Abstract
Objective(s):
The enzymatic activity of fungi has recently inspired the scientists with re-explore the fungi as potential biofactories rather than the causing agents of humans and plants infections. In very recent years, fungi are considered as worthy, applicable and available candidates for synthesis of smaller gold, silver and other nano-sized particles.
Materials and Methods:
A standard strain of Aspergillus parasiticus was grown on a liquid medium containing mineral salt. The cell-free filtrate of the culture was then obtained and subjected to synthesize SNPs while expose with 1mM of AgNO3. Further characterization of synthesized SNPs was performed afterward. In addition, antifungal activity of synthesized SNPs was evaluated against a standard strain of Candida albicans. The reduction of Ag+ ions to metal nanoparticles was investigated virtually by tracing the color of the solution which turned into reddish-brown after 72h.
Results:
The UV-vis spectra demonstrated a broad peak centering at 400nm which corresponds to the particle size much less than 70nm. The results of TEM demonstrated that the particles were formed fairly uniform, spherical, and small in size with almost 90% in 5-30nm range. The zeta potential of silver nanoparticles was negative and equal to -15.0 which meets the quality and suggested that there was not much aggression. Silver nanoparticles synthesized by A. parasiticus showed antifungal activity against yeast strain tested and exhibited MIC value of 4 μg/mL.
Conclusion:
The filamentous fungus, A. parasiticus has successfully demonstrated potential for extra cellular synthesis of fairly monodispersed, tiny silver nanoparticles.
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.
Biological method for the preparation of nanoparticles(Sheersho)Sheersha Pramanik 🇮🇳
I have described about the biological processes(other than physical,chemical) for the preparation of Nanoparticles.
do like comment share if you like it.
ABSTRACT- In our present study, we account for eco-friendly biosynthesis of copper nanoparticles using aqueous leaves extract of Artocarpus heterophyllus against first to fourth instar larvae of Aedes aegypti. The synthesized CuNPs were characterized by UV, XRD, FTIR and SEM analyses were clearly distinguishable. The four different immature mosquito larval stages of A. aegypti were exposed to varying concentrations of aqueous leaf extract of A. heterophyllus, copper sulphate (CuSO4) and synthesized CuNPs for 24 h. The mortality was observed at aqueous extract (LC50= 48.40, 60.55, 70.36, and 82.79 mg/ml), CuSO4 (LC50=21.81, 26.92, 41.38, and 55.12 mg/ml) synthesized CuNPs against first to fourth instars of A. aegypti (LC50= 3.85, 4.24, 4.66, and 5.08 mg/ml), respectively. The novel properties created not only improve the quality of human’s life; it also helps in saving energy and environment.
Key-words: Copper nanoparticles, Jackfruit, Aedes aegypti, aqueous leaf extract
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.
Biological method for the preparation of nanoparticles(Sheersho)Sheersha Pramanik 🇮🇳
I have described about the biological processes(other than physical,chemical) for the preparation of Nanoparticles.
do like comment share if you like it.
ABSTRACT- In our present study, we account for eco-friendly biosynthesis of copper nanoparticles using aqueous leaves extract of Artocarpus heterophyllus against first to fourth instar larvae of Aedes aegypti. The synthesized CuNPs were characterized by UV, XRD, FTIR and SEM analyses were clearly distinguishable. The four different immature mosquito larval stages of A. aegypti were exposed to varying concentrations of aqueous leaf extract of A. heterophyllus, copper sulphate (CuSO4) and synthesized CuNPs for 24 h. The mortality was observed at aqueous extract (LC50= 48.40, 60.55, 70.36, and 82.79 mg/ml), CuSO4 (LC50=21.81, 26.92, 41.38, and 55.12 mg/ml) synthesized CuNPs against first to fourth instars of A. aegypti (LC50= 3.85, 4.24, 4.66, and 5.08 mg/ml), respectively. The novel properties created not only improve the quality of human’s life; it also helps in saving energy and environment.
Key-words: Copper nanoparticles, Jackfruit, Aedes aegypti, aqueous leaf extract
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.
Term ‘Nano’ comes from the Greek word ‘nanos’ meaning dwarf and denotes a measurement on the scale of one billionth (10⁹) of a meter in size. Nanoparticles are defined as a particulate dispersions of solid particles with atleast one dimension at a size range of 10-1000 nm. The most important feature of Nanoparticles is their surface area to volume aspect ratio, allowing them to interact with other particles easier.
It an overall view on two research papers. Biological synthesis of Nano particles from plants and microorganisms
and the synthesis of metallic Nano particles using plant extract
Green nanotechnology & its application in biomedical researchRunjhunDutta
This presentation gives detailed description of Green Nanotechnology including its principles & significance. Illustrated with examples for its application in various biomedical research fields.
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.
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.
Green Synthesis of ZnO Nanoparticles using Jasminum Fluminense Leaf Extract a...ijtsrd
The main objective of the present study is to deal with the green synthesis of Zinc Oxide [ZnO] nanoparticles utilizing aqueous leaf extract of Jasminum Fluminense.` Zinc acetate [Zn(O2CCH3)2(H2O)2] and sodium hydroxide [NaOH] were used as starting materials and Jasminum Fluminense [Nithyamalli] leaf extract is used as precursor in the synthesis of ZnO nanoparticles. The resultant nanopowder was characterized by using Ultraviolet [UV] “ Visible Spectroscopy, Fourier Transform Infrared Spectroscopy [FTIR] and Transmission Electron Microscopic [TEM] studies. Formation of ZnO nanoparticles has been confirmed by UV-visible spectroscopy and the TEM analysis spectacles that the synthesized ZnO nanoparticles are of face centered cubic (fcc) structure and the size is found to be around 20 nm. FTIR spectral analysis indicated the leaf extract acts as the reducing and capping agents on the surface of ZnO nanoparticles. This simplistic and green approach may provide a useful tool to hefty extent in the synthesis of ZnO nanoparticles. These synthesized nanostructures illustrate novel applications in many fields such as cosmetics, optoelectronics, sensors, transducers and biomedical science because it is environmentally friendly and does not involve any harmful substances. S. Amudha"Green Synthesis of ZnO Nanoparticles using Jasminum Fluminense Leaf Extract and its Spectral and Optical Characterization Studies" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd12908.pdf http://www.ijtsrd.com/physics/nanotechnology/12908/green-synthesis-of-zno-nanoparticles-using-jasminum-fluminense-leaf-extract-and-its-spectral-and-optical-characterization-studies/s-amudha
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.
Term ‘Nano’ comes from the Greek word ‘nanos’ meaning dwarf and denotes a measurement on the scale of one billionth (10⁹) of a meter in size. Nanoparticles are defined as a particulate dispersions of solid particles with atleast one dimension at a size range of 10-1000 nm. The most important feature of Nanoparticles is their surface area to volume aspect ratio, allowing them to interact with other particles easier.
It an overall view on two research papers. Biological synthesis of Nano particles from plants and microorganisms
and the synthesis of metallic Nano particles using plant extract
Green nanotechnology & its application in biomedical researchRunjhunDutta
This presentation gives detailed description of Green Nanotechnology including its principles & significance. Illustrated with examples for its application in various biomedical research fields.
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.
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.
Green Synthesis of ZnO Nanoparticles using Jasminum Fluminense Leaf Extract a...ijtsrd
The main objective of the present study is to deal with the green synthesis of Zinc Oxide [ZnO] nanoparticles utilizing aqueous leaf extract of Jasminum Fluminense.` Zinc acetate [Zn(O2CCH3)2(H2O)2] and sodium hydroxide [NaOH] were used as starting materials and Jasminum Fluminense [Nithyamalli] leaf extract is used as precursor in the synthesis of ZnO nanoparticles. The resultant nanopowder was characterized by using Ultraviolet [UV] “ Visible Spectroscopy, Fourier Transform Infrared Spectroscopy [FTIR] and Transmission Electron Microscopic [TEM] studies. Formation of ZnO nanoparticles has been confirmed by UV-visible spectroscopy and the TEM analysis spectacles that the synthesized ZnO nanoparticles are of face centered cubic (fcc) structure and the size is found to be around 20 nm. FTIR spectral analysis indicated the leaf extract acts as the reducing and capping agents on the surface of ZnO nanoparticles. This simplistic and green approach may provide a useful tool to hefty extent in the synthesis of ZnO nanoparticles. These synthesized nanostructures illustrate novel applications in many fields such as cosmetics, optoelectronics, sensors, transducers and biomedical science because it is environmentally friendly and does not involve any harmful substances. S. Amudha"Green Synthesis of ZnO Nanoparticles using Jasminum Fluminense Leaf Extract and its Spectral and Optical Characterization Studies" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd12908.pdf http://www.ijtsrd.com/physics/nanotechnology/12908/green-synthesis-of-zno-nanoparticles-using-jasminum-fluminense-leaf-extract-and-its-spectral-and-optical-characterization-studies/s-amudha
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.
TÉCNICA DE VISUALIZAÇÃO AUMENTADA PARA TECLADOS VIRTUAIS USP
A presente invenção consiste em uma Técnica de visualização aumentada para teclados virtuais controlados por um dispositivo de apontamento como o olhar ou a cabeça. A Técnica inova no campo da tecnologia da informática e comunicação e cumpre papel social de inclusão e acessibilidade, ao possibilitar que pessoas com deficiência motora severa tenham acesso às tecnologias modernas. Dentre as principais contribuições do invento estão o maior conforto e velocidade de digitação alcançadas por meio do enriquecimento das informações visuais do teclado que incluem, entre outras, informações do contexto digitado e aceleração de palavras.
