This document summarizes a study that used the leaf extract of Hibiscus rosa sinensis to biologically synthesize gold and silver nanoparticles. Varying experimental conditions such as the ratio of metal salts to leaf extract and pH allowed modulation of the nanoparticles' size, shape, and properties. Nanoparticles were characterized using techniques like UV-vis spectroscopy, transmission electron microscopy, X-ray diffraction, and FTIR spectroscopy. Results confirmed the production of crystalline gold and silver nanoparticles in the face-centered cubic structure, as well as the ability to control nanoparticle shape through simple adjustments to the synthesis method. This green chemistry approach provides a simple, cost-effective way to produce metal nanoparticles with potential applications.
Chemo bio synthesis of silver nanoparticlesJagpreet Singh
Silver nanoparticles have a lot of ways of synthesis like physical and chemical
methods; some of these methods use a lot of chemical substances and are
very hazardous for humans and environment, so a novel, great, environmental
friendly, cheap and easy to use world of green chemistry has been used. A
number of characterization techniques such as UV-visible spectroscopy, Fourier
transformation infrared spectroscopy, X-ray diffraction study and scanning
electron microscopy revealed that silver nanoparticles have been used. Thus
the different response of the functional groups and the difference in the peaks
and UV-visible data was studied and then compared to understand and know
the way these different reducing agents react to the same starting material. The
green synthesis had a UV-visible peak at 446 nm while the one with chemical
synthesis had a peak at 395 nm. FTIR results of silver nanoparticles synthesis
by trisodium citrate (TSC) showed a peak at 1505 cm-1 which shows that the
compound has a stretching of the -C=C – bond. In another case, which was done
by using Sodium borohydride (NaBH4) a peak at 1695 cm-1 showed a –C=O- bond
indicating stretching and a weak absorption intensity. Another peak was present
which indicates a –O-H bond formation and presence which is a strong bond are
found to exist. A notable peak came for synthesis by orange peel at 1517 cm-1
which represents a –C=C- bond stretching as in aromatic compounds. Another
peak at 1732 cm-1 indicates the –C=O- bond. The XRD results on one of the
silver sample prepared by green methods showed silver nanomaterials formed
which had a average particle size of around 42 nm. FE-SEM results revealed that
silver nanomaterials were formed and had a flake like appearance in one of the
results. All the overall comparison showed that different modes of synthesis
of silver nanomaterials and different reducing agents give same materials but
with different peaks and intensities. All this data provided knowledge about the
fact that an alternative method can be used to create new nanoparticles if one
of the previously considered to tried method fails thus helping in extending the
broadways for research.
Silver Nanoparticles Synthesis, Properties, Applications and Future Perspecti...iosrjce
Silver nanoparticles (Ag NPs) have gained significant interest due to their unique optical,
antimicrobial, electrical, physical properties and their possible application. The change of energy level from
continuous band to discrete band of Ag NPs with decrease in size of particles gives strong size dependent
chemical and physical properties. Ag NPs show lower toxicity to human health while Ag NPs show higher
toxicity to various micro-organisms. For this reason Ag NPs having scope for medical instruments,
antimicrobial application, products for health care such as scaffolds, burn dressing, water purification,
agriculture uses. Ag NPs can be synthesized by using various methods which is primarily classified into two
type’s namely physical process which includes laser ablation, condensation, evaporation etc. and chemical
process which includes hydrazine, sodium borohydride, green synthesis etc. Among all these methods green
synthesis is non-toxic, eco-friendly and cost effective. In this review paper different synthesis process especially
green synthesis, properties, applications of silver nanoparticles and their recent advances are described. We
also highlight the toxicity and compares Ag NPs with others nanoparticles.
Chemo bio synthesis of silver nanoparticlesJagpreet Singh
Silver nanoparticles have a lot of ways of synthesis like physical and chemical
methods; some of these methods use a lot of chemical substances and are
very hazardous for humans and environment, so a novel, great, environmental
friendly, cheap and easy to use world of green chemistry has been used. A
number of characterization techniques such as UV-visible spectroscopy, Fourier
transformation infrared spectroscopy, X-ray diffraction study and scanning
electron microscopy revealed that silver nanoparticles have been used. Thus
the different response of the functional groups and the difference in the peaks
and UV-visible data was studied and then compared to understand and know
the way these different reducing agents react to the same starting material. The
green synthesis had a UV-visible peak at 446 nm while the one with chemical
synthesis had a peak at 395 nm. FTIR results of silver nanoparticles synthesis
by trisodium citrate (TSC) showed a peak at 1505 cm-1 which shows that the
compound has a stretching of the -C=C – bond. In another case, which was done
by using Sodium borohydride (NaBH4) a peak at 1695 cm-1 showed a –C=O- bond
indicating stretching and a weak absorption intensity. Another peak was present
which indicates a –O-H bond formation and presence which is a strong bond are
found to exist. A notable peak came for synthesis by orange peel at 1517 cm-1
which represents a –C=C- bond stretching as in aromatic compounds. Another
peak at 1732 cm-1 indicates the –C=O- bond. The XRD results on one of the
silver sample prepared by green methods showed silver nanomaterials formed
which had a average particle size of around 42 nm. FE-SEM results revealed that
silver nanomaterials were formed and had a flake like appearance in one of the
results. All the overall comparison showed that different modes of synthesis
of silver nanomaterials and different reducing agents give same materials but
with different peaks and intensities. All this data provided knowledge about the
fact that an alternative method can be used to create new nanoparticles if one
of the previously considered to tried method fails thus helping in extending the
broadways for research.
Silver Nanoparticles Synthesis, Properties, Applications and Future Perspecti...iosrjce
Silver nanoparticles (Ag NPs) have gained significant interest due to their unique optical,
antimicrobial, electrical, physical properties and their possible application. The change of energy level from
continuous band to discrete band of Ag NPs with decrease in size of particles gives strong size dependent
chemical and physical properties. Ag NPs show lower toxicity to human health while Ag NPs show higher
toxicity to various micro-organisms. For this reason Ag NPs having scope for medical instruments,
antimicrobial application, products for health care such as scaffolds, burn dressing, water purification,
agriculture uses. Ag NPs can be synthesized by using various methods which is primarily classified into two
type’s namely physical process which includes laser ablation, condensation, evaporation etc. and chemical
process which includes hydrazine, sodium borohydride, green synthesis etc. Among all these methods green
synthesis is non-toxic, eco-friendly and cost effective. In this review paper different synthesis process especially
green synthesis, properties, applications of silver nanoparticles and their recent advances are described. We
also highlight the toxicity and compares Ag NPs with others nanoparticles.
