File Name: strain specificity in antimicrobial activity of silver and copper nanoparticles .zip
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Received: January 01, Published: ,. Citation: DOI:. Download PDF. Nanosciences along with the emergence of nanobiotechnolgy and nanomedicine in the last few decades provided a number of opportunities for exploring the bactericidal and fungicidal activities of metal nanoparticles. In the present scenario silver in the form of nanoparticles are playing a major role in the field of Nanotechnology and Nano medicine, their unique size dependent properties make them superior and indispensable.
The use of nanotechnology in the field of medicine could revolutionize the way we detect and treat damage to the human body and disease in the future, and many techniques only imagined a few years ago are making remarkable progress towards becoming realities. Silver nanoparticles have been synthesized through various routes in the laboratories in India and as well as many foreign research institutes. These routes can be chemical as well as biological. Nanotechnology has provided a number of nanoparticle-based therapeutics and diagnostic agents.
Silver-impregnated wound dressings have the potential to reduce both bio burden and healing time. Nanoscience and nanotechnology have received much interest since last few decades and metal nanoparticles are at the leading edge of rapidly developing field of nanotechnology.
The concept of nanotechnology was visualized in by the physicist Richard P. Feynman who got the Nobel Prize in this field. One nanometer spans atoms lined upon in a row. Nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic or molecular structures .
It is basically science, engineering and technology conducted at the nanoscale which is about 1 to nm. The U. National Nanotechnology Initiative NNI defined it as understanding and control of matter At Dimensions between approximately 1and nanometers where unique phenomenon enable novel application . The substance in nano-regime exhibits a large number of new properties.
The properties of substances in nanosize are entirely different from the corresponding bulk or atomic and molecular counterparts. The word nanotechnology was firstly popularized by K. Eric Drexler in s and he meant about building machines on the scale of molecules, a few nanometer wide motors, robot arms and even whole computer, for smaller than a cell .
Nanotechnology since long time ago helping to considerably improve even revolutionize, many technology and industry sectors, Information technology, energy environmental science medicine, homeland security, food safety and transportation among many others . Their unique size-dependent properties make them superior and indispensable in many areas ranging from electronics and communications, through optics, chemistry, energy and of course biology .
The advancement in the field of nanoscience has truly brought revolutionary changes in industrial, medicine, textile, food packaging and agriculture fields .
We all are very much aware of silver as an antimicrobial agent since time immemorial in the form of metallic silver, silver nitrate, silver sulfadiazine for the treatment of burns, wounds and several bacterial infections .
After the flooding of a number of antibiotics, usage of silver for the treatment of bacterial infection reduced. Moyer introduced the use of 0.
He proposed that it possess antibacterial property against Staphylococcus aureus , Pseudomonasareuginosa, and Escherichia coli . Silver nanoparticles also act as effective fungicide against common fungi including Aspergillus, Candida and Saccharomyces .
The antifungal activity of silver nanoparticle has received less attention, yet some of the studies revealed that silver nanoparticles can be as effective for fungal strains as like that of bacterial strains. Ales Panacek et al. Silver nanoparticles inhibit growth of yeast at very low concentration as compared to those of common antifungal .
Virucidal effect of silver nanoparticles is still in closed envelops, however recently the antiviral effect of silver nanoparticles on the hepatitis B virus have been reported using a HepAD38 human hepatoma cell line [ 30]. Although antiviral effect of silver nanoparticle has not been come in attention yet there are some of the evidences given by Humberto H Lara et al. Sun and colleagues showed that agNPs were superior to gold nanoparticles for cytoprotective activities towards HIVinfected helper cells.
Nanosilver may interfere with the fusion of the viral membrane, inhibiting viral penetration into the host cell. Silver nanoparticles specifically refer to silver containing material with modified physicochemical properties due to their nanosized scale.
Antimicrobial properties of silver nanoparticles are being exploited by many pharmaceutical companies for making antibiotics, used in biomedical applications . The use of Silver nanoparticles in the field of medicine could revolutionize the way we detect and treat damage to the human body and disease in the future, and many techniques only imagined a few years ago are making remarkable progress towards becoming realities .
This rapidly developing field of nanoscience has raised the possibility of using therapeutic nanoparticles in the diagnosis and treatment of human cancers . Silver nanoparticles have been synthesized through an array of methods, e. For the synthesis of nanoparticles, the first priority is to achieve large-scale production in an economical manner .
There are two main methods for the preparation of nanoparticles showing in Figure 1 . Top down approach is solely based on physical and microlithographic philosophy, in contrast to the other approach, where atomic or molecular units are used to assemble molecular structure, ranging from atomic dimensions up to supramolecular structure in nanometer range. Vapor phase synthesis: Nanoparticles of wide range can be prepared by a variety of methods.