Green Synthesis of Nano-Particles and its Application in Treatment of Rheumat...ijcoa
This paper presents an overview of silver nanoparticles (Ag NPs) preparation by green synthesis approaches that have advantages over conventional methods involving chemical agents associated with environmental toxicity and also explains its application in the cure of Rheumatoid arthritis. We have used Night Jasmine (Nyctanthes arbor-tristis), one of the best medicinal plants to synthesis Ag NPs. The plant extract contain some biomolecules like proteins carbohydrates etc., which act as both reducing and capping agents forming stable and shape-controlled Ag NPs. The basic principle behind the synthesis is that the silver (Ag+) of AgNO3 is reduced to Ag0 by the bio-molecules present in the extract. Rather than applying the conventional method of using micro waves to induce the reduction reaction, we have used direct sunlight as the inducer by which the reduction is faster than the former. The synthesized silver nanoparticles were characterized with UV-Visible spectroscopy, X-ray Diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The results of all these analysis were shown. Our work mainly concerns about the cure for Rheumatoid arthritis so, we have checked the Nano-particles for the Anti-Arthritic activity and the results were positive. The procedure for Invitro analysis of anti-arthritic activity and its result are clearly shown.
Antibacterial agents are very important in the textile industry, water disinfection, medicine, and food packaging. Organic compounds used for disinfection have some disadvantages, including toxicity to the human body; therefore, the interest in inorganic disinfectants such as metal oxide nanoparticles (NPs) is increasing. This review focuses on the Preparation and their potential with good antimicrobial activity of Ag-NPs and Se-NPs against biofilm forming S. aureus. Such improved antibacterial agents locally destroy bacteria, without being toxic to the surrounding tissue. We also provide an overview of opportunities and risks of using NPs as antibacterial agents. In particular, we discuss the role of Ag-NPs and Se-NPs materials. Several manufactured nanoparticlesparticles with one dimension less than 100 nm are increasingly used in consumer products. At nano size range, the properties of materials differ substantially from bulk materials of the same composition, mostly due to the increased specific surface area and reactivity, which may lead to increased bioavailability and toxicity. Thus, for the assessment of sustainability of nanotechnologies, methods of manufacturing Nanoparticles, properties have to be studied.
The formation of nanoparticle and physiochemical parameters such as pH, monomer concentration, ionic strength as well as surface charge, particle size and molecular weight are important for drug delivery. Further, these nanoparticles have the capability to reverse
multidrug resistance a major problem in chemotherapy. Well-established therapies commonly employed in cancer treatment include surgery, Chemotherapy, immunotherapy, and
radiotherapy. The silver nanoparticles might be involved in neutralizing these adhesive substances, thus preventing biofilm formation. Selenium is also one of essential trace elements in the human body and has great importance in nourishment and medicine. Medicaldiagnostic field also developed to use the selenium nanoparticles and also studies on the increase efficiency of glutathione peroxidase and thioredosin reductase.
Effects of combination of magnesium and zinc oxide nanoparticles and heat on ...Nanomedicine Journal (NMJ)
Objective: The objective of this study was to investigate the antibacterial activities of combination of MgO and ZnO nanoparticles in the presence of heat against Escherichia coli and Staphylococcus aureus.
Materials and Methods:Bacteria were grown on either agar or broth media followed by the addition of ZnO and MgO nanoparticles. Then the combined effect of ZnO and MgO nanoparticles was investigated. Furthermore, the media containing nanoparticles were treated with mild heat and their synergistic antibacterial activity was investigated against E. coli and S. aureus in milk.
Results: The data showed that the nanoparticles used in this study had no effect on the bacteria in the agar medium. However, the results showed that ZnO and MgO nanoparticles resulted in a significant decrease in the number of E. coli (P<0.000) and S. aureus (Pd”0.05) in the broth medium. The combination of nanoparticles and mild heat exhibited a significant decrease in the number of E. coli and S. aureus indicating the synergistic effects of nanoparticles and heat.
Conclusion: Using a combination of mild heat, ZnO and MgO nanoparticles, E. coli and S. aureus can be controlled successfully in the milk. Mild heating plus ZnO and MgO nanoparticles has a synergistic effect which would reduce the need for high temperature and also the concentrations of ZnO and MgO nanoparticles required for pathogen control in minimally processed milk during maintaining.
A primary screening of antitumor substances was carried out among strains of actinomycetes isolated from the samples of natural substrates of arid zones in the Ile-Balkhash region. Antitumor properties of actinomycetes against Staphylococcus aureus209Р(S. aureus 209P) and its mutants UF-2 and UF-3 were studied using the agar block technique. The diameter of growth inhibition zone was measured after incubation of the test microorganisms at a temperature of 37 °C for 24 hours. 16 strains of actinomycetes (10,2%) from sandy soils and from the plant rhizosphere of the Kapshagai area virtually having no effect or only slightly affecting the growth of wild-type culture.22 strains of actinomycetes (14,0%) from takyrs and takyr-like soils of the Balkhash area had an activity against staphylococcal mutants two or more times higher than against the stock staphylococcal strain.This strains may be the potential producers of antitumor antibiotics.It was established that 24.2% of the strains of actinomycetes may be potential producers of antitumor antibiotics.
ABSTRACT- In this study, the effect of ZnO and TiO2-NPs on beneficial soil microorganisms and their secondary metabolites production was investigated. The antibacterial potential of NPs were determined by growth kinetics of P. aeruginosa, P. fluorescens and B. amyloliquefaciens. Significantly decreased in the cell viability based on optical density measurements were observed upon treatment with increasing concentrations of NPs. While comparing the effect of the different concentrations of the NPs (200 µg/ml) on IAA production by different bacterial strains, ZnO nanoparticles showed greater inhibitory effect than TiO2-NPs on IAA production by bacterial strains. The effect of Nanoparticles on phosphate solubilization was found inhibitory at 200 µg/ml. Treatment with ZnO showed concentration dependent enhancement in siderophore production by bacteriaby exposure to ZnO-NPs whereas TiO2-NPs showed concentration dependent progressive decline for iron binding siderophore molecules. Reduction in antibiotic production by P. aeruginosa and P. fluorescens was noticed in the presence of ZnO and TiO2 as compared to the control. The fluorescence of NADH released by P. aeruginosa was observed to be quenched in presence of ZnO and TiO2-NPs as compared to control. The present study highlights that the impact of nanoparticles on bacterial strains and the release of plant growth promoting substances by PGPR strains was dose dependent, which gives an idea about the level of toxicity of these nanoparticles in the environment. Therefore, the discharge of nanoparticles in the environment should be carefully monitored so that the loss of both structure and functions of agronomically important microbes could be protected from the toxicity of MO-NPs.
Key-words- MO-NPs, IAA, Phosphate Solubilization, Siderophore, PCA, NADH, ZnO-NPs, TiO2-NPs
Synthesis and evaluation of bactericidal properties of CuO nanoparticles agai...Nanomedicine Journal (NMJ)
Objective(s):
CuO is one of the most important transition metal oxides due to its captivating properties. It is used in various technological applications such as high critical temperature superconductors, gas sensors, in photoconductive applications, and so on. Recently, it has been used as an antimicrobial agent against various bacterial species.
Materials and Methods:
Here, we synthesized CuO nanoparticles (NPs) and explored the antibacterial activity of CuO NPs preparation.
Results:
Single crystalline nanoparticles of copper oxide having almost uniform particle size of 5-6 nm has been synthesized by a facile and versatile route. XRD spectra confirmed the formation of single phase CuO NPs. Transmission electron microscopy results corroborate well with XRD results. The technique employed is free from toxic solvents, organics and amines, is based on a simple reaction of copper sulfate and de-ionized water (DI), and their bactericidal effects against of Aeromonas hydrophila ATCC 7966T bacteria were investigated. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) with liquid culture for all of the Aeromonas hydrophila culture Medias was done.
Conclusion:
Present study confirms that Copper oxide nanoparticles have great promise as antimicrobial agent against Aeromonas hydrophila.
Staphylococcus aureus is a most important bacterium that causes nosocomial infections and the etiologic
agent of a wide range of diseases related with major mortality and morbidity. Total 36 positive clinical
samples viz. urine, blood and pus collected from different patients were found to harbor Staphylococcus
aureus with a maximum isolation from pus samples i.e. 30 (83.33%) and minimum isolation from urine
samples i.e. 2 (5.56%). The degree of capacity to biofilm forming Staphylococcus aureus isolates to
different phenotypic analysis of biofilm formation by Congo red agar (CRA) Nil, Tube method (TM) 5
(13.89%), and Tissue culture plate method (TCP) 12 (33.33%). The application of silver and Selenium
nanoparticles as antimicrobials are gaining relevance in the medical field. Silver nanoparticles, due to
their unique properties, use in day-by-day many applications in human life. The major uses of silver
nanoparticles in the clinical and medical fields consist of investigative applications and curative
applications. Selenium metal is an essential micronutrient for human beings and animals. Selenium
nanoparticles showed the highest bactericidal and antimicrobial properties. Minimal biofilm eradication
concentrations (MBEC) were determined by 96-well microtitre plate. The antibacterial effects of silver and
selenium nanoparticles were evaluated with respect to growth, biofilm formation of Staphylococcus aureus
strains. Among the three biofilm forming Staphylococcus aureus strains showed OD450 i.e. 0.019, 0.039,
0.075 value ≤0.080 for AgNPs whereas SeNPs couldn’t showed any ≤ 0.080 value against biofilm forming
S. aureus strains. In case of MBEC test, AgNPs showed more affective against biofilm forming
Staphylococcus aureus strains compared of SeNPs. Finally we suggested that AgNPs showing best
antimicrobial activity against SeNPs.