The current research aimed at fabricating plant extract mediated biosynthesized silver nanoparticles (AgNPs) utilizing thorn extract of Bombax ceiba (TEBC). The synthesized AgNPs was characterized by UV spectroscopy where the surface plasmonic resonance peak (SPR) was located at 222 nm. The scanning electron microscopy (SEM) studies demonstrated that the morphology of fabricated nanomaterials was primarily cylindrical of average size of 20-30 nm with some spindles of size >50 nm. The anti-microbial evaluation against Staphylococcus aureus revealed that AgNPs exhibited notable activity with ZOI of 27.2 mm at MIC of 25 μg/mL. The outcome of this research evidently signified that the biofabricated AgNPs using TEBC may be a new greener approach or technology to formulate anti-bacterial nanodrugs in future.
Green synthesis and characterization of silver nanoparticles using tinosopora...IJARIIT
User authentication is an important topic in the field of information security. To enforce security of information,
passwords were introduced. Text based password is a popular authentication method used from ancient times. However text
based passwords are prone to various attacks. Strong text-based password schemes could provide with certain degree of security.
However, the fact that strong passwords are difficult to memorize often leads their users to write them down on papers or even
save them in a computer file. Human actions such as choosing bad passwords and inputting passwords in an insecure way are
regarded as the weakest link in the authentication chain. Graphical password is one of the alternative solution to alphanumeric
password as it is very simple process to remember alphanumeric password. One of the major reasons behind this method
implementation is that, according to psychological studies human mind can easily remember images than alphabets or digits.
Graphical authentication has been proposed as a possible alternative solution to text-based authentication. A new technique of
captcha and OTP is being used for the verification purpose. Three times a person is given chance to try for login if the person
fails then he is blocked till the session expires.
A convenient method of synthesizing Silver Nanoparticles form Bonatea steudneri leave extract and evaluation of their electrocatalytic and phenol removal properties.
Green biosynthesis of silver nanoparticles using Clitoria ternatea and its ch...ESHIT BANERJEE
Extraction of aqueous extract from Clitoria ternatea and using the aqueous extract for the biosynthesis of silver nanoparticles. Statistical analysis of the aqueous extract using Ultraviolet-visible spectroscopy. And morphological analysis using FE-SEM .And further analysis using XRD to determine the element composition of the sample
The review article summarizes the applications of silver nanoparticles for diverse sectors. Over the decades, nanoparticles used as dignified metals such as silver exhibited distinctive characteristics basically correlated
to chemical, physical and biological property of counterparts having bulkiness. Numerous studies reported that Nanoparticles of about 100 nm diameter play a crucial role in widely spread industries due to unique properties including the dimension of small particle, high surface area and quantum confinement and they dispersed without agglomeration. Decade of discoveries clearly established that shape, size and distribution of Silver nanoparticles strongly affect the electromagnetic, optical and catalytic properties, which are often an assortment of changeable synthetic methods and reducing agents with stabilizers. Generation after generation the postulates come forth about properties of silver for the ancient Greeks cook from silver pots and the old adage ‘born with a silver spoon in his mouth’ thus show that eating with a silver spoon was wellknown
as uncontaminated. Impregnation of metals with silver nanoparticles is a practical way to exploit the microbe aggressive properties of silver at very low cost. The nanoparticles help in targeted delivery of drugs, enhancing bioavailability, sustaining drug or gene effect in target tissues, and enhancing the stability. Implementations of silver partials in medical science and biological science have been noticed from years ago; however alteration with nanotechnology is innovative potential. Over 23% of all nanotechnology based products, diagnostic and therapeutic applications implanted with silver nanoparticles (e.g. In arthritic disease and wound healing, etc.) and widely known for their antifungal, antibacterial, antiviral effect, employed in textile fabrics and added into cosmetic products as antiseptic to overcome skin problems. Thus, Silver
nanoparticles (AgNPs) have been urbanized as an advanced artifact in the field of nanotechnology.
ABSTRACT- Tagetes erecta L. was raised in pots containing soil treated with various concentrations of Pb(NO3)2 (500, 1000, 1500, 2000 and 2500mg/kg). At maturity plants were separated into root, stem, leaves and inflorescence and lead accumulated in each part was quantified. The effects of lead accumulation on growth was analyzed by the measurement of various growth parameters like root and shoot length, fresh and dry weight of root and shoot and total leaf area per plant. Moreover effect of lead accumulation on biochemical parameters was checked by quantitative estimation of various biochemical parameters like chlorophyll, total protein, free amino acids, total sugar, reducing sugar and starch. Results showed that there is no remarkable negative effect of accumulation of lead on the morphological growth of the plant. Biochemical analysis showed that amount of total protein continuously decreased whereas that of free amino acids continuously increased with increasing concentrations of lead. Amount of chlorophyll, total sugar, reducing sugar and starch contents continuously increased till mid-level i.e., Pb 1500 mg/kg and then continuously decreased at higher concentrations. Results of quantitative estimation of Pb in root, stem, leaves and inflorescence showed that roots accumulated highest amount of Pb followed by stem and leaves, whereas inflorescence contained least amount of Pb.
Key-words- Lead (Pb), Heavy metal, Tagetes erecta L., Accumulation, Phytoremediation
Green synthesis of zinc oxide nano particles using flower extract cassia dens...IJERD Editor
Green synthesis of metal nanoparticles is an interesting issue of the nanoscience and
nanobiotechnology. There is a growing attention to biosynthesis the metal nanoparticles using organisms.
