Sub-lethal photodynamic inactivation renders Staphylococcus aureus susceptible to silver nanoparticles

2013 ◽  
Vol 12 (9) ◽  
pp. 1622 ◽  
Author(s):  
Joanna Nakonieczna ◽  
Aleksandra Rapacka-Zdonczyk ◽  
Anna Kawiak ◽  
Krzysztof P. Bielawski ◽  
Mariusz Grinholc
2019 ◽  
Vol 22 (10) ◽  
pp. 184-190
Author(s):  
Rasha Hadi Saleh ◽  
Entisar J. Al-Mukhtar ◽  
Zaytoon A. Al-Khafaji ◽  
Mohammed H. Al Hasnawy ◽  
Huda H. Al-Hasnawy

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1343
Author(s):  
Caroline Tyavambiza ◽  
Abdulrahman Mohammed Elbagory ◽  
Abram Madimabe Madiehe ◽  
Mervin Meyer ◽  
Samantha Meyer

Cotyledon orbiculata, commonly known as pig’s ear, is an important medicinal plant of South Africa. It is used in traditional medicine to treat many ailments, including skin eruptions, abscesses, inflammation, boils and acne. Many plants have been used to synthesize metallic nanoparticles, particularly silver nanoparticles (AgNPs). However, the synthesis of AgNPs from C. orbiculata has never been reported before. The aim of this study was to synthesize AgNPs using C. orbiculata and evaluate their antimicrobial and immunomodulatory properties. AgNPs were synthesized and characterized using Ultraviolet-Visible Spectroscopy (UV-Vis), Dynamic Light Scattering (DLS) and High-Resolution Transmission Electron Microscopy (HR-TEM). The antimicrobial activities of the nanoparticles against skin pathogens (Staphylococcus aureus, Staphylococcus epidermidis, Methicillin Resistance Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans) as well as their effects on cytokine production in macrophages (differentiated from THP-1 cells) were evaluated. The AgNPs from C. orbiculata exhibited antimicrobial activity, with the highest activity observed against P. aeruginosa (5 µg/mL). The AgNPs also showed anti-inflammatory activity by inhibiting the secretion of pro-inflammatory cytokines (TNF-alpha, IL-6 and IL-1 beta) in lipopolysaccharide-treated macrophages. This concludes that the AgNPs produced from C. orbiculata possess antimicrobial and anti-inflammation properties.


2020 ◽  
Vol 11 (4) ◽  
pp. 5382-5387
Author(s):  
Irshad Ul Haq Bhat ◽  
Maisarah Binti Alias

The approach towards green synthetic methods has been enormously encouraged to synthesise nanoparticles for various uses. In this study, the one-pot synthetic method was adapted to synthesise silver nanoparticles (AgNPs) using Melastoma malabathricum (M. malabathricum) aqueous extract. The formation of AgNPs was confirmed by observing the results obtained by optical characterisation methods. The plasma resonance band along with shoulder at 375 nm and 595 nm, respectively, in Uv-Visible spectra supported the conversion of silver (Ag) to AgNPs reduced by functional groups present in the plant extract. The size of AgNPs was 31 nm and cubic in shape as confirmed by X-ray diffractometry (XRD) using Scherer equation. X-Ray Fluorescence (XRF) results also confirmed the presence of silver. The FTIR characterisation confirmed the presence of reducing functional groups. The antibacterial activity of AgNPs against Staphylococcus aureus (S. aureus) was carried out by disc diffusion method with increasing concentration of AgNPs, and enhanced inhibition zone was observed. The AgNPs obtained can be further explored against different bacterial strains and can a potential candidate as an antibacterial agent using the green synthetic approach.


2020 ◽  
Vol 26 (6) ◽  
pp. 200454-0
Author(s):  
Sabaoon Shamshad ◽  
Jamshaid Rashid ◽  
Ihsan-ul-haq ◽  
Naseem Iqbal ◽  
Saif Ullah Awan

Multidrug resistance of bacteria is an emerging human health hazard and warrants development of novel antibacterial agents with more effective mode of action. Here, zinc oxide and silver nanomaterials were prepared using Ficus palmata Forssk leaf extract with efficient antibacterial activity. SEM coupled with EDS confirmed the spherical symmetry with average particle diameter 50 to 65 nm while the XRD confirmed crystalline face centered cubic structure of silver and hexagonal crystallize phase of zinc oxide nanoparticles. Antibacterial activity was evaluated for 8 pathogenic bacterial strains including 3 drug resistant pathogenic strains. The nanoparticles showed enhanced growth inhibition for resistant strains in comparison with the broad-spectrum antibiotics i.e. roxithromycin and cefixime. Minimum inhibitory concentration in μg.mL<sup>-1</sup> of silver nanoparticles was found to be as low as 33.3 for resistant Streptococcus haemolyticus; 11.1 for Staphylococcus aureus and E Coli; and 3.7 μg.mL<sup>-1</sup> for resistant Pseudomonas aeruginosa. Similarly, the minimum inhibitory concentration of zinc oxide nanoparticles was found to be 100 μg.mL<sup>-1</sup> against resistant Streptococcus haemolyticus and Staphylococcus aureus; 11.1 μg.mL<sup>-1</sup> for resistant Pseudomonas aeruginosa; and 3.7 μg.mL<sup>-1</sup> against resistant E coli. Ficus palmata Forssk leaf extracts can be explored effectively for synthesizing active antibacterial nanomaterials as a non-toxic and environmentally benign synthesis route.


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