The effect of silver nanoparticles on Staphylococcus epidermidis biofilm biom...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Bacterial biofilm has been considered responsible for many deaths and high health costs worldwide. Their better protection against antibacterial agents compared to free living cells leads to poor treatment efficiency. Nanotechnology is promising approach to combat biofilm infections. The aim of the present study was to eradicate Staphylococcus epidermidis biofilm with silver nanoparticles (SNPs).
Materials and Methods:
SNPs were used at different concentrations (two fold dilutions) and incubation times (24, 48, 72 h). The crystal violet staining and pour plate assays were used to assess biofilm biomass and bacterial viability, respectively. The ability of SNPs on biofilm matrix eradication was assessed through optical density ratio (ODr). Positive control was defined as an ODr =1.0.
Results:
The crystal violet assay indicated that the biofilm matrixes were intact at different concentrations of SNOs and incubation times. There were no significant differences between these parameters (P >0.05). Bacterial enumeration studies revealed that higher concentrations of SNPs were more effective in killing bacteria than lower ones. Although, longer incubation times led to enhancement of anti-biofilm activity of SNPs.
Conclusion:
The anti-biofilm activity of SNPs was concentration- and time-dependent. The results of this study highlighted that SNPs were effective against cell viability; however they were ineffective against biomass.
Nanotechnology has become one of the most promising technologies applied in
all areas of science. Metal nanoparticles produced by nanotechnology have
received global attention due to their extensive applications in the biomedical
and physiochemical
fields. Recently, synthesizing metal nanoparticles using
microorganisms and plants has been extensively studied and has been recog-
nized as a green and efficient way for further exploiting microorganisms as
convenient nanofactories. Here, we explore and detail the potential uses of
various biological sources for nanoparticle synthesis and the application of
those nanoparticles. Furthermore, we highlight recent milestones achieved for
the biogenic synthesis of nanoparticles by controlling critical parameters,
including the choice of biological source, incubation period, pH, and
temperature.
In vitro assessment of antibacterial activity of Salicornia herbacea L. seed ...Innspub Net
In this study, the antibacterial activities of Salicornia herbacea L. seed extract against two gram-negative and two gram- positive bacteria were evaluated with the agar disc diffusion and MIC methods. Result showed that inhibition zones of 9.5±0.01, 6.2±0.00, 4±0.00 and 3.5±0.10 mm for Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli, respectively. Among four bacteria the maximum and minimum inhibition seed ethanolic extract were related to S. aureus with inhibition zones of 9.5mm and MIC 189.5 mg/ml and E. coli with inhibition zones of 3.5 mm and MIC 420 mg/ml, respectively. The antimicrobial activity of ethanol seed extract of S. herbacea is the result of phenolic compounds, fatty acids, osmotic compound (betaine)
or synergic and additive effect of several compounds present in it. Our results suggest the possibility of using S. herbacea seed, which possesses strong antibacterial activity, in the treatment of diseases caused by the microorganisms tested. Get the full articles at: http://www.innspub.net/volume-4-number-6-march-2014/
Abstract
Objective(s):
The present study aimed to investigate the antiseptic properties of a colloidal nano silver wound rinsing solution to inhibit a wide range of pathogens including bacteria, viruses and fungus present in chronic and acute wounds.
Materials and Methods:
The wound rinsing solution named SilvoSept® was prepared using colloidal nano silver suspension. Physicochemical properties, effectiveness against microorganism including Staphylocoocous aureus ATCC 6538P, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 8739, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, MRSA, Mycobacterium spp., HSV-1 and H1N1, and biocompatibility tests were carried out according to relevant standards.
Results:
X-ray diffraction (XRD) scan was performed on the sample and verify single phase of silver particles in the compound. The size of the silver particles in the solution, measured by dynamic light scattering (DLS) techniqu, ranged 80-90 nm. Transmission electron microscopy (TEM) revealed spherical shape with smooth surface of the silver nanoparticles. SilvoSept® reduced 5 log from the initial count of 107 CFU/mL of Staphylocoocous aureus ATCC 6538P, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 8739, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, MRSA, Mycobacterium spp. Further assessments of SilvoSept solution exhibited a significant inhibition on the replication of HSV-1 and H1N1. The biocompatibility studies showed that the solution was non-allergic, non-irritant and noncytotoxic.
Conclusion:
Findings of the present study showed that SilvoSept® wound rinsing solution containing nano silver particles is an effective antiseptic solution against a wide spectrum of microorganism. This compound can be a suitable candidate for wound irrigation.
Study of Biocidal Activity of Copper A Reviewijtsrd
Copper ions, either alone or in copper complexes, have been used to disinfect liquids, solids and human tissue for centuries. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide as well as an anti bacterial and anti fouling agent. Copper also displays potent anti viral activity. We have explained i the biocidal properties of copper ii the possible mechanisms by which copper is toxic to microorganisms and iii the systems by which many microorganisms resist high concentrations of heavy metals, with an emphasis on copper. Health care associated infections HAIs are a global problem associated with significant morbidity and mortality. Controlling the spread of antimicrobial resistant bacteria is a major public health challenge, and antimicrobial resistance has become one of the most important global problems in current times. The antimicrobial effect of copper has been known for centuries, and ongoing research is being conducted on the use of copper coated hard and soft surfaces for reduction of microbial contamination and, subsequently, reduction of HAIs. Dr. Pragya Tank "Study of Biocidal Activity of Copper: A Review" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-5 , August 2022, URL: https://www.ijtsrd.com/papers/ijtsrd50696.pdf Paper URL: https://www.ijtsrd.com/chemistry/other/50696/study-of-biocidal-activity-of-copper-a-review/dr-pragya-tank
PREVALENCE AND CHARACTERIZATION OF VIRULENCE PROPERTIES OF PSEUDOMONAS AERUGI...SUS GROUP OF INSTITUTIONS
Pseudomonas aeruginosa is the epitome of an opportunistic pathogen of humans that cause urinary tract infections, respiratory system infection, particularly in victim of severe burns, cancer and AIDS patient who are immunocompromised. Most Pseudomonas infections are both invasive and toxigenic. The particular bacterial determinants of virulence mediate different stages of infection and are ultimately responsible for the characteristic syndromes that accompany the disease. In the present study P. aeruginosa was found to be more prevalent in burn patients (100%) followed by urinary tract infection samples (71%), sputum samples (66%) and wound samples (59%). 85% isolates recovered from clinical samples were mucoid. A total of 35% isolates were strong siderophore producers, 19% isolates were strong protease producers while 52% were strong phospholipase producers. Isolates from burns, sputum and environment sample were strong rhamnolipid producers. Elevated level of hemolysin production was observed in burn, urine and wound isolates. The prominence of haemagglutination ability in environmental isolates followed by burns isolates provided evidence for its being a nosocomial pathogen. The association between virulence determinants and disease can indicate the precise role played by the determinant in estabilishing the disease. Isolates were maximally sensitive towards lactam antibiotics.
Silver Nanoparticles from a Plant Echinacea Purpurea Extract for its Antipath...ijtsrd
Nanotechnology is gaining tremendous impetus in the present century due to its capability of modulating metals into their nanosize. The synthesis, characterization, and application of biologically synthesized nanomaterials have become an important branch of nanotechnology. Research in nanotechnology highlights the possibility of green chemistry pathways to produce technologically important nanomaterials. Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are often toxic and flammable. Silver nanoparticles are the metal of choice as they hold the promise to kill microbes effectively. The present study describes a cost effective and environment friendly technique for green synthesis of silver nanoparticles from 1mM silver nitrate solution through the a plant Echinacea purpurea cone flower extract. The appearance of brown colour indicates the synthesis of silver nanoparticles. Nanoparticles were characterized using UV Vis absorption spectroscopy and SEM analysis. UV Vis spectrum of the aqueous medium containing silver nanoparticles showed absorption peak at 450nm. SEM analysis showed the average particle size of 50 70nm and spherical shape of the silver nanoparticles. Further studies on the silver nanoparticles showed that it has the antibacterial activities. Antipathogenic activity study was carried out by spread plate, pour plate on Escherichia coli and disc diffusion methods on pathogenic organisms such as Escherichia coli, Proteus vulgaricus, Klebsiella pneumoniae, Pseudomonas aeruginosa. Compared to spread plate, pour plate method showed the maximum antibacterial activity. Zone of inhibition was observed by disc diffusion methods and among these four pathogens, Klebsiella pneumoniae and Escherichia coli showed the maximum activity. Satheesh Kumar B. "Silver Nanoparticles from a Plant Echinacea Purpurea Extract for its Antipathogenic Efficacy" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-6 , October 2022, URL: https://www.ijtsrd.com/papers/ijtsrd50001.pdf Paper URL: https://www.ijtsrd.com/biological-science/biotechnology/50001/silver-nanoparticles-from-a-plant-echinacea-purpurea-extract-for-its-antipathogenic-efficacy/satheesh-kumar-b
Abstract
Objective(s):
Gold nanoparticles (GNPs) command a great deal of attention for biomedical applications nowadays. The data about the degree of toxicity and the accumulation of gold nanoparticles in-vivo is not enough to judge.