Among these organisms, plants seem to be the best and they are suitable for large scale biosynthesis of
nanoparticles. Nanoparticles produced by plants are more stable, and the rate of synthesis is faster than that in
the case of other organisms. The present investigation was carried out to green synthesis of zinc oxide
nanoparticles by using the medicinal plant cassia densistipulata taub. The flower was collected from the campus
of Anantapuramu, Andhra Pradesh and their petals were separated. The petals were taken and cleaned with
dimeneralized water and soaked for an hour on dry cloth to remove moisture from the petals.
Synthesis of Zinc Nanoparticles was done by mixing 5gms of Zinc Nitrate with 50ml of aqueous
extract of cassia densistipulata taub petals. The formation of nanoparticles was monitored by visualizing color
changes and it was confirmed by Electron microscope (SEM), UV-Vis spectrophotometer and Fourier
Transform Infra-Red (FT-IR) spectroscopy. The results of various techniques confirmed the presence Zinc oxide
nanoparticles.
Review on green synthesis of silver nanoparticles using plant extract. Various green materials are used for the synthesis of Ag. Several synthesis method main emphasis on green method.
Abstract
A rapid advance of nanotechnology has the potential approach for significant improvements in disease prevention, diagnosis and treatment. In this article, we report a simple and eco-friendly biosynthesis of silver nanoparticles (Ag-NPs) using silver nitrate as metal precursor in Curcuma longa. These Ag-NPs were characterized by UV–vis spectroscopy, and Transmission electron microscopy (TEM). These nanoparticles exhibited maximum absorbance in specific nano meter range in UV–vis spectroscopy. TEM micrographs revealed the formation of well-dispersed Ag-NPs with its size and morphology. Microbiology assay founds that Ag-NPs are effective against V.cholera bacteria. These developments raise exciting opportunities to diagnose and treat pathogenic mode of infection based on the various profiles to target diseases.
Formulation Of Acalypha Wilkesiana Muell. Arg. Ethanol Leaf Extract into Crea...inventionjournals
International Journal of Pharmaceutical Science Invention (IJPSI) is an international journal intended for professionals and researchers in all fields of Pahrmaceutical Science. IJPSI publishes research articles and reviews within the whole field Pharmacy and Pharmaceutical Science, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The current research aimed at fabricating plant extract mediated biosynthesized silver nanoparticles (AgNPs) utilizing thorn extract of Bombax ceiba (TEBC). The synthesized AgNPs was characterized by UV spectroscopy where the surface plasmonic resonance peak (SPR) was located at 222 nm. The scanning electron microscopy (SEM) studies demonstrated that the morphology of fabricated nanomaterials was primarily cylindrical of average size of 20-30 nm with some spindles of size >50 nm. The anti-microbial evaluation against Staphylococcus aureus revealed that AgNPs exhibited notable activity with ZOI of 27.2 mm at MIC of 25 μg/mL. The outcome of this research evidently signified that the biofabricated AgNPs using TEBC may be a new greener approach or technology to formulate anti-bacterial nanodrugs in future.
Green synthesis and characterization of silver nanoparticles using tinosopora...IJARIIT
User authentication is an important topic in the field of information security. To enforce security of information,
passwords were introduced. Text based password is a popular authentication method used from ancient times. However text
based passwords are prone to various attacks. Strong text-based password schemes could provide with certain degree of security.
However, the fact that strong passwords are difficult to memorize often leads their users to write them down on papers or even
save them in a computer file. Human actions such as choosing bad passwords and inputting passwords in an insecure way are
regarded as the weakest link in the authentication chain. Graphical password is one of the alternative solution to alphanumeric
password as it is very simple process to remember alphanumeric password. One of the major reasons behind this method
implementation is that, according to psychological studies human mind can easily remember images than alphabets or digits.
Graphical authentication has been proposed as a possible alternative solution to text-based authentication. A new technique of
captcha and OTP is being used for the verification purpose. Three times a person is given chance to try for login if the person
fails then he is blocked till the session expires.
A convenient method of synthesizing Silver Nanoparticles form Bonatea steudneri leave extract and evaluation of their electrocatalytic and phenol removal properties.
Green biosynthesis of silver nanoparticles using Clitoria ternatea and its ch...ESHIT BANERJEE
Extraction of aqueous extract from Clitoria ternatea and using the aqueous extract for the biosynthesis of silver nanoparticles. Statistical analysis of the aqueous extract using Ultraviolet-visible spectroscopy. And morphological analysis using FE-SEM .And further analysis using XRD to determine the element composition of the sample
The review article summarizes the applications of silver nanoparticles for diverse sectors. Over the decades, nanoparticles used as dignified metals such as silver exhibited distinctive characteristics basically correlated
to chemical, physical and biological property of counterparts having bulkiness. Numerous studies reported that Nanoparticles of about 100 nm diameter play a crucial role in widely spread industries due to unique properties including the dimension of small particle, high surface area and quantum confinement and they dispersed without agglomeration. Decade of discoveries clearly established that shape, size and distribution of Silver nanoparticles strongly affect the electromagnetic, optical and catalytic properties, which are often an assortment of changeable synthetic methods and reducing agents with stabilizers. Generation after generation the postulates come forth about properties of silver for the ancient Greeks cook from silver pots and the old adage ‘born with a silver spoon in his mouth’ thus show that eating with a silver spoon was wellknown
as uncontaminated. Impregnation of metals with silver nanoparticles is a practical way to exploit the microbe aggressive properties of silver at very low cost. The nanoparticles help in targeted delivery of drugs, enhancing bioavailability, sustaining drug or gene effect in target tissues, and enhancing the stability. Implementations of silver partials in medical science and biological science have been noticed from years ago; however alteration with nanotechnology is innovative potential. Over 23% of all nanotechnology based products, diagnostic and therapeutic applications implanted with silver nanoparticles (e.g. In arthritic disease and wound healing, etc.) and widely known for their antifungal, antibacterial, antiviral effect, employed in textile fabrics and added into cosmetic products as antiseptic to overcome skin problems. Thus, Silver
nanoparticles (AgNPs) have been urbanized as an advanced artifact in the field of nanotechnology.
