Impact of nanosilver surface electronic distributions on serum protein interaction and hemocompatibility.

ABSTRACT

Translation of silver-based nanotechnology "from bench to bedside" requires a deep understanding of the molecular aspects of its biological action, which remains controversial at low concentrations and non-spherical morphologies. Here, we present a hemocompatibility approach based on the effect of the distinctive electronic charge distribution in silver nanoparticles (nanosilver) on blood components. On basis of spectroscopic, volumetric, microscopic, dynamic light scattering measurements, pro-coagulant activity tests and cellular inspection we determine that, at extremely low nanosilver concentrations (0.125 - 2.5 µg mL-1) there is a relevant interaction effect on serum albumin and on red blood cells. The explanation has its origin in the surface charge distribution of nanosilver and their electron-mediated energy transfer mechanism. Prism-shaped nanoparticles, with anisotropic charge distributions, act at the surface level generating a compaction of the native protein molecule, while the spherical nanosilver, by exhibiting isotropic surface charge, generates a polar environment comparable to the solvent. Both morphologies induce aggregation at NPs / BSA ≅ 0.044 molar ratio values without altering the coagulation cascade tests, although the spherical-shaped nanosilver has a negative impact on red blood cells. Overall, our results suggest that the electron distributions of nanosilver, even at extremely low concentrations, are a critical factor influencing the molecular structure of blood proteins and red blood cells' membranes. Isotropic forms of nanosilver should be considered with caution, as they are not always the least harmful.