Materials and Methods:
A total of 32 healthy male Wistar rats were randomly divided into 4 including: three GNP-treated and one control group. Groups 1, 2 and 3 received 0.5 cc of a solution containing 5, 10, and 100 ppm Au daily via intraperitoneal (IP) injection for 7 days, respectively. The control group was treated with 0.5 cc normal saline with same procedure. Then, several biochemical parameters such as serum glutamate oxaloacetat transaminase (SGOT) and serum glutamate pyrvate transaminase (SGPT) were evaluated at 2, 7 and 14 days after the last injection. After 14 days, all the rats were sacrificed and liver, lung tissues were separated and evaluated.
Results:
SGOT two days after intervention was significantly greater in the group 2 than the control group. In liver histological assessment, in group 1, basophils were observed around the central veins, in group 2 fading and no observation of central veins was seen, and in group 3 hepatic damage was noticed. The lung histological results showed severe vascular hyperemia in group 1, air sacs damage in group 2, and complete air sacs destruction in group 3.
Conclusion:
The results showed extreme changes in the histopathology of lung and liver tissues caused by spherical nanogold with 5-10 nm size in all of three treatment groups.
Evaluation of the effect of crocetin on antitumor activity of doxorubicin enc...Nanomedicine Journal (NMJ)
Objective(s): The current study reports investigation of codelivery by PLGA nanoparticles (NPs) loaded with crocetin (Cro), a natural carotenoid dicarboxylicHYPERLINK “http://en.wikipedia.org/wiki/Carboxylic_acid” acid that is found in the crocus flower, and Doxorubicin (DOX).
Materials and Methods: Double emulsion/solvent evaporation method was used for preparation of PLGA nanoparticles containing Dox and Cro. Characterizations of prepared NPs were investigated by atomic force microscopy (AFM) and dynamic light scattering analysis. In vitro Cytotoxicity of DOX and Cro loaded PLGA NPs (PLGA-DOX-Cro) on MCF-7 cell line was evaluated using MTT test. Flow cytometry experiments were implemented to distinguish cells undergoing apoptosis from those undergoing necrosis. Furthermore the expression of caspase 3 was examined by western blot analysis.
Results: The prepared formulations had size of 150- 300 nm. Furthermore, PLGA-DOX-Cro nanoparticles inhibited MCF-7 tumor cells growth more efficiently than either DOX or Cro alone at the same concentrations, as quantified by MTT assay and flow cytometry. Studies on cellular uptake of DOX-Cro-NPs demonstrated that NPs were effectively taken up by MCF-7 tumor cells.
Conclusion: This study suggested that DOX-Cro-NPs may have promising applications in breast cancer therapy.
Preparation and evaluation of electrospun nanofibers containing pectin and ti...Nanomedicine Journal (NMJ)
Objective(s):The aim of this study was to prepare electrospun nanofibers of celecoxib using combination of time-dependent polymers with pectin to achieve a colon-specific drug delivery system for celecoxib.
Materials and Methods:Formulations were produced based on two multilevel 22 full factorial designs. The independent variables were the ratio of drug:time-dependent polymer (X1) and the amount of pectin in formulations (X2). Electrospinning process was used for preparation of nanofibers. The spinning solutions were loaded in 5 mL syringes. The feeding rate was fixed by a syringe pump at 2.0 mL/h and a high voltage supply at range 10-18 kV was applied for electrospinning. Electrospun nanofibers were collected and evaluated by scanning electron microscopy and drug release in the acid and buffer with pH 6.8 with and without pectinase.
Results:Electrospun nanofibers of celecoxib with appropriate morphological properties were produced via electrospinning process. Drug release from electrospun nanofibers was very low in the acidic media; while, drug release in the simulated colonic media was the highest from formulations containing pectin.
Conclusion: Formulation F2 (containing drug:ERS with the ratio of 1:2 and 10% pectin) exhibited acceptable morphological characteristics and protection of drug in the upper GI tract and could be a good candidate as a colonic drug delivery system for celecoxib.
The combined effects of Aloe vera gel and silver nanoparticles on wound heali...Nanomedicine Journal (NMJ)
Objective(s): This study was aimed at investigating the synergy effects of Aloe vera gel and silver nanoparticles on the healing rate of the cutting wounds.
Materials and Methods: In order to determine the concentration of silver nanoparticles in Aloe vera gel, the MBC methods were applied on the most common bacteria infecting wounds, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa. The cutting wounds with Full-thickness skin were dorsally created on rats; then the rats were divided into 4 groups. The treatments groups included: mixture of Aloe vera gel and silver nanoparticles, Aloe vera gel alone and silver nanoparticles alone in addition to control groups. The treatment was carried out for 2 weeks and the size of the wound closures were measured by an image software analysis.
Results:There was no significant difference (p<0.05) in healing rate between the control and mixture group. However, there were significant differences between the silver nanoparticles and Aloe vera groups using Tukey’s analysis on the 6th, 8th and 10th days.
Conclusion:The Aloe vera gel increased the rate of wound healing whereas the silver nanoparticles had a delay effect; and when they were mixed, it was similar to the average effect of both Aloe vera gel and silver nanoparticles.
Simultaneous loading of 5-florouracil and SPIONs in HSA nanoparticles: Optimi...Nanomedicine Journal (NMJ)
Objective(s): Over the past two decades, considerable interest has been focused on utilizing biocompatible magnetic nanoparticles (MNPs) for biomedical applications. In this study, production of human serum albumin (HSA) nanoparticles using desolvation technique that were simultaneous loaded with high amounts of superparamagnetic iron oxide nanoparticles (SPIONs) and 5-flourouracil (5-FU) was investigated.
Materials and Methods: 5-FU loading (%) and SPIONs entrapment efficiency (%) were optimized using response surface methodology (RSM). The design expert software used to analyse the interactive effects of pH, 5-FU and SPIONs concentrations.
Results:The optimum conditions found to be pH of 8.2, drug concentration of 1.5 mg/ml and SPIONs concentration of 2.79 mg/ml. Under the mentioned optimum conditions, particles with the size of 111.8 nm, zeta potential of -37.1 mV, 5-FU loading of 15.8% and SPIONs entrapment efficiency of 41.1% were obtained. In vitro cumulative release of 5-FU from the nanoparticles was evaluated in phosphate buffer saline (pH 7.4, 37 °C). Results indicated that 85% of the 5-FU released during 95 h, which revealed a sustained release profile. In addition, Vibrating Sample Magnetometer (VSM) analyses confirmed the superparamagnetic properties of magnetic albumin nanoparticles manufactured under the optimum conditions.
Conclusion: According to the findings,SPIONs and 5-FU loaded HAS nanoparticles arepromising for use as novel targeted delivery system due to proper magnetic and drug release behaviours.
Antimicrobial and cytotoxicity effect of silver nanoparticle synthesized by C...Nanomedicine Journal (NMJ)
Objective(s): For the development of reliable, ecofriendly, less expensive process for the synthesis of silver nanoparticles and to evaluate the bactericidal, and cytotoxicity properties of silver nanoparticles synthesized from root extract of Croton bonplandianum, Baill.
Materials and Methods: The synthesis of silver nanoparticles by plant part of Croton bonplandianum was carried out. The formation of nanoparticles was confirmed by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), XRD and UV-Vis spectrophotometric analysis. The biochemical properties were assayed by antibacterial study, cytotoxicity assay using cancer cell line.
Results: The formation of silver nanoparticles was confirmed by UV-VIS spectroscopic analysis which showed absorbance peak at 425 nm. X-ray diffraction photograph indicated the face centered cubic structure of the synthesized AgNPs. TEM has displayed the different dimensional images of biogenic silver nanoparticles with particle size distribution ranging from 15-40 nm with an average size of 32 nm. Silver particles are spherical in shape, clustered. The EDX analysis was used to identify the elemental composition of synthesized AgNPs. Antibacterial activity of the synthesized AgNPs against three Gram positive and Gram negative bacteria strains like Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa carried out showed significant zones of inhibition. The cytotoxicity study by AgNPS also showed cytotoxicity on ovarian cancer cell line PA-1 and lung epithelial cancer cell line A549.
Conclusion: The present study confirms that the AgNPs have great promise as antibacterial, and anticancer agent.
Investigation of the effect of different parameters on the phase inversion te...Nanomedicine Journal (NMJ)
Objective(s): Nanoemulsions are a kind of emulsions that can be transparent, translucent (size range 50-200 nm) or “milky” (up to 500 nm). Nanoemulsions are adequatly effective for transfer of active component through skin which facilitate the entrance of the active component . The transparent nature of the system and lack of the thickener and fluidity are among advantages of nanoemulsion.
Materials and Methods: In this study, a nanoemulsion of lemon oil in water was prepared by the phase inversion temperature (PIT) emulsification method in which the tween 40 was used as surfactant. The effect of concentration of NaCl in aqueous phase, pH and weight percent of surfactant and aqueous on the PIT and droplet size were investigated. Results: The results showed that with increasing of concentration of NaCl from 0.05 M to 1 M, PIT decrease from 72 to 50. The average droplet sizes, for 0.1, 0.5 and 1 M of NaCl in 25 ºC are 497.3, 308.1 and 189.9 nm, respectively and the polydispersity indexes are 0.348, 0.334 and 0.307, respectively.
