AgNPs characterization by TEM (A), PCCS (B) and UV–vis (C). TEM images of the AgNPs confirmed the primary size stated by the manufacturers (A). The hydrodynamic size distribution was performed in cell medium (BEGM) using PCCS. Data is presented as density distribution by volume together with the corresponding scattered light intensity (B). All the AgNPs agglomerated in cell medium as seen by the size and position of the density distribution peaks. All but the 10 nm PVP coated AgNPs sedimented significantly over time as indicated by the reduction of the scattered light intensity. The UV–vis spectra of the 10 nm citrate (C right) and 10 nm PVP (C left) coated AgNPs indicated particle sedimentation over time as seen from the 400 nm peak reduction.