Simple reactor for the synthesis of silver nanoparticles with the assistance of ethanol by gas—liquid discharge plasma. Plasma Science and Technology , 21 4 , Solution Plasma Reactions and Materials Synthesis. Microchimica Acta , 1 DOI: Bulletin of the Chemical Society of Japan , 91 12 , Point discharge microplasma reactor for high efficiency conversion of H2S to SO2 for speciation analysis of sulfide and sulfite using molecular fluorescence spectrometry.
Analytica Chimica Acta , , SeungHyo Lee, Nagahiro Saito. Enhancement of nitrogen self-doped nanocarbons electrocatalyst via tune-up solution plasma synthesis. RSC Advances , 8 62 , Atmospheric discharge plasma in aqueous solution: Importance of the generation of water vapor bubbles for plasma onset and physicochemical evolution.
Journal of Applied Physics , 10 , Nano , , Applied Sciences , 8 7 , Materials , 11 6 , Synthesis of Pt nanoparticles as catalysts of oxygen reduction with microbubble-assisted low-voltage and low-frequency solution plasma processing.
Journal of Power Sources , , Bulletin of the Chemical Society of Japan , 91 3 , Degradation of chitosan hydrogel dispersed in dilute carboxylic acids by solution plasma and evaluation of anticancer activity of degraded products. Japanese Journal of Applied Physics , 57 1 , B5. Anyarat Watthanaphanit, Nagahiro Saito. Japanese Journal of Applied Physics , 57 1 , A3. Solution plasma: A new reaction field for nanomaterials synthesis. Japanese Journal of Applied Physics , 57 1 , A4. Green synthesis of gold nanoparticles using the algae extract of seaweed Turbinaria conoides was carried out.
Preliminarily confirmation was done from the color changing from yellow to dark pink in the reaction mixture, and from the broad surface plasmon resonance band centered at — nm.
Transmission electron microscopy confirmed the formation of polydispersed gold nanoparticles with the size range of 6—10 nm . Kalabegishvili et al. Recently, Singh et al. In another study by Jena and coworkers , synthesis of silver nanoparticles using fresh extract and whole cell of microalga Chlorococcum humicola was reported. Myconanotechnology is the boundary between mycology and nanotechnology. After the extensive literature survey carried out, it is clear that the fungal systems are the better alternatives for the synthesis of metal nanoparticles.
Many fungal species have been explored for the production of different metal nanoparticles of different shapes and sizes. Colletotrichum species, an endophytic fungus growing in the leaves of geranium produces gold nanoparticles when exposed to chloroaurate ions.
These particles were predominantly decahedral and icosahedral in shape, ranging in size from 20 to 40 nm, this was experimentally reported by Shivshankar et al.
Lichen fungi Usnea longissima have shown synthesis of bioactive nanoparticles usnic acid in specified medium used. The synthesized nanoparticles were found in the range of 50— nm . Shivshankar and coworkers  reported the use of geranium leaves Pelargonium graveolens and its endophytic fungus in the extracellular synthesis of gold nanoparticles.
In their experiment, they have treated sterilized geranium leaves and an endophytic fungus Colletotrichum sp. In both cases, rapid reduction of the metal ions was observed, which resulted in the formation of stable gold nanoparticles of variable size. The gold nanoparticles synthesized by fungi were found to be spherical in shape, whereas these particles synthesized by using plant leaves were found to be rod, flat sheets, and triangular in shapes.
Chen et al. Some soil-borne fungi like Aspergillus fumigatus were reported to produce the silver nanoparticles extracellularly, when the cell extract was challenged with aqueous silver ions . Gade et al. Out of different fungal genera used for the synthesis of nanoparticles, the genus Fusarium was found to be used many times. Ahmad et al.
They have reported that aqueous silver ions when exposed to the fungus F. The silver nanoparticles were in the range of 5—15 nm in dimensions and stabilized in solution by proteins secreted by the fungus. It is believed that the reduction of the metal ions occurs by an enzymatic process. Bansal et al. It leads to the formation of crystalline zirconia nanoparticles. Duran et al. They found that aqueous silver ions when exposed to several F.
The silver nanoparticles were in the range of 20—50 nm in dimensions. Similarly, other Fusarium species like F. Other fungal species used for the production of metal nanoparticles includes Trichoderma viride , Penicillium fellutanum, and Penicillium purpurogenum  for silver nanoparticle synthesis .
Atomic resolution analysis confirmed the nucleation and growth of Au nanoparticles inside the alfalfa plant. Armendariz et al. Persimmon Diopyros kaki leaf extract helps to make Au and Ag nanoparticles of 15—90 nm size, the study was carried out by Song and Kim .