Conclusion: Considering the characteristics of nanoemulsions such as being transparent, endurance of solution and droplet size can provide suitable reaction environment for polymerization process used in making hygienic and medical materials.
Mechanism of oxidative stress involved in the toxicity of ZnO nanoparticles a...Nanomedicine Journal (NMJ)
ZnO NPs (zinc oxide nanoparticles) has generated significant scientific interest as a novel antibacterial and anticancer agent. Since oxidative stress is a critical determinant of ZnO NPs-induced damage, it is necessary to characterize their underlying mode of action. Different structural and physicochemical properties of ZnO NPs such as particle surface, size, shape, crystal structure, chemical position, and presence of metals can lead to changes in biological activities including ROS (reactive oxygen species) production. However, there are some inconsistencies in the literature on the relation between the physicochemical features of ZnO NPs and their plausible oxidative stress mechanism. Herein, the possible oxidative stress mechanism of ZnO NPs was reviewed. This is worthy of further detailed evaluations in order to improve our understanding of vital NPs characteristics governing their toxicity. Therefore, this study focuses on the different reported oxidative stress paradigms induced by ZnO NPs including ROS generated by NPs, oxidative stress due to the NPs-cell interaction, and role of the particle dissolution in the oxidative damage. Also, this study tries to characterize and understand the multiple pathways involved in oxidative stress induced by ZnO NPs. Knowledge about different cellular signaling cascades stimulated by ZnO NPs lead to the better interpretation of the toxic influences induced by the cellular and acellular parameters. Regarding the potential benefits of toxic effects of ZnO NPs, in-depth evaluation of their toxicity mechanism and various effects of these nanoparticles would facilitate their implementation for biomedical applications.
Combined effects of PEGylation and particle size on uptake of PLGA particles ...Nanomedicine Journal (NMJ)
Abstract
Objective:
At the present study, relationship between phagocytosis of PLGA particles and combined effects of particle size and surface PEGylation was investigated.
Materials and Methods:
Microspheres and nanospheres (3500 nm and 700 nm) were prepared from three types of PLGA polymers (non-PEGylated and PEGylation percents of 9% and 15%). These particles were prepared by solvent evaporation method. All particles were labeled with FITC-Albumin. Interaction of particles with J744.A.1 mouse macrophage cells, was evaluated in the absence or presence of 7% of the serum by flowcytometry method.
Results:
The study revealed more phagocytosis of nanospheres. In the presence of the serum, PEGylated particles were phagocytosed less than non-PEGylated particles. For nanospheres, this difference was significant (P<0/05) and their uptake was affected by PEGylation degree. In the case of microsphere formulation, PEGylation did not affect the cell uptake. In the serum-free medium, the bigger particles had more cell uptake rate than smaller ones but the cell uptake rate was not influenced by PEGylation.
Conclusion:
The results indicated that in nanosized particles both size and PEgylation degree could affect the phagocytosis, but in micron sized particles just size, and not the PEGylation degree, could affect this.
Synthesis of silver nanoparticles and its synergistic effects in combination ...Nanomedicine Journal (NMJ)
Abstract
Objectives:
Biofilms are communities of bacteria attached to surfaces through an external polymeric substances matrix. In the meantime, Acinetobacterbaumannii is the predominant species related to nosocomial infections. In the present study, the effect of silver nanoparticles alone and in combination with biocides and imipenem against planktonic and biofilms of A. baumannii was assessed.
Materials and Methods:
Minimum inhibitory concentrations (MICs) of 75 planktonic isolates of A. baumannii were determined by using the microdilution method as described via clinical and laboratory standards institute (CLSI). Among all strains, 10 isolates which formed strong biofilms were selected and exposed to silver nanoparticles alone and in combination with imipenem, bismuth ethandithiol (BisEDT) and bismuth propanedithiol (BisPDT) to determine minimum biofilm inhibitory concentrations (MBIC). Subsequently, minimum biofilm eradication concentrations (MBECs) of silver nanoparticles alone and in combination with imipenem against mature biofilm of the isolates were evaluated.
Results:
Results showed that 29.3% of isolates were susceptible to silver nanoparticles and could inhibit the growth and eradicate biofilms produced by the isolates. For this reason, ∑FIC, ∑FBIC and ∑FBEC ≤ 0.05 were reported which shows synergism between silver nanoparticles and imipenem against not only planktonic cells but also inhibition and eradication of biofilms. The results of ∑FBIC >2 indicated to antagonistic impacts between silver nanoparticles and BisEDT/BisPDT against biofilms.
Conclusion:
It can be concluded that silver nanoparticles alone can inhibit biofilm formation but in combination with imipenem are more effective against A. baumannii in planktonic and biofilm forms.
Abstract
Objective(s):
Zinc oxide nanoparticles (ZNP) are increasingly used in sunscreens, biosensors, food additives and pigments. In this study the effects of ZNP on liver of rats was investigated.
Materials and Methods:
Experimental groups received 5, 50 and 300 mg/kg ZNP respectively for 14 days. Control group received only distilled water. ALT, AST and ALP were considered as biomarkers to indicate hepatotoxicity. Lipid peroxidation (MDA), SOD and GPx were detected for assessment of oxidative stress in liver tissue. Histological studies and TUNEL assay were also done.
Results:
Plasma concentration of zinc (Zn) was significantly increased in 5 mg/kg ZNP-treated rats. Liver concentration of Zn was significantly increased in the 300 mg/kg ZNP-treated animals. Weight of liver was markedly increased in both 5 and 300 mg/kg doses of ZNP. ZNP at the doses of 5 mg/kg induced a significant increase in oxidative stress through the increase in MDA content and a significant decrease in SOD and GPx enzymes activity in the liver tissue. Administration of ZNP at 5 mg/kg induced a significant elevation in plasma AST, ALT and ALP. Histological studies showed that treatment with 5 mg/kg of ZNP caused hepatocytes swelling, which was accompanied by congestion of RBC and accumulation of inflammatory cells. Apoptotic index was also significantly increased in this group. ZNP at the dose of 300 mg/kg had poor hepatotoxicity effect.
Conclusion:
It is concluded that lower doses of ZNP has more hepatotoxic effects on rats, and recommended to use it with caution if there is a hepatological problem.
Synthesis of graphene oxide-TiO2 nanocomposite as an adsorbent for the enrich...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
In our study, graphene oxide-TiO2 nanocomposite (GO/TiO2) was prepared and used for the enrichment of rutin from real samples for the first time.
Materials and Methods:
The synthesized GO/TiO2 was characterized by X-ray diffraction, scanning electron microscopy, and FT-IR spectra. The enrichment process is fast and highly efficient. The factors including contact time, pH, and amount of GO/TiO2 affecting the adsorption process were studied.
Results:
The maximum adsorption capacity for ciprofloxacin was calculated to be 59.5 mg/g according to the Langmuir adsorption isotherm. The method yielded a linear calibration curve in the concentration ranges from 15 to 200 μg/L for the rutin with regression coefficients (r2) of 0.9990. The limits of detection (LODs, S/N=3) and limits of quantification (LOQs, S/N=10) were found to be 8 μg/Land 28 μg/L, respectively. Both the intra-day and inter-day precisions (RSDs) were < 10% .
Conclusion:
The developed approach offered wide linear range, and good reproducibility. Owing to the diverse structures and unique characteristic, GO/TiO2 possesses great potential in the enrichment and analysis of trace rutin in real aqueous samples.
Preparation and evaluation of vitamin A nanosuspension as a novel ocular drug...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
The aim of this study was to prepare a nanosuspension formulation as a new vehicle for the improvement of the ocular delivery of vitamin A.
Material and Methods:
Formulations were designed based on full factorial design. A high pressure homogenization technique was used to produce nanosuspensions. Fifteen formulations were prepared by the use of different combinations of surfactants Tween 80, benzalkonium chloride and Pluronic and evaluated for pH, particle size, entrapment efficiency, differential scanning calorimetry (DSC), stability and drug release. Also, Draize test was used to evaluate the irritation of rabbit eye by formulations.
Results:
All formulations showed a small mean size that is well suited for ocular application. Also it was observed that the particle size decreased with increase in the amount of surfactant. Drug entrapment increased with increasing amount of surfactant. It was shown that initial and final drug release can be controlled by the ratio and the total amount of surfactants, respectively.
Conclusion:
It was concluded that the use of Tween 80 and Pluronic in the formualtions with a proper ratio does not show eye irritation and could be useful to achieve a suitable nanosuspension of vitamin A as a novel ocular delivery system.
A comparative study about toxicity of CdSe quantum dots on reproductive syste...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Medicinal benefits of quantum dots have been proved in recent years but there is little known about their toxicity especially in vivo toxicity. In order to use quantum dots in medical applications, studies ontheir in vivo toxicity is important.
Materials and Methods:
CdSe:ZnS quantum dots were injected in 10, 20, and 40 mg/kg doses to male mice10 days later, mice were sacrificed and five micron slides were prepared structural and optical properties of quantum dots were evaluated using XRD.
Results:
Histological studies of testis tissue showed high toxic effect of CdSe:ZnS in 40 mg/kg group. Histological studies of epididymis did not show any effect of quantum dots in terms of morphology and tube structure. Mean concentration of LH and testosterone and testis weight showed considerable changes in mice injected with 40 mg/kg dose of CdSe:ZnS compared to control group. However, FSH and body weight did not show any difference with control group.
