Caffeine-mediated synthesis of CuO nanoparticles: characterization, morphology changes, and bactericidal activity

Article abstract of DOI:10.1080/24701556.2020.1769667

This study aims the synthesis of CuO nanoparticles using caffeine as stabilizing agent by precipitation method. The effect of caffeine on the morphology of CuO NPs was studied by varying the concentrations of caffeine. The synthesized CuO NPs were charact

Full text of DOI:10.1080/24701556.2020.1769667

Inorganic and Nano-Metal Chemistry
ISSN: 2470-1556 (Print) 2470-1564 (Online) Journal homepage: https://www.tandfonline.com/loi/lsrt21
Caffeine-mediated synthesis of CuO nanoparticles:
characterization, morphology changes, and
bactericidal activity
A. P. Angeline Mary, A. Thaminum Ansari & R. Subramanian
To cite this article: A. P. Angeline Mary, A. Thaminum Ansari & R. Subramanian (2020): Caffeine-
mediated synthesis of CuO nanoparticles: characterization, morphology changes, and bactericidal
activity, Inorganic and Nano-Metal Chemistry, DOI: 10.1080/24701556.2020.1769667
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INORGANIC AND NANO-METAL CHEMISTRY
https://doi.org/10.1080/24701556.2020.1769667
Caffeine-mediated synthesis of CuO nanoparticles: characterization, morphology
changes, and bactericidal activity
A. P. Angeline Marya, A. Thaminum Ansarib, and R. Subramanianc
b
aDepartment of Chemistry, Sacred Heart College, Tirupattur, Vellore, Tamil Nadu, India; PG & Research Department of Chemistry,
c
Muthurangam Government Arts College (Autonomous), Vellore, Tamil Nadu, India; Department of Chemistry, Sun Arts and Science College,
Tiruvannamalai, Tamil Nadu, India
ABSTRACT
ARTICLE HISTORY
Received 21 February 2020
Accepted 22 April 2020
This study aims the synthesis of CuO nanoparticles using caffeine as stabilizing agent by precipita-
tion method. The effect of caffeine on the morphology of CuO NPs was studied by varying the
concentrations of caffeine. The synthesized CuO NPs were characterized using Fourier-transform
infrared spectroscopy (FTIR), X-ray diffraction study (XRD) scanning electron microscopy coupled
with energy-dispersive X-ray diffraction (SEM-EDAX), and transmission electron microscope with
selected area diffraction (TEM-SAED). The morphological study of the nanoparticles shows that the
leafy particles transformed into spherical nanoparticles at higher concentration of caffeine. The
synthesized CuO NPs showed antibacterial activity against pathogenic bacteria. This research sup-
port to understand the role of caffeine in the synthesis of CuO NPs and further it could be used
as material for biomedical applications.
KEYWORDS
Caffeine; organic modifier;
copper oxide; spherical
nanoparticles
Introduction
hull,[15] Ixora coccinea leaf,[16] Syzygium alternifolium (Wt.)
Walp,[17] Ferulago angulata (Schlecht) Boiss,[18] Rosa canina
fruit,[19] Azadirachta indica,[20] Bauhinia tomentosa
leaves,[21] Moringa oleifera leaves,[22] wheat seed extract,[23]
Euphorbia chamaesyce leaf extract[24] and many more plant
extracts,[25] and tragacanth gel[26] have been used natural
reducing in the green synthesis of CuO NPs.
Tea is a methylxanthine compound, rich source of caf-
feine. Caffeine activates the central nervous system (CNS). It
is a psychoactive drug legally used around the world.[27] It
reported to improve physical performance, memory, and
cognitive performance. It increases energy, alertness, anxiety,
and the capability to concentrate attention and reduces the
fatigue.[28,29] Famous beverages such as black tea and coffee
have been used to produce metal oxide nanoparticles Black
tea.[3,30,31] It has many more health benefits. It is freely sol-
uble in hot water. In the present work, we studied the effect
of caffeine on crystalline structure, size, shape, and morph-
ology of the copper nanoparticles.
Nanomaterials such as metal and metal oxide nanoparticles
attract the researchers around the world due to their peculiar
properties and application.[1–4] Various properties and appli-
cations of nanomaterials make the researcher move toward
green synthesis. Green synthesis of nanoparticles has attracted
the researchers due to enormous applications. The numerous
toxic effects of metal nanoparticles put effort to develop a
green method to fabricate metal nanoparticles. Green fabrica-
tion of copper nanoparticles is of vast curiosity because of the
many benefits. Environmental applications such as dye deg-
radation, metal removal, and catalytic activities of nanopar-
ticles also inspired for nanomaterial research.[1,5–9]
Copper is well known for its electrical conductivity than
silver and gold.[10] Copper oxide nanoparticles are industri-
ally important due to their physio-chemical properties. They
used as superconductors, catalysis, batteries, and gas sensors.
