min (Sathiyamoorthi et al., 2018). ...
... The broad peak at 1211 cm À1 is due to the stretching modes of CeH and polyol CeO. The band at 762 cm À1 shows distortion vibration of C]C in benzene rings (Sathiyamoorthi et al., 2018). FTIR spectrum of BNNs revealed the presence of surface anchored tannins, proteins, carbonyl groups of amino acid, and peptides. ...
This is the first report on a green and sustainable approach for the in situ growth of gold (Au) and silver (Ag) nanoparticles onto h-boron nitride nanosheets (BNNs) surface, through the use of gallnut extract (GNE) as a natural and potential reducing agent instead of chemical reductants, commonly reported for their harmful effects on the environment and human health. BNNs were synthesized by ultrasonic exfoliation of boron nitride using GNE. GNE functional groups on BNNs surface were able to act as reducing sites for metal salts enabling the in situ growth of either Au or Ag nanoparticles on their surface. The synthesized Au-BNNs and Ag-BNNs nanohybrids were characterized in terms of transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray photoelectron spectroscopy (EDS), X-ray diffraction (XRD), UV–visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques. UV–visible spectroscopy confirmed the formation of Au and Ag nanoparticles at 517 and 391 nm. The size of Au and Ag nanoparticles grown on BNNs surface was approximately 4 and 7 nm, respectively. XRD and XPS also confirmed the formation of nanoparticles onto BNNs. FTIR analysis revealed that most of the GNE functional groups present on BNNs were not observed in Au-BNNs and Ag-BNNs spectra, confirming the reduction of metal ions by polyphenols present on BNNs. The produced Au-BNNs and Ag-BNNs nanohybrids displayed a 4-nitrophenol reduction of 88.7 and 76.5%, respectively, with a greater peroxidase mimicking activity compared to either nanoparticles or BNNs alone. The antimicrobial activity of the synthesized nanocomposites was evaluated against Escherichia coli and Staphylococcus aureus. Regardless of the bacterial strain, Ag-BNNs nanohybrids showed higher antimicrobial potential in inhibiting bacterial growth compared to the pristine Ag nanoparticles, with a higher antibacterial effect against Gram-positive than Gram-negative bacteria. Our results present new elements regarding BNNs-based nanohybrids which may help expand their applications in various fields such as catalyst, antimicrobial, biomedical, biosensor, and fillers in polymer matrix.
... The histogram analysis predicated the maximum particle size of AgNPs at 17nm ( Figure 7B). The verification of planes of the crystalline, connected to the structure of the face-centred cubic component of silver, is reflected in the selected region electron diffraction design of AgNPs (111), (200), (220), and (311) (Figure 7 C) (Sathiyamoorthi et al., 2018).The results revealed that the S.swartzii extract acts as a suitable neutralizing substance for forming polydisperse crystalline AgNPs. ...
Full-text available
In current trends of green synthesis of nanoparticles is rapidly shifting from plants based to marine algae as it is widely available as well as highly explore for pharmaceutical work. Presented work focuses on synthesising silver nanoparticles using marine algae Sargassum swartzii and its characterization through multiple authentic methods like UV-Vis spectrophotometer, X-Ray Diffraction, Fourier transform infrared spectroscopy, Scanning Electron Microscopy and Transmission Electron microscopes.The primary confirmation was done by the visible appraisal of the color difference from the light yellow-brown to dark brown colour. The UV-Visible absorbance spectra verified the formation of silver nanoparticles and spectra increased with incubation time. The Surface Plasmon Resonance (SPR) absorbance peak was observed at 439nm. SEM and TEM confirmed particles' surface morphology and size of AgNPs from 14 to 30nm. XRD approved particles' face-centric cubic and crystal structure and the size (15.33 nm) calculated through the Scherer equation. FTIR analysis reflected the various functional groups associated with the algal extracts, which help in the bindings of Ag molecules during AgNPs synthesis. The synthesized silver nanoparticles revealed significant antibacterial activity against Bacillus subtilis (27.17±0.73mm) and Staphylococcus aureus (23.53±0.29mm). The work reported that Sargassum swartzii widely available brown macroalgae, could be used as an alternative source for synthesis of AgNPs without destroying high plants and the produced AgNPs have efficient antibacterial activity against both gram positive and gram negative bacteria, which can be explore in curing several human diseases.