Conclusion:
Although it has been reported that CdSe is highly protected from the environment by its shell, but this study showed high toxicity for CdSe:ZnS when it is used in vivo which could be suggested that shell could contribute to increased toxicity of quantum dots. Considering lack of any previous study on this subject, our study could potentially be used as an basis for further extensive studies investigating the effects of quantum dots toxicity on development of male sexual system.
Functionalization of carbon nanotubes and its application in nanomedicine: A ...Nanomedicine Journal (NMJ)
Abstract
This review focuses on the latest developments in applications of carbon nanotubes (CNTs) in medicine. A brief history of CNTs and a general introduction to the field are presented.
Then, surface modification of CNTs that makes them ideal for use in medical applications is highlighted. Examples of common applications, including cell penetration, drug delivery, gene delivery and imaging, are given. At the same time, there are concerns about their possible adverse effects on human health, since there is evidence that exposure to CNTs induces toxic effects in experimental models. However, CNTs are not a single substance but a growing family of different materials possibly eliciting different biological responses. As a consequence, the hazards associated with the exposure of humans to the different forms of CNTs may be different. Understanding the structure–toxicity relationships would help towards the assessment of the risk related to these materials. Finally, toxicity of CNTs, are discussed. This review article overviews the most recent applications of CNTs in Nanomedicine, covering the period from 1991 to early 2015.
The role of surface charge of ISCOMATRIX nanoparticles on the type of immune ...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
ISCOMATRIX vaccines have now been shown to induce strong antigen-specific cellular or humoral immune responses to a broad range of antigens of viral, bacterial, parasite or tumor. In the present study, we investigated the role of ISCOMATRIX charge in induction of a Th1 type of immune response and protection against Leishmania major infection in BALB/c mice.
Materials and Methods:
Positively and negatively charged ISCOMATRIX were prepared. BALB/C mice were immunized subcutaneously, three times with 2-week intervals, with different ISCOMATRIX formulations. Soluble Leishmania antigens (SLA) were mixed with ISCOMATRIX right before injection. The extent of protection and type of immune response were studied in different groups of mice.
Results:
The group of mice immunized with negatively charged ISCOMATRIX showed smaller footpad swelling upon challenge with L. major and the highest IgG2a production compared with positively charged one. The mice immunized with positively charged ISCOMATRIX showed the lowest splenic parasite burden compared to the other groups. Cytokine assay results indicated that the highest level of IFN- γ and IL-4 secretion was observed in the splenocytes of mice immunized with negatively charged ISCOMATRIX as compared to other groups.
Conclusion:
The results indicated that ISCOMATRIX formulations generate an immune response with mixed Th1/Th2 response that was not protective against challenge against L. major.
Abstract
In the last decade, developments in nanotechnology have provided a new field in medicine called “Nanomedicine”. Nanomedicine has provided new tools for photodynamic therapy. Quantum dots (QDs) are approximately spherical nanoparticles that have attracted broad attention and have been used in nanomedicine applications. QDs have high molar extinction coefficients and photoluminescence quantum yield, narrow emission spectra, broad absorption, large effective stokes shifts. QDs are more photostable and resistant to metabolic degradation. These photosensitizing properties can be used as photosensitizers for Photodynamic Therapy (PDT). PDT has been recommended for its unique characteristic, such as low side effect and more efficiency. Therefore, nanomedicine leads a promising future for targeted therapy in cancer tumor. Furthermore, QDs have recently been applied in PDT, which will be addressed in this review letter. Also this review letter evaluates key aspects of nano-particulate design and engineering, including the advantage of the nanometer scale size range, biological behavior, and safety profile.
Preparation of protein-loaded PLGA-PVP blend nanoparticles by nanoprecipitati...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Despite of wide range applications of polymeric nanoparticles in protein delivery, there are some problems for the field of protein entrapment, initial burst and controlled release profile.
Materials and Methods:
In this study, we investigated the influence of some changes in PLGA nanoparticles formulation to improve the initial and controlled release profile. Selected parameters were: pluronic F127, polysorbate 80 as surfactant, pH of inner aqueous phase, L/G ratio of PLGA polymer, volume of inner aqueous phase and addition of polyvinylpyrrolidone as an excipient. FITC-HSA was used as a model hydrophilic drug. The nanoparticles were prepared by nanoprecipitation.
Results:
Initial release of FITC-HSA from PLGA-tween 80 nanoparticles (opt-4, 61%) was faster than control (PLGA-pluronic) after 2.30 h of incubation. Results showed that decrease in pH of inner aqueous phase to pI of protein can decrease IBR but the release profile of protein is the same as control. Release profile with three phases including a) initial burst b) plateau and c) final release phase was observed when we changed volume of inner aqueous phase and L/G ratio in formulation. Co-entrapment of HSA with PVP and pluronic reduced the IBR and controlled release profile in opt-19. Encapsulation efficiency was more than 97% and nanoparticles size and zeta potentials were mono-modal and -18.99 mV, respectively.
Conclusion:
In this research, we optimized a process for preparation of PLGA-PVP-pluronic nanoparticles of diameter less than 300 nm using nanoprecipitation method. This formulation showed a decreased initial burst and long lasting controlled release profile for FITC-HSA as a model drug for proteins.
Abstract
Objective(s):
Abdominal adhesions are one of the most important problems, occurring after intra-abdominal surgery in more than 90% of cases. This condition is the leading cause of bowel obstruction, infertility, and abdominal/pelvic pain. Gold nanoparticles (GNPs) have been shown to be non-toxic and exhibit anti-inflammatory, anti-angiogenic and antioxidant activities. The purpose of this study was to determine the effect of intraperitoneal lavage with GNP solutions on the development of postoperative peritoneal adhesion (PPA).
Materials and Methods:
In the current experimental study, thirty-five male Wistar rats were randomly assigned to seven groups of five rats. After a standardized peritoneal injury, GNP solutions in different concentrations (1, 2.5, 5, 10, 50 and 100 ng/ml) were locally administered through nebulization; normal saline (NS) was administered to the control group. Two weeks later, the rats were sacrificed and cecum and peritoneal samples were harvested for histopathological assessment. Blood samples were obtained to determine serum concentrations of inflammatory biomarkers including tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β) and vascular endothelial growth factor (VEGF).
Results:
The rats treated with GNPs had significantly lower microscopic and macroscopic peritoneal adhesion scores, compared to the control group (P<0.05). Score 5 of macroscopic adhesions was reported in all the rats of the control group, unlike the GNP groups. Furthermore, microscopic adhesions were reported with all rats in the control group, unlike the GNP groups (reported in 0 out of 5 rats in all GNP groups). In addition, serum levels of IL-1β, TNF-α and VEGF underwent no significant changes.
Conclusion:
Compared to the control group, GNPs decreased the severity of peritoneal adhesions, although they did not alter TNF-α, IL-1β or VEGF serum levels.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
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Green synthesis of silver nanoparticles: The reasons for and against Aspergillus parasiticus
1. Nanomed J, Vol. 1, No. 4, Summer 2014 267
Received: Des. 15, 2013; Accepted: Feb. 12, 2014
Vol. 1, No. 4, Summer 2014, page 267-275
Online ISSN 2322-5904
http://nmj.mums.ac.ir
Original Research
Green synthesis of silver nanoparticles: The reasons for and against
Aspergillus parasiticus
Maryam Moazeni1
, Ahmad Reza Shahverdi2
, Mojtaba Nabili1, 3
, Fatemeh Noorbakhsh4
,
Sassan Rezaie5,6*
1
Invasive Fungi Research Centre, Department of Medical Mycology & Parasitology, School of Medicine,
Mazandaran, University of Medical Sciences, Sari, Iran
2
Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center,
Tehran University of Medical Sciences, Tehran, Iran
3
Social Security Organization, Golestan, Iran
4
Department of Biology, Islamic Azad University, Varamin-Pishva Branch, Varamin, Iran
5
Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of
Medical Sciences, Tehran, Iran
6
Department of Medical Mycology & Parasitology, School of Public Health, Tehran University of Medical
Sciences, Tehran, Iran
Abstract
Objective(s): The enzymatic activity of fungi has recently inspired the scientists with re-
explore the fungi as potential biofactories rather than the causing agents of humans and plants
infections. In very recent years, fungi are considered as worthy, applicable and available
candidates for synthesis of smaller gold, silver and other nano-sized particles.
Materials and Methods: A standard strain of Aspergillus parasiticus was grown on a liquid
medium containing mineral salt. The cell-free filtrate of the culture was then obtained and
subjected to synthesize SNPs while expose with 1mM of AgNO3. Further characterization of
synthesized SNPs was performed afterward. In addition, antifungal activity of synthesized
SNPs was evaluated against a standard strain of Candida albicans. The reduction of Ag+
ions
to metal nanoparticles was investigated virtually by tracing the color of the solution which
turned into reddish-brown after 72 h.
Results: The UV-vis spectra demonstrated a broad peak centering at 400 nm which
corresponds to the particle size much less than 70 nm. The results of TEM demonstrated that
the particles were formed fairly uniform, spherical, and small in size with almost 90% in 5-30
nm range. The zeta potential of silver nanoparticles was negative and equal to 15.0 which
meets the quality and suggested that there was not much aggression. Silver nanoparticles
synthesized by A. parasiticus showed antifungal activity against yeast strain tested and
exhibited MIC value of 4 μg/mL.
Conclusion: The filamentous fungus, A. parasiticus has successfully demonstrated potential
for extra cellular synthesis of fairly monodispersed, tiny silver nanoparticles.
