scholarly journals Synthesis, characterization and antibacterial activity of silver nanoparticles using Rhazya stricta

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e6086 ◽  
Author(s):  
Adeeb Shehzad ◽  
Munibah Qureshi ◽  
Saima Jabeen ◽  
Rizwan Ahmad ◽  
Amira H. Alabdalall ◽  
...  

Background Green synthesis of metallic nanoparticles has gained significant attention in the field of nanomedicine as an environment-friendly and cost-effective alternative in comparison with other physical and chemical methods. Several metals such as silver, gold, iron, titanium, zinc, magnesium and copper have been subjected to nanoformulation for a wide range of useful applications. Silver nanoparticles (AgNPs) are playing a major role in the field of nanomedicine and nanotechnology. They are widely used in diagnostics, therapeutic and pharmaceutical industries. Studies have shown potential inhibitory antimicrobial, anti-inflammatory and antiangiogenesis activities of AgNPs. Methods AgNPs have been synthesized using silver nitrate and methanolic root extract of Rhazya stricta that belongs to the Apocynaceae family. Stability and dispersion of nanoparticles were improved by adding xylitol. Synthesized nanoparticles were characterized by UV–Vis spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometer and Fourier transforms infrared spectroscopy. Furthermore, the antibacterial effect of the plant extract and the nanoparticles were evaluated against gram-positive (Bacillus subtilis) and gram-negative (Escherichia coli) bacteria. Results The average size of AgNPs synthesized, was 20 nm with the spherical shape. Rhazya stricta based nanoparticles exhibited improved antibacterial activity against both gram-positive and negative strains.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mona A. Alqahtani ◽  
Monerah R. Al Othman ◽  
Afrah E. Mohammed

Abstract Recently, increase bacterial resistance to antimicrobial compounds issue constitutes a real threat to human health. One of the useful materials for bacterial control is Silver nanoparticles (AgNPs). Researchers tend to use biogenic agents to synthesize stable and safe AgNPs. The principal aim of this study was to investigate the ability of lichen in AgNPs formation and to find out their suppression ability to MDR bacteria as well as their cytotoxic activity. In the current study, lichens (Xanthoria parietina, Flavopunctelia flaventior) were collected from the south of the Kingdom of Saudi Arabia. Lichens methanolic extracts were used for conversion of Ag ions to AgNPs. Prepared biogenic AgNPs were characterized by Ultraviolet–Visible (UV–Vis) Spectroscopy, Transmission electron microscopy (TEM), Dynamic Light Scattering (DLS) and Zeta potential and Energy-Dispersive X-ray Spectroscopy (EDS). Lichens Secondary metabolites were determined by Fourier-Transform Infrared Spectroscopy (FTIR) and Gas Chromatography–Mass Spectrometry (GC–MS). The antibacterial activity and synergistic effect of AgNPs were evaluated against pathogenic bacteria, including gram-positive; Methicillin-resistant Staphylococcus aureus (MRSA), Vancomycin-resistant Enterococcus (VRE), and gram-negative; (Pseudomonas aeruginosa, Escherichia coli) as well as the reference strains (ATCC) using the agar disk diffusion method. Cytotoxic effect of biogenic AgNPs was tested against HCT 116 (Human Colorectal Cancer cell), MDA-MB-231 (Breast cancer cell), and FaDu (Pharynx cancer cell) by MTT test. TEM imaging showed well-dispersed spherical particles of 1–40 nm size as well as zeta size showed 69–145 nm. Furthermore, FTIR and GC–MS identified various lichen chemical molecules. On the other hand, the highest antibacterial activity of AgNPs was noticed against P. aeruginosa, followed by MRSA, VRE, and E. coli. AgNPs influence on gram-negative bacteria was greater than that on gram-positive bacteria and their synergistic effect with some antibiotics was noted against examined microbes. Moreover, higher cytotoxicity for biogenic AgNPs against FaDu and HCT 116 cell line in relation to MDA-MB-231 was noted. Given the current findings, the biogenic AgNPs mediated by lichens had positive antibacterial, synergistic and cytotoxic powers. Therefore, they might be considered as a promising candidate to combat the multi-drug resistance organisms and some cancer cells.