Its potentials also explored in the field of harvesting solar
energy.[11] Copper oxide, a leading semi-conducting metal
oxide, having a bandgap of 1.2 eV has inspired the attention
of the researchers in industry and academia due to its tre-
mendous applications.[12] The CuO NPs have been widely
used for various applications such as solar cells, sensors,
Experimental
Chemicals
catalyst for dye degradations, and detecting biomolecules in Copper nitrate and sodium hydroxide were procured from
the analysis.[13] The bioactive molecules present in the plant Loba Chemie, Mumbai, India. Distilled water was used as a
extract act as reducing agent for the synthesis of CuO NPs. solvent to prepare all the reagents. Caffeine was isolated
Numerous plant extracts have been used ad reducing agent from the tea dust using standard procedures and applied as
to fabricate the CuO NPs. Carica papaya leaves,[14] Oak fruit a modifier.
*CONTACT A. Thaminum Ansari
drthaminum@gmail.com
PG & Research Department of Chemistry, Muthurangam Government Arts College
(Autonomous), Vellore-632002, Tamil Nadu, India.
ß 2020 Taylor & Francis Group, LLC

2
A. P. A. MARY ET AL.
Isolation of caffeine
Caffeine was isolated according to the procedure cited in the
literature.[32] Briefly, 100 g of tea dust was soaked in distilled
water and boiled for 30 min and filtered. Dichloromethane
was added to the tea filtrate, which taken into a separating
funnel and shaken well. The organic layer was separated and
evaporated to get the caffeine. The caffeine was used as sta-
bilizing agent to synthesize CuO NPs.
Synthesis of CuO NPs
CuO NPs were synthesized by precipitation method. Copper
nitrate was used as a precursor and sodium hydroxide as
hydrolyzing agent. In brief, the requisite amount of caffeine
was dissolved in 0.1 M of the copper nitrate solution, which
taken in a 250 ml conical flask and heated on magnetic stir-
rer at 80 ꢀC for half an hour. Then, the sodium hydroxide
solution was slowly added to the above reaction mixture
and continuously stirred for 4 h. The precipitate formed was
thoroughly washed with distilled water to remove untreated
reactants and organic matter. The precipitate was dried in
an oven at 100 ꢀC for 3 h. The copper hydroxide was
annealed at 500 ꢀC in a muffle furnace for 3 h to obtain the
copper oxide. The samples prepared using 50, 100, and
200 mg of caffeine with the same procedure were named as
CF1, CF2, and CF3. A blank one prepared without caffeine
was named as CF0.
Figure 1. FTIR spectrum of caffeine.
Characterization techniques
The X-ray diffraction studies were carried out using Cu-Ka
radiation (Model: X’Pert-PRO) instrument and scanned in
the range of 10–80 ꢀC of 2h values. Functional group identi-
fication and formation of Cu-O bond were analyzed by
Jasco 6300 FT-IR spectrophotometer in the frequency range
from 500 to 4000 cmꢁ1. Nucleation and Morphology of CuO
NPs were examined by JEOL Model JSM-6390LV scanning
electron microscope. The elemental composition was ana-
lyzed using energy-dispersive study (EDS). JEOL/JEM 2100
transmission electron microscope was used to analyze the
shape and surface morphology of the nanoparticles. The
state of the chemical state and elemental composition of the
elements existence in CuO NPs was determined by X-ray
photoelectron spectroscopy (XPS, Thermo Scientific K-
Alpha) equipped with an Al Ka X-ray source. XPS with
Auger electron spectroscopy (AES) Module: Model/
Supplier:PHI 5000 Versa Prob II, FEI Inc. was used to find
out the electronic states of copper oxide nanoparticles.
Figure 2. Structure of Caffeine.
bacterium and dispersed in 10ml of Milli-Q water in each
test tube. The bacterial suspension used to be 106 CFU m/L
by diluting with normal saline solution. The sterilized nutri-
ent agar was poured in each Petri plate and was mixed softly.
After solidification, the sterilized filter paper disks were
wrapped up in test samples and positioned at delineates pos-
ition on agar medium. The Petri plates were incubated at
37ꢀC for 24 h. The concentration of CuO NPs used was
100 lg/ml. The zone of inhibition around the disks was deter-
mined and mentioned as mean standard error of the mean.