Keywords: Aspergillus parasiticus, Biosynthesise, Extracellular, Silver nanoparticles
*Corresponding Author: Sassan Rezaie Ph.D. Department of Medical Mycology & Parasitology, School of
Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Tel: +98-21-88 95 13 92, Email: srezaie@tums.ac.ir
2. Biosynthesis of Nanoparticles by Aspergillus parasiticus
268 Nanomed J, Vol. 1, No. 4, Summer 2014
Introduction
The need to evolve eco-friendly, non-toxic
approaches for biosynthesis of nano
materials and nanostructures has been
newly stands out in the world of modern
nanoscience which toxic synthesis
protocols being used to meet the need. To
pursue the objective, both multicellular
and unicellular organisms have been
recently regarded as well-known apparatus
to produce inorganic materials either intra
or extra cellular (1-3). However, in very
recent years, there has been an increasing
tendency for re-exploring of
microorganisms as potential biofactories
for synthesis of functional metallic nano-
particles such as silver, cadmium, gold and
etc (4). In fact, heavy metal ions are not
biodegradable and persist in nature in such
a way that they inhibit microbial growth as
a consequence of their toxicity.
Nevertheless, microorganisms including
fungi play a remarkable role in
bioremediation of toxic metals by several
kinds of mechanisms including using
efflux pumps, reduction or oxidation,
biosorption and bioaccumulation (5,6).
The great interest in the synthesis of
nanoparticles is due to the unique optical
(7), chemical (8), photoelectrochemical
(9), and electronic (10), properties they
possess. These characteristics lead to
beneficial effects on health settings via
their wide range of application in
combating with microbes (11), treatment
of cancer (12), and also biolabling (13).
The exhibition of unusual magnetic, optic,
catalytic and thermal properties by
nanoparticles entirely depends on their size
and shape (1). Notably, the smaller size the
particles possess, the higher surface area-
to-volume ratio is. Hence, the biological
effectiveness of nanoparticles increase as
their specific surface area is extended on
the account of a rise in surface energy
(14). Despite the fact that nanoparticles
can be synthesized by conventional
chemical methods in different desirable
size and shape, there is a strong possibility
that microorganisms produce particles in
more minimized size and more uniform
shape. So obviously, the major advantage
of biosynthesis of nanoparticles over
chemical production is the controlled
synthesis of nanoparticles by micro-
organisms (15).
Moreover, most of the chemical
approaches are considered as highly
environmental cost (1). Various metal
nanoparticles, Au, Ag, Pt, Pd and an alloy
of Au–Ag are synthesized by biological
processes. Amongst, the silver
nanoparticles (SNPs) have received
considerable attention as a consequence of
their attractive physic-chemical properties
(16). In addition to bacteria, a growing
number of various genera of fungi have
been under investigation in this field of
research. Besides, there are sufficient
evidences which support the involvement
of the metabolic activity of fungi in
making them competent to precipitate of
nanoparticles in external environment of
the cell (17), and eventually, presents them
as worthy, applicable and available
candidates for synthesis of gold (18, 19),
silver (20), and other nano-sized particles
(3).
Although SNPs are synthesized both intra
as well as extracellulary, ease of control
over the environment, large-scale synthesis
and straightforward processing steps (21)
represent the extracellular method of
biosynthesis more advantageous rather
than the other one. A vast number of
microorganisms are capable to synthesize
SNPs extra-cellularly, among which
Fusarium oxysporum (22), Bacillus
licheniformis (23), Aspergillus fumigatus
(5), Aspergillus niger (24), Aspergillus
clavatus (25), Penicillium brevicompactum
(26), Escherichia coli (14), Cladosporium
cladosporioides (17), Fuserium
semitectum (27), and Klebsiella
pneumoniae (28), have been well
described extensively.
Apart from the significant negative impact
of members of the genus Aspergillus on
public health as potent pathogens to induce
life-threatening systemic infections, the
3. Moazeni M, et al
Nanomed J, Vol. 1, No. 4, Summer 2014 269
highly useful utilization of the genus
should not be ignored in industrial
applications and also other science such as
nanotechnology. In view of nanoscience,
members of the genus Aspergillus are
newly considered to bring up a simple,
straightforward and eco-friendly system to
synthesise SNPs. Considering the
published data, Aspergillus parasiticus is
not regarded as highly virulent as
Aspergillus fumigates. This species is not
even included in the five-member group of
the most infectious species of Aspergilli
(29). As a matter of fact, the frequency of
reports of invasive aspergillosis caused by
A. fumigates has been gradually rising and
is relatively higher than A. parasiticus
(30). Furthermore, it is well-established
that the species A. parasiticus is competent
to produce aflatoxin, the most highly toxin
carcinogen with immunosuppressive
properties (31). The above reasons led us
to investigate the other possible beneficial
properties of this fairly safe species, rather
than its negative impact on public health.
Accordingly, in the current study, we
apply A. parasiticus so as to biosynthesis
the SNPs extracellulary.
Materials and Methods
Fungal strain
A standard strain of A. parasiticus (ATCC
15517) was used for this investigation. The
fungus was preserved on Potato Dextrose
Agar medium (PDA) (Sigma, USA) until
use.
Preparation of cell-free fungal filtrate
The liquid medium containing mineral
salts was used in order to high efficiency
in fungal growth and establishing a
biomass competent for silver nanoparticles
biosy-nthesis. The medium contains:
KH2PO4 7.0 (g/l), K2HPO4 2.0 (g/l),
MgSO4.7H2O 0.1 (g/l), (NH4)2SO4 1.0
(g/l), yeast extract 0.6 (g/l), and glucose
10.0 (g/l). The constituents were mixed
completely by stirring on a magnetic
stirrer and then the solution was boiled to
digest the undissolved substances and
filtered through filter paper. Erlenmeyer
flasks containing 200 ml of the mentioned
medium were inoculated with A.
parasiticus spores and incubated
aerobically on orbital shaker at 25◦
C
agitating at 150 rpm for 72 h. Afterward,
the biomass was extensively washed out
twice with distilled sterile water and then
harvested by sieving through a plastic
sieve, followed by extensive washing to
remove all medium ingredients from the
biomass.
Fifteen mg of fresh and clean biomass was
then taken into a new flask containing 150
ml of Milli-Q deionized water and was
agitated at the same condition as described
above. After 72 h of incubation, cell-free
filtrate was obtained by utilizing Watman
filter paper No.1.
Synthesis of silver nanoparticles
Eventually the filtrate was applied to
biosynthesis of silver nanoparticles. To
achieve the aim, AgNO3 was added to 100
ml of cell-free filtrate in such a way that a
solution with 1 mM of AgNO3 in final
concentration was made.
The flask was agitated at 150 rpm in dark.
A negative control, (only filtrate, without
the silver ion) was also run along with the
experimental flask.
Characterization of synthesized SNPs
Aliquots of 1ml of the reaction solution
were removed after 24 and 72 h and
consequently subjected to UV-vis spect-
roscopy (LABOMED. Inc, USA). The
absorbance was measured at a resolution
of 1nm. The shape and also estimated size
of the silver nanoparticles was determined
by transmission electron microscopy
(TEM) as well. The TEM image of the
sample was obtained using transmission
electron micro-scope (Philips 30ML20) at
a voltage of 100 kv. In addition, particle
sizing experiments as well as the zeta
potential measurements were carried out
by means of a Zetasizer Nano ZS (Malvern
Instruments, South-borough, UK).
4. Biosynthesis of Nanoparticles by Aspergillus parasiticus
270 Nanomed J, Vol. 1, No. 4, Summer 2014
Evaluation of antifungal activity of
synthesized SNPs
In order to assess the antimicrobial effect
of synthesized silver nanoparticles, one
standard (Candida albicans ATCC 10261)
and 12 Fluconazole-resistant Candida
albicans strains were applied. The isolates
was kept at -80° C as 20% glycerol stocks
and were sub-cultured, as required, on
SDA plates at 30°C.
Microdilution antifungal susceptibility
testing of the C. albicans isolate was
performed by the broth microdilution
method described in CLSI (Clinical and
Laboratory Standards Institute) document
M27-A3 (32) for SNPs.
Fluconazole was used as a reference
antifungal agent. RPMI 1640 medium with
L-glutamine and phenol red without
bicarbonate was used. The medium was
buffered to pH 7.0 with 0.165 mol/L
MOPS (3-(N-morpholino) propanesulfonic
acid). Fluconazole was dissolved in sterile
diluted water to 64µg/L, and then diluted
to the final concentration of 0.0125-16
µg/L with the medium according to the
standard in the CLSI reference method.
After growing on SDA (Merk, Germany)
at 35°C for 24 h, the yeasts were re-
suspended in culture medium to prepare a
working solution at a concentration of
2.5×103
cells/mL. The prepared yeast
solution was exposed to diluted
fluconazole (0.0125-64 µg/L) and finally
incubated at 35°C for 48 h. All tests were
carried out in duplicate. The interpretive
criteria for susceptibility to fluconazole
were published by the CLSI (32), and are
as follows: (i) susceptible ≤8 μg/mL;
susceptible dose- dependent (S-DD) 16 to
32μg/mL; and resistant ≥64 μg/mL.
For silver nanoparticles, a solution of
16µg/mL was prepared and diluted to the
final concentration of 0.0125–16 µg/L
with the medium.
The same inoculum size was applies for
SNPs susceptibility test and finally, the
96-well plate was incubated at 35° C for
48 h.