... FTIR spectra (Fig. S3) of gallic acid (GA) and tannic acid (TA) showed characteristic peaks at 3389 cm − 1 which are attributed to stretching of O-H groups and 1711 cm − 1 for -CO. The peaks at 1615, 1450, and 1327 cm − 1 can be assigned to the aromatic ring C = C stretching vibrations, C-C aromatic groups stretching vibrations, and stretching of hydroxyl and carboxylate group [23,24]. The peak at 1223 cm − 1 signifies the C-O polyol group. ...
Enzyme-mimicking nanoparticles or nanozymes have received increasing interest as potentially viable alternatives to overcome natural enzyme limitations including low thermal stability and high cost of synthesis, isolation, and purification. Nanomaterial-based biomimetic catalysts with multiple functions are essential to address challenges in artificial enzyme mimicking processes. Here, we report novel gold nanoparticles (AuNPs) catalyzing multienzyme cascade reaction (glucose oxidase and peroxidase mimicking activity) synthesized via a green process using gallnut extract (GNE) as a reducing and capping agent. First, with glucose oxidase mimicking activity, glucose is oxidized to gluconic acid and H2O2. Second, the in situ generated H2O2 by glucose oxidation assists the subsequent peroxidase mimicking reaction that oxidizes the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine. The synthesized GNE-based AuNPs showed an optimum catalytic activity at 40 °C within a pH range of 6–8. Apparent Michaelis constant (Km) values for glucose and H2O2 were estimated to be 0.089 and 0.118 mM, respectively. These low Km values demonstrate the strong affinity of the synthesized GNE-based AuNPs towards both substrates. GNE-based AuNPs exhibited an average ζ-potential value of –32.2 mV, indicating good physical stability of the nanosuspension. The nanoparticles displayed good reproducibility with long-term stability during storage at 4 °C for 10 days. In addition, the green synthesized AuNPs showed higher dual enzyme mimicking activity compared to chemically synthesized AuNPs due to their unique rhombic dodecahedron morphology. This work provides new insights regarding the investigation of green synthesized nanoparticles as multienzyme substitutes for glucose oxidase and peroxidase in different applications such as diagnostic kits for glucose level detection.
... Macrofungi is another category of fungi that includes edible and medicinal mushrooms growing on organic substrates in nature [82]. Nowadays, many studies focus on synthesizing MNPs, using different genera of edible and medicinal mushrooms, due to the innumerable bioactive compounds with diverse biological activities that are present within them [83]. A quite wide variety of amino acids, proteins and polysaccharides that are present in the mushrooms have been utilized in both the intracellular and extracellular synthesis of MNPs, including AgNPs [84]. ...
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The transmission of a wide range of diseases, related to the infection by pathogenic microorganisms is a major public health problem that daily endangers the safety of human population. Silver has been thoroughly studied and used against bacteria due to its antimicrobial properties. Nanostructured silver gathers all the advantages of the silver itself, as well as the advanced performance of the nanomaterials. Thus, currently, silver nanoparticles constitute the most widely used kind of nanoparticles in biomedicine, due to their attractive antimicrobial properties. A variety of physical and chemical methods are employed for the AgNPs synthesis. However, many of them include the use of toxic reagents or require large amounts of energy, during the synthesis process. For this reason, many eco-friendly methods are proposed in order to synthesize AgNPs. Hence, biogenic synthesis of AgNPs, utilizing biological resources opens a novel route for the development of alternative production processes. These methods seem to have significant advantages, as the extracts contribute positively to the formation and enhancement of the antimicrobial activity of AgNPs, also acting as protective agents of the produced particles. In this review an integrated approach of AgNPs bio-synthetic methods using microorganisms, such as bacteria and fungi, plants and plant extracts, as well as several templates, like DNA and viruses is discussed, shedding light on the comparative advantages of them.
