Antimicrobial activity of fluorescent Ag nanoparticles

The antimicrobial activity of fluorescent Ag nanoparticles of 1·5 nm (nAg‐Fs) is demonstrated and compared with the other Ag nanoparticles of different shapes and size. The antimicrobial activity was evaluated using Gram‐positive (Staphylococcus epidermidis NCIM2493 and Bacillus megaterium) and Gram‐negative bacteria (Pseudomonas aeruginosa ATCC27853 and Escherichia coli) and fungal strains (Candida albicans and Aspergillus niger). Insights into the possible mechanism were investigated using fluorescence microscope and cytoplasmic materials release assay. The fluorescence microscopic measurements show that the nAg‐Fs are localized at the centre of the cell, and 50% decrease in the fluorescence intensity was observed upon 2‐h incubation. Maximum cytoplasmic release was observed with spherical Ag nanoparticles of 10 nm. Although the nAg‐F shows minimum cytoplasmic release, it has the highest activity. The microbial killing effect of nAg‐Fs is actually originates from its intracellular activity. The antimicrobial activity of nAg‐Fs is significantly higher than the other synthesized nanoparticles of different shapes and size. The activity of the nanoparticles has been rationalized by considering the shape, size and surface structure of the particles.

[1]  J. Lombardi,et al.  Photoinduced Shape Evolution: From Triangular to Hexagonal Silver Nanoplates , 2007 .

[2]  V. Sharma,et al.  Silver nanoparticles: green synthesis and their antimicrobial activities. , 2009, Advances in colloid and interface science.

[3]  C. R. Raj,et al.  A facile photochemical route for the synthesis of triangular Ag nanoplates and colorimetric sensing of H2O2 , 2013 .

[4]  Oswaldo Luiz Alves,et al.  Potential use of silver nanoparticles on pathogenic bacteria, their toxicity and possible mechanisms of action , 2010 .

[5]  C. Milanese,et al.  Synthesis, characterization and antibacterial activity against Gram positive and Gram negative bacteria of biomimetically coated silver nanoparticles. , 2011, Langmuir : the ACS journal of surfaces and colloids.

[6]  J. Song,et al.  Does the Antibacterial Activity of Silver Nanoparticles Depend on the Shape of the Nanoparticle? A Study of the Gram-Negative Bacterium Escherichia coli , 2007, Applied and Environmental Microbiology.

[7]  M. Patrini,et al.  Antibacterial activity of glutathione-coated silver nanoparticles against Gram positive and Gram negative bacteria. , 2012, Langmuir : the ACS journal of surfaces and colloids.

[8]  Zhiqiang Hu,et al.  Size dependent and reactive oxygen species related nanosilver toxicity to nitrifying bacteria. , 2008, Environmental science & technology.

[9]  Rong Chen,et al.  Size-dependent antibacterial activities of silver nanoparticles against oral anaerobic pathogenic bacteria , 2013, Journal of Materials Science: Materials in Medicine.

[10]  Shuping Xu,et al.  Fluorescent Ag nanoclusters templated by carboxymethyl-β-cyclodextrin (CM-β-CD) and their in vitro antimicrobial activity. , 2013, Materials science & engineering. C, Materials for biological applications.

[11]  Fred C Tenover,et al.  Mechanisms of antimicrobial resistance in bacteria. , 2006, The American journal of medicine.

[12]  S. Silver,et al.  Bacterial heavy metal resistance: new surprises. , 1996, Annual review of microbiology.

[13]  Rajender S. Varma,et al.  Greener Techniques for the Synthesis of Silver Nanoparticles Using Plant Extracts, Enzymes, Bacteria, Biodegradable Polymers, and Microwaves , 2013 .

[14]  S. Mandal,et al.  Effects of lactoferricin B against keratitis-associated fungal biofilms , 2012, Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy.

[15]  Dae Hong Jeong,et al.  Antimicrobial effects of silver nanoparticles. , 2007, Nanomedicine : nanotechnology, biology, and medicine.

[16]  Xi Qian,et al.  Engineering Nanomaterials for Biomedical Applications Requires Understanding the Nano-Bio Interface: A Perspective. , 2012, The journal of physical chemistry letters.

[17]  M. Yacamán,et al.  The bactericidal effect of silver nanoparticles , 2005, Nanotechnology.

[18]  E. Hoek,et al.  A review of the antibacterial effects of silver nanomaterials and potential implications for human health and the environment , 2010 .

[19]  C. R. Raj,et al.  Enzyme-Cofactor-Assisted Photochemical Synthesis of Ag Nanostructures and Shape-Dependent Optical Sensing of Hg(II) Ions , 2010 .

[20]  Kyungjae Lee,et al.  Hydrogel networks as nanoreactors: A novel approach to silver nanoparticles for antibacterial applications , 2007 .

[21]  M. Ferraro.  Performance standards for antimicrobial susceptibility testing , 2001 .

[22]  Young Jik Kwon,et al.  "Nanoantibiotics": a new paradigm for treating infectious diseases using nanomaterials in the antibiotics resistant era. , 2011, Journal of controlled release : official journal of the Controlled Release Society.

[23]  Xiaoying Wang,et al.  One-pot green synthesis and antimicrobial activity of exfoliated Ag NP-loaded quaternized chitosan/clay nanocomposites , 2013 .

[24]  D. Evanoff,et al.  Synthesis and optical properties of silver nanoparticles and arrays. , 2005, Chemphyschem : a European journal of chemical physics and physical chemistry.

[25]  M. Rai,et al.  Silver nanoparticles as a new generation of antimicrobials. , 2009, Biotechnology advances.

[26]  P. Gupta,et al.  Atomic force microscopic study on morphological alterations induced by photodynamic action of Toluidine Blue O in Staphylococcus aureus and Escherichia coli. , 2009, Journal of photochemistry and photobiology. B, Biology.

[27]  P. Tam,et al.  Silver nanoparticles: partial oxidation and antibacterial activities , 2007, JBIC Journal of Biological Inorganic Chemistry.

[28]  T. Pradeep,et al.  A fifteen atom silver cluster confined in bovine serum albumin , 2011 .

[29]  Guohua Chen,et al.  Potent antibacterial activities of Ag/TiO2 nanocomposite powders synthesized by a one-pot sol-gel method. , 2009, Environmental science & technology.

[30]  J. Maillard,et al.  Silver as an antimicrobial: facts and gaps in knowledge , 2013, Critical reviews in microbiology.