ABSTRACT- Tagetes erecta L. was raised in pots containing soil treated with various concentrations of Pb(NO3)2 (500, 1000, 1500, 2000 and 2500mg/kg). At maturity plants were separated into root, stem, leaves and inflorescence and lead accumulated in each part was quantified. The effects of lead accumulation on growth was analyzed by the measurement of various growth parameters like root and shoot length, fresh and dry weight of root and shoot and total leaf area per plant. Moreover effect of lead accumulation on biochemical parameters was checked by quantitative estimation of various biochemical parameters like chlorophyll, total protein, free amino acids, total sugar, reducing sugar and starch. Results showed that there is no remarkable negative effect of accumulation of lead on the morphological growth of the plant. Biochemical analysis showed that amount of total protein continuously decreased whereas that of free amino acids continuously increased with increasing concentrations of lead. Amount of chlorophyll, total sugar, reducing sugar and starch contents continuously increased till mid-level i.e., Pb 1500 mg/kg and then continuously decreased at higher concentrations. Results of quantitative estimation of Pb in root, stem, leaves and inflorescence showed that roots accumulated highest amount of Pb followed by stem and leaves, whereas inflorescence contained least amount of Pb.
Key-words- Lead (Pb), Heavy metal, Tagetes erecta L., Accumulation, Phytoremediation
Green synthesis of zinc oxide nano particles using flower extract cassia dens...IJERD Editor
Green synthesis of metal nanoparticles is an interesting issue of the nanoscience and
nanobiotechnology. There is a growing attention to biosynthesis the metal nanoparticles using organisms.
Among these organisms, plants seem to be the best and they are suitable for large scale biosynthesis of
nanoparticles. Nanoparticles produced by plants are more stable, and the rate of synthesis is faster than that in
the case of other organisms. The present investigation was carried out to green synthesis of zinc oxide
nanoparticles by using the medicinal plant cassia densistipulata taub. The flower was collected from the campus
of Anantapuramu, Andhra Pradesh and their petals were separated. The petals were taken and cleaned with
dimeneralized water and soaked for an hour on dry cloth to remove moisture from the petals.
Synthesis of Zinc Nanoparticles was done by mixing 5gms of Zinc Nitrate with 50ml of aqueous
extract of cassia densistipulata taub petals. The formation of nanoparticles was monitored by visualizing color
changes and it was confirmed by Electron microscope (SEM), UV-Vis spectrophotometer and Fourier
Transform Infra-Red (FT-IR) spectroscopy. The results of various techniques confirmed the presence Zinc oxide
nanoparticles.
Review on green synthesis of silver nanoparticles using plant extract. Various green materials are used for the synthesis of Ag. Several synthesis method main emphasis on green method.
Abstract
A rapid advance of nanotechnology has the potential approach for significant improvements in disease prevention, diagnosis and treatment. In this article, we report a simple and eco-friendly biosynthesis of silver nanoparticles (Ag-NPs) using silver nitrate as metal precursor in Curcuma longa. These Ag-NPs were characterized by UV–vis spectroscopy, and Transmission electron microscopy (TEM). These nanoparticles exhibited maximum absorbance in specific nano meter range in UV–vis spectroscopy. TEM micrographs revealed the formation of well-dispersed Ag-NPs with its size and morphology. Microbiology assay founds that Ag-NPs are effective against V.cholera bacteria. These developments raise exciting opportunities to diagnose and treat pathogenic mode of infection based on the various profiles to target diseases.
Formulation Of Acalypha Wilkesiana Muell. Arg. Ethanol Leaf Extract into Crea...inventionjournals
International Journal of Pharmaceutical Science Invention (IJPSI) is an international journal intended for professionals and researchers in all fields of Pahrmaceutical Science. IJPSI publishes research articles and reviews within the whole field Pharmacy and Pharmaceutical Science, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
De rol van voorraadbeheerder zal drastisch veranderen, stelt supply chain-expert Walther Ploos van Amstel. Door voorraden slim te alloceren naar die afzetkanalen waar de hoogste marge zit, maakt hij het verschil tussen winst of verlies. Cruciaal hierin is zijn kennis over product lifecycle management.
In the present work, green synthesis of copper oxide nanoparticles has wide interest due to its inherent features such as eco-friendly and low costs. Here we propose a cost effective and eco-friendly green synthesis of copper oxide nanoparticles using aloe barbadensis and copper acetate. Aloe barbadensis has antioxidant property that helps in the formation of nanoparticles. Aloe barbadensis extract was obtained by heating it in distilled water and mixed to copper acetate to form copper oxide nanoparticles. The synthesised nanoparticles were analysed using UV-Visible spectroscopy, X-ray diffraction studies (XRD) and Fourier-transform infrared spectroscopy (FTIR).
Is Nano Medicine And Nano Technology The Most Trending Thing Now?science journals
Nano medicine is nothing but application of Nano technologies as medicines. It may include application of non-material as biological devices or nano-electronic biosensors. Molecular nanotechnology as biological machines may have medical applications in future.
Synthesis & Characterization of Fluorescent Silver Nanoparticles stabilized b...IJERA Editor
Synthesis of silver nanoparticles (Ag-NPs) was achieved by a simple green procedure using Tinospora Cordifolia leaf extract as stabilizer/reducing agents. Ag-NPs in the size range of 2–19 nm is obtained by the treatment of aqueous silver ions with leaf extracts of Tinospora Cordifolia. This eco-friendly approach is simple, amenable for large scale commercial production and technical applications. Further, photoluminiscence studies of these Ag-NPs were recorded & suggested that the present particles were suitable for fluorescence emitting probes. These red emitting Ag-NPs exhibited distinct fluorescence properties (both emission and stokeshift).
Synthesis of silver nanoparticle using Portulaca oleracea L. extracts. Articl...Nanomedicine Journal (NMJ)
Objective(s):
To evaluate the influences of aqueous extracts of plant parts (stem, leaves, and root) of Portulaca oleracea L. on bioformation of silver nanoparticles (AgNPs).
Materials and Methods:
Synthesis of silver nanoparticles by different plant part extracts of Portulaca oleracea L. was carried out and formation of nanoparticles were confirmed and evaluated using UV-Visible spectroscopy and AFM.
