Limits...
Removal of Protein Capping Enhances the Antibacterial Efficiency of Biosynthesized Silver Nanoparticles.

Jain N, Bhargava A, Rathi M, Dilip RV, Panwar J - PLoS ONE (2015)

Bottom Line: The synthesized nanoparticles were found to be homogenous, spherical, mono-dispersed and covered with multi-layered protein shell.The results revealed that bare nanoparticles were more effective as compared to the protein-capped silver nanoparticles with varying antibacterial potential against the tested Gram positive and negative bacterial species.In conclusion, our results illustrate that presence of protein shell on silver nanoparticles can decrease their bactericidal effects.

View Article: PubMed Central - PubMed

Affiliation: Centre for Biotechnology, Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, 333 031, India.

ABSTRACT
The present study demonstrates an economical and environmental affable approach for the synthesis of "protein-capped" silver nanoparticles in aqueous solvent system. A variety of standard techniques viz. UV-visible spectroscopy, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) measurements were employed to characterize the shape, size and composition of nanoparticles. The synthesized nanoparticles were found to be homogenous, spherical, mono-dispersed and covered with multi-layered protein shell. In order to prepare bare silver nanoparticles, the protein shell was removed from biogenic nanoparticles as confirmed by UV-visible spectroscopy, FTIR and photoluminescence analysis. Subsequently, the antibacterial efficacy of protein-capped and bare silver nanoparticles was compared by bacterial growth rate and minimum inhibitory concentration assay. The results revealed that bare nanoparticles were more effective as compared to the protein-capped silver nanoparticles with varying antibacterial potential against the tested Gram positive and negative bacterial species. Mechanistic studies based on ROS generation and membrane damage suggested that protein-capped and bare silver nanoparticles demonstrate distinct mode of action. These findings were strengthened by the TEM imaging along with silver ion release measurements using inductively coupled plasma atomic emission spectroscopy (ICP-AES). In conclusion, our results illustrate that presence of protein shell on silver nanoparticles can decrease their bactericidal effects. These findings open new avenues for surface modifications of nanoparticles to modulate and enhance their functional properties.

No MeSH data available.


Related in: MedlinePlus

(A) A representative transmission electron micrograph showing spherical shaped silver nanoparticles (scale bar equivalent to 50 nm). Inset showing SAED pattern recorded from a single nanoparticle. Particle size distribution histogram of silver nanoparticles as determined using (B) transmission electron microscope and (C) dynamic light scattering measurements.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4520467&req=5

pone.0134337.g002: (A) A representative transmission electron micrograph showing spherical shaped silver nanoparticles (scale bar equivalent to 50 nm). Inset showing SAED pattern recorded from a single nanoparticle. Particle size distribution histogram of silver nanoparticles as determined using (B) transmission electron microscope and (C) dynamic light scattering measurements.

Mentions: TEM micrograph (Fig 2A) revealed the presence of mono-dispersed and predominantly spherical particles with no visible aggregation. The SAED pattern (Fig 2A inset) attests the crystallanity of silver nanoparticles. The particle size distribution histogram obtained from TEM measurements revealed that most of the particles ranged between 40–80 nm with a mean diameter of 54 ± 8.9 nm (Fig 2B). These results were in well agreement with the values obtained by DLS measurements (Fig 2C). It has been well reported that different fungi can synthesize nanoparticles of varied composition, sizes and shapes which may be due to the differences in their extracellular protein profiles [38–40].


Removal of Protein Capping Enhances the Antibacterial Efficiency of Biosynthesized Silver Nanoparticles.

Jain N, Bhargava A, Rathi M, Dilip RV, Panwar J - PLoS ONE (2015)

(A) A representative transmission electron micrograph showing spherical shaped silver nanoparticles (scale bar equivalent to 50 nm). Inset showing SAED pattern recorded from a single nanoparticle. Particle size distribution histogram of silver nanoparticles as determined using (B) transmission electron microscope and (C) dynamic light scattering measurements.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4520467&req=5

pone.0134337.g002: (A) A representative transmission electron micrograph showing spherical shaped silver nanoparticles (scale bar equivalent to 50 nm). Inset showing SAED pattern recorded from a single nanoparticle. Particle size distribution histogram of silver nanoparticles as determined using (B) transmission electron microscope and (C) dynamic light scattering measurements.
Mentions: TEM micrograph (Fig 2A) revealed the presence of mono-dispersed and predominantly spherical particles with no visible aggregation. The SAED pattern (Fig 2A inset) attests the crystallanity of silver nanoparticles. The particle size distribution histogram obtained from TEM measurements revealed that most of the particles ranged between 40–80 nm with a mean diameter of 54 ± 8.9 nm (Fig 2B). These results were in well agreement with the values obtained by DLS measurements (Fig 2C). It has been well reported that different fungi can synthesize nanoparticles of varied composition, sizes and shapes which may be due to the differences in their extracellular protein profiles [38–40].

Bottom Line: The synthesized nanoparticles were found to be homogenous, spherical, mono-dispersed and covered with multi-layered protein shell.The results revealed that bare nanoparticles were more effective as compared to the protein-capped silver nanoparticles with varying antibacterial potential against the tested Gram positive and negative bacterial species.In conclusion, our results illustrate that presence of protein shell on silver nanoparticles can decrease their bactericidal effects.

View Article: PubMed Central - PubMed

Affiliation: Centre for Biotechnology, Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, 333 031, India.

ABSTRACT
The present study demonstrates an economical and environmental affable approach for the synthesis of "protein-capped" silver nanoparticles in aqueous solvent system. A variety of standard techniques viz. UV-visible spectroscopy, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) measurements were employed to characterize the shape, size and composition of nanoparticles. The synthesized nanoparticles were found to be homogenous, spherical, mono-dispersed and covered with multi-layered protein shell. In order to prepare bare silver nanoparticles, the protein shell was removed from biogenic nanoparticles as confirmed by UV-visible spectroscopy, FTIR and photoluminescence analysis. Subsequently, the antibacterial efficacy of protein-capped and bare silver nanoparticles was compared by bacterial growth rate and minimum inhibitory concentration assay. The results revealed that bare nanoparticles were more effective as compared to the protein-capped silver nanoparticles with varying antibacterial potential against the tested Gram positive and negative bacterial species. Mechanistic studies based on ROS generation and membrane damage suggested that protein-capped and bare silver nanoparticles demonstrate distinct mode of action. These findings were strengthened by the TEM imaging along with silver ion release measurements using inductively coupled plasma atomic emission spectroscopy (ICP-AES). In conclusion, our results illustrate that presence of protein shell on silver nanoparticles can decrease their bactericidal effects. These findings open new avenues for surface modifications of nanoparticles to modulate and enhance their functional properties.

No MeSH data available.


Related in: MedlinePlus