Figure 6. Transvascular and interstitial transport of nanoparticles and macromolecules to tumors.

(A) Transvascular flux and penetration of quantum dot particles of hydrodynamic diameters (HD): 12 nm, 60 nm and 125 nm and distinct emission wavelengths, λ. A solution of these nanoparticles was co-injected into mice bearing tumors and their flux through a specific vessel was imaged 120 min after injection (reproduced with permission from [111]). (B) Rods can more effectively extravasate into the tumor compared with spherical particles of the same hydrodynamic diameter (reproduced with permission from [117]). (C) Diffusion coefficient of macromolecules of varying hydrodynamic radius in phosphate buffer saline (PBS) and in U87 glioblastoma implanted in the skin or cranium of immunodeficient mice (reproduced with permission from [108]). Fluorescence image shows the heterogeneous distribution of 90 nm liposomes (bright red color) that are accumulated in perivascular regions (dark color) (reproduced with permission from [116]). (D) Rods can more effectively distribute into the tumor interstitial space compared with spherical nanoparticles of the same hydrodynamic diameter. Intratumor distribution refers to the area of tumor sections occupied by the particles and the distribution of the spherical and rod-like particles in a tumor section (reproduced with permission from [117]).