Results:
The plant extracts exposed with silver nitrate showed gradual change in color of the extract from yellow to dark brown. Different silver nanoperticles were formed using extracts of different plant parts.
Conclusion:
It seems that the plant parts differ in their ability to act as a reducing and capping agent.
Green synthesis, Characterization and anti microbial activity of silver nano ...IJERA Editor
The exploitation of various plant materials for the biosynthesis of silver nano particles is considered a green
technology. Because it does not involve any harmful chemicals. Nanotechnology field is one of the most
attractive researches. The field of nanotechnology is applied to bio materials. This review focuses on the green
synthesis of silver nanoparticles using various plant sources. A detailed study on the reduction of silver ions to
silver nanoparticles from medical plant leaves extract were demonstrated with a brief experimental procedure.
Characterization of the synthesized nanoparticles performed through UV spectroscopy, Fourier Transform Infra
Red spectroscopy analysis, X-Ray Diffraction analysis, Scanning Electron Microscopy and Transmission
Electron Microscopy. This review mainly focus on anti microbial activities of synthesized silver nano particles.
Effluents containing heavy metals can be
remediated with the help of dead microorganisms by the process
known as biosorption. In this study the dead biomass 1of fungus
Aspergillus flavus was used for the biosorption of heavy metals
i.e., Zinc and Nickel. The capacity of biosorption by the dead
biomass of Aspergillus flavus was evaluated at room temperature
with different parameters which are; pH, contact time, biomass
concentration and metal ion concentration. The biosorption
capacity for Zn was found to be 47.36% at room temperature, at
pH 6.5, with biomass concentration of 2g/L having contact time of
50 min and solution concentration of 2ppm. Biosorption capacity
for Ni was found to be 61.60% at room temperature, at pH 5,
with biomass concentration of 2g/L having contact time of 60 min
and solution concentration of 2ppm. . In this study, desorption of
the heavy metals by 0.1M HCl was found to be effective. Fungal
biomass was recovered for reuse.
Plant Mediated Synthesis of Silver Nanoparticles by Using Dried Stem Powder o...IJERA Editor
The Tinospora Crispa is an important medicinal plant to synthesize silver Nanoparticles provides environmentally benign and a feasible alternative to the most of the chemical, physical and biological methods. Utilizing the reduced property of Tinospora Crispa dried stem powder from 1mM aqueous silver nitrate, the average size of 40nm silver nanoparticles were synthesized at room temperature. The stem powder extracts mixed with silver nitrate showed a gradual change in the color of the extracts from yellow to dark brown. The formation of silver nanoparticles was confirmed by UV-Visible spectrophotometer, X-Ray diffraction (XRD), Fourier transform infrared (FTIR), Energy dispersive spectroscopy (EDAX) and Transmission electron microscopy (TEM). The photoluminescence studies of silver nanoparticles shows that they are efficient fluorescence emitting probes.
assessment of biomass of leaves of water hyacinth (eichhornia crassipes)IJAEMSJORNAL
Green chemistry methods for nanoparticles synthesis have implemented the valorization of renewable waste that reduces the use of chemicals and sub-products to minimize the environmental impact. Herein, we report a method to synthesize Ag and Au nanoparticles (AgNPs, AuNPs) using one of the world´s worst aquatic weeds, water hyacinth. From a reaction between a solution of AgNO3 or HAuCl4 and controlling the pH, the nanoparticles were synthesized. The optimum pH value to obtained uniform quantum dots was found to be acidic for AgNPs and neutral for AuNPs. The size was highly dependent on pH for AgNPs, a smaller size was for acidic pH, and the larger size was for basic pH, and cubic and hexagonal are the predominant structures, no dependent was observed in AuNPs, and orthorhombic is the most common form. This method was sustainable because water hyacinth is a renewable resource in all world, and their use is not being exploited in any process. The bioreduction process using water hyacinth promotes the metallic nanoparticles formation and applied standard conditions for temperature and pressure. Also, the rate of synthesis is fast.
Phyto-mediated Synthesis of Copper Nanoparticles by Cassia auriculata and its...IJEAB
An eco-friendly loom has been taking up in the present study to synthesize copper nanoparticles using Cassia auriculata. The leaf extract of Cassia auriculata acts as reducing as well as capping agent. Synthesis of copper nanoparticles was initially confirmed by the visual observation i.e color change (dark green color). The synthesized copper nanoparticles were primarily characterized by UV-vis spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy. Further, the formation of amorphous and crystalline phase was analyzed by X-Ray Diffraction pattern. The size and morphology of the synthesized Copper nanoparticles was characterized by Scanning Electron Microscopy (SEM) and the elemental composition was analyzed by EDAX. The present study is a preliminary investigation to know about the capability of Cassia auriculata to synthesize copper nanoparticles from its salts. The results of the present study confirmed that the leaf extract of Cassia auriculata be capable of recovering copper from printed circuit boards in the form of nanoparticles in near future.
How to Build a Module in Odoo 17 Using the Scaffold MethodCeline George
Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
Group Presentation 2 Economics.Ariana Buscigliopptx
S0001
1. Green synthesis of gold and silver nanoparticles using Hibiscus rosa sinensis
Daizy Philip n
Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, India
a r t i c l e i n f o
Article history:
Received 23 August 2009
Received in revised form
15 November 2009
Accepted 24 November 2009
Available online 5 December 2009
Keywords:
Hibiscus rosa sinensis
Biosynthesis
Gold nanoparticles
Silver nanoparticles
a b s t r a c t
Biological synthesis of gold and silver nanoparticles of various shapes using the leaf extract of Hibiscus
rosa sinensis is reported. This is a simple, cost-effective, stable for long time and reproducible aqueous
room temperature synthesis method to obtain a self-assembly of Au and Ag nanoparticles. The size and
shape of Au nanoparticles are modulated by varying the ratio of metal salt and extract in the reaction
medium. Variation of pH of the reaction medium gives silver nanoparticles of different shapes. The
nanoparticles obtained are characterized by UV–vis, transmission electron microscopy (TEM), X-ray
diffraction (XRD) and FTIR spectroscopy. Crystalline nature of the nanoparticles in the fcc structure are
confirmed by the peaks in the XRD pattern corresponding to (1 1 1), (2 0 0), (2 2 0) and (3 1 1) planes,
bright circular spots in the selected area electron diffraction (SAED) and clear lattice fringes in the high-
resolution TEM image. From FTIR spectra it is found that the Au nanoparticles are bound to amine
groups and the Ag nanoparticles to carboxylate ion groups.
