Despite numerous existing potent antibiotics and other antimicrobial means, bacterial infections are still a major cause of morbidity and mortality. Moreover, the need to develop additional bactericidal means has significantly increased due to the growing concern regarding multidrug-resistant bacterial strains and biofilm associated infections. Consequently, attention has been especially devoted to new and emerging nanoparticle-based materials in the field of antimicrobial chemotherapy. The present review discusses the activities of nanoparticles as an antimicrobial means, their mode of action, nanoparticle effect on drug-resistant bacteria, and the risks attendant on their use as antibacterial agents. Factors contributing to nanoparticle performance in the clinical setting, their unique properties, and mechanism of action as antibacterial agents are discussed in detail.

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Alternative Antimicrobial Approach: Nano-Antimicrobial Materials

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Green synthesized ZnO nanoparticles against bacterial and fungal pathogens

This work investigates the role of oxidation state in the antibacterial activity of copper oxide nanoparticles (NPs). The findings add strong support to a contact killing mechanism of copper oxides (CuO and Cu2O) through which bacteria initially suffer severe damage to the cell envelope. Then further damage ensues by an independent pathway of each copper oxide nanoparticle. Formation of copper(I)–peptide complex from cuprous oxide (Cu2O) and free radical generation from cupric oxide (CuO) were identified as key sources of toxicity towards E.coli. Cu2O rapidly inactivated Fumarase A, an iron sulphur cluster enzyme suggesting the cuprous state of copper binding to the proteins. This inactivation was not noticed in CuO. The percentage of biocidal/bacteriostatic activity is closely related to the oxidation state of the copper oxides. In the case of E.coli, Cu2O nanoparticles showed more efficient antibacterial activity and higher affinity to the bacterial cells. CuO nanoparticles produced significant ROS in terms of super oxides while Cu2O did not. The diminishing defective emission peaks of Cu2O after incubation with microbes strongly suggest the formation of protein complexes. This work is carried out to enable better understanding of the mechanistic pathways of copper oxide nanoparticles.

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Understanding the pathway of antibacterial activity of copper oxide nanoparticles

Metal oxide nanoparticles as antimicrobial agents: a promise for the future

The newest achievements in synthesis, immobilization and practical applications of antibacterial nanoparticles

Copper oxide nanoparticles were prepared by electrochemical reduction method using tetra butyl ammonium bromide (TBAB) as structure directing agent in an organic medium viz. tetra hydro furan (THF) and acetonitrile (ACN) in 4:1 ratio by optimizing current density and molar concentration of the ligand. The reduction process takes place under inert atmosphere of nitrogen over a period of 2 h. Such nanoparticles are prepared using simple electrolysis cell in which the sacrificial anode as a commercially available copper metal sheet and platinum (inert) sheet act as a cathode. The parameters such as current density, solvent polarity, distance between electrodes, and concentration of stabilizers are used to control the size of nanoparticles. The synthesized copper oxide nanoparticles were characterized by using UV–Visible, FT-IR, XRD, SEM–EDS and TEM analysis techniques. The nanoparticles were tested for antibacterial activity against human pathogens like Escherichia coli (E. coli) and Staphylococcus strains and which was proved to be excellent.

Copper Oxide Nanoparticles: Synthesis, Characterization and Their Antibacterial Activity

Molybdenum oxide nanoparticles were prepared by electrochemical reduction method using tetra ethyl ammonium bromide as structure directing agent in an organic medium tetrahydrofuran/acetonitrile in 4:1 ratio and at current density 14 mA/cm2. The synthesized molybdenum oxide nanoparticles were characterized by using ultra violet–visible spectroscopy, infra red spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and transmission electron microscope analysis techniques. The nanoparticles were tested for antibacterial activity against human pathogens like gram negative Escherichia coli, Salmonella typhi and gram positive Staphylococcus aureus, Bacillus subtilis strains, which showed excellent antibacterial properties.

Molybdenum Oxide Nanoparticles as Antimicrobial Agents

Molybdenum oxide nanoparticle has been shown to be an inexpensive, efficient and mild catalyst for the one-pot synthesis of octahydroquinazolinone derivatives using dimedone, urea/thiourea and appropriate aromatic aldehydes under microwave-irradiation. Molybdenum oxide nanoparticles were prepared by electrochemical reduction method in which parameters such as current density, solvent polarity, distance between electrodes, and concentration of stabilizers are used to control the size of nanoparticles. Molybdenum oxide nanoparticle has been shown to be an inexpensive, efficient and mild catalyst for the one-pot synthesis of octahydroquinazolinone derivatives using dimedone, urea/thiourea and appropriate aromatic aldehydes under microwave-irradiation.

Microwave-Assisted One-Pot Synthesis of Octahydroquinazolinone Derivatives Using Molybdenum Oxide Nanoparticles in Solvent-Free Condition

An electrochemical reduction method was used for the preparation of TiO2 nanoparticles in which agglomeration with formation of undesired metal powders is prevented by the presence of ammonium stabilizers. These synthesized nanoparticles were characterized by UV–Visible, XRD, SEM–EDS and TEM analysis techniques. These synthesized nanoparticles of TiO2 were tested as heterogeneous catalyst for the synthesis of tetrahydrobenzo[b]pyran derivative using three components reaction of aromatic aldehyde, dimedione and malononitrile by simply stirring at room temperature in a solvent free condition.

Nanosized TiO 2 as a Recyclable Heterogeneous Catalyst for the Synthesis of Tetrahydrobenzo[ b ]pyran Derivatives

Copper oxide nanoparticles were prepared by electrochemical reduction method which is environmental benign. Tetra ethyl ammonium bromide (TEAB), tetra propyl ammonium bromide (TPAB), tetra butyl ammonium bromide (TBAB) were used as stabilizing agent in an organic medium viz . tetra hydro furan (THF) and acetonitrile (ACN) in 4:1 ratio by optimizing current density. The reduction process takes place under atmospheric condition over a period of 2 h. Such nanoparticles were prepared using simple electrolysis cell in which the sacriﬁcial anode was a commercially available copper metal sheet and platinum (inert) sheet acted as a cathode. The stabilizers were used to control the size of a nanoparticles. The synthesized copper oxide nanoparticles were characterized by using UV-Visible, FT-IR, XRD, SEM-EDS and TEM analysis techniques. DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7501

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Sunita Jadhav

Papers

Copper Oxide Nanoparticles: Synthesis, Characterization and Their Antibacterial Activity

Molybdenum Oxide Nanoparticles as Antimicrobial Agents

Microwave-Assisted One-Pot Synthesis of Octahydroquinazolinone Derivatives Using Molybdenum Oxide Nanoparticles in Solvent-Free Condition

Nanosized TiO 2 as a Recyclable Heterogeneous Catalyst for the Synthesis of Tetrahydrobenzo[ b ]pyran Derivatives

Copper Oxide Nanoparticles Synthesis by Electrochemical Method