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. Author manuscript; available in PMC: 2015 Nov 21.
Published in final edited form as: Phys Med Biol. 2014 Oct 20;59(22):6775–6795. doi: 10.1088/0031-9155/59/22/6775

Figure 8.

Figure 8

Excess concentration in the focal plane of tumor at various times during and after treatment for model small molecules (a, assuming D and ζeff are increased by factors of 100 compared to IgG) and nanoparticles (b, assuming D and ζeff are decreased by factors of 100). Note that the concentration advantage peaks around 60 seconds for small molecule then rapidly drops back to zero by 20 minutes, whereas for the nanoparticles, the advantage peaks at 2.5 min and remains there. Because small molecules will diffuse into the tissue quite rapidly even in the absence of any treatment, the delivery advantage for them is overall limited. Macromolecules and nanoparticles, however, having limited diffusion, do not penetrate into the tissue, and therefore any delivery advantage is sustained.