& 2009 Elsevier B.V. All rights reserved.
1. Introduction
The size, shape and surface morphology play a vital role in
controlling the physical, chemical, optical and electronic proper-
ties of nanomaterials. Nanoparticles of noble metals are even used
for the purification of water which is one of the essential enablers
of life on earth [1]. Gold nanoparticles have been considered as
important area of research due to their unique and tunable
surface Plasmon resonance (SPR) and their applications in
biomedical science including drug delivery, tissue/tumor imaging,
photothermal therapy and immunochromatographic identifica-
tion of pathogens in clinical specimens [2]. Integration of green
chemistry principles to nanotechnology is one of the key issues in
nanoscience research. Since the development of the concept of
green nanoparticle preparation by Raveendran et al.[3], there has
been growing need for environmentally benign metal-nanoparti-
cle synthesis process that do not use toxic chemicals in the
synthesis protocols to avoid adverse effects in medical applica-
tions. The inspiration for green chemistry and bioprocesses comes
from nature through yeast, fungi, bacteria and plant extracts in
the synthesis of biocompatible metal and semiconductor nano-
particles [4,5].
The work reported all over the world on the microorganisms
and plants in the synthesis of Au nanoparticles has been reviewed
by Mohanpuria et al.[6]. Coreander leaf-mediated synthesis of Au
nanoparticles has been carried out by Narayanan and Sakthivel [7]
and the reduction is reported to be complete in 12 h. Kasturi
et al.[8] have reported the synthesis of silver and gold nanopar-
ticles using purified apiin compound extracted from henna leaf.
The use of edible mushroom and natural honey in the synthesis of
Au and Ag nanoparticles have also been reported very recently
[9,10]. The present study is a report on the aqueous synthesis of
gold and silver nanoparticles of anisotropic and spherical shapes
obtained by adjusting the concentrations of metal ions and
hibiscus (Hibiscus rosa sinensis) leaf extract at ambient conditions.
This is simple, cost-effective, stable for long time, reproducible
and previously unexploited method to obtain a self-assembly of
Au/Ag nanoparticles.
Hibiscus is a medicinal herb usually used effectively in native
medicines against hypertension, pyrexia and liver disorder [11]. It
blocks adipogenesis [12] and is also used to treat dandruff and
stimulate hair growth. Living systems have been reported to
receive non-enzymatic protection from lipid peroxidation by
antioxidants such as tocopherol, ascorbic acid, b-carotene and
uric acid found in large quantities in fruits and vegetables. Food
antioxidants act as reducing agents, reversing oxidation by
donating electrons and hydrogen ions [13]. Hibiscus leaf extract
contains antioxidant compounds and is applicable to prevent
atherosclerosis in humans via its anti-hyperlipidaemic effect and
anti-LDL oxidation [14]. Hypoglycemic activity of this extract has
also been reported [15]. Hibiscus leaf extract contains [16]
proteins, vitamin C, organic acids (essentially malic acid),
flavinoids and anthocyanins. The ability of hibiscus extract as a
natural starch and sucrose blocker is found to lower starch and
sucrose absorption when injested at reasonable doses [17] by
inhibiting amylase which in turn an influence the glycemic load
favourably. The antioxidant potential and anti-implantation
activity of hibiscus extract were also studied [18,19]. Several
plants like alalfa, lemon grass, geranium leaves, Cinnamomum
ARTICLE IN PRESS
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journal homepage: www.elsevier.com/locate/physe
Physica E
1386-9477/$ - see front matter & 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.physe.2009.11.081
n
Tel.: +91 471 2530887.
E-mail addresses: philipdaizy@yahoo.co.in, daizyp@rediffmail.com.
Physica E 42 (2010) 1417–1424
2. ARTICLE IN PRESS
camphora, tamarind, neem, Aloe vera, coriander and capsicum
annum were used to synthesize metal nanoparticles [6–8,20–27].
The present paper describes for the first time, Hibiscus
rosa sinensis leaf-mediated biosynthesis of gold and silver
nanoparticles.
2. Experimental
Hibiscus leaf shown in Fig. 1 was washed several times with
de-ionized water. 20 g of hibiscus leaf was finely cut and stirred
with 200 mL de-ionized water at 300 K for 1 min and filtered
to get the extract. The filtrate is used as reducing agent
and stabilizer. HAuCl4 Á 3H2O and AgNO3 were procured from
Sigma-Aldrich.
Fig. 1. Digital photograph of hibiscus leaf used in the synthesis.
Fig. 2. UV–visible spectra of gold colloids: (a) g1, (b) g2, (c) g3 and (d) g4.
Fig. 3. TEM images of colloid g2 (a) and (b) under different magnification; (c)
single multi-branched gold nanoparticle.
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2.1. Synthesis of gold nanoparticles
5 mL hibiscus extract is added to a vigorously stirred 30 mL
aqueous solution of HAuCl4 Á 3H2O (5 Â 10À4
M) and stirring
continued for 1 min. Slow reduction takes place and is complete
in 1.5 h as shown by stable light violet colour of the solution
which gives colloid g1. To obtain colloids g2, g3 and g4, the
addition of the extract is varied as 10, 20 and 30 mL, respectively.
It is found that reduction takes place rapidly with increase in
addition of the extract and colloid g4 is obtained in 30 min. The
colloids are found to be stable for 2 months.
2.2. Synthesis of silver nanoparticles
20 mL hibiscus extract is added to a vigorously stirred 25 mL
aqueous solution of AgNO3 (0.8 Â 10À
3 M) and stirring continued
for 1 min. To initialize the reduction of Ag ions, the pH of the
solution is adjusted to be 6.8 using NaOH. Reduction takes place
rapidly as indicated by golden yellow colour of the solution which
gives colloid s1. The colloids s2, s3, s4, s5 and s6 are obtained by
adjusting the pH of the solution to 7.2, 7.5, 7.8, 8.0 and 8.5. These
colloids are found to be stable for 4 months.
