Modeling of retrograde nanoparticle transport in axons and dendrites

This paper presents a pioneering modeling study on nanoparticle internalization and transport in neurons. The model developed in this paper is based on recent experimental results that indicate that after entering a neurite by endocytosis, nanoparticles are transported toward the neuron soma in endocytic vesicles by retrograde molecular-motor-driven transport. Experimental results also indicate that nanoparticles enter axons at axon terminals while in dendrites they enter through the entire plasma membrane. The model equations developed in this paper are based on these experimental observations. The analytical solution of these equations is obtained; the solution predicts the distribution of the concentration of nanoparticles associated with free nanoparticle-loaded vesicles (NLVs) (not transported on microtubules (MTs)) as well as the distribution of the concentration of nanoparticles associated with NLVs transported on MTs by dynein motors. The fluxes of nanoparticles by diffusion and motor-driven transport as well as the total (combined) flux of nanoparticles are also predicted.