... [11][12][13][14] Silver nanoparticles (AgNPs) have obvious therapeutic potential in treating a variety of diseases, including osteomyelitis and cancer, and have antiproliferative effects. [15][16][17][18][19][20] Tumor angiogenesis has been defined as a result of blood vessel development which has a great impact on growth of solid tumors. 21 Angiogenesis is controlled by the stability of several agents. ...
Full-text available
The use of plant extracts is a low-cost and green way to synthesize nanoparticles. In this research, the authors investigated the antibacterial, cytotoxic and antiangiogenic properties of silver nanoparticles (AgNPs) synthesized using Amaranthus cruentus extract. The fabricated nanoparticles were characterized by transmission electron microscopy (TEM), field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, dynamic light scattering and X-ray diffraction. The TEM results showed that the typical size of the AgNPs recorded was 15nm. Biological tests indicated that the biosynthesized AgNPs had caused a decrease in cancerous cells (MCF-7) and had a high antibacterial activity against Escherichia coli, Staphylococcus epidermidis and Staphylococcus aureus. According to data analysis, the number and length of the blood vessels in different concentrations of AgNPs reduced significantly (depending on the dose). The chorioallantoic membrane assay revealed a large decrease in the number and length of angiogenic blood vessels in the presence of AgNPs. Real-time polymerase chain reaction and flow cytometry studies showed a dramatic increase in the gene expression of caspase-3 and caspase-8.
... However, the plant extract synthesized nanoparticles have acquired significant importance due to their cost effectiveness, stability, ease of availability, and preparation, compared to the nanoparticles synthesized by chemicals and microbes. Plant extracts such as gallnut extract [6], Kalopanax pictus extract [7], etc. have been explored in order to synthesize metal based nanoparticles i.e., silver, gold, iron oxide, indium oxide, copper, palladium, selenium nanoparticles, manganese dioxide, etc. ...
Full-text available
This study reports a facile and ecofriendly approach for the ultrasound assisted synthesis of silver and iron oxide nanoparticles and their enhanced antibacterial and antioxidant activities. The fenugreek seed extract was used as reducing, capping, and stabilizing agent in the synthesis of nanoparticles. The transmission electron microscopy results showed that nanoparticles synthesized by ultrasonication have a smaller size (~20 nm) as compared to the nanoparticles fabricated by magnetic stirring (~40 nm). The color change of the solution from milky white to brown suggested the formation of silver nanoparticles which was confirmed by the presence of an absorbance peak at 396 nm. The results of powder X-ray diffraction and energy dispersive X-ray spectroscopy confirmed the crystallinity and elements present in nanoparticles synthesized using fenugreek seed extract. Fourier transform infrared analysis showed that the fenugreek seed phytochemicals were coated on the nanoparticle surface. Thermal gravimetric analysis showed the thermal degradation and stability of nanoparticles. Magnetization study of iron oxide nanoparticles confirmed the superparamagnetic nature. The silver nanoparticles showed antibacterial activities against both gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria, while no antibacterial activities were observed for iron oxide nanoparticles. The ultrasound assisted nanoparticles showed higher stability and antibacterial and antioxidant activity compared with the nanoparticles fabricated by magnetic stirring.