Sathishkumara and coworkers  reported the synthesis of nanocrystalline palladium particle of size 15—20 nm from Cinnamomum zeylanicum bark extract. Similarly, Smitha et al. Krishnaraj et al. Silver nanoparticles were rapidly synthesized using leaf extract of Acalypha indica and the formation of nanoparticles was observed within 30 min.
Antibacterial activity of synthesized silver nanoparticles showed effective inhibitory activity against water-borne pathogens viz. Rai et al. They also proposed that plant is a good source for the synthesis of quantum dots.
They evaluated antibacterial activity against E. Antibacterial activity of a commercially available antibiotic was increased in combination with silver nanoparticles as it already has bactericidal activity.
They also proposed the mechanism for the synthesis of silver nanoparticles that quercetin present in a high concentration was responsible for the synthesis of silver nanoparticles. Bonde et al. Similarly, some other plants like Solanum tricobatum, Syzygium cumini, Centella asiatica and Citrus sinensis , Moringa oleifera , Coleus aromaticus  for silver nanoparticles, and Ananas comosus  have been used for the synthesis of gold nanoparticles.
For the past decade, a variety of inorganic nanoparticles have been newly created or modified to provide superior material properties with functional versatility. Simultaneously, due to their size features similar to biological species e.
These nanobiomaterials can be used as convenient surface for molecular assembly  and may be composed of inorganic or polymeric materials. The spherical-shaped nanoparticles are often used, but some other like cylindrical, plate-like are also being used. The nanoparticle size and size distribution might be important in some cases, for example, penetration through a pore structure of cellular membrane requires small size and uniform nanoparticles.
Similarly, narrow size distribution of sizes allows creating very efficient fluorescent probes that emit narrow light in a very wide range of wavelength.
This helps to produce biomarkers with many and well distinguished color . Quantum dots , gold nanoparticles , and superparamagnetic nanoparticles  were the most promising nanostructures for in vitro diagnostic applications. These nanoparticles can be conjugated to recognition of moieties such as antibodies or oligonucleotides for detection of target biomolecules. Nanoparticles have been also utilized in wide range of biological application like immunoassays, immunohistochemistry, DNA diagnostics, bioseparation of specific cell populations, and cellular imaging.
Nanoparticle-based diagnostics may open new frontiers for detection of tumors, infectious diseases, bioterrorism agents, and neurological diseases . Metallic nanoparticles have been used as strategies to deliver conventional pharmaceuticals or substances such as peptides, recombinant proteins, vaccines, and nucleotides. The silver, gold, and magnetic nanoparticles are important carriers for new pharmaceutical formulations .
Some parasitic diseases such as malaria, schistosomiasis, trypanosomiasis, leishmaniasis, tuberculosis, leprosy, filiarasis, etc. In such disease liposomes, polymeric nanoparticles and nanostructured lipid carriers have been applied. These nanocarrier systems showed promising results in the treatment of such parasitic diseases with diminished toxicity and increased efficacy and prolonged release of drug with reduced number of dosage . Solid lipid nanoparticles, polymeric nanoparticles, liposomes, micelles, functionalized nanoparticles, nanotubes, and metallic nanoparticles have been used to deliver conventional pharmaceutical drugs or biological molecules such as recombinant protein, enzymes, vaccines, nucleotides .
Being excellent carriers for biological molecules, nanoparticles can improve the therapeutic efficiency. Single quantum dot of compound semiconductors was successfully used as a replacement of organic dyes in various bio-tagging applications . Quantum dots were also used in in vivo imaging of breast cancer cells expressing HER2 protein .
Jiang et al. Inorganic nanoparticles were used in labeling of macrophages expressing mannose receptors and in vivo cancer imaging . Quantum dots and gold nanoparticles were widely used in immunohistochemistry to identify protein-protein interaction . It can be used in labeling DNA or proteins for detection of biological targets.
They are also primarily utilized in imaging, immunoassay, and molecular diagnostic applications [, ]. Supermagnetic nanoparticles were made of magnetic materials such as iron, nickel, cobalt, or alloys of magnetic metals. The nanoparticles exhibit the phenomenon of super magnetism where thermal energy is sufficient to change the direction of magnetization of the nanoparticles .
Ultra small supermagnetic iron oxide particles used as contrast agents not only have greater magnetic susceptibility but also more widespread tissue distribution because of their ultra small size, which facilitate their uptake in various tissues. Artemov et al. Superparamagnetic nanoparticles can also be used to separate pathogenic cells from normal cells . In addition, there are many more applications of inorganic nanoparticles, which are given below.
