scholarly journals Photodynamic Antimicrobial Action of Asymmetrical Porphyrins Functionalized Silver-Detonation Nanodiamonds Nanoplatforms for the Suppression of Staphylococcus aureus Planktonic Cells and Biofilms

2021 ◽  
Vol 9 ◽  
Author(s):  
Yolande I. Openda ◽  
Bokolombe P. Ngoy ◽  
Tebello Nyokong

New asymmetrical porphyrin derivatives containing a p-hydroxyphenyl moiety and p-acetylphenyl moieties along with their functionalized silver-detonation nanodiamonds nanohybrids were characterized and their photophysicochemical properties were established. The study provides evidence that the metalated porphyrin derivatives were red-shifted in absorption wavelength and possessed high singlet oxygen quantum yield comparative to the unmetalated core, thus making them suitable agents for photodynamic antimicrobial chemotherapy. As a result of conjugation to detonation nanodiamonds and silver nanoparticles, these compounds proved to be more effective as they exhibited stronger antibacterial and anti-biofilm activities on the multi-drug resistant S. aureus strain due to synergetic effect, compared to Ps alone. This suggests that the newly prepared nanohybrids could be used as a potential antimicrobial agent in the treatment of biofilms caused by S. aureus strain.

2020 ◽  
Vol 19 (10) ◽  
pp. 1442-1454
Author(s):  
Yolande Ikala Openda ◽  
Refilwe Matshitse ◽  
Tebello Nyokong

Photodynamic antimicrobial chemotherapy (PACT) activity of phthalocyanines against planktonic cells and biofilms of S. aureus improved in the presence of detonation nanodiamonds, chitosan and Ag nanoparticles.


Author(s):  
Manashi Garg ◽  
Banasmita Devi ◽  
Rashna Devi

 Objectives: Hydrocotyle sibthorpiodes is known to contain several phytoconstituents which are constantly involved in the formation of Silver nanoparticles that may affect several multi-drug resistant microbes. Therefore, the study was undertaken to evaluate the efficacy of different concentration of nano silver solution on three bacterial isolates. It was also aimed to qualitatively assess the different phytoconstituents responsible for the synthesis. Methods: Three bacterial isolates of Klebsiella pneumonia, Pseudomonas aeroginosa and Staphylococcus aureus were identified. Synthesis of AgNPs with different concentration (2/4/6/8/10μl/ml) was done and applied to the selected isolates. The phytochemical compounds of the ethyl acetate extract were assayed by several colored reactions qualitatively. Results: The size and stability biosynthesis of the metallic silver nanoparticles were confirmed by photophysical characterization as well as SEM (Scanning Electron Microscopy), XRD (XRay Diffraction), Zeta potential and DLS (Dynamic Light Scattering) with an average size of 13.37 ±10 nm. The increasing concentration of the particle solution showed significant inhibition zone for all the three isolates viz., Klebsiella pneumonia, Pseudomonas aeroginosa and Staphylococcus. aureus showing the value of 3.0±0.17, 2.7±0.32 and 3.6±0.57 respectively for 10 μl/ml concentration. Phytochemical screening of the whole plant extract also revealed an array of bioactive compounds which may have an effective role in the reduction process. Conclusion: The study demonstrated a simple, efficient and eco-friendly synthesis of stable silver nanoparticles from the ethyl acetate extract of Hydrocotyle sibthorpiodes having fairly superior antimicrobial activity against human pathogens.


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

2020 ◽  
Vol 21 (24) ◽  
pp. 9746
Author(s):  
Shahina Akter ◽  
Sun-Young Lee ◽  
Muhammad Zubair Siddiqi ◽  
Sri Renukadevi Balusamy ◽  
Md. Ashrafudoulla ◽  
...  

It is essential to develop and discover alternative eco-friendly antibacterial agents due to the emergence of multi-drug-resistant microorganisms. In this study, we isolated and characterized a novel bacterium named Terrabacter humi MAHUQ-38T, utilized for the eco-friendly synthesis of silver nanoparticles (AgNPs) and the synthesized AgNPs were used to control multi-drug-resistant microorganisms. The novel strain was Gram stain positive, strictly aerobic, milky white colored, rod shaped and non-motile. The optimal growth temperature, pH and NaCl concentration were 30 °C, 6.5 and 0%, respectively. Based on 16S rRNA gene sequence, strain MAHUQ-38T belongs to the genus Terrabacter and is most closely related to several Terrabacter type strains (98.2%–98.8%). Terrabacter humi MAHUQ-38T had a genome of 5,156,829 bp long (19 contigs) with 4555 protein-coding genes, 48 tRNA and 5 rRNA genes. The culture supernatant of strain MAHUQ-38T was used for the eco-friendly and facile synthesis of AgNPs. The transmission electron microscopy (TEM) image showed the spherical shape of AgNPs with a size of 6 to 24 nm, and the Fourier transform infrared (FTIR) analysis revealed the functional groups responsible for the synthesis of AgNPs. The synthesized AgNPs exhibited strong anti-bacterial activity against multi-drug-resistant pathogens, Escherichia coli and Pseudomonas aeruginosa. Minimal inhibitory/bactericidal concentrations against E. coli and P. aeruginosa were 6.25/50 and 12.5/50 μg/mL, respectively. The AgNPs altered the cell morphology and damaged the cell membrane of pathogens. This study encourages the use of Terrabacter humi for the ecofriendly synthesis of AgNPs to control multi-drug-resistant microorganisms.


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