The UV–visible spectra were recorded on a Jasco V-550
UV–visible spectrophotometer with samples in quartz cuvette.
X-ray diffraction pattern of dry nanoparticle powder was obtained
using Siemens D5005 X-ray diffractometer with CuKa radiation
(l=0.1542 nm). The FTIR spectra were obtained on a Nicolet 5700
FTIR instrument with the sample as KBr pellets. The morphology
of the nanoparticles was analysed using the high-resolution
images obtained with a JEOL 3010 transmission electron micro-
scope.
3. Results and discussion
3.1. UV–visible and TEM analysis of gold nanoparticles
UV–visible spectroscopy is an important technique to ascertain
the formation and stability of metal nanoparticles in aqueous
solution. Fig. 2 shows the UV–visible spectra of the gold colloids
(g1–g4) obtained after 1.5 h of reaction. The colour of the colloid
arises because of the surface plasmon vibrations with gold
nanoparticles [28]. The surface Plasmon resonance (SPR) band of
colloid g1 occurs around 573 nm. The Plasmon bands of Au
nanoparticles are broad with an absorption tail in the longer
wavelength region that extends well into the near infrared region
in colloids g1, g2 and g3. This long wavelength absorption is
attributed to the excitation of the longitudinal (in-plane) SPR and
indicates significant anisotropy in the shape of gold nanoparticles.
The band becomes narrower from g1 to g4 (Fig. 2) with a shift
towards lower wavelength as the quantity of extract is increased.
The fairly sharp SPR observed for colloid g4 (Fig. 2(d)) at 548 nm is
indicative of almost spherical nanoparticles. A similar result has
been reported in gold nanoparticles synthesized using coriander
leaf, apiin and edible mushroom [7–10].
The morphology and size of the synthesized nanoparticles
were also determined by TEM images. Typical TEM images
obtained for colloids g2, g3 and g4 are shown in Figs. 3–5. The
long wavelength tail in the SPR arising due to anisotropy of Au
Fig. 4. TEM images of colloid g3 (a)–(c) under different magnification; (d) single nanocrystal.
D. Philip / Physica E 42 (2010) 1417–1424 1419
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nanoparticles is evident from the TEM images of nanoparticles in
colloids g2 (Fig. 3) and g3 (Fig. 4). Colloid g2 consists of a large
number of anisotropic particles with smaller ones being multi-
branched (Fig. 3(c)). Nanoparticles with triangular, hexagonal,
dodecahedral and spherical shapes are seen in g3. The size and
propensity of triangular particles decrease from colloid g2 to g4
and there is an increase in dodecahedral and spherical ones. In
colloid g4 (Fig. 5) the particles are almost spherical with size
$14 nm. The ability to modulate the shape of nanoparticles as
observed in this study for Au nanoparticles opens up exciting
possibility of further synthetic routes using biological sources. The
typical high-resolution TEM image (Fig. 5(e)) with clear lattice
fringes having a spacing of 0.23 nm reveals that the growth of Au
nanoparticles occurs preferentially on the (1 1 1) plane. The inter-
planar distance of the Au (1 1 1) plane is in agreement (29) with
the (1 1 1) d-spacing of bulk Au (0.2355 nm). Fig. 5(f) shows the
selected area electron diffraction (SAED) pattern of one of the
spherical particles in colloid g4. The clear lattice fringes in high-
resolution TEM image and the typical SAED pattern with bright
circular rings corresponding to the (1 1 1), (2 0 0), (2 2 0) and
(3 1 1) planes show that the nanoparticles obtained are highly
crystalline.
The decrease in intensity of the long wavelength tail of the SPR
with increase in quantity of hibiscus extract and non-uniform
dispersion of the nanoparticles may be explained as follows:
When an excess of extract was used to reduce the aqueous
Fig. 5. TEM images of colloid g4 (a)–(d) under different magnification; (e) single nanocrystal showing lattice fringes with spacing of 0.23 nm; (e) SAED pattern.
D. Philip / Physica E 42 (2010) 1417–14241420
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HAuCl4, the biomolecules acting as capping agents strongly
shaped spherical particles rather than nanotriangles, dodecahe-
dral and hexagonal nanoparticles though the reductive biomole-
cules were enhanced [8–10]. Although lower quantities of the
extract fulfilled the reduction of chloroaurate ions, they failed to
protect most of the quasi-spherical nanoparticles from aggregat-
ing because of the deficiency of biomolecules to act as protecting
agents. The nascent nanocrystals devoid of protection were
unstable and gold nanotriangles and dodecahedrons might grow
by a process involving rapid reduction, assembly and room
temperature sintering of spherical gold nanoparticles [9,10,26].
Sintering of gold nanoparticles and their adherence to the
nanotriangle is evident from Figs. 3(b) and 4(c). The formation
of blunt-angled nanotriangles seen in the TEM images is a result
of the shrinking process arising from the minimization of surface
energy [9,10,26]. The presence of large quantity of extract causes
strong interaction between protective biomolecules and surface of
nanoparticles preventing nascent nanocrystals from sintering.
With larger quantities of the extract the interaction is intensified,
leading to size reduction of spherical nanoparticles. Similar
results have been reported in biological synthesis of gold
nanoparticles using apiin as reducing and stabilizing agent [8].
The present study also shows that in presence of a large quantity
of the extract a uniform dispersion of spherical nanoparticles
could be obtained.
3.2. UV–visible and tem analysis of silver nanoparticles
Fig. 6 shows the UV–visible spectra of silver nanoparticles
formed at various pH values ranging from 6.8 to 8.5 of the
reaction mixture consisting of aqueous AgNO3 and hibiscus
Fig. 6. UV–visible spectra of silver colloids (a) s1, (b) s2, (c) s3, (d) s4, (e) s5
and (f) s6.
Fig. 7. TEM images of colloid s3 (a)–(c) under different magnification; (d) single nanocrystal showing clear lattice fringes.