It has been used for thousands of years for preparing ornaments, utensils, jewelry for trade, etc. Nowadays, silver metal has been used in a wide array of applications including electrical contacts and conductors, in mirrors, and in chemical reaction catalysis. The antimicrobial properties of silver have been known from ancient days. Metalic silver is relatively inert and poorly absorbed by mammalian or bacterial cells.
Similar to other heavy metals, silver is toxic to microorganisms by poisoning respiratory enzymes and components of the microbial electron transport system and impairing some DNA function [, ]. In vitro studies provide evidence for the bactericidal effect of silver, which is attributable largely to the binding of the silver ion to free sulfhydral group of proteins or on its surface leading to inactivation of the enzyme phosphomannose isomerase. Owing to the discovery of several antibiotics, the use of silver compounds has been declined remarkably.
Nowadays, there is growing concern about the emergence and re-emergence of drug-resistant pathogen such as bacterial strains, fungi, and parasites . Therefore, the development of new antimicrobial compounds, or the modification of those available to improve their antimicrobial activity, is the necessity of time and this is in high priority of research. Owing to its broad spectrum activity, efficacy, and lower costs, the search for newer and superior silver-based antimicrobial agents was necessary.
Therefore, it has been used in the different formulations such as silver nitrate, silver sulfadiazine for the treatment of several microbial infections, in burn cases, etc. Among the various alternatives available, silver nanoparticles have been in focus and are being considered as a precursor and an excellent candidate for therapeutic purposes. The ionized silver is highly reactive, when it binds to tissue proteins; it brings structural changes in the bacterial cell wall and nuclear membrane leading to cell distortion and death.
Feng et al. In the case of E. There was detachment of cytoplasmic membrane from cell walls and electron light region observed in the center of the cytoplasm, which contains condensed form of DNA.
Condensed form of DNA occurs due to protecting it from the silver ion injury. Small electron dense granules surrounding the cell wall or deposited inside the cell were also observed. The only difference found in the case of S.
Thus, a thicker cell wall protects the cell from the penetration of silver ions in the cytoplasm. The proposed possible mechanism for the silver ion action was that the silver ion penetrates through the cell wall, and the DNA gets condensed, which reacts with the -thiol groups of protein and results in cell death .
In a similar direction, antimicrobial activity of silver nanoparticles against Gram-negative E. Silver nanoparticles interact with the building blocks of the bacterial membrane and damaged the cells. Silver nanoparticles reside in the cell membrane confirmed by the TEM and energy-dispersive X-ray analyses EDAX , which showed the formation of pits on the cell surface. Baker et al. The antibacterial activity of silver nanoparticles was due to increased surface area-to-volume ratio.
Susceptibility constants of E. The result showed that B. One possible reason for the lower sensitivity of E. Morones et al. Scanning transmission electron microscopy showed the presence of silver nanoparticles in the cell membrane and inside the bacteria, whereas high angled annular dark field images showed that the smaller-sized nanoparticles has efficient antibacterial activity, and thus, it showed size-dependent antimicrobial activity.
Another mechanism was proposed by Lok and colleagues ; according to them, even a short exposure of silver nanoparticles to E.
Therefore, these particles can penetrate and disrupt the membranes of bacteria, loss of intracellular potassium was induced, and ATP level decreased. The phospholipid integrity of the cell membrane also may be the site of action for the silver nanoparticles. All these effects culminate in the loss of cell viability. A possibility of free radical involvement near the silver nanoparticle surface in its antimicrobial activity was proved by electron spin resonance ESR measurement.
Relationship between antibacterial activity and free radical was demonstrated by the antioxidant NAC test. The result of test suggested that the free radical may be derived from the surface of silver nanoparticles and responsible for the antimicrobial activity .
Shrivastava et al. The major mechanism through which silver nanoparticles manifested antibacterial properties was by anchoring to and penetrating the bacterial cell wall and modulating cellular signaling by dephosphorylating putative key peptide substrates on tyrosine residues.
They found the inhibition of bacterial growth by spherical nanoparticles at silver content of These findings confirmed that the antibacterial activity of silver nanoparticles is shape dependent. Streptococcus mutans causes dental caries, which is a well-known public health problem throughout the world. Sierra et al. They used nanoparticles of silver, zinc oxide, and gold with an average size of 25 nm, nm, and 80 nm, respectively, prepared by colloidal solution with oversaturation of salt.
