Preparation of a Nanosilver Composite Plant Medium with Antimicrobial Capability through a Nontoxic Method

A nanosilver composite plant medium with a good antimicrobial capability was successfully prepared via a two-step method in this work. First, nanosilver particles were prepared in a silver nitrate (AgNO3) solution by using D-glucose as a reduction reagent at room temperature. The effect of AgNO3 concentration levels on the size of the nanosilver particles was investigated. The sedimentation activation energy of the nanosilver particles was also measured. Second, the solvent containing the nanosilver particles was added to a Murashige-Skoog medium (a plant growth medium used in the laboratory for the cultivation of plant cell cultures, which was invented by Toshio Murashige and Folke K. Skoog) to form a composite plant medium. The antimicrobial capability of the composite medium was investigated by cultivating in it some fresh strawberry slices. The results showed that the concentration level of AgNO3 significantly influenced the average size of the prepared nanosilver particles. When the AgNO3 concentration was increased from 1.0×10−3 mol/L to 4.0×10−3 mol/L, the average diameter of the nanosilver particles increased from 52 nm to 72 nm, and the sedimentation activation energy of the particles increased from -20.0 kJ/mol to -63.3 kJ/mol. Images from the transmission electron microscope showed that the size distribution of the particles was within narrow parameters. The results of sedimentation activation energy strongly supported the size results obtained from the TEM measurement. It meant that the preparation method could offer good control over the size and size distribution of the nanosilver particles. The cultivation experiments proved that the composite medium has a good antimicrobial capability. Since D-glucose is a nontoxic material, this method of preparing the composite MS medium with an antimicrobial capability was a ‘green’ method