scholarly journals Synthesis of gold and silver nanoparticles using Malva verticillata leaves extract: Study of gold nanoparticles catalysed reduction of nitro-Schiff bases and antibacterial activities of silver nanoparticles

2020 ◽  
Vol 3 ◽  
pp. 100006 ◽  
Author(s):  
Ismail Sk ◽  
Mehebub Ali Khan ◽  
Anamika Haque ◽  
Soumen Ghosh ◽  
Dola Roy ◽  
...  
2021 ◽  
Vol 9 (6) ◽  
pp. 678
Author(s):  
Kaliyamoorthy Kalidasan ◽  
Nabikhan Asmathunisha ◽  
Venugopal Gomathi ◽  
Laurent Dufossé ◽  
Kandasamy Kathiresan

This work deals with the identification of a predominant thraustochytrid strain, the optimization of culture conditions, the synthesis of nanoparticles, and the evaluation of antioxidant and antimicrobial activities in biomass extracts and nanoparticles. Thraustochytrium kinnei was identified as a predominant strain from decomposing mangrove leaves, and its culture conditions were optimized for maximum biomass production of 13.53 g·L−1, with total lipids of 41.33% and DHA of 39.16% of total fatty acids. Furthermore, the strain was shown to synthesize gold and silver nanoparticles in the size ranges of 10–85 nm and 5–90 nm, respectively. Silver nanoparticles exhibited higher total antioxidant and DPPH activities than gold nanoparticles and methanol extract of the strain. The silver nanoparticles showed higher antimicrobial activity than gold nanoparticles and petroleum ether extract of the strain. Thus, Thraustochytrium kinnei is proven to be promising for synthesis of silver nanoparticles with high antioxidant and antimicrobial activity.


2020 ◽  
Vol 4 (2) ◽  

Metal nanoparticles possess an extensive scientific and technological significance due to their unique physiochemical properties and their potential applications in different fields like medicine. Silver and gold nanoparticles have shown to have antibacterial and cytotoxic activities. Conventional methods used in the synthesis of the metal nanoparticles involve use of toxic chemicals making them unsuitable for use in medical field. In our continued effort to explore for simple and eco-friendly methods to synthesize the metal nanoparticles, we here describe synthesis and characterization of gold and silver nanoparticles using Gonaderma lucidum, wild non-edible medicinal mushroom. G. lucidum mushroom contain bioactive compounds which can be involved in the reduction, capping and stabilization of the nanoparticles. Antibacterial activity analysis was done on E. coli and S. aureus. The synthesis was done on ultrasonic bath. Characterization of the metal nanoparticles was done by UV-VIS., High Resolution Transmission Electron Microscope (HRTEM) and FTIR. HRTEM analysis showed that both silver and gold nanoparticles were spherical in shape with an average size of 15.82±3.69 nm for silver and 24.73±5.124nm for gold nanoparticles (AuNPs). FTIR analysis showed OH and -C=C- stretching vibrations, an indication of presence of functional groups of biomolecules capping both gold and silver nanoparticles. AgNPs showed inhibition zones of 15.5±0.09mm and 13.3±0.14mm while AuNPs had inhibition zones of 14.510±0.35 and 13.3±0.50mm on E. coli and S. aureus respectively. The findings indicate the potential use of AgNPs and AuNPs in development of drugs in management of pathogenic bacteria.


2020 ◽  
Vol 42 (3) ◽  
pp. 440-440
Author(s):  
Xin Bin Yang Xin Bin Yang ◽  
Chun Mei Wang Chun Mei Wang ◽  
Yu Huang Yu Huang

Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) were synthesized by using water-soluble Kaempferol–3′–sulfonate acid sodium (KS) alone as the reducing agent. The UV-vis spectra confirmed the formation of the ks-AuNPs and ks-AgNPs which were stable for up to 3 months without any other stabilizing agents at room temperature. The TEM studies exhibited monodispersed and mainly spherical nanoparticles with the size in the range of 15-30 nm and 20-50 nm for ks-AuNPs and ks-AgNPs, respectively. The XRD revealed crystallinity of nanoparticles. The chemical state of Au and Ag on the surface of nanoparticles was analyzed by XPS. The FTIR analysis indicated that the hydroxyl of KS were responsible for the reduction of Au3+ and Ag+ to ks-AuNPs and ks-AgNPs, respectively. Cytotoxic activity of ks-AuNPs and ks-AgNPs on MCF-7 cells is higher than the KS.


2014 ◽  
Vol 38 (11) ◽  
pp. 5633-5640 ◽  
Author(s):  
Muhammad Raza Shah ◽  
Shujat Ali ◽  
Muhammad Ateeq ◽  
Samina Perveen ◽  
Shakil Ahmed ◽  
...  

Monitoring the antibacterial action of gold and silver nanoparticlesviaAFM.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Tatiana B. V. Neves ◽  
Gustavo F. S. Andrade

The Raman spectrum of the indocyanine-type dye IR-820 has been assigned for both solid and solution. SERS spectra of IR-820 on both silver and gold nanoparticles suspensions excited at 1064 nm were obtained. AgNPs allowed the detection of the dye through SERS down to 0.1 micromoles per liter; for the AuNPs the lowest concentration of the dye detectable was 10 micromoles per liter. Changes in the SERS relative intensities compared to the Raman spectrum in solution are subtle, mostly due to the preresonance effect of the dye. However, a perpendicular orientation relative to the metallic surface was inferred for the dye on both AgNPs and AuNPs. The easily distinguishable SERS spectra of the dye excited at 1064 nm, together with the high biological compatibility of cyanine dyes, are both indicative that IR-820 could be used as a high-performance probe molecule for SERS.


2015 ◽  
Vol 2 (5) ◽  
pp. 518-527 ◽  
Author(s):  
Victor M. Kariuki ◽  
Idris Yazgan ◽  
Ali Akgul ◽  
Andrzej Kowal ◽  
Magdalena Parlinska ◽  
...  

We hereby report a rapid and simple synthesis of silver (AgNPs) and gold nanoparticles (AuNPs) using conductive, electroactive and biodegradable poly(amic)acid (PAA) polymer as both the reductant and stabilizer.


2020 ◽  
pp. 2150009
Author(s):  
Shadeeb Hossain

This paper highlights on the coronavirus outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At the time of writing this paper, there has been over 6 million confirmed cases worldwide. It is a person–person transmittable infection but there have been cases of asymptomatic carriers. Hence, development of an effective biosensing diagnostic tool can curb its rapid transmission rate. The first part of the paper highlights on the SARS-CoV-2 structure and its resemblance to SARS-CoV. The second part of the paper analyzes on the potential application of gold and silver nanoparticles to generate a red shift that had enhanced the calorimetric property of the MERS-CoV analysis due to transition in its optical property. Other electrochemical techniques that utilized the application of gold nanoparticles are also reviewed. Gold and silver nanoparticles (AuNP and Ag NP) can accelerate the sensitivity upon electrodeposition on the diagnostic tool.


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