2021 ◽  
Vol 22 (4) ◽  
pp. 1905
Author(s):  
Jimmy Gouyau ◽  
Raphaël E. Duval ◽  
Ariane Boudier ◽  
Emmanuel Lamouroux

Multidrug-resistant (MDR) bacteria constitute a global health issue. Over the past ten years, interest in nanoparticles, particularly metallic ones, has grown as potential antibacterial candidates. However, as there is no consensus about the procedure to characterize the metallic nanoparticles (MNPs; i.e., metallic aggregates) and evaluate their antibacterial activity, it is impossible to conclude about their real effectiveness as a new antibacterial agent. To give part of the answer to this question, 12 nm gold and silver nanoparticles have been prepared by a chemical approach. After their characterization by transmission electronic microscopy (TEM), Dynamic Light Scattering (DLS), and UltraViolet-visible (UV-vis) spectroscopy, their surface accessibility was tested through the catalytic reduction of the 4-nitrophenol, and their stability in bacterial culture medium was studied. Finally, the antibacterial activities of 12 nm gold and silver nanoparticles facing Staphylococcus aureus and Escherichia coli have been evaluated using the broth microdilution method. The results show that gold nanoparticles have a weak antibacterial activity (i.e., slight inhibition of bacterial growth) against the two bacteria tested. In contrast, silver nanoparticles have no activity on S. aureus but demonstrate a high antibacterial activity against Escherichia coli, with a minimum inhibitory concentration of 128 µmol/L. This high antibacterial activity is also maintained against two MDR-E. coli strains.


2019 ◽  
Vol 3 (1) ◽  
pp. 75-82
Author(s):  
Samaresh Ghosh ◽  
Mridula Acharyya ◽  
Santi M. Mandal

Background:Hybrids, composed of silver nanoparticles (AgNPs) dispersed inside a polymer matrix thus combining properties of both the components offer antibacterial activity and several advantages. Nevertheless, the development of antibacterial hybrid material comprising both novolac type phenolic resin and AgNPs remains one of the untouched issues in human healthcare.Objective:We report herein the simple preparation of hybrid derived from functionalized novolac resin and AgNPs. The hybrid was tested for antibacterial activity towards Gram-positive and Gramnegative bacteria.Method and Results:Preparation and characterization of functionalized novolac resin and hybrid were achieved. Gram-positive bacteria (Staphylococcus aureus MTCC 3160, Staphylococcus epidermidis NCIM2493, Bacillus subtilis) and Gram-negative bacteria (Pseudomonas aeruginosa ATCC27853, Escherichia coli) were used to test the bactericidal efficiency of hybrid. The antibacterial effectiveness of hybrid was determined in terms of the minimum inhibitory concentration (MIC). In addition, treatment with hybrid caused cytoplasmic contents leakage evidencing membrane damage.Conclusion:The hybrid developed thus could provide opportunities to fabricate a wide range of antibacterial functional materials for different purposes in human health associated sectors.


Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3377
Author(s):  
Karen Khachatryan ◽  
Lusine Khachatryan ◽  
Marcel Krzan ◽  
Magdalena Krystyjan ◽  
Lidia Krzemińska-Fiedorowicz ◽  
...  

Natural polysaccharides, including hyaluronic acid, find a wide range of applications in biomedical sciences. There is a growing interest in nanocomposites containing hyaluronic acid and nanoparticles such as nanometals or graphene. In this study, we prepared foils of pure sodium hyaluronate and sodium hyaluronate containing nanosilver, graphene oxide, nanosilver/graphene oxide and characterized their properties. UV-vis spectroscopy and scanning electron microscopy (SEM) confirmed the formation of 10–20 nm silver nanoparticles. The structural changes were investigated using Fourier transforms infrared (FTIR) spectra and size exclusion chromatography. The obtained results suggest changes in molecular weights in the samples containing nanoparticles, which was highest in a sample containing nanosilver/graphene oxide. We also assessed the mechanical properties of the foils (thickness, tensile strength and elongation at break) and their wettability. The foils containing nanosilver and nanosilver/graphene oxide presented bacteriostatic activity against E. coli, Staphylococcus spp. and Bacillus spp., which was not observed in the control and sample containing graphene oxide. The composites containing graphene oxide and nanosilver/graphene oxide exhibited a cytotoxic effect on human melanoma WM266-4 cell lines (ATCC, Manassas, VA, USA).


2019 ◽  
Vol 3 (2) ◽  
pp. 61 ◽  
Author(s):  
Van Thang Nguyen ◽  
Viet Tien Vu ◽  
The Huu Nguyen ◽  
Tuan Anh Nguyen ◽  
Van Khanh Tran ◽  
...  