Results and discussion
An attempt has been made to study the effect of caffeine on
the surface morphology, size, and shape of copper oxide
nanoparticles. Caffeine is a natural substance was isolated
from the tea dust used as stabilizing agent. The FTIR spec-
trum of caffeine was shown in Figure 1. The spectrum of
caffeine show the absorbance band at 827, 921, 987, 1045,
Bactericidal activity
The antibacterial activity of caffeine stabilized CuO NPs was
examined according to the procedure cited in the litera-
ture.[20] About 28g of Muller Hinton agar was dissolved in
1000ml distilled water. The disks were prepared using 1103, 1267, 1346, 1411, 1633, 2933, and 3263 cmꢁ1. The
Whatman filter paper no. 1 with 6 mm diameter. Bacterial structure of caffeine is shown in Figure 2 comprises of C-H,
culture broths were prepared by using a loop of each CH3, C-N, C ¼ O, and C-C bonds. The band at 827, 921,

INORGANIC AND NANO-METAL CHEMISTRY
3
Figure 4. XRD pattern of CuO NPs (CF0) CuO NPs produced without caffeine
(CF1-CF3) CuO NPs produced using 50, 100, and 200 mg caffeine.
Figure 3. FTIR spectra of CuO NPs synthesized using caffeine; CF0-CuO without
caffeine; CF1-CF3-CuO NPs synthesized using 50, 100, and 200 mg caffeine.
where D is the mean size of the crystalline; K is a dimen-
sionless shape factor, with a value close to unity (0.9). k is
the X-ray wavelength; b is the line broadening at half the
maximum intensity (FWHM); h is the Bragg angle. The
average crystallite size of the CF0, CF1, CF2, and CF3 calcu-
lated were found to be 125, 116, 123, and 138 nm,
respectively.
987, and 1045 cmꢁ1 are attributed the stretching of C-C
bonds of caffeine. The bands observed at 1103 and
1267 cmꢁ1 are attributed to the stretching vibrations of
C ¼ O and C-N bonds. The bands observed at 1346 and
1411 cmꢁ1 relevant to stretching vibrations of C-N and
C ¼ C of caffeine. A band noted at 1633 cmꢁ1 due to the
stretching vibration of the carbonyl group (C ¼ O). Two
larger bands noticed at 2933 and 3263 cmꢁ1 are ascribed
to the C-H bonds of methyl groups (CH3).[33]
The FTIR spectrum CuO NPs synthesized using caffeine
is shown in Figure 3(a–d). The characteristic absorption
bands at 521, 602, 773,854, 1024, 1390, 1618, 3330, and
3140 cmꢁ1 observed in the FTIR spectra reveal the forma-
tion of CuO NPs. The band at 521 and 602 cmꢁ1 are due to
stretching vibrations of Cu-O bond in CuO NPs. Two bands
observed at 773 and 854 cmꢁ1 are attributed to the metal-
oxygen, stretching vibrations of CuO NPs.[34] The bands
observed at 1618 and 3410 cmꢁ1 are represented to stretch-
ing vibrations of moisture content on the surface of CuO
NPs. The characteristic absorption bands observed at 522,
773,842, 1093, 1401, 1629, and 3422 cmꢁ1 confirms the for-
mation of CuO NPs.[35,36]
The XRD pattern of pure and CuO NPs synthesized
using 50, 100, and 200 mg are shown in Figure 4(a–d). The
given spectrum shows the crystalline nature of CuO NPs.
The XRD pattern revealed a sequence of diffraction peaks at
2h of X-axis at 32.45ꢀ, 35.69ꢀ, 38.71ꢀ, 48.08ꢀ, 53.56ꢀ, 58.32ꢀ,
61.68ꢀ, 66.58, 68.51ꢀ, 2.62ꢀ, and 75.65ꢀ coincide with (110),
(002), (111), (202), (020), (202), and (113) planes, respect-
ively. The diffraction peaks are matched with JCPDS Card
(No. 89-2529), which evidently reveal the caffeine mediated
synthesized CuO NPs are in mono-clinic structure.[37–39]
The absence of extra peaks in the spectrum revealed that the
Figure 5(a) shows the SEM images of CuO synthesized
without caffeine. It shows leafy and irregular shaped micro-
particles. Figure 5(b) shows the SEM images of CuO synthe-
sized using 50 mg of caffeine. It obviously shows that the
particles are leaf and arranged in such a way to form, which
are free from agglomeration. Further, it is observed that
microstructure is dependent concentration of caffeine.
Figure 5(c,d) shows that the CuO NPs are leafy and irregu-
lar fiber-like particles. From the SEM images, CuO NPs syn-
thesized using 50 mg of caffeine considered as good in shape
when compared with CuO prepared with 100 and 200 mg of
caffeine as well as blank one. As noticed in figure, the
images reveal lengthy and leafy microparticles. The presence
of Cu and O confirmed by EDS as shown in Figure 5(e).
