A tetraethylene glycol coat gives gold nanoparticles long in vivo half-lives with minimal increase in size

Immunofilaments Are Well Tolerated after Local or Systemic Administration in Mice

“…36−39 In addition, the tetraethylene glycol in the side chains of the IFs can further increase the circulation time and reduce protein absorption, as was previously demonstrated for gold nanoparticles. 40,41 Remarkably, we could detect radioactivity of Indium-labeled IFs for up to 3 days in the blood, suggesting that IFs are not rapidly eliminated through renal clearance. 17 Given an average polymer length of 400 nm and a width of 1 nm, plus conjugated molecules, that can further increase the hydrodynamic diameter, along with the high accumulation in the liver, supports the hypothesis that the majority of our IFs are eliminated from the body through the hepatobiliary route.…”

“…In contrast, our IFs are nanometer-scale filamentous polymers with an aspect ratio of 1:400, which likely endows them with different pharmacokinetic and clearance properties from the body compared to spheres . Previous work suggests that rod-like particles circulate longer in the blood as they cannot be as easily taken up by phagocytes as compared to spherical particles, resulting in higher accumulation in tumor tissues underlying the enhanced retention and permeability effect. − In addition, the tetra-ethylene glycol in the side chains of the IFs can further increase the circulation time and reduce protein absorption, as was previously demonstrated for gold nanoparticles. , Remarkably, we could detect radioactivity of Indium-labeled IFs for up to 3 days in the blood, suggesting that IFs are not rapidly eliminated through renal clearance . Given an average polymer length of 400 nm and a width of 1 nm, plus conjugated molecules, that can further increase the hydrodynamic diameter, along with the high accumulation in the liver, supports the hypothesis that the majority of our IFs are eliminated from the body through the hepatobiliary route .…”