Nanoparticle uptake in tumors is mediated by the interplay of vascular and collagen density with interstitial pressure.

Unlabelled: Nanoparticle delivery into solid tumors is affected by vessel density, interstitial fluid pressure (IFP) and collagen, as shown in this article by contrasting the in vivo macroscopic quantitative uptake of 40 nm fluorescent beads in three tumor types.The fluorescence uptake was quantified on individual animals by normalization with the transmitted light and then normalized to normal tissue uptake in each mouse. Mean data for uptake in individual tumor lines then showed expected trends with the largest uptake in the most vascularized tumor line.