The morphology of nanoparticles synthesized using 100 and
200 mg appeared to be similar in morphology. But they dif-
fer from pure and CuO NPs synthesized using 50 mg of caf-
feine. The EDS investigation exposed the percentage of Cu
and O in all the samples.
Figure 6(a–d) show the variation of the size of obtaining
nanoparticles with various concentrations of caffeine. As
seen in the images, with caffeine increasing, the size of
nanoparticles found to be similar which varies from the
SEM morphology. Reduction of nanoscale size is due to the
interaction between caffeine and Cu2þ ions. A subsequent
increase in size of the particles might be attributed to the
fairly increasing growth rate of particles during the nucle-
ation. The arrangement of particles seen in the SEM images
CuO NPs are in pure phase. Crystallite size was calculated further confirmed by the SAED pattern. Bright particles are
using the Scherrer Equation (1).
observed in the SAED pattern of CuO NPs without caffeine
reveal bigger size particles. The SAED pattern of CuO pro-
duced with 50 mg caffeine found to be a uniform pattern in
the (Figure 6) The TEM study is performed to understand
Kk
D ¼
(1)
bcosh

4
A. P. A. MARY ET AL.
Figure 5. SEM photographs of CuO NPs; (CF0) CuO NPs produced without caffeine, (CF1-CF3) CuO NPs produced using 50, 100, and 200 mg caffeine.

INORGANIC AND NANO-METAL CHEMISTRY
5
Figure 6. (a) TEM morphographs of CuO NPs; (CF0) CuO NPs produced without caffeine (CF1-CF3) CuO NPs produced using 50, 100, and 200 mg caffeine. (b)
Selected area diffraction pattern of CuO nanoparticles; CF0(b) SAED pattern of CuO synthesized without caffeine, CF1-CF3(b)-SAED pattern of CuO synthesized using
50, 100, and 200 mg caffeine.
the morphology, shape, size and the crystalline characteris- respectively. In Figure 7(c), the Cu 2p3/2 is allocated at
931.22 eV with a shoulder peak at about 941.55 eV and Cu
2p1/2 lies at 951.26 eV with a peak at about 959.94 eV due to
due to the 3d9 shell resultant for the Cuþ state. The differ-
ence between the Cu 2p3/2 and Cu 2p1/2 is 20.09 eV, which
is in concordance with the standard value of 20.10 eV for
CuO. The XPS spectra of O 1s evidenced by two broad
peaks that correspond to the O2 in CuO NPs. The main
peak appeared at the lower binding energy of 526.98 eV is
attributed to Cu-O (Figure 7(b)). A broad peak at 282.15 eV
(Figure 7(a)), lower binding energy attributed to C 1s may
be due to the biomass content and an adsorbed carbon
dioxide molecule on the surface of CuO.[42–44]
tics of the nanoparticles. The particles are observed to be
spherical in shape and the size is found to be in the range
of 10–50 nm. It is well known that sugarcane juice contains
glucose and fructose as major components CuO NPs synthe-
sized using caffeine. It has been proved that the caffeine can
act as a surface modifier, stabilizing and capping agents,
which control the morphology.[40,41] The formation mechan-
ism of CuO NPs is given by Equations (2) and (3). Copper
nitrate reacts with reducing agent (sodium hydroxide solu-
tion) to produce copper hydroxide. During the reaction, caf-
feine has interacted with react with the copper hydroxide
and produce changes in surface morphology.
CuðNO3Þ2 þ 2NaOH ! CuðOHÞ2 þ 2NaNO3
(2)
Bactericidal activity
CuðOHÞ2 þ C8H10N4O2ðCaffeineÞ 5008C CuO þ H2O (3)
The bactericidal activity of ciprofloxacin (25 lg) and CuO
NPs (100 mg) were tested in a Petri plate. The zone of inhib-
ition exhibited by CuO against Escherichia coli, Bacillus sub-
tilis, Pseudomonas epidermidis, and Staphylococcus aureus.
The zone of inhibition shown by all the samples is presented
in Table 1. Among the four samples, CF2 and CF3 showed
maximum zone inhibition against tested bacteria. The
obtained results are compared with standard antibiotic sub-
stance ciprofloxacin.