Results
Silver reduction
After addition of Ag+
ions into the filtered
cell-free culture in the dark, samples
changed in colour gradually from nearly
colorless to reddish-brown, with intensity
increasing during the time of incubation.
After 72 h of incubation, the process was
stopped and the particles were subjected to
further analysis comprising of
transmission electron microscopy, size
determination and zeta potential
measurements.
The reduction of the Ag+
ions into metal
nanoparticles was investigated virtually, so
that, the color of the solution changed into
intense reddish-brown after 72 h of
incubation, which has been indicated in
Figure 1a. However, control sample
(without silver ions) showed no change in
color of the cell filtrates when incubated in
the same environmental conditions (Figure
1b). The appearance of a reddish-brown
color in the reaction suggested the
formation of silver nanoparticles (33). The
solution stayed on as hydrosol and no
precipitation was observed even after 72h
of incubation.
UV–visible spectroscopy
Formation of colloidal silver particles can
be easily followed by changes of UV-Vis
absorption (Figure 2).
The UV spectroscopy method can be
applied for size measurement of silver
nanoparticles based on localized
surface plasmon resonance band
exhibiting at different wavelength.
Figure 1. Cell filtrate of A. parasiticus with silver
ion (1 mM): (a) at the beginning of the reaction (b)
after 72h of reaction.
a b
5. Moazeni M, et al
Nanomed J, Vol. 1, No. 4, Summer 2014 271
The light absorption pattern of the cell
filtrate was continuously monitored after
24 and 72 h in the range of 200-800 nm by
using UV-visible spectrophotometer.
As illustrated in Figure 2, after 24 h of
incubation, a very wide peak located
between 350 and 442 nm was obtained.
The average wavelength at which the peak
occurred was around 420 nm. After 72 h
of starting of the reaction, a strong, broad
peak located between 362 and 417 nm,
centering at around 400 nm, was observed
for the silver nanoparticles. Observation of
this peak which assign to a surface
plasmon, is well-documented for silver
metal nanoparticles with sizes much less
than 70nm (34). As a result, the fact that
silver nanoparticles broad peak remains
close to the range between 370 and 420
nm even after 72 h of incubation indicates
that the particles were more likely to be
well dispersed in the solution.
Electron microscopy, size and zeta
potential of SNPs
TEM analysis was employed to determine
the morphology and shape of silver
nanoparticles. The representative TEM
image is indicated in Figure 3.
Accordingly, the majorities of the SNPs
are relatively uniform in diameter and
present in spherical shape. Additionally,
TEM images depicted that the particles are
predominantly formed at even less than 50
nm. The size histogram of SNPs
determined from Zetasizer Nano ZS was
shown in figure 4.
Figure 2. UV–visible spectrum of liquid medium
containing cell filtrate and silver ion (1 mM).
Figure 3. TEM micrograph of silver particles
synthesized by A. parasiticus (scale bar: 100 nm).
It is well-demonstrated that the particles
were produced in various different sizes,
though less than 50 nm. From this
histogram, it is depicted that there is
variation in the particle sizes with more
than 90% of the particles in 5-30 nm range
and 4% of the particles were formed in 30-
40 nm. Only 1.5% of the particles were
larger than 40 nm.
The zeta potential of silver nanoparticles
was also investigated (Figure 5). At natural
conditions (pH close to 8), the zeta
potential was negative and equal to -15.0.
Obviously, the obtained result meets the
quality and indicated the small amount of
aggression.
Figure 4. The particle size distribution histogram
of silver nanoparticles synthesized by A.
parasiticus.
0
0.5
1
1.5
2
0 500 1000
72
24
h
6. Biosynthesis of Nanoparticles by Aspergillus parasiticus
272 Nanomed J, Vol. 1, No. 4, Summer 2014
Figure 5. Zeta potentioal of silver nanoparticles
synthesized by A. parasiticus.
Evaluation of antifungal activity of
synthesized SNPs
In this study, fluconazole, an antifungal
agent which is widely used to treat
Candida-
associated infections, was used as a
positive control to compare with SNPs.
According to CLSI guideline, the standard
strain was susceptible dose-dependent (S-
DD) against fluconazole, showing MIC
values of 16 μg/mL toward the fungal
strain tested.
Silver nanoparticles synthesized by A.
parasiticus showed antifungal activity
against both standard and clinical
fluconazole-resistant strains tested and
exhibited MIC value of 4 μg/mL.
Apparently, it was a notable finding for
fluconazole-resistant C. albicans strains
even for non-resistant ones.
Discussion
The field of nanoscience has emerged over
the last two decades and the need for
nanotechnology will only expand rapidly
while miniaturization becomes more
impor-tant in areas such as biomedical
applications (34).
The synthesis of nanoparticles, however, is
a fairly established field so that they have
been unintentionally synthesized for
centuries.
Several methods for the synthesis of Ag
nanoparticles have been reported in the
literature and can be arbitrarily divided
into chemical and biological categories.
In spite of successful employment of
chemical and physical methods, interest-
ingly, nature has provided exciting poss-
ibilities of utilizing biological systems to
achieve this aim. This capacity owes to the
fact that microorganisms can reduce the
ions into metallic particles while
interacting with heavy metal ions such as
Ag+
, Au+
, Se+
, and Ca2+
.
Regarding this wonderful capacity,
extracellular biosynthesis of SNPs was
investigated in this study by using A. para-
siticus as a biological model.
It was observed that upon addition of the
silver ion (1 mM) into the flask containing
the cell filtrate, the color of the medium
turn into reddish-brown (Figure 1b). The
intensity of color increased due to
excitation of surface plasmon vibrations in
the metal nanoparticles.
This significant observation indicates that
the reduction of the Ag+
ions takes place
extracellulary.
The production and stability of the reduced
SNPs in the colloidal solution was inves-
tigated by using UV–vis spectral analysis.
The unique optical properties of metal
nanoparticles originate from the collective
oscillations of conduction electrons,
which, when excited by electromagnetic
(35) rad-iation, are termed surface
plasmon polariton resonances (SPPR) (34).
This characteristics of nanoparticles are
well-determined by using a UV-vis
spectrophotometer. The shape of SPPR
spectrum and the wavelength at which the
maximum absorbance is occurred is
strongly related to the particle size and
relative dimensions. In the present study,
the UV–visible spectra demonstrated a
broad spectrum with a peak at 400 nm
after 72 h of incubation. As the size
increases, the field across the particle
becomes nonuniform, so the dipole
resonance will broadens and excites
higher multipole resonances, such as the
quadrupole, octupole and etc (34).
Respecting above and also according to
the fact that longer maximum wavelength
(450 nm) represents the particle size
beyond 70 nm, the SNPs produced with
cell-free filtrate of A. parasiticus are
7. Moazeni M, et al
Nanomed J, Vol. 1, No. 4, Summer 2014 273
supposed to be spherical in shape, fairly
uniform and even very smaller than 70nm.
Apparently, the size and uniformity of our
results of TEM and Zetasizer studies
confirmed the mentioned findings.
Another benefit which motivates the
scientists to make use of small-sized
particles is catalytic activities including the
antimicrobial properties which are a result
of increasing the surface area-to-volume
ratio. Our results for evaluation the
antimicrobial properties of synthesized
silver nanoparticles were accurately
proven. Moreover, it was well
demonstrated that the inhibitory effect of
synthesized SNPs was even more effective
than the common anti-Candida antifungal
drug, fluconazole. However, there is still
work to do on the control of particle size
and shape uniformity by modifying the
temperature, pH or Ag+
concentration. In
the present study, a biological protocol
was applied for the synthesis of SNPs by
using extracellulary mycelia-free filtrate of
the species A. parasiticus. It is strongly
suggestive that the proteins,
polysaccharides and more important, the
secreting hydrolytic and photolytic
enzymes of the fungus (particularly nitrate
reductase) are in charge of biosynthesis of
silver nanoparticles (11).
Nelson Duran et al.(11) have proven the
presence of NADH dependent nitrate
reductase as the corresponding agent for
reduction of Ag+
ions in case of Fusarium
oxysporium strains.
Anil Kumar et al. (22) have also
demonstrated that an enzymatic route
using α-NADPH dependent nitrate
reductase along with phytochelatin is
required for the synthesis of silver
nanoparticles.
Moreover, Ahmad et al.
(27) have reported that certain NADH
dependent nitrate reductase was involved
in reduction of silver ions in case of F.
oxysporum.
Generally, utilization of specific enzymes
released by organisms such as fungi is so
interesting as to be applied in emerging the
genetically engineering microbes in order
to overexpress specific reducing molecules
and capping agents and thereby, control
the size and shape of the biogenic
nanoparticles.
The rapid synthesis of nanoparticles would
be proper for developing a biological
process for mass scale production.
Furthermore, the extracellular synthesis
would make the process simpler and easier
for following processes. Moreover,
extracellular biosynthesis of SNPs offers a
great advantage over an intracellular
process in the aspect of application. Since
the nanoparticles formed inside the
biomass would have required additional
step of processing for release of the
nanoparticles from the biomass by
ultrasound treatment or by reaction with
suitable detergents.
Conclusion
In conclusion, the filamentous fungus A.
parasiticus has successfully demonstrated
potential for extracellular synthesis of
fairly monodispersed, SNPs in the range of
2-50 nm.
Acknowledgements
This research has been financially
supported by a Tehran University of
Medical sciences (TUMS) grant.
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