Rhus chinensis Mill (also known as Rhus semialata Murray, Family Anacardiaceae) is a deciduous underutilized wild edible fruit tree. It is native to China and Japan and distributed in tropical and subtropical regions at an altitude of 1300 to 2400 m asl in India, Nepal, Bhutan, Malaysia, Mayamar, Java, Europe, Ceylon, Korea. Fruits and galls (Galla chinensis) of this tree are utilized in medicine, food, fiber, juice and ingredients of traditional products. A number of phytoconstituents such as gallotannin, gallic acid, ellagic acid, phenols, flavonoids, organic acids and mineral isolated from R. chinensis were reported to have various pharmacological activities. This chapter is an attempt to synthesis the existing knowledge and scientific progress on this underutilized tree to evaluate its potential in nutritional, pharmaceutical and cosmoceutical industries.
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The main goal of this study is to prepare antibacterial poly(lactic acid) (PLA) containing cinnamaldehyde and geraniol and to evaluate the antibacterial activity and assess the changes of physical properties of the PLA films. Cinnamaldehyde- and geraniol-incorporated (10%, 20%, 30%, and 50% v/w) PLA films were prepared via solution-casting. While preparing these films, plasticizers were not added to the matrix. Antibacterial activities of these films against Escherichia coli and Staphylococcus aureus were investigated by the disk diffusion method. Thermal degradation characteristics were analyzed via thermogravimetric analysis (TGA), glass transition, crystallization, and melting temperatures, and enthalpies of the films were determined from differential scanning calorimetry (DSC) scans. Tensile strength and elongation-at-break values of neat PLA and antibacterial-compound-containing films were evaluated and compared after the mechanical tests. Moreover, the changes in the polymer morphology were observed by SEM analysis, and opacity of the films was determined by UV-vis spectroscopy. Our results showed that both compounds provided antibacterial effect to the PLA, with cinnamaldehyde being more effective than geraniol. Moreover, plasticization effects of the compounds were confirmed by DSC analysis.
Herein, the authors have developed an efficient green method for the reduction of graphene oxide by using seed extract from the easily available and cheap plant Punica granatum L. (pomegranate). Phytochemical constituents present in the extract are responsible for reduction, stabilization and capping of reduced graphene. There are a number of methods reported for the physical and chemical reduction of graphene oxide, but the green reduction approach has become more popular. Utilization of the P. granatum L. seed extract for the reduction of graphene oxide is reported for the first time. The method is essential because the reaction set-up is simple, it takes less time, is non-toxic, uses a mild reducing agent and obtains a very good yield. The reduction of graphene oxide is confirmed by different characterization techniques such as Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, thermogravimetric analysis and morphological study using scanning and transmission electron microscopy. The resultant reduced graphene and graphene oxide nanosheets show stable dispersion in water and other solvents. In the case of graphene materials, the pristine form shows zero band gap; however, the study of new band gap openings for electronics applications is possible using the disperse form. The reduced graphene oxide shows biocompatibility and excellent radical-scavenging activity against 2,2-diphenyl-1-picrylhydrazyl free radicals.
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A cost effective and environment friendly technique for green synthesis of silver nanoparticles has been reported. Silver nanoparticles have been synthesized using ethanol extract of fruits of Santalum album (Family Santalaceae), commonly known as East Indian sandalwood. Fruits of S.album were collected and crushed. Ethanol was added to the crushed fruits and mixture was exposed to microwave for few minutes. Extract was concentrated by Buchi rotavaporator. To this extract, 1mM aqueous solution of silver nitrate (AgNO3) was added. After about 24 hr incubation Ag⁺ ions in AgNO3 solution were reduced to Ag atoms by the extract. Silver nanoparticles were obtained in powder form. X-ray diffraction (XRD) pattern of the prepared sample of silver nanoparticles was recorded The diffractogram has been compared with the standard powder diffraction card of JCPDS silver file. Four peaks have been identified corresponding to (hkl) values of silver. The XRD study confirms that the resultant particles are silver nanoparticles having FCC structure. The average crystalline size D, the value of the interplanar spacing between the atoms, d, lattice constant and cell volume have been estimated. Thus, silver nanoparticles with well-defined dimensions could be synthesized by reduction of metal ions due to fruit extract of S.album.