First, copper nitrate is converted into copper hydroxide
when 0.1 M sodium hydroxide was used as a hydrolyzing
agent in the presence of caffeine. It is assumed that the caf-
feine interacts with copper hydroxide to produce different
shapes of nanoparticles. As the concentration of caffeine
increased from 50 mg to 200 mg, nanorods transformed into
spherical particles. The copper hydroxide colloids were
stored in the laboratory, after three months, the particles
totally settled down.
Further, the formation of CuO nanoparticles was con-
firmed by high-resolution XPS to study the electronic struc-
ture, oxidation state, and the composition of the atoms
involved, and the results are shown in Figure 7(a–c). Three
peaks were indexed to Cu, C, and O. The survey of the sur-
face presents all the elements detected as shown in the fig-
ure represents binding energy peaks at 282.15, 526.98, and
Conclusions
This research work reports the synthesis of CuO NPs using
caffeine as a stabilizing agent. FTIR and XRD pattern ana-
lysis confirmed the formation of CuO NPs and their crystal-
line nature. The SEM morphographs confirmed the
formation of microparticles with various shapes. The TEM
931.16 eV which are attributed to C 1s, O 1s, and Cu 2p, images revealed the transformation, shape, and size of the

6
A. P. A. MARY ET AL.
Table 1. Average zone of inhibition for various concentrations of CuO NPs
nanoparticles in (mm).
Microorganisms
CF0
CF1
CF2
CF3
Ciprofloxacin (25 mg)
E. coli
10
8
10
12
11
7
11
9
12
14
8
16
12
10
12
23
19
18
17
B. subtilis
S. epidermidis
S. aureus
12
particles disappeared at higher concentrations and produced
spherical-shaped particles. This work proved that the sugar-
cane is a suitable green stabilizing agent to produce copper
oxide nanoparticles. CuO NPs exhibited significant bacteri-
cidal activity against E. coli, S. aureus, Pseudomonas aerugi-
nosa, and B. subtilis. Synthesis of copper oxide nanoparticles
suggests that the caffeine acts as a surface modifier and sta-
bilizing agent.
Acknowledgments
The authors gratefully acknowledge the authority of STIC, CUSAT,
Cochin for providing the SEM and TEM images for this study. The
authors thank the Director, IIT Indore for providing XPS analysis.
Disclosure statement
The authors declare that they have no conflict of interest.
References
1. Moradnia, F.; Fardood, S. T.; Ramazani, A.; Vinod Kumar, G.
Green Synthesis of Recyclable MgFeCrO4 Spinel Nanoparticles
for Rapid Photodegradation of Direct Black 122 Dye. J. Photoch.
Photobio. A 2020, 392, 112433. DOI: 10.1016/j.jphotochem.2020.
112433.
2. Fardood, S. T.; Ramazani, A.; Moradnia, F.; Afshari, Z.;
Ganjkhanlu, S.; Yekke Zare, F. Green Synthesis of ZnO
Nanoparticles via Sol-Gel Method and Investigation of Its
Application
Tetrahydrobenzo[a]Xanthene-11-One
Microwave Irradiation. Chem. Method 2019, 3, 696–706.
in
Solvent-Free
Synthesis
of
12-Aryl-
under
Derivatives
3. Fardood, S. T.; Ramazani, A.; Joo, S. W. Sol-Gel Synthesis and
Characterization of Zinc Oxide Nanoparticles Using Black Tea
Extract. J. Appl. Chem. Res. 2017, 11, 8–17.
4. Ramazani, A.; Fardood, S. T.; Hosseinzadeh, Z.; Sadri, F.; Joo,
S. W. Green Synthesis of Magnetic Copper Ferrite Nanoparticles
Using Tragacanth Gum as a Biotemplate and Their Catalytic
Activity for the Oxidation of Alcohols. Iran. J. Catal. 2017, 7,
181–185.
5. Atrak, K.; Ramazani, A.; Fardood, S. T. Green Synthesis of
Amorphous and Gamma Aluminum Oxide Nanoparticles by
Tragacanth Gel and Comparison of Their Photocatalytic Activity
for the Degradation of Organic Dyes. J. Mater. Sci. Mater.
Electron. 2018, 29, 8347–8353. DOI: 10.1007/s10854-018-8845-2.
6. Fardood, S. T.; Forootan, R.; Moradnia, F.; Afshari, Z.;
Ramazani, A. Green Synthesis, Characterization, and
Photocatalytic Activity of Cobalt Chromite Spinel Nanoparticles.
Mater. Res. Express. 2020, 7, 015086. DOI: 10.1088/2053-1591/
ab6c8d.
