Drug delivery with carbon nanotubes for in vivo cancer treatment
  Chemically functionalized single-walled carbon nanotubes (SWNTs) have shown promise in tumor targeted accumulation in mice and exhibit biocompatibility, excretion and little toxicity. Here, we demonstrate in-vivo SWNT drug delivery for tumor suppression in mice. We conjugate paclitaxel (PTX), a widely used cancer chemotherapy drug to branched polyethylene-glycol (PEG) chains on SWNTs via a cleavable ester bond to obtain a water soluble SWNT-paclitaxel conjugate (SWNT-PTX). SWNT-PTX affords higher efficacy in suppressing tumor growth than clinical Taxol in a murine 4T1 breast-cancer model, owing to prolonged blood circulation and 10-fold higher tumor PTX uptake by SWNT delivery likely through enhanced permeability and retention (EPR). Drug molecules carried into the reticuloendothelial system are released from SWNTs and excreted via biliary pathway without causing obvious toxic effects to normal organs. Thus, nanotube drug delivery is promising for high treatment efficacy and minimum side effects for future cancer therapy with low drug doses. 
Zhuang Liu, Kai Chen, Corrine Davis, Sarah Sherlock, Qizhen Cao,   Xiaoyuan Chen, Hongjie Dai