TRANSIENT DiFFSION OF NANOVECTORS IN PERMEABLE CAPILLARIES
F. Gentile, M. Ferrari, P. Deczzi (66.021.3/46.16-006-07)
Abstract
The strategy currently followed to deliver nano-sized particulates to solid tumors is based on the
well known enhanced permeability and retention effect where particles sufficiently small to
spontaneously extravasate through the fenestrated tumor vessels can be transported from the
vascular compartment to the inner region of the tumor mass and from there release their
payload. An alternative active strategy is gaining consensus and is based on the targeting of the
tumor vasculature through ligand-receptor specific interactions exploiting the biological and
biophysical differences between normal and tumor vessel walls. Such an active strategy
requires a detailed analysis of the transport and adhesive interaction of nano-sized particulate
systems within the tumor vasculature which is characterized by permeable walls; high
interstitial fluid pressure; and expression of specific receptor molecules.
In this work, the analysis of the transport of solute molecules resembling nano-sized
particles under laminar flow is presented solving the classical diffusion-advection equation in a
straight capillary. The effect of vessel wall permeability as well as the complex rheological
behavior of blood are considered explicitly keeping the formulation tractable. Possible future
directions of research are then presented in the closing paragraph where a finite element
approach is described to treat the transport of non- conventional particulate systems having a
non spherical shape.