D. Philip / Physica E 42 (2010) 1417–1424 1421
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extract. The rapid colour change of the solution to golden yellow
is indicative of the formation of silver nanoparticles. SPR band
appears around 399 nm and becomes sharper as pH is increased
upto 7.5 and thereafter it is broadened. The sharp SPR for s3
indicating the formation of spherical nanoparticles is further
confirmed by the TEM images in Fig. 7. Colloid s3 consists of
nearly spherical particles with an average size of $13 nm.
Crystallinity of silver nanoparticles is evidenced by the clear
lattice fringes with a spacing of 0.23 nm (Fig. 7(d)). Broad SPR
bands observed at higher and lower pH values are due to large
anisotropic nanoparticles. Typical TEM images of anisotropic
nanocrystals obtained for colloid s6 are shown in Fig. 8. These
anisotropic silver nanoparticles can act as suitable substrates for
surface enhanced Raman scattering (SERS) spectroscopy using
near IR (NIR) laser source.
3.3. XRD and FTIR studies
The crystalline nature of Au and Ag nanoparticles was further
confirmed from X-ray diffraction (XRD) analysis. Fig. 9(a) shows
the XRD pattern of the dried nanoparticles obtained from colloid
g4. Four peaks were observed at 38.21, 44.31, 64.71 and 77.81 in the
2y range 30–801 which can be indexed to the (1 1 1), (2 0 0),
(2 2 0) and (3 1 1) reflections of fcc structure of metallic gold,
respectively (JCPDS no. 04-0784), revealing that the synthesized
gold nanoparticles are composed of pure crystalline gold. The
ratio between the intensity of the (2 0 0) and (1 1 1) diffraction
peaks of 0.37 is lower than the conventional bulk intensity ratio
(0.52), suggesting that the (1 1 1) plane is the predominant
orientation as confirmed by high-resolution TEM measurements.
Similar results were reported earlier in gold nanoparticles
[9,10,29,30]. The average crystallite size according to Scherrer
equation calculated using the width of the (1 1 1) peak is found to
be 13 nm nearly in agreement with the particle size obtained
from TEM image of colloid g4. The XRD pattern of silver
nanoparticles is shown in Fig. 9(b). In addition to the Bragg
peaks representative of fcc silver nanocrystals, additional as
yet unassigned peaks are also observed suggesting that the
crystallization of bio-organic phase occurs on the surface of the
silver nanoparticles. Similar results were reported in silver
Fig. 8. TEM images of colloid s6 (a) and (b) as viewed from different areas of the
film. Fig. 9. XRD pattern of dried nanoparticle powder (a) gold and (b) silver.
D. Philip / Physica E 42 (2010) 1417–14241422
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nanoparticles synthesized using geranium leaf extract [22] and
mushroom extract [9].
FTIR measurements were carried out to identify the potential
biomolecules in hibiscus leaf responsible for reduction and
capping of the bioreduced gold and silver nanoparticles. The IR
bands (Fig. 10(a)) observed at 1317 and 1733 in dried hibiscus leaf
are characteristic of the C–O and C=O stretching modes
[7,9,22,31,32] of the carboxylic acid group possibly of malic acid
present in it. The amide I band appears as very strong band
at 1619 cmÀ1
and amide II band as a medium broad shoulder at
1546 cmÀ1
in the leaf. These amide I and II bands arise due to
carboxyl stretch and N–H deformation vibrations in the amide
linkages of the proteins [9,33–36] present in it. The medium broad
band at 1399 cmÀ1
is the C–N stretching mode of aromatic amine
group [7]. The C–O–C and C–OH vibrations [9,37] of the protein in
the leaf appear as a very strong IR band at 1022 cm-1
.
The medium intense band at 1721 cmÀ1
is observed for the
C=O stretching mode in the IR spectrum of gold nanoparticles
(Fig. 10(b)) indicates the presence of –COOH group in the material
bound to Au nanoparticles. However, in the spectrum of Ag
nanoparticles (Fig. 10(c)), this mode is very weak or rather absent.
Further, the band due to C–O stretching at 1314 cmÀ1
is intense
in the spectrum of silver nanoparticles. The amide II band has
become more prominent in the spectrum of gold and amide I band
is shifted to higher frequency (1638 cmÀ1
) compared to that of
plain leaf (1619 cmÀ1
). From these observations it is clear that the
biomolecules responsible for reduction and capping are different
in gold and silver nanoparticles. It is well-known that proteins can
bind to Au nanoparticles through the free amine groups
or carboxylate ion of aminoacid residue in it [31,34,38]. The
presence of the IR bands due to C=O stretch at 1721 cmÀ1
and
the prominent appearance of the amide I and amide II bands with
large shift from that of the plain leaf indicate the possibility that
gold nanoparticles are bound to proteins through free amine
groups. Observation of almost unshifted positions of amide I and
II bands compared to that of the plain leaf and the absence of C=O
stretch of free –COOH in silver nanoparticles indicate the
stabilization of the system through the –COOÀ
(carboxylate ion)
groups of aminoacid residues with free carboxylate groups in the
protein [31,34,38]. However, the role of malic acid molecules
present in the leaf extract on bioreduction and stabilization
cannot be ruled out and needs further study as the band due to
C–O stretch at 1314 cmÀ1
is appearing in the IR spectrum of silver
nanoparticles.
4. Conclusions
Gold nanoparticles of different size and shape were synthe-
sized using hibiscus leaf extract by varying the ratio of metal salt
and the extract. Variation of pH of the reaction medium consisting
of silver nitrate and hibiscus leaf extract gave silver nanoparticles
of different shapes. The nanoparticles were characterized by UV–
vis, TEM, XRD and FTIR measurements. Crystalline nature of the
nanoparticles is evident from bright circular spots in the SAED
pattern, clear lattice fringes in the high resolution TEM images
and peaks in the XRD pattern. From FTIR spectra it is found that
the stabilization occurs through amine groups in gold nanopar-
ticles and carboxylate ion in silver nanoparticles.
Acknowledgements
This research has been sponsored by the University Grants
Commission, New Delhi, under the Research Award scheme.
The author is grateful to Professor T. Pradeep, DST unit on
Nanoscience, IIT Madras for TEM measurements.
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