7. Moradnia, F.; Ramazani, A.; Fardood, S. T.; Gouranlou, F. A
Novel Green Synthesis and Characterization of Tetragonal-Spinel
MgMn2O4 Nanoparticles by Tragacanth Gel and Studies of its
Photocatalytic Activity for Degradation of Reactive Blue 21 Dye
under Visible Light. Mater. Res. Express. 2019, 6, 075057. DOI:
10.1088/2053-1591/ab17bc.
Figure 7. XPS analysis of caffeine stabilized CuO NPs: (CF0) CuO NPs without
caffeine; (CF1-CF3) CuO NPs stabilized with 50, 100, and 200 mg caffeine; (a) C
1s (b) O 1s (c) Cu 2p.
particles from irregular to spherical. The size and shape of
the particles found to be reduced at higher concentration of
caffeine. In addition, the above mentioned various shapes of

INORGANIC AND NANO-METAL CHEMISTRY
7
8. Yeganeh, M. S.; Reza Kazemizadeh, A.; Ramazani, A.; Eskandari,
P.; Angourani, H. R. Plant-Mediated Synthesis of
Cu0.5Zn0.5Fe2O4 Nanoparticles Using Minidium leavigatum and
Their Applications as an Adsorbent for Removal of Reactive
Blue 222 Dye. Mater. Res. Express. 2020, 6, 1250f4. DOI: 10.
1088/2053-1591/ab6637.
9. Fardood, S. T.; Moradnia, F.; Mostafaei, M.; Afshari, Z.;
Faramarzi, V.; Ganjkhanlu, S. Biosynthesis of MgFe2O4 Magnetic
Nanoparticles and Their Application in Photodegradation of
Malachite Green Dye and Kinetic Study. Nanochem. Res. 2019,
4, 86–93.
10. Suresh, Y.; Annapurna, S.; Singh, A. K.; Bhikshamaiah, G. Green
Synthesis and Characterization of Tea Decoction Stabilized
Copper Nanoparticles. Int. J. Innov. Res.Sci. Eng. Technol. 2014,
3, 11265–11270.
11. Peternela, J.; Silva, M. F.; Vieira, M. F.; Bergamasco, R.; Salcedo
Vieira, A. M. Synthesis and Impregnation of Copper Oxide
Nanoparticles on Activated Carbon Through Green Synthesis for
Water Pollutant Removal. Mater. Res. 2018, 21, e20160460.
12. Chen, H.; Zhao, G.; Liu, Y. Low-Temperature Solution Synthesis
of CuO Nanorods with Thin Diameter. Mater. Lett. 2013, 93,
60–63. DOI: 10.1016/j.matlet.2012.11.055.
Impregnated on Activated Carbon Using Moringa oleifera Leaves
Extract for the Removal of Nitrates from Water. Can. J. Chem.
Eng. 2018, 96, 2378–2379. DOI: 10.1002/cjce.23185.
23. Buazar, F.; Sweidi, S.; Badri, M.; Kroushawi, F. Biofabrication of
Highly Pure Copper Oxide Nanoparticles Using Wheat Seed
Extract and Their Catalytic Activity: A Mechanistic Approach.
Green Process Synth. 2019, 8, 691–702. DOI: 10.1515/gps-2019-
0040.
24. Maham, M.; Sajadi, S. M.; Kharimkhani, M. M.; Nasrollahzadeh,
M. Biosynthesis of the CuO Nanoparticles Using Euphorbia cha-
maesyce Leaf Extract and Investigation of Their Catalytic
Activity for the Reduction of 4-Nitrophenol. IET Nanobiotechnol.
2017, 11, 766–772. DOI: 10.1049/iet-nbt.2016.0254.
25. Ananda Murthy, H. C.; Abebe, B.; C H, P.; Shantaveerayya, K. A
Review on Green Synthesis and Applications of Cu and CuO
Nanoparticles. Mat. Sci. Res. India 2018, 15, 279–295. DOI: 10.
13005/msri/150311.
26. Fardood, S. T. ;A.; Ramazani, A.; Joo, S. W. Green Chemistry
Approach for the Synthesis of Copper Oxide Nanoparticles
Using Tragacanth Gel and Their Structural Characterization. J.
Struct.
Chem.
2018,
59,
482–486.
DOI:
10.1134/
S0022476618020324.
13. Chang, Y. N.; Zhang, M.; Xia, L.; Zhang, J.; Xing, G. The Toxic
Effects and Mechanisms of CuO and ZnO Nanoparticles.
Materials 2012, 5, 2850–2871. DOI: 10.3390/ma5122850.
14. Sankar, R.; Manikandan, P.; Malarvizhi, V.; Fathima, T.;
Shivashangari, K. S.; Ravikumar, V. Green Synthesis of Colloidal
Copper Oxide Nanoparticles Using Carica Papaya and Its
Application in Photocatalytic Dye Degradation. Spectrochim.
