Thermal annealing and laser-induced mechanisms in controlling the size and size-distribution of silver nanoparticles in Ag+-Na+ ion-exchanged silicate glasses

2021 ◽  
Vol 563 ◽  
pp. 120815
Author(s):  
Atowar Rahman ◽  
G. Mariotto ◽  
E. Cattaruzza ◽  
E. Trave ◽  
F. Gonella ◽  
...  
2018 ◽  
Vol 18 (11) ◽  
pp. 7739-7748 ◽  
Author(s):  
Bidyut Barman ◽  
Hrishikesh Dhasmana ◽  
Abhishek Verma ◽  
Amit Kumar ◽  
D. N Singh ◽  
...  

2019 ◽  
Vol 13 (3) ◽  
pp. 223-231
Author(s):  
Zahra Goli ◽  
Cobra Izanloo

Background: Silver nanoparticles have a profound role in the field of high sensitivity biomolecular detection, catalysis, biosensors and medicine. In the present study, aqueous extract of Dracocephalum kotschyi has been used for the synthesis of silver nanoparticles. Objective: In this study, we evaluated the antioxidant features and the possibility of biosynthesis of AgNPs using an aqueous extract of Dracocephalum kotschyi and also evaluated the antibacterial activities of the synthesized nanoparticles. Methods: An eco-friendly and cost-effective protocol for the synthesis of Ag nanoparticles by utilizing a renewable natural resource, aqueous solution of Dracocephalum kotschyi, was proposed. Synthesized nanoparticles were characterized by UV–Vis spectroscopy, SEM, EDS, and XRD pattern. Results: At first, the extract of Dracocephalum kotschyi was assessed to determine and confirm the presence of an antioxidant feature. Resuscitation of one mM silver nitrate solution was carried out by the herbal extract. The solution containing AgNPs obtained from green synthesis had a maximum optical density at 225 nm. In addition, the presence of AgNPs was approved by energy-dispersive X-ray spectroscopy (EDS). Images of the scanning electron microscope demonstrated that the synthesized AgNPs had the shape of rods and the size distribution of 48-51 nm. One of the benefits of this method is a uniform size distribution. Moreover, the effects of reaction time and concentration of the herbal extract were assessed by ultraviolet-visible (UV-Vis) spectroscopy. In the end, we assessed the antibacterial impact of the synthesized AgNPs against some pathogenic bacterial strains. According to the results, the produced nanostructures had a proper impact on two bacteria of Escherichia coli and Staphylococcus aureus. Conclusion: According to the results of the present study, Dracocephalum kotschyi can be a suitable compound for the synthesis of nanostructures due to its indigenous cultivation and great medicinal properties.


2018 ◽  
Vol 71 (8) ◽  
pp. 587 ◽  
Author(s):  
Na Zhang ◽  
Jianping Duan ◽  
Dajiang Zhao ◽  
Guisheng Yang

Without using protecting agent and solvent, silver nanoparticles (Ag NPs) were synthesised by using lactams as reducing agents. Being the most commercially available lactam, ϵ-caprolactam (CL) was taken as a model to illustrate the evolution of Ag NPs in the medium of lactams. The results showed that there were two different stages involved in the Ag NP evolution process. In the first stage, particles were stabilised against further coalescence at a smaller size (< 5 nm) because of face-bound CL. In the second stage, the Ostwald ripening mechanism cooperated with continuous reduction of residual silver ions, which resulted in the resultant particles being distributed with different size distribution. The participation of CL in the reducing and protecting procedures raised a complex evolution of Ag NPs.


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