’Just Add Water’ – ‘Instant’ singly-dispersed suspensions of silver nanoparticles on demand.

摘要

The intrinsic instability of silver nanoparticles (AgNPs) is a substantial challenge to achieving stable long-term storage for on-demand use of AgNPs. Here, a "Just Add Water" approach is presented for achieving suspensions of principally singly dispersed AgNPs. By lyophilizing (freeze-drying) the formulated AgNPs into a solid powder, or cake, water is removed thereby eliminating solutionbased chemical changes such as oxidative dissolution. Storing under inert gas should further reduce surface reactions. An example of an optimized lyophilization formulation is presented for 75 nm AgNPs. This "Just Add Water" approach enables ease of use for the researcher desiring on-demand singly dispersed AgNP suspensions from a single master batch. Implementation of this methodology will enable studies to be performed over long periods of time and across different laboratories using particles that are identical chemically and physically and available on-demand, and serve as prototypes for future nanoscale reference materials.