The result interpreted that the nanoparticles of silver, compared to gold and zinc oxide showed maximum antibacterial activity at lower concentration, and hence, silver nanoparticles were most effective for controlling S. The antimicrobial activity of nanoballs was due to the overall negative charge on the bacterial cell at physiological pH. The pH values were negative because of excess number of carboxylic groups, which upon dissociation makes cell surface negative.
The opposite charges developed attract each other due to electrostatic forces. Nanoballs on entering the bacteria, inhibit the cell wall synthesis, damage the cytoplasmic membrane, inhibit nucleic acid and protein synthesis, inhibit specific enzyme systems, which results in the inhibition of complete bacterial cell .
Li et al. When amoxicillin and silver nanoparticles were combined, it results in greater bactericidal efficiency on E.
Test confirms that combining amoxicillin with silver nanoparticles resulted in a synergistic antibacterial effect on E. The synergism was probably caused by a binding reaction between amoxicillin molecules, which exhibit groups such as hydroxyl and amido groups that can react easily with silver nanoparticles.
The silver nanoparticles probably operate as an antibiotic carrier. Shahaverdi et al. Silver nanoparticles were synthesized by K. It was observed that the antibacterial activity of antibiotics enhanced in the combination of silver nanoparticles. The highest synergistic activity was observed with erythromycin against S.
Similarly, Ingle et al. Birla et al. They investigated that silver nanoparticles in combination with antibiotics enhance their antibacterial activity against S. Similarly, P. Antibacterial activity of commercially available antibiotics was increased in the presence of silver nanoparticles against K. The increase in fold area is due to the synergistic activity of antibiotics and silver nanoparticles. As the silver nanoparticles showed the synergistic activity with different antibiotics, they can be used in combination with commercially available antibiotics for the development of effective antimicrobial agent .
Pattabi et al. Shameli et al. Silver nanoparticles found to have broad spectrum activity against a variety of Gram-positive and Gram-negative bacteria. Devi and Joshi  screened 53 isolates of different fungi isolated from soils of different microhabitats of Eastern Himalayan range for mycosynthesis of silver nanoparticles and also studied their efficacy as antimicrobials alone and in combination with commonly used antibiotics against S.
MP5 were found to synthesize silver nanoparticles. The mycosynthesized nanoparticles showed potent antibacterial activity, and their syngergistic effect with erythromycin, methicillin, chloramphenicol, and ciprofloxacin was significantly higher compared to inhibitions by silver nanoparticles alone.
The results obtained by Devi and Joshi  showed the resemblance with the findings reported in past few studies on demonstration of syngergistic effect of silver nanoparticles on different bacteria like E.
Silver nanoparticles showed effective antifungal activity.
Silver nanoparticle-grafted dressing with a silver content of 2. Antibacterial activity of commercially available antibiotics was increased in the presence of silver nanoparticles against K.
Dielectric permeability of the medium has two part namely a real part and an imaginary part. It was found that the animal group treated with the silver nanoparticle ointments showed significant reduction in the period of epithelization.
It leads to the formation of crystalline zirconia nanoparticles. It is used in Solar cells, medical imaging, optical limiters, plasmonic devices etc.
Dar, A. Paul, A. Highly ionic metal oxides have various physical and chemical properties and also show antimicrobial activity. Rodl, B. Chung, C. Krishnaraj et al.
Amornkitbamrung, S. It can be used in labeling DNA or proteins for detection of biological targets. This experiment confirms that reduction of silver occurs first few seconds of the synthesis and made impossible of growth mechanism of particles happens by reduction of silver ions on the surface of previously formed clusters. Micro-emulsion may be defined as a thermodynamically stable isotropic dispersion of two immiscible liquid consisting of nanosize domains of one or both liquids in the others, stabilized by an interfacial film of surface active molecule. Mittal, A. Jones et al.
Further desired properties can be obtained by preparing composite by using Ag NPs as reinforcement into polymer matrix. Nakkala, R. Streptococcus mutans causes dental caries, which is a well-known public health problem throughout the world.
Gnanajobitha, K. High ratio of surface area to volume ratio of Ag NPs exhibits microbial resistance and develops resistant strains . Traum, vol.
Biosynthesis will be described later. Chem, Commun, vol. Zheng, Z.
However aggregation and toxic nature of silver nanoparticles limits its uses in some application. Chen, N. Benn, P. Fatma, B. Posch, et al.
Similarly, various other chemical approaches have been used for the synthesis of different metal nanoparticles like copper iodide , zinc oxide , ZnS-Co-doped , and gold .