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Silver nanoparticles (AgNPs) are valuable metal nanoparticles that exhibit exceptional properties compared to their bulk materials. Pronounced surface area, quantum confinement effect complemented by small particle dimension, and many other extraordinary characteristics make AgNPs suitable in a variety of applications. Different methods have been adopted to synthesize AgNPs. Biological methods can formulate AgNPs in an environmentally friendly manner without producing toxic waste. Among the biological methods, plants are simple and attractive sources for AgNP synthesis. Compared to AgNPs produced via other modes of synthesis, phyto-synthesized AgNPs, due to their safety features, have been found to be advantageous for a variety of applications, especially biological applications. Strong research efforts have investigated the utility of phyto-synthesized AgNPs for different applications. Investigators are coming up with innovative applications of phyto-synthesized AgNPs for the development of science and technology and to benefit humankind. The present article focuses on phyto-synthesized AgNPs for biological applications, with a brief review of their synthesis, mechanism, and size/shape control.
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Biogenic synthesis of silver nanoparticles (AgNP) was performed at room temperature using Aloe vera plant extract in the presence of ammoniacal silver nitrate as a metal salt precursor. The formation of AgNP was monitored by UV-visible spectroscopy at different time intervals. The shape and size of the synthesized particle were visualized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. These results were confirmed by X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses and further supported by surface-enhanced Raman spectroscopy/Raman scattering (SERS) study. UV-visible spectrum has shown a sharp peak at 420 nm and further evidenced by FTIR peak profile (at 1587.6, 1386.4, and 1076 cm⁻¹ with corresponding compounds). The main band position with SERS was noticed at 1594 cm⁻¹ (C–C stretching vibration). When samples were heated under microwave radiation, AgNP with octahedron shapes with 5–50 nm were found and this method can be one of the easier ways to synthesis anisotropic AgNP, in which the plant extract plays a vital role to regulate the size and shape of the nanoparticles. Enhanced antibacterial effects (two- to fourfold) were observed in the case of Aloe vera plant protected AgNP than the routinely synthesized antibiotic drugs. Graphical Abstract Shape and size-controlled synthesis of silver nanoparticles using Aloe vera plant extract Electronic supplementary material The online version of this article (doi:10.1186/s11671-016-1725-x) contains supplementary material, which is available to authorized users.
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Background: The present study focused on a simple and eco-friendly method for the synthesis of silver nanoparticles (AgNPs) with multipurpose anticancer and antimicrobial activities. Materials and methods: We studied a green synthesis route to produce AgNPs by using an aqueous extract of Pimpinella anisum seeds (3 mM). Their antimicrobial activity and cytotoxicity on human neonatal skin stromal cells (hSSCs) and colon cancer cells (HT115) were assessed. Results: A biophysical characterization of the synthesized AgNPs was realized: the morphology of AgNPs was determined by transmission electron microscopy, energy dispersive spectroscopy, X-ray powder diffraction, and ultraviolet-vis absorption spectroscopy. Transmission electron microscopy showed spherical shapes of AgNPs of P. anisum seed extracts with a 3.2 nm minimum diameter and average diameter ranging from 3.2 to 16 nm. X-ray powder diffraction highlighted the crystalline nature of the nanoparticles, ultraviolet-vis absorption spectroscopy was used to monitor their synthesis, and Fourier transform infrared spectroscopy showed the main reducing groups from the seed extract. Energy dispersive spectroscopy was used to confirm the presence of elemental silver. We evaluated the antimicrobial potential of green-synthesized AgNPs against five infectious bacteria: Staphylococcus pyogenes (29213), Acinetobacter baumannii (4436), Klebsiella pneumoniae (G455), Salmonella typhi, and Pseudomonas aeruginosa. In addition, we focused on the toxicological effects of AgNPs against hSSC cells and HT115 cells by using in vitro proliferation tests and cell viability assays. Among the different tested concentrations of nanoparticles, doses 10 μg showed few adverse effects on cell proliferation without variations in viability, whereas doses 10 μg led to increased cytotoxicity. Conclusion: Overall, our results highlighted the capacity of P. anisum-synthesized AgNPs as novel and cheap bioreducing agents for eco-friendly nanosynthetical routes. The data confirm the multipurpose potential of plant-borne reducing and stabilizing agents in nanotechnology.
