Synthesis and coating of nanosilver by vanillic acid and its effects on Dunaliella salina Teod.

Plant phenolics have high reducing capacity which can be exploited in the synthesis of nanomaterials. In the present study, phytoreductant vanillic acid is used to produce and coat silver nanoparticles. The effects of Ag nanoparticles on the unicellular green algae D. Salina were then investigated. Under optimum  pH and temperature, silver ions were reduced to silver metal by vanillic acid. The absorption spectra of the silver nanoparticles showed a maximum band of 410 nm, which is characteristic of the surface plasmon resonance of silver nanoparticles. Dynamic light scattering (DLS) showed a narrow distribution size with an average of 52 nm. High concentrations of Ag nanoparticles reduced growth, total carotenoids, chlorophyll content, phenolics and antioxidant activity of the algae. Based on these results, phytoreductant vanillic acid can be used for synthesis and coating of nanosilver. Due to the projected increase in quantities and types of nanomaterials which leads to their elevated release into the environment and also because of the toxicity of nanomaterials, an urgent need to evaluate the impacts of nano-sized particles on the environment and living organisms is felt.