Acta Part A Mol. Biomol. Spectrosc. 2014, 121, 746–750. DOI:
10.1016/j.saa.2013.12.020.
15. Sorbiun, M.; Shayegan, E.; Ali, M. Green Synthesis of Zinc
Oxide and Copper Oxide Nanoparticles Using Aqueous Extract
of Oak Fruit Hull (Jaft) and Comparing Their Photocatalytic
Degradation Of Basic Violet 3. Int. J. Environ. Res. 2018, 12,
29–37
27. Nehlig, A.; Daval, J. L.; Debry, G. Caffeine and the Central
Nervous System: Mechanisms of Action, Biochemical, Metabolic
and Psycho Stimulant Effects. Brain Res. Brain Res. Rev. 1992,
17, 139–170. DOI: 10.1016/0165-0173(92)90012-B.
28. Glade, M. J. Caffeine-Not Just a Stimulant. Nutrition 2010, 26,
932–938. DOI: 10.1016/j.nut.2010.08.004.
29. Baratloo, A.; Rouhipour, A.; Forouzanfar, M. M.; Safari, S.;
Amiri, M.; Negida, A. The Role of Caffeine in Pain
Management: A Brief Literature Review. Anesth. Pain Med.
2016, 6, e33193. DOI: 10.5812/aapm.33193.
30. Fardood, S. T.; Ramazani, A. Green Synthesis and
Characterization of Copper Oxide Nanoparticles Using Coffee
Powder Extract. J. Nanostruct. 2016, 6, 167–171.
31. Fardood, S. T.; Ramazani, A. Black Tea Extract Mediated Green
Synthesis of Copper Oxide Nanoparticles. J. Appl. Chem. Res.
2018, 12, 8–15.
32. Subramanian, R.; Murugan, P.; Chinnadurai, G.; Ponmurugan,
K.; Al-Dhabi, N. A. Experimental Studies on Caffeine Mediated
16. Vishveshvar, K.; Krishnan, M. V. A.; Haribabu, K.;
Vishnuprasad, S. Green Synthesis of Copper Oxide
Nanoparticles Using Ixiro coccinea Plant Leaves and Its
Characterization. BioNanoSci. 2018, 8, 554–537. DOI: 10.1007/
s12668-018-0508-5.
Synthesis
of
Hydroxyapatite
Nanorods
and
Their
17. Yugandhar, P.; Vasavi, T.; Jayavardhana Rao, Y.; Uma
Maheswari Devi, P.; Narasimha, G.; Savithramma, N. Cost
Effective, Green Synthesis of Copper Oxide Nanoparticles Using
Fruit Extract of Syzygium alternifolium (Wt.) Walp.,
Characterization and Evaluation of Antiviral Activity. J. Clust.
Sci. 2018, 29, 743–755. DOI: 10.1007/s10876-018-1395-1.
18. Shayegan, E.; Mina, M.; Ali, S.; Saeid, R.; Fardood, T. Plant-
Mediated Synthesis of Zinc Oxide and Copper Oxide
Nanoparticles by Using Ferulago angulata (schlecht) Boiss
Extract and Comparison of Their Photocatalytic Degradation of
Rhodamine B (RhB) under Visible Light Irradiation. J. Mater.
Sci. Mater. Electron. 2018, 29, 1333–1340.
19. Hemmati, S.; Mehrazin, L.; Hekmati, M.; Izadi, M.; Veisi, H.
Biosynthesis of CuO Nanoparticles Using Rosa canina Fruit
Extract as a Recyclable and Heterogeneous Nanocatalyst for C-N
Ullmann Coupling Reactions. Mater. Chem. Phys. 2018, 214,
527–532. DOI: 10.1016/j.matchemphys.2018.04.114.
20. Sharma, B. L.; Shah, D. V.; Roy, D. R. Green Synthesis of CuO
Nanoparticles Using Azadirachta indica and Its Antibacterial
Activity for Medicinal Applications. Mater. Res. Express. 2018, 5,
095033. doi:MRX-109160.R1 DOI: 10.1088/2053-1591/aad91d.
21. Sharmila, G.; Sakthi Pradeep, R.; Sandiy, K.; Santhiya, S.;
Muthukumaran, C.; Jeyanthi, J.; Manoj Kumar, N.;
Thirumarimurugan, M. Biogenic Synthesis of CuO Nanoparticles
Using Bauhinia tomentosa Leaves Extract: Characterization and
Its Antibacterial Application. J. Mol. Struct. 2018, 1165, 288–292.
DOI: 10.1016/j.molstruc.2018.04.011.
