Fig. 2.

A PEG density threshold of 20 PEG chains per 100 nm² is necessary to avoid early clearance from the bloodstream. a The early circulation of nanoparticles with diameters of 55, 90, and 140 nm appears to be mainly affected by the density of PEG chains on their surface. Below a threshold around 20 PEG chains per 100 nm², the nanoparticles are cleared rapidly; above this value, the nanoparticles exhibit roughly the same circulation profiles, irrespective of their diameter or extent of PEGylation. b Pharmacokinetic analysis of blood exposure (AUC_0–6h) and elimination constants (k _e) also highlight the presence of a threshold above which greater PEG coverage does not increase benefits on prolonging the circulation of nanoparticles. Values are means ± SD (n = 3–5); numbers in blue represent the PEG chains per 100 nm² of surface