File Name: synthesis and characterization of silver nanoparticles .zip
Michael Ndikau, Naumih M.
Using aqueous cyanobacterial extracts in the synthesis of silver nanoparticle is looked as green, ecofriendly, low priced biotechnology that gives advancement over both chemical and physical methods.
In the current study, an aqueous extract of Oscillatoria limnetica fresh biomass was used for the green synthesis of Ag-NPs, since O. FT-IR analysis demonstrated the presence of free amino groups in addition to sulfur containing amino acid derivatives acting as stabilizing agents as well as the presence of either sulfur or phosphorus functional groups which possibly attaches silver. In this study, synthesized Ag-NPs exhibited strong antibacterial activity against multidrug-resistant bacteria Escherichia coli and Bacillus cereus as well as cytotoxic effects against both human breast MCF-7 cell line giving IC50 6.
Nowadays, nanoscience is a rapidly developing field contributed to produce a wide range of various synthesized metal nanoparticles MNPs. Owing to the unique physicochemical properties of MNPs and their shapes, a promising scientific area of research appeared for biotechnical applications in biomedicine, environmental bioremediation, optical and electronic fields as well as usage in drug delivery and bioimaging 1 , 2.
For instance, MNPs possess increased electrical conductivity, roughness and the ability to strength metals and alloys 3. Silver is the most noble metal in fabrication of nanoparticles due to its wide spectrum of bactericidal and fungicidal activities as well as its ability to coordinate with various ligands and macromolecules in microbial cell.
Silver has been widely used in control of microbial proliferation as well as curing wound healing due to its anti-inflammatory effect 4 , 5. Usually, coatings containing various silver salts have been applied to inhibit the microbial infections subordinated with medical tools catheters, wound dressing and orthopedic and cardiovascular implants 6.
Silver nanoparticles have opened new various disciplines in biomedical protocols, since this marked reactivity of nano-silver was attributed to their larger surface area-to-volume ratios 4. Production of AgNPs was attained physically and chemically by different approaches where these protocols in spite of producing pure and characterized nanoparticles have some disadvantages as being expensive in addition to their hazard effects on the environment.
Generally, biogenic synthesis of silver nanoparticles becomes necessary via green chemistry concepts to produce silver nanoparticles with enhanced stability 7.
Green formation of metal nanoparticles by naturally biodegradable components including polysaccharides, biopolymers, vitamins, plant extracts and microorganisms represent sustainable resources in biosynthesis of metal nanoparticles 8 , 9.
Subsequently, using microorganisms as bacteria, fungi, microalgae and cyanobacteria in addition to plant extracts and macro algae could induce the required reduction for metal nano synthesis providing an eco-friendly, low priced technology as well as simplicity in scaling up for high production Plant-based silver nanoparticles synthesis is feasible, ecofriendly as well as possessing catalytic activity for degrading different organic pollutants as azo dyes Eukaryotic algae as Chaetocerros calcitrans and Chlorella salina could be used to reduce silver for the formation of nanoparticles Cyanobacteria have a significant potential among microorganisms for the green synthesis of metal nanoparticles on large scale with various sizes and shapes due to being a sustainable resource for various metabolic products with significant biotechnological applications Cepoi et al.
Usage of microorganisms enables synthesis of silver nanoparticles through acting as a reducing agent as well as functionalizing nanoparticles surface Consequently, these multifunctional cyanobacteria significantly decrease reaction stages as well as prevent the need of external stabilizing agents.
Shukla et al. Paszkiewicz et al. Currently, bacteria signify a main threat facing medical remediation since the appearance of antibiotic resistant bacterial strains as a consequence of some complicated influences of the evolution and spread of resistance mechanisms Recently, drug resistance had been emerged as a complicated remediation problem according to the over usage of the antibiotics and drugs in treating infectious diseases in addition to the harmful effects and drawbacks associated with antibiotics as immune-suppression, hypersensitivity and allergic effects.
Consequently, developing new antimicrobial drugs for treating microbial pathogens and therapeutic antimicrobial agents of marine plant origin have high remediation effects The new developing discipline, nanotechnology, stimulated the production of metal NPs especially AgNPs characterized by low toxic influences to human and high bactericidal potential.
AgNPs may be used as an alternative to antibiotic drugs exhibiting better effect on multidrug resistant bacteria The existence of protein caps on nanoparticles support both stabilization and binding to bacterial cell surface leading to increments in binding and absorption of drug on patient cells The mode of action of AgNPs antibacterial potential is discussed on the basis of disturbing bacterial cell permeability, cellular respiration as well as penetration inside the bacterial cell causing damage via reacting with DNA and protein phosphate and sulphate containing compounds Nowadays, nontoxicity of the biosynthesized AgNPs when used in low doses become a research interesting issue for medical biotechnology especially in production of non-plant origin polymers, wound recovery and drug delivery At present the war against cancer are progressively continued including the development of therapies and recovery protocols, where the challenge lies in formulating drugs with high potential anticancer effective compounds with cytotoxic action have been derived from algae 25 , Cancer is a complicated very serious genetic disease characterized by uncontrolled and abnormal cells division whereas cancer cells use blood and lymph systems to spread throughout the body In spite of accepting chemotherapy and radiation therapy as modes of cancer bioremediation, these protocols destroy both normal and cancer cells as well as the usable chemotherapeutic agents resulted in detrimental side effect In order to overcome these disadvantages a biocompatible, cost-effective protocols, with lowest side effects must be conducted.
