Elucidating the influence of tumor presence on the polymersome circulation time in mice

Robin M. de Kruijff*, René Raavé, Annemarie Kip, Janneke Molkenboer-Kuenen, Stefan J. Roobol, Jeroen Essers, Sandra Heskamp, Antonia G. Denkova

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)
70 Downloads (Pure)


The use of nanoparticles as tumor-targeting agents is steadily increasing, and the influence of nanoparticle characteristics such as size and stealthiness have been established for a large number of nanocarrier systems. However, not much is known about the impact of tumor presence on nanocarrier circulation times. This paper reports on the influence of tumor presence on the in vivo circulation time and biodistribution of polybutadiene-polyethylene oxide (PBd-PEO) polymersomes. For this purpose, polymersomes were loaded with the gamma-emitter111In and administered intravenously, followed by timed ex vivo biodistribution. A large reduction in circulation time was observed for tumor-bearing mice, with a circulation half-life of merely 5 min (R2 = 0.98) vs 117 min (R2 = 0.95) in healthy mice. To determine whether the rapid polymersome clearance observed in tumor-bearing mice was mediated by macrophages, chlodronate liposomes were administered to both healthy and tumor-bearing mice prior to the intravenous injection of radiolabeled polymersomes to deplete their macrophages. Pretreatment with chlodronate liposomes depleted macrophages in the spleen and liver and restored the circulation time of the polymersomes with no significant difference in circulation time between healthy mice and tumor-bearing mice pretreated with clodronate liposomes (15.2 ± 1.2% ID/g and 13.6 ± 2.7% ID/g, respectively, at 4 h p.i. with p = 0.3). This indicates that activation of macrophages due to tumor presence indeed affected polymersome clearance rate. Thus, next to particle design, the presence of a tumor can also greatly impact circulation times and should be taken into account when designing studies to evaluate the distribution of polymersomes.

Original languageEnglish
Article number241
Number of pages14
Issue number5
Publication statusPublished - 2019


  • Circulation time
  • Clodronate liposomes
  • Healthy and tumor-bearing mice
  • Macrophages
  • Radiolabeled polymersomes


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