Methods for detection of silver nanoparticles

A method for detection of presence and/or quantities of silver nanoparticles in a specimen when the silver nanoparticles have a size ranging from 4.5 to 9 nm or with an average size of 7 nm in diameter and the silver nanoparticles have a concentration of 8.9 to 75 μg/L, comprising:

• providing a detection organism suspended in a medium and yielding a detection organism-suspended medium, wherein the detection organism auto-fluoresces in the presence of zinc ions and de-fluoresces in the presence of silver ions, wherein the detection organism is an adenine deficient Saccharomyces cerevisiae, and wherein the biomass of the adenine deficient yeast indicative of the concentration thereof in the detection organism-suspended medium ranges from OD600=0.005 to OD600=0.02,
• treating the detection organism with zinc ions thus effecting auto-fluorescence therefrom, and then measuring a degree of fluorescence of the detection organism-suspended medium,
• adding the specimen to the detection organism-suspended medium, treating the detection organism therein with the specimen for a period of time, and measuring a change of fluorescence of the detection organism-suspended medium over time,
• calculating a concentration of silver ions intracellularly dissolved from the silver nanoparticles and accumulated in the detection organism in view of the change of fluorescence, and
• extrapolating the concentration of silver nanoparticles in the specimen in view of the change of fluorescence and the concentration of the intracellularly dissolved silver ions.