Titanium dioxide and table sugar enhance the leaching of silver out of nanosilver packaging

We manufactured laboratory-scale food packages containing 2.57 +/- 0.18 x 10(-3) wt% silver nanoparticles (AgNPs) and used them to show that table sugar (sucrose) and microcrystalline titanium dioxide (mu TiO2) enhance Ag migration from these packages and into aqueous food simulants. Ag migration into purified water was detected but was below the limit of ICP-MS quantitation, giving a range of potential Ag migration between 0.059 and 0.082 ng cm(-2) packaging surface area. Ag migration into 9 wt% aqueous sucrose solution was 0.547 +/- 0.084 ng cm(-2) and migration into 9 wt% sucrose solution containing 0.01 wt% mu TiO2 was 0.724 +/- 0.032 ng cm(-2). Total Ag migration into a 0.01 wt% mu TiO2 aqueous dispersion without sucrose was between 0.122 and 0.162 ng cm(-2), with upper and lower limits defined by the detectability of Ag in the supernatant phase of the simulant. If the midpoint of this range is taken as a baseline, these results imply that, compared to purified water, Ag migration was increased by approximately 10.3 times when the water simulant contained mu TiO2 and sucrose at commercially-relevant concentrations. Notably, the Ag migrated into water containing both ingredients exceeded the total Ag migrated into either of the single-ingredient simulants, pointing to a potential cooperative relationship between sucrose and mu TiO2 that possibly derives from binding and redox interactions between these two ingredients. Sucrose and mu TiO2 also both reduced a portion of migrated Ag+ back into AgNPs, and mu TiO2 particles efficiently captured (>25% by mass) migrated Ag on their surfaces. Similar effects on migration were observed with nanocrystalline TiO2. These experiments are the first to show that TiO2 particles exert a strong influence on the quantity and form of Ag that could migrate from AgNP-enabled packaging, suggesting that food formulations and interactions between individual food components may be important to consider when evaluating the fate of nanoparticles in these consumer applications.

Automated summary

The study found that sucrose and microcrystalline titanium dioxide enhance the migration of silver nanoparticles from food packaging, and there may be a synergistic relationship between sucrose and microcrystalline titanium dioxide. In addition, titanium dioxide particles also affect the migration of silver. These findings reveal that food formulations and interactions between different components are important factors to consider in the fate of nanoparticles in consumer applications.