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In recent years, green synthesized nanoparticles from plant extract have drawn a great interest due to their prospective nanomedicinal application. This study investigates a proficient, safer and sustainable way for the preparation of AgNPs using medicinal plant Pongamia pinnata (family: Leguminoseae, Species: Pinnata) seeds extract without using any external reducing and stabilizing agent. Both UV–Vis spectrum at λmax = 439 nm and EDX spectra proof the formation of AgNPs. An average diameter of the AgNPs was 16.4 nm as revealed from TEM. Hydrodynamic size (d = ~19.6 nm) was determined by DLS. Zeta potential of AgNPs was found to be -23.7 mV which supports its dispersion and stability. FT-IR study revealed that the O–H, C=O and C-O-C groups were responsible for the formation of AgNPs. The antibacterial activity of the synthesized AgNPs was checked against E. coli ATCC 25922. AgNPs at its LD50 dose exhibited synergistic effect with ampicillin. Since protein-AgNPs association greatly affects its adsorption, distribution, functionality and can also influence the functions of biomolecules. So in order to understand the adsorption and bioavailability, the interaction of synthesized AgNPs towards human serum albumin was investigated by fluorescence, UV-Vis and circular dichroism (CD) spectroscopic methods. The binding affinity and binding sites of HSA towards AgNPs were measured by using the fluorescence quenching data. The CD spectroscopic results revealed that there was a negligible change of α-helical content in their native structure. Overall, these AgNPs show versatile biological activities and may be applied in the field of nanomedicine.
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The bark extract of medicinal plant Hovenia dulcis was used for rapid, low cost, and ecofriendly synthesis of silver nanoparticles (AgNPs). The biosynthesized AgNPs demonstrated absorption peak at 433 nm in UV-visible spectroscopy and binding energies at 368.2 and 374 eV in X-ray photoelectron spectroscopy. Transmission electron microscopy micrographs of AgNPs exhibited spherical shapes with average size of 33 nm and selected area electron diffraction pattern suggested their crystalline nature. Fourier transform-infrared spectroscopy analysis revealed role of plant metabolites as reducing and capping agent in synthesis of AgNPs. Enhancement of antibacterial potential of biosynthesized AgNPs after combination with ten different antibiotics with diverse documented mode of action is reported in the present study. The antibacterial effect of AgNP combination with antibiotics was observed to be synergistic. The highest synergistic effects were 3.04 folds for Penicillin against Bacillus cereus and 1.55 folds for Tetracycline against Escherichia coli. This unique property of AgNPs can be therapeutically valuable for fabrication of innovative hybrid drugs for enhancing effectiveness of antibiotics to kill bacteria.
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Background: The methods like bio-green are advantageous over chemical and physical methods due to ecofriendly and cost-effective synthesis of nanoparticles. Current study was designed for green synthesis of silver nanoparticles (AgNPs) and their biological evaluation. Methods: Methanolic extract of Bergenia ciliata (BC) rhizomes prepared by maceration was used for the synthesis of AgNPs and confirmed by UV–visible and Fourier Transform Infra-Red (FTIR) spectroscopy. Further field emission scanning electron microscope (SEM) was used for the shape and size determination. In vitro Antioxidant, antimicrobial and cytotoxic potential was determined by using standard protocols. Results: The nanoparticles were spherical in shape having average particle size of 35 nm. FTIR analysis revealed the possible involvement of phyto-constituents in silver nanoparticles of crude extract. Green synthesized nanoparticles (BCAgNPs) showed the enhanced antioxidant properties compared to the crude extract. These nanoparticles showed the cytotoxic effects against brine shrimp (Artemia salina) nauplii with a value of 33.92 μg/ml LD50. BCAgNPs were found effective against the pathogenic fungal and bacterial strains in comparison to the Bergenia ciliata extract. Conclusion: Green synthesized BCAgNPs showed enhanced biological activities. Present results also support the advantages of using bio-green method for the production of nanoparticles having the potential of antimicrobial and cytotoxic activities.