Hahn presented a useful overview of gas-phase synthesis of nanocrystalline material. In vapor-phase synthesis, conditions are created where the vapor-phase mixture is thermodynamically unstable relative to formation of solid material to be prepared in nanoparticulate form . Pyrolysis: In pyrolysis, vaporous precursor is forced through a hole or opening at high pressure and burned.
The resulting solid in air is classified to recover oxide particles from byproduct gases. Inert gas condensation: In this process solid material is heated to evaporate it into a background gas, and then the vapor is mixed with cold gas to reduce the temperature.
This method is well suited for production of metal nanoparticles. Solvo thermal synthesis: In this method, precursors are dissolved in hot solvent e. Solvents other than water can provide milder and friendlier reaction condition. The sol-gel process is a wet-chemical technique widely used in the field of material science and ceramic engineering; it involves the following steps:.
The precursor sol can be either deposited on a substrate to form a fi lm, cast into a suitable container with the desired shape or used to synthesize powders e.
This is the mixing of two microemulsion carrying metal salt and reducing agent. It is common knowledge that the method of chemical reduction involves the reduction of relevant metal salts in the presence of a suitable protecting agent . Reduction of relevant metal salts in the presence of a suitable protecting agent, reduction of relevant metal salts in the presence of a suitable protecting agent. The use of a strong reductant such as borohydride, resulted in small particles that were somewhat monodisperse, but controlling the generation of the larger particles became difficult .
The use of citrate, a weaker reductant, resulted in a slower reduction rate, but the size distribution was far from narrow . The controlled synthesis of silver colloid particles was attempted using a two-step reduction process in order to control the particle size.
Recent era have explored critical role of microorganisms, and other biological entities such as extracts of different parts of the plants for the synthesis of metal nanoparticles. Green synthesis of metal nanoparticles is ecofreindly method without using harsh toxic and expensive chemicals. Biosynthesis of metallic nanoparticles using plant extract is a fabulous and emerging ecofreindly science of well-defined sizes, shapes and controlled monodisparity.
Synthesis of nanoparticles using plant extract is very cost effective and therefore can be used as agar medium and transferring them to shoot of the plant in the same oxidation state. In this shoot these Ag atoms arrange themselves to form nanoparticles by joining themselves to form larger arrangements.
Within use of Emblica officinalis fruit extract, as reducing agent, the extracellular synthesis of highly stable Ag and Au NPs has been achieved , Achlypha indica leaf extract have produced silver nanoparticles had excellent antimicrobial activity against water borne pathogens like E. A diagrammatic presentation is given below in Figure 2 showing green synthesis of silver nanoparticle using plant extract . There are number of plants and their parts which has been exploited for the biological synthesis of silver nanoparticles as listed in the Table 1.
Not only plants but other biological entities in the world have great potential to synthesize metal nanoparticles specifically silver in the nanorange have been fabricated using microoraganisms by many researchers. Among the microorganisms, prokaryotic bacteria have received the most attention in the area of bio-synthesis of nanoparticles.
Bacteria involved in silver leaching have been reported to accumulate silver sulfide within their membrane , the microbial reduction of water soluble Ag to Ag0 using an airborne bacteria Bacillus sp. The microbial synthesis of single crystals of silver with well-defined composition and shapes such as equilateral triangles and hexagons by the culture Pseudomonas stutzeri has been reported earlier .
The exact reaction mechanisms leading to the formation of silver nanoparticles by the silver resistant bacteria is yet to be elucidated. Nano-particle usually forms the core of nano-biomaterial.
Aqueous silver ions when exposed to the fungus Fusarium oxysporum are reduced in solution, thereby leading to the formation of an extremely stable silver hydrosol .
Extracellular biosynthesis of silver nanoparticles exploiting storage fungus Aspergillus niger was reported in by Gade end coworkers . Silver nanoparticles in the size range of 2—5 nm were synthesized extracellular by a silver-tolerant yeast strain MKY3, when challenged with 1 mM soluble silver in the log phase of growth . The organisms used in the synthesis of nanoparticles vary from simple prokaryotic bacterial cells to complex eukaryotes.
Important steps are:. The exact mechanism of the antimicrobial effect of silver as well as copper nanoparticles is not well known, however the three most common mechanism of antimicrobial activity proposed to date are . There are certain reports regarding mode of action of silver nanoparticles against pathogenic microbes.
