One-step Green Preparation of Nano-silver Aqueous Solution, Characterization, and Its Antibacterial Potential for Cut Carnation Flowers

Abstract

The green synthesis of nano-silver (NS) has gained increasing attention owing to its cost-effectiveness and environmental friendliness. Herein, we have described a novel one-step green preparation method of stable NS aqueous solution using Tollens reagent as the silver ion source, D-fructose as the reduction agent, and polyvinyl pyrrolidone (PVP) as the stabilizing and capping agent. The optimum preparation parameters were 40 mL 10 g L−1 PVP, 100 mL 0.116 mol L−1 D-fructose, and 200 mL 0.001 mol L−1 Tollens at a reaction temperature of 25 °C for 2 h. The prepared NS solution had a pH value of 7.10, with approximately spherical NS particles in the range of 13.95–87.36 nm. The resulting NS solution was stable under normal temperature, boiling water bath, and acidic environment; however, it did not exhibit stability under an alkaline environment. The NS solution had a remarkable absorption peak at 410 nm in its ultraviolet visible spectrum. Moreover, it exerted strong inhibitory effect on the growth of the bacteria isolated from the vase water of cut carnation ‘Prince’ flowers. These findings indicate that the obtained NS aqueous solution is potentially a practical and effective antibacterial agent for preserving cut carnations and other cut flowers.