title: Development and evaluation of pH-responsive single-walled carbon nanotube-doxorubicin complexes in cancer cells.
abstract: Single-walled carbon nanotubes (SWNTs) have been identified as an efficient drug carrier. Here a controlled drug-delivery system based on SWNTs coated with doxorubicin (DOX) through hydrazone bonds was developed, because the hydrazone bond is more sensitive to tumor microenvironments than other covalent linkers. The SWNTs were firstly stabilized with polyethylene glycol (H(2)N-PEG-NH(2)). Hydrazinobenzoic acid (HBA) was then covalently attached on SWNTs via carbodiimide-activated coupling reaction to form hydrazine-modified SWNTs. The anticancer drug DOX was conjugated to the HBA segments of SWNT using hydrazine as the linker. The resulting hydrazone bonds formed between the DOX molecules and the HBA segments of SWNTs are acid cleavable, thereby providing a strong pH-responsive drug release, which may facilitate effective DOX release near the acidic tumor microenvironment and thus reduce its overall systemic toxicity. The DOX-loaded SWNTs were efficiently taken up by HepG2 tumor cells, and DOX was released intracellularly, as revealed by MTT assay and confocal microscope observations. Compared with SWNT-DOX conjugate formed by supramolecular interaction, the SWNT-HBA-DOX featured high weight loading and prolonged release of DOX, and thus improved its cytotoxicity against cancer cells. This study suggests that while SWNTs have great potential as a drug carrier, the efficient formulation strategy requires further study.
authors: Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, China.
authors: Yan-Juan
authors: YJ
authors: Gu
authors: Jinping
authors: J
authors: Cheng
authors: Jiefu
authors: J
authors: Jin
authors: Shuk Han
authors: SH
authors: Cheng
authors: Wing-Tak
authors: WT
authors: Wong
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology*; D001565:Benzoates / Q000737:chemistry; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000493:pharmacokinetics* / Q000494:pharmacology; D004317:Doxorubicin / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008113:Liver Neoplasms / Q000188:drug therapy / Q000378:metabolism; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry
chemical_list: D000903:Antibiotics, Antineoplastic; D001565:