Characterization of Alginate/Silver Nanobiocomposites Synthesized by Solution Plasma Process and Their Antimicrobial Properties

Solution plasma process (SPP) was adopted to prepare alginate/silver nanoparticle (AL/AgNP) biocomposites. The biocomposites were synthesized in solutions of varying concentrations of AgNO3 (1−5 mM) and alginate (0.1−0.3%, w/w) by discharging plasma for 7 min at 800 V with 30 kHz frequency using a pulsed unipolar power supply. The AL/AgNP emulsion was fabricated into 3D scaffolds by freeze drying and lyophilization and then stabilized by cross-linking via UV irradiation. UV-Vis spectroscopy of the biocomposites showed a characteristic absorbance at the maximum of 415–440 nm with increase in the intensity of the peaks as the concentration of AgNO3 increased. FE-SEM analysis showed that the 3D scaffolds had microporous structures with fine and uniform pores of 3–9 ± 2.0 μm in diameter. TEM analysis revealed that AgNPs in the biocomposites were in spherical shape with size range of 5–40±2.0 nm (AL0.3/Ag5) and well distributed in the matrix. The AL/AgNP biocomposites showed microbicidal activity against 9 human pathogens with MIC of 9.6–21 μg/mL for bacteria and 85–425 μg/mL for fungi. Almost all of the E. coli cells (99.8%) were killed by the treatment with 42.5 μg/mL of AgNPs at room temperature for 1 h

Biodiversity and molecular evolution of microalgae on different epiphytes and substrates

10.3923/pjbs.2012.813.820Pakistan Journal of Biological Sciences1517813-82

Biogenic synthesis, characterization of antibacterial silver nanoparticles and its cell cytotoxicity

The advanced research and development of silver nanoparticles (AgNPs) is vast due to their incredible applications today. In this work, AgNPs were synthesized using soil derived Pseudomonas putida MVP2. The AgNPs formation on the P. putida cell membrane and its cell free supernatant was studied. The synthesized AgNPs were characterized by UV–visible spectroscopy, scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), energy dispersive X-ray (EDAX) and Fourier transform infrared (FTIR) spectrum analysis. The mode of action of AgNPs on the bacteria was studied against clinically isolated bacterial pathogens, Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa and Helicobacter pylori by membrane integrity, and protein leakage using confocal and electron microscopy. Interestingly, AgNPs had no cytotoxicity under 25 μg/mL and it was toxic at above 50 μg/mL on human epidermoid larynx carcinoma (HEp-2) cells. This study evidenced that biogenic nanoparticles could affect the bacterial replication, protein leakage and eventually cell death. This might be used for active antimicrobial agents for the chronic infections

Biogenic synthesis, characterization of antibacterial silver nanoparticles and its cell cytotoxicity

The advanced research and development of silver nanoparticles (AgNPs) is vast due to their incredible applications today. In this work, AgNPs were synthesized using soil derived Pseudomonas putida MVP2. The AgNPs formation on the P. putida cell membrane and its cell free supernatant was studied. The synthesized AgNPs were characterized by UV–visible spectroscopy, scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), energy dispersive X-ray (EDAX) and Fourier transform infrared (FTIR) spectrum analysis. The mode of action of AgNPs on the bacteria was studied against clinically isolated bacterial pathogens, Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa and Helicobacter pylori by membrane integrity, and protein leakage using confocal and electron microscopy. Interestingly, AgNPs had no cytotoxicity under 25 μg/mL and it was toxic at above 50 μg/mL on human epidermoid larynx carcinoma (HEp-2) cells. This study evidenced that biogenic nanoparticles could affect the bacterial replication, protein leakage and eventually cell death. This might be used for active antimicrobial agents for the chronic infections.Published versio