title: Delivery of paclitaxel by physically loading onto poly(ethylene glycol) (PEG)-graft-carbon nanotubes for potent cancer therapeutics.
abstract: Physically loading of paclitaxel (PTX) onto carbon nanotubes (CNTs) is achieved through immersion of poly(ethylene glycol) (PEG)-graft-single walled CNTs (PEG-g-SWNTs) or PEG-graft-multi-walled CNTs (PEG-g-MWNTs) in a saturated solution of PTX in methanol. After loading once the loading capacity (LD%) is 26% (w/w) and 36% (w/w) for PEG-g-SWNTs or PEG-g-MWNTs, respectively. With these PTX contents, PTX loaded PEG-g-SWNTs and PTX loaded PEG-g-MWNTs still have good dispersity in aqueous solution and individual CNTs can be observed in TEM images. PTX can be released from PEG-g-CNTs several times faster than from free PTX but still in a sustained profile with less than 40% of PTX being released in 40 days at pH 7 or 5. In vitro cytotoxicity of samples is evaluated in HeLa cells and MCF-7 cells. PEG-g-SWNTs and PEG-g-MWNTs show low cytotoxicity in both cells with insignificant effects on the cell proliferation rates. However, both PTX loaded PEG-g-SWNTs and PTX loaded PEG-g-MWNTs show high efficacy to kill HeLa cells and MCF-7 cells, as reflected by IC(50) lower than free PTX. Therefore, PTX loaded PEG-g-CNTs are promising for cancer therapeutics.
  
  
  BACKGROUND
  carbon nanotubes, poly(ethylene glycol), drug delivery, cancer therapy, nanomedicine.
authors.affiliation: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore.
authors.forename: Chee Leng
authors.initials: CL
authors.lastname: Lay
authors.forename: Hui Qi
authors.initials: HQ
authors.lastname: Liu
authors.forename: Hui Ru
authors.initials: HR
authors.lastname: Tan
authors.forename: Ye
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage* / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004337:Drug Carriers / Q000737:chemistry*; D006801:Humans; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009369:Neoplasms / Q000188:drug therapy; D017239:Paclitaxel / Q000008:administration & dosage* / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000737:chemistry*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004337:Drug Carriers; D037742:Nanotubes, Carbon; D011092:Polyethylene Glycols; D017239:Paclitaxel