Figure 4. Long blood circulation of PLA-PEG-NPs with a controlled topographical structure.

(a) Blood circulation of DiD-labeled PLA-TPEG-NPs prepared with 0%, 5%, 10% and 20% PLA-PEG-MAL. (b) Circulation half-lives of PLA-TPEG-NPs obtained by fitting the circulation profile data (a) into a one-compartment model via PKSolver. Values indicate mean ± SD (n = 4-6, from two independent experiments). **, P < 0.01.