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In recent years, biosynthesis and the utilisation of silver nanoparticles (AgNPs) has become an interesting subject. In this study, the authors investigated the biosynthesis of AgNPs using Trifolium resupinatum (Persian clover) seed exudates. The characterisation of AgNPs were analysed using ultraviolet–visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infra-red spectroscopy. Also, antifungal efficacy of biogenic AgNPs against two important plant-pathogenic fungi (Rhizoctonia solani and Neofusicoccum Parvum) in vitro condition was evaluated. The XRD analysis showed that the AgNPs are crystalline in nature and have face-centred cubic geometry. TEM images revealed the spherical shape of the AgNPs with an average size of 17 nm. The synthesised AgNPs were formed at room temperature and kept stable for 4 months. The maximum distributions of the synthesised AgNPs were seen to range in size from 5 to 10 nm. The highest inhibition effect was observed against R. solani at 40 ppm concentration of AgNPs (94.1%) followed by N. parvum (84%). The results showed that the antifungal activity of AgNPs was dependent on the amounts of AgNPs. In conclusion, the AgNPs obtained from T. resupinatum seed exudate exhibit good antifungal activity against the pathogenic fungi R. solani and N. Parvum.
Microalgae are the fledging feedstocks yielding raw materials for the production of third generation biofuel. Assorted and conventional cell wall disruption techniques were helpful in extracting lipids and carbohydrates, nevertheless the disadvantages have led the biotechnologists to explore new process to lyse cell wall in a faster and an economical manner. Silver nanoparticles have the ability to break the cell wall of microalgae and release biomolecules effectively. Green synthesis of silver nanoparticles was performed using a novel bacterial isolate of Bacillus subtilis. Characterisation of nanosilver and its effect on cell wall lysis of microalgae were extensively analysed. Cell wall damage was confirmed by lactate dehydrogenase assay and visually by SEM analysis. This first piece of research work on direct use of nanoparticles for cell wall lysis would potentially be advantageous over its conventional approaches and a greener, cost effective and non laborious method for the production of biodiesel.
The present study reports on biogenic-synthesised silver nanoparticles (AgNPs) derived by treating Ag ions with an extract of Cassia fistula leaf, a popular Indian medicinal plant found in natural habitation. The progress of biogenic synthesis was monitored time to time using a ultraviolet–visible spectroscopy. The effect of phytochemicals present in C. fistula including flavonoids, tannins, phenolic compounds and alkaloids on the homogeneous growth of AgNPs was investigated by Fourier-transform infrared spectroscopy. The dynamic light scattering studies have revealed an average size and surface Zeta potential of the NPs as, −39.5 nm and −21.6 mV, respectively. The potential antibacterial and antifungal activities of the AgNPs were evaluated against Bacillus subtilis, Staphylococcus aureus, Candida kruseii and Trichophyton mentagrophytes. Moreover, their strong antioxidant capability was determined by radical scavenging methods (1,1-diphenyl-2-picryl-hydrazil assay). Furthermore, the AgNPs displayed an effective cytotoxicity against A-431 skin cancer cell line by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, with the inhibitory concentration (IC 50) predicted as, 92.2 ± 1.2 μg/ml. The biogenically derived AgNPs could find immense scope as antimicrobial, antioxidant and anticancer agents apart from their potential use in chemical sensors and translational medicine.