Photoluminescent Carbon Nanotubes Interrogate the Permeability of Multicellular Tumor Spheroids

Abstract

The near-infrared photoluminescence from non-covalently dispersed single-walled carbon nanotubes (SWCNT) is optimally suited to probe distinct classes of biological environments. With aspect ratios of >100:1, nanotubes present an opportunity to observe atypical interactions between linear filamentous particles and three-dimensional biological environments. A pressing concern in therapeutic biomedicine is the inability of drug-carrying nanoparticles that function well in two dimensional cell cultures, to show efficacy in vivo. The inability of spherical nanoparticles to penetrate dense three-dimensional structures in a well defined point of failure. By exploiting the ability to image single carbon nanotubes via widefield fluorescence microscopy, we quantified the relative permeability of multi cellular tumor spheroids to a linear nanoparticle1. The results indicate the ability of nanoparticles to penetrate tumor spheroids depends strongly on the nanoparticle shape. Additionally, this platform portends a new approach to characterize the permeability of living multicellular environments.