(336c) Anomalous Diffusion of Targeted Carbon Nanotubes in Cellular Spheroids

Understanding transport of carbon nanotubes (CNTs) within tissues is essential for biomedical imaging and drug delivery using these carriers.  Compared to animal studies and traditional cell cultures, three-dimensional tissue replicas approach the complexity of the actual organs and enable high temporal and spatial resolution of the CNT permeation.  We investigated diffusional transport of CNTs in highly uniform spheroids of hepatocellular carcinoma and found that apparent diffusion coefficients of CNTs in these tissue replicas are surprisingly high and comparable to diffusion rates of similarly charged molecules with molecular weight 10,000× lower. Moreover, diffusivity of CNTs in tissues is enhanced after functionalization with TGFβ1. The anomalous trend is attributed to the planar diffusion of CNTs along cellular membranes reducing effective dimensionality of diffusional space. These findings indicate that nanotubes and potentially similar nanostructures are capable of fast and deep permeation into the tissue that is often difficult to realize with anticancer agents.