Nanoparticles as anticancer drug are successfully applied due to their high surface volume ratio and high binding activity which facilitate entrance of cells by diffusion. Nanomedicine is a promising area that could probably induce change affecting cancer treatment protocols, which gives a modern viewpoint for detection, prevention, and bioremediation of tumor The green synthesized AgNPs are effective anticancer mediators used in evaluation of their cytotoxic effect against different cancer cells in vitro Algal mediated silver nanoparticles synthesis has good potential in vitro cytotoxicity investigation in malignant cell culture as human breast MCF-7 cell line and human colon cancer HCT cell line Silver nanoparticles synthesized by macro algae as Turbinaria turbinata and some micro-algae such as Anabeana oryzae , Nostoc muscorum and Calothrix marchica have high cytotoxic effect against Ehrlich ascites carcinoma EAC tumor 33 , Aqueous extract of the microchlorophyte Dunaliella salina can be used for the bioreduction of silver atoms to form AgNPs Numerous comparison studies were conducted to differentiate between the effects of recognized anticancer drug, cisplatin and algal mediated synthesized AgNPs for treating MCF-7 cancer cell lines exhibiting the potency of AgNPs against MCF-7 cancer.
Antitumor potentiality cytotoxicity of both AgNPs and silver cations was expressed via oxidative stress as well as inflammation through production of reactive oxygen species that lead to DNA destruction and mitochondrial membrane potential disorder, releasing cytochrome c and resulting in mitochondrial related apoptosis and necrosis to cell proliferation and carcinogenesis The antileukemic effect of silver nanoparticles on some leukemic cell lines K, MOLT3 and REH in order to study the biocidal effect on leukemic cell division Their results demonstrated significant antiproliferative impact of AgNPs synthesized by Lyngbya majuscula on the used cell lines in a dose and time independent manner.
This study focused on the green synthesis on AgNPs using Oscillatoria limnetica aqueous extract as a reducing and stabilizing agents. Furthermore, the antimicrobial activities of silver nanoparticles synthesized would be evaluated against different human pathogens as well as hemolytic activity and cytotoxic effects against both human breast MCF-7 cell line and human colon cancer HCT were investigated.
Nanometals showed conspicuous spectral characteristics according to the surface plasmon resonance SPR due to mutual vibrations of the free electrons resonance with light wave which influenced by each of size and shape of the synthesized NPs 45 , Many studies have been reported the potentiality of various cyanobacteria crude extracts for synthesizing silver nanoparticles 15 , 39 , Mahdieh et al.
This is followed by reduction of ions to metal nanoparticles due to the secretion of cellular reductases by algal cells. In addition Sathishkumar et al. The current result Fig. After absorbing light, chromospheres excited molecules from the ground state to an electronic excited one Consequently under illumination, AgNO 3 may be reduced in the reaction mixture as a result of electrons that jump between energy levels forming silver nanoparticles.
Ali et al. Moreover, Shankar et al. Whereas, the size, number and shape of the produced NPs are reliant on the concentrations and the exposure time to silver ions 54 using Spirulina platensis. For optimizing the O-AgNPs synthesis the following effective factors must be investigated.
UV-visible absorption spectrum of O. In this study, the effect of pH on the formation of AgNPs was investigated over these values 4.
Coloration of the reaction mixture as well as peak intensity were pH dependent as appeared in case of pH 4. At pH 6. Rajesh et al. In support of the present results Gan et al.
Concentration of the bio-reducing agents is one of the significant parameters that affect characteristics of NPs through controlling its size and shape. Figure 2B showed that increasing concentration of O.
These observations may be attributed to the high reducing capacity of O. Figure 2C 42 , The maximum absorbance 0. Biosynthesis of AgNPs has been proved to be a time dependent process The dispersion stability of the O-AgNPs with increasing the storage time demonstrated no significant change in color. The TEM micrographs Fig. Moreover, the biosynthesized nanoparticles were well dispersed without significant agglomeration or morphological variations.
The present data are in agreement with Singh et al. In the same context, Abdel-Raouf et al. The present results were in accordance with that of plaza et al. SEM images Fig. FT-IR measurements were conducted to reveal the possible potential biomolecules that participated in the bioreduction of silver and stabilization of AgNPs FT-IR profile Fig.
The peak shifting in AgNPs spectral profile could be attributed to the interactions between those chemical functional groups and AgNPs It was documented that protein molecules cooperate with AgNPs via free amide groups 68 , FT-IR data demonstrated that the amide linkage of the protein possessed the higher potential to join silver and consequently forming protein covering around AgNPs to prevent agglomeration and thereby stabilize the medium FT-IR spectrum of O.
Owing to the observed resistance of many pathogenic bacteria towards the already used antibiotics, exploiting AgNPs may be another urgent choice for controlling proliferation of bacterial human pathogens Jun et al. In the present study the appearance of clear inhibitory zones confirmed the complete growth inhibition of either E.
Concerning E. Biosynthesized silver nanoparticles exhibit pronounced antibacterial action towards E. The current results are in accordance with the findings of Sondi et al. They recommended that these results might be effective in antibiotic-resistant human pathogens. On the other hand, O. In general, the tested silver nanoparticles induced a significant inhibitory response on both tested bacteria at comparison with cefaxone represented by The magnitude of response recorded as Using disc diffusion method, the inhibition zone around disc was directly proportional with AgNPs concentration which considered a function in toxicity
This is to certify that the thesis entitled “Synthesis and Characterization of. Silver Nanoparticles using leaf extract of Azadirachta indica” by Tamasa. Panigrahi.
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