WSEAS Transactions on Biology and Biomedicine
Print ISSN: 1109-9518, E-ISSN: 2224-2902
Volume 14, 2017
Green Synthesis, Long-Term Stability and Toxicity of Colloidal Ag Nanoparticles
Authors: ,
Abstract: The influence of algae life cycle and the solutions pH on the green synthesis of colloidal Ag nanoparticles (AgNPs) as well as effect of different storage conditions on AgNPs long-term stability, and toxicity was investigated. The extracts of Parachlorella kessleri algae were used for synthesis of silver nanoparticles. The results confirmed formation of polyhedron and/or near polyhedron AgNPs, (~5-60 nm in diameter). The synthesis rate, size, stability and an amount of AgNPs in solution can be influenced by the age of algae, and depend on the pH of solution. The best results were obtained using extract of tree weeks old algae. AgNPs formed in solutions of higher pH (8 and 10) are fine, with narrow size interval and stabile. Nanoparticles formed in solutions of low pH (2, 4 and 6) started to lose their stability on 10th day of experiment, and the particle size interval was wide. The long-term stability of AgNPs can be influenced by light and temperature conditions. The most significant stability loss was observed at day light and room temperature (21°C). After 200-days significant amount of agglomerated particles settled on the bottom of the Erlenmeyer flask. AgNPs stored at dark and room temperature showed better long-term stability, weak particles agglomeration was observed. AgNPs stored at dark and at temperature 5°C showed the best long-term stability. Such AgNPs remained spherical, fine (5-20 nm), with narrow size interval and stable (no agglomeration) even after more than six months. The AgNPs had strong toxic action against algae and microorganisms found in indoor air, the storage time did not influence the antibacterial effect of AgNPs.
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Pages: 112-119
WSEAS Transactions on Biology and Biomedicine, ISSN / E-ISSN: 1109-9518 / 2224-2902, Volume 14, 2017, Art. #16