Anomalously Fast Diffusion of Targeted Carbon Nanotubes in Cellular Spheroids

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• 作者：Yichun Wang ; Joong Hwan Bahng ; Quantong Che ; Jishu Han ; Nicholas A. Kotov
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：August 25, 2015
• 年：2015
• 卷：9
• 期：8
• 页码：8231-8238
• 全文大小：599K
• ISSN：1936-086X

文摘

Understanding transport of carbon nanotubes (CNTs) and other nanocarriers within tissues is essential for biomedical imaging and drug delivery using these carriers. Compared to traditional cell cultures in animal studies, three-dimensional tissue replicas approach the complexity of the actual organs and enable high temporal and spatial resolution of the carrier 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 anomalously high and comparable to diffusion rates of similarly charged molecules with molecular weights 10000脳 lower. Moreover, diffusivity of CNTs in tissues is enhanced after functionalization with transforming growth factor 尾1. This unexpected trend contradicts predictions of the Stokes鈭扙instein equation and previously obtained empirical dependences of diffusivity on molecular mass for permeants in gas, liquid, solid or gel. It is attributed to the planar diffusion (gliding) 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, which is often difficult to realize with anticancer agents.