Synthesis of 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) capped silver nanoparticles using 3,6-di(pyridin-2-yl)-1,4-dihydro-1,2,4,5-tetrazine as reducing agent: Application in naked eye sensing of Cu2+, Ni2+ and Ag+ ions in aqueous solution and paper platform

2014 ◽  
Vol 202 ◽  
pp. 23-30 ◽  
Author(s):  
Suvendu Samanta ◽  
Sudipto Das ◽  
Papu Biswas
Cellulose ◽  
2021 ◽  
Author(s):  
Nina Čuk ◽  
Martin Šala ◽  
Marija Gorjanc

Abstract The development of cellulose-based textiles that are functionalised with silver nanoparticles (AgNP), synthesised according to a green approach, and offer protection against ultraviolet (UV) radiation and pathogenic bacteria is very important today. In the present work we demonstrate the environmentally friendly approach to obtain such textile material by AgNP synthesis directly (in-situ) on cotton fabrics, using water extracts of plant food waste (green tea leaves, avocado seed and pomegranate peel) and alien invasive plants (Japanese knotweed rhizome, goldenrod flowers and staghorn sumac fruit) as reducing agents. The extracts were analysed for their total content of phenols and flavonoids and their antioxidant activity. The synthesised AgNP on cotton were round, of different size and amount depending on the reducing agent used. The highest amount of AgNP was found for samples where Japanese knotweed rhizome extract was used as reducing agent and the lowest where extracts of goldenrod flowers and green tea leaves were used. Regardless of the reducing agent used to form AgNP, all cotton samples showed excellent protection against E. coli and S. aureus bacteria and against UV radiation with UV protection factor values above 50. The best results for UV protection even after the twelve repetitive washing cycles were found for the sample functionalized with AgNP synthesised with an extract of the Japanese knotweed rhizome. Due to the presence of AgNP on cotton, the air permeability and thermal conductivity decreased. AgNP had no effect on the change in breaking strength or elongation of fabrics. Graphic abstract


2015 ◽  
Vol 51 ◽  
pp. 90-94 ◽  
Author(s):  
Hyun Yong Jo ◽  
Gyeong Jin Park ◽  
Kwon Hee Bok ◽  
Kyung-Min Park ◽  
Pahn-Shick Chang ◽  
...  
Keyword(s):  

2013 ◽  
Vol 873 ◽  
pp. 206-210
Author(s):  
Kai Li ◽  
Rao Fu ◽  
Qing Ran Gao ◽  
Ai Wei Tang ◽  
Ying Feng Wang

This paper continues our previous work on preparation of triangular silver nanoparticles. The method proceeds with reaction of silver nitrate with hydrazine hydrate in the presence of polyvinyl pyrrolidone in aqueous solution. Effects of the concentration of PVP on the morphologies of Ag NPs were systematically investigated. The obtained Ag NPs were characterized by transmission electron microscopy and UV-visible spectrophotometer. The results showed that, triangular Ag NPs with edge lengths in the range of 50-200 nm were obtained using PVP as protective agent with lower concentration. As the concentration of PVP increased, spherical Ag NPs with their sizes about 6.2 nm were prepared and triangular Ag NPs were not obtained. The formation mechanism of triangular Ag NPs has been studied. Ostwald ripening is the driving force on the conversion of spherical Ag NPs to triangular Ag NPs in the presence of PVP.


2014 ◽  
Vol 28 (3) ◽  
pp. 311-317 ◽  
Author(s):  
Agnieszka Nawrocka

Abstract Silver nanoparticles have antimicrobial properties since they can be regarded as an efficient protector against pathogenic microorganisms. Fourier transform infrared spectroscopy was used to examine conformational changes in the secondary structure of wheat gluten washed out from grain treated with an aqueous solution of silver nanoparticles stabilized by tri-sodium citrate. Silver nanoparticles were used as a protective layer on the grain surface against bacterial and fungal infections (antimicrobial agent). Analysis of the amide I band revealed significant changes in the secondary structure after using silver nanoparticles. An increase in the β-sheet content (from 36.2 to 39.2%) was observed at the expense of the α-helix and β-turn content. To find factors causing these changes, the wheat grains were treated by an aqueous solution of trisodium citrate and water. The results obtained indicate that the changes in the gluten structure were connected mainly with the trisodium citrate action due to presence of a small number of free molecules of the stabilizer in the solution of silver nanoparticles. Additionally, the conformational changes in gluten pointed out that gluten flexibility increased (decrease in the αH/βS ratio from 1.40 for the control sample to 1.26 for the silver nanoparticle-treated samples) as well as the solubility of gluten decreased (decrease in the β-turn content from 13.1 to 11.4%).


2017 ◽  
Vol 2 (6) ◽  
pp. 2131-2138 ◽  
Author(s):  
José González-Rivera ◽  
Celia Duce ◽  
Vincenzo Ierardi ◽  
Iginio Longo ◽  
Alessio Spepi ◽  
...  

2020 ◽  
Vol 36 (6) ◽  
pp. 1103-1106
Author(s):  
Darwin F. Reyes ◽  
Gil Fabien S. Cabrera ◽  
Shemma Mica V. Mata ◽  
azmin Pariz D. San Pedro ◽  
add Christian C. Palioc ◽  
...  

The synthesis of silver nanoparticles via plant-mediated approach is an emerging area of research interest worldwide. The procedure is cost-effective and does not require the use of toxic chemicals and complicated reaction conditions. In the present investigation, silver nanoparticles were prepared using the leaf extracts of Ixora coccinea Linn., a common ornamental shrub in the Philippines, as the reducing agent. The effect of pH on the synthesis was investigated, and results showed that the quality of the synthesized silver nanoparticles changes in varying pH of the reducing agent.


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