This work emphasizes the use of the silver decorative method to enhance the antibacterial activity of TiO2 and ZnO nanoparticles. These silver-decorated nanoparticles (hybrid nanoparticles) were synthesized using sodium borohydride as a reducing agent, with the weight ratio of Ag precursors/oxide nanoparticles = 1:30. The morphology and optical properties of these hybrid nanoparticles were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns, and UV-Vis spectroscopy. The agar-well diffusion method was used to evaluate their antibacterial activity against both Staphylococcus aureus and Escherichia coli bacteria, with or without light irradiation. The TEM images indicated clearly that silver nanoparticles (AgNPs, 5–10 nm) were well deposited on the surface of nano-TiO2 particles (30–60 nm). In addition to this, bigger AgNPs (<20 nm) were dispersed on the surface of nano-ZnO particles (30–50 nm). XRD patterns confirmed the presence of AgNPs in both Ag-decorated TiO2 and Ag-decorated ZnO nanoparticles. UV-Vis spectra confirmed that the hybridization of Ag and oxide nanoparticles led to a shift in the absorption edge of oxide nanoparticles to the lower energy region (visible region). The antibacterial tests indicated that both oxide pure nanoparticles did not exhibit inhibitory effects against bacteria, with or without light irradiation. However, the presence of AgNPs in their hybrids, even at low content (<40 mg/mL), leads to a good antibacterial activity, and higher inhibition zones under light irradiation as compared to those in dark were observed.


2013 ◽  
Vol 57 (10) ◽  
pp. 4945-4955 ◽  
Author(s):  
Divya Prakash Gnanadhas ◽  
Midhun Ben Thomas ◽  
Rony Thomas ◽  
Ashok M. Raichur ◽  
Dipshikha Chakravortty

ABSTRACTThe emergence of multidrug-resistant bacteria is a global threat for human society. There exist recorded data that silver was used as an antimicrobial agent by the ancient Greeks and Romans during the 8th century. Silver nanoparticles (AgNPs) are of potential interest because of their effective antibacterial and antiviral activities, with minimal cytotoxic effects on the cells. However, very few reports have shown the usage of AgNPs for antibacterial therapyin vivo. In this study, we deciphered the importance of the chosen methods for synthesis and capping of AgNPs for their improved activityin vivo. The interaction of AgNPs with serum albumin has a significant effect on their antibacterial activity. It was observed that uncapped AgNPs exhibited no antibacterial activity in the presence of serum proteins, due to the interaction with bovine serum albumin (BSA), which was confirmed by UV-Vis spectroscopy. However, capped AgNPs [with citrate or poly(vinylpyrrolidone)] exhibited antibacterial properties due to minimized interactions with serum proteins. The damage in the bacterial membrane was assessed by flow cytometry, which also showed that only capped AgNPs exhibited antibacterial properties, even in the presence of BSA. In order to understand thein vivorelevance of the antibacterial activities of different AgNPs, a murine salmonellosis model was used. It was conclusively proved that AgNPs capped with citrate or PVP exhibited significant antibacterial activitiesin vivoagainstSalmonellainfection compared to uncapped AgNPs. These results clearly demonstrate the importance of capping agents and the synthesis method for AgNPs in their use as antimicrobial agents for therapeutic purposes.


2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Faisal GG ◽  
Zakaria SM ◽  
Najmuldeen GF

Introduction: Currently, researchers are aiming to explore herbal plants to replace synthetic drugs because herbal plants contain high active compounds and fewer side effects. Our study was done to determine the antibacterial activity of Eurycoma longifolia Jack (E. longifolia) root using ethanol based extract. Methods: Five types of pathogenic bacterial strains were used; Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative (Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa). Disc diffusion assay and Minimum Inhibitory Concentration (MIC) tests were used to determine the inhibition zone and turbidity of suspension which reflects the antibacterial activity of the extract. Results: The ethanolic extract of E. longifolia Jack root extract showed positive results against Gram-positive bacteria (S. aureus and B. cereus) and Gramnegative (S. typhi). B.cereus and S.typhi showed inhibition zone values of 11.76mm and 14.33mm at the extract concentration of 150mg/ml that were higher than the positive control values (9.00, 12.67mm) respectively. However, E. coli and P. aeruginosa did not show any inhibition by the ethanol-based extract. Conclusion: From the results we can conclude that E.Longifolia root extract possesses antibacterial activity that can be further explored to produce new medicinal products.


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