AgNPs interact with a wide range of molecular processes within microorganisms resulting in a range of effects from inhibition of growth, loss of infectivity to cell death which depends on shape, size, and concentration of AgNPs and the sensitivity of the microbial species.
Amro et al. The medical properties of silver have been known for over 2, years. Since nineteenth century, silver-based compounds have been used in many antimicrobial applications . As it is well known that silver nanoparticles are very small particles which measure not more than three or four atoms across, they are also versatile enough, and therefore they can be used in many types of medical procedures.
Nano silver reacts cell changing the structures of membrane and damaging DNA. It is estimated that of all the nanomaterials in medical and healthcare sector, nanosilver application has the highest degree of commercialization . Therefore, exposure to nanosilver in the body is becoming increasingly widespread and intimate.
Consequently, silver in the form of nanoparticles has gained an increasing access to tissues, cells and biological molecules within the human body . Silver nanoparticles are used for coating intraventricular catheter inside our body.
Recent Studies on new targeted silver nanoparticle contrast agents for early characterization of atherosclerosis and cardiovascular pathology at the cellular and molecular levels that might represent the next frontier for combining imaging and rational drug delivery to facilitate personalized medicine .
Today development of antimicrobial compounds having bactericidal potential against multidrug resistant bacteria is a priority area of research. In this concern M. Rai and coworker have studied bactericidal activity of silver nanoparticles against multi drug resistant bacteria.
This Multifunctional Nano weapon can be used for the treatment of drug resistant microbes such as Pseudomonas aeruginosa, ampicillin resistant E. Silver nanoparticles ions have capacity to inhibit the bactericidal replication by binding and denaturing bactericidal DNA .
Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. DOI: Ruparelia and A. Chatterjee and S. Duttagupta and S. Ruparelia , A.
The design of cheap and safe antibacterial materials for widespread use has been a challenge in materials science. The use of copper nanostructures combined with abundant biopolymers such as cellulose offers a potential approach to achieve such materials though this has been less investigated as compared to other composites. Here, nanocomposites comprising copper nanofillers in cellulose matrices have been prepared by in situ and ex situ methods. Two cellulose matrices vegetable and bacterial were investigated together with morphological distinct copper particulates nanoparticles and nanowires. A study on the antibacterial activity of these nanocomposites was carried out for Staphylococcus aureus and Klebsiella pneumoniae , as pathogen microorganisms.
Request PDF | Strain Specificity in Antimicrobial Activity of Silver and Copper Nanoparticles | The antimicrobial properties of silver and copper.
This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli , Staphylococcus aureus , and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay 3-[4,5-dimethylthiazolyl]-2,5-diphenyltetrazolium bromide was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E.
Nanotechnology is a rapidly growing field due to its unique functionality and a wide range of applications. Nanomedicine explores the possibilities of applying the knowledge and tools of nanotechnology for the prevention, treatment, diagnosis and control of disease. The current paper reviews various types of physical, chemical and biological methods used in the production of silver nanoparticles. It also describes approaches employing silver nanoparticles as antimicrobial and antibiofilm agents, as antitumour agents, in dentistry and dental implants, as promoters of bone healing, in cardiovascular implants and as promoters of wound healing.
Silver nanoparticles Ag NPs are known to have antibacterial properties. They are commonly produced by chemical synthesis which involves the use of harmful reducing agents. Contras, the laser technique is able to generate high-purity Ag NPs in water with specified surface charge characteristics. In the past, the molecular mechanisms contributing to the bactericidal effects of Ag NPs have been investigated extensively, but little is known of the antibacterial and toxic effects and mechanisms involved in laser-generated Ag NPs. In the current study Ag NPs were generated by picosecond laser ablation.
Received: January 01, Published: ,. Citation: DOI:. Download PDF. Nanosciences along with the emergence of nanobiotechnolgy and nanomedicine in the last few decades provided a number of opportunities for exploring the bactericidal and fungicidal activities of metal nanoparticles.
Просто неформальная дипломатическая любезность, - солгал. - Дипломатическая любезность? - изумился старик.
Ей хотелось поскорее оказаться в Третьем узле, и она достаточно хорошо изучила своего шефа, чтобы знать: Стратмор никуда не уйдет, пока она не разыщет ключ, спрятанный где-то в компьютере Хейла. Ей почти удалось проскользнуть внутрь, и теперь она изо всех сил пыталась удержать стремившиеся захлопнуться створки, но на мгновение выпустила их из рук. Створки стали стремительно сближаться. Стратмор попытался их удержать, но не сумел. За мгновение до того, как они сомкнулись, Сьюзан, потеряв равновесие, упала на пол за дверью.
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