Characterization. Mater. Res. Express. 2020, 7, 015022. DOI: 10.
1088/2053-1591/ab619a.
33. Elango, M.; Deepa, M.; Subramanian, R.; Saraswathy, G. Effect of
Piperine on Size, Shape and Morphology of Hydroxyapatite
Nanoparticles Synthesized by the Chemical Precipitation
Method. Mater. Chem. Phys. 2018, 216, 305–315. DOI: 10.1016/j.
matchemphys.2018.05.049.
34. Paradkar, M. M.; Irudayaraj, J. A Rapid FTIR Spectroscopic
Method for Estimation of Caffeine in Soft Drinks and Total
Methylxanthines in Tea and Coffee. J Food Sci. 2002, 67,
2507–2511. DOI: 10.1111/j.1365-2621.2002.tb08767.x.
35. Prakash, S.; Elavarasan, N.; Venkatesan, A.; Subashini, K.;
Sowndharya, M.; Sujatha, V. Green Synthesis of Copper Oxide
Nanoparticles and Its Effective Applications in Biginelli Reaction,
BTB Photodegradation and Antibacterial Activity. Adv. Powder
Tech. 2018, 29, 3315–3326. DOI: 10.1016/j.apt.2018.09.009.
ꢀ
ꢁ
36. Thekkae Padil, V. V.; Cernık, M. Green Synthesis of Copper
Oxide Nanoparticles Using Gum Karaya as a Biotemplate and
Their Antibacterial Application. Int. J. Nanomed 2013, 8,
889–898.
37. Liu, P.; Li, Z.; Cai, W.; Fang, M.; Luo, X. Fabrication of Cuprous
Oxide Nanoparticles by Laser Ablation in PVP Aqueous
Solution. RSC Adv. 2011, 1, 847–851. DOI: 10.1039/c1ra00261a.
38. Kuppusamy, P.; Ilavenil, S.; Srigopalram, S.; Maniam, G. P.;
Yusoff, M. M.; Govindan, N.; Choi, K. C. Treating of Palm Oil
Mill Effluent Using Commelina nudiflora Mediated Copper
Nanoparticles as a Novel Bio-Control Agent. J. Clean. Prod.
2017, 141, 1023–1029. DOI: 10.1016/j.jclepro.2016.09.176.
22. Galan, C. R.; Silva, M. F.; Mantovani, D.; Bergamasco, R.; Vieira,
M. F. Green Synthesis of Copper Oxide Nanoparticles

8
A. P. A. MARY ET AL.
39. Bhattacharjee, A.; Ahmaruzzaman, M. CuO Nanostructures: 42. Nagajyothi, P. C.; Muthuraman, P.; Sreekanth, T. V. M.; Hwan
Facile
Synthesis
and
Applications
for
Enhanced
Kim, D.; Shim, J. Green Synthesis: In-Vitro Anticancer Activity
of Copper Oxide Nanoparticles against Human Cervical
Carcinoma Cells. Arab. J. Chem. 2017, 10, 215–225. DOI: 10.
1016/j.arabjc.2016.01.011.
Photodegradation of Organic Compounds and Reduction of p-
Nitrophenol from Aqueous Phase. RSC Adv. 2016, 6,
41348–41363. DOI: 10.1039/C6RA03624D.
40. Angeline Mary, A. P.; Thaminum Ansari, A.; Subramanian, R.
Sugarcane Juice Mediated Synthesis of Copper Oxide Nanoparticles,
Characterization and Their Antibacterial Activity. J. King Saud Uni.
Sci. 2019, 31, 1103–1114. DOI: 10.1016/j.jksus.2019.03.003.
41. Subramanian, R.; Sathish, S.; Murugan, P.; Mohamed Musthafa,
A.; Elango, M. Effect of Piperine on Size, Shape and Morphology
of Hydroxyapatite Nanoparticles Synthesized by the Chemical
Precipitation Method. J. King Saud Uni. Sci. 2019, 31, 667–673.
DOI: 10.1016/j.jksus.2018.01.002.
43. Sasikala, S.; Ganesh, V.; Seong, J. K. Biosynthesis of Copper
Oxide (CuO) Nanowires and Their Use for the Electrochemical
Sensing of Dopamine. Nanomaterials 2018, 8, 823.
44. Munawar, K.; Mansoor, M. A.; Basirun, W. J.; Misran, M.;
Huang, N. M.; Mazhar, M. Single Step Fabrication of
CuO–MnO–2TiO2 Composite Thin Films with Improved
Photoelectrochemical Response. RSC Adv. 2017, 7, 15885–15893.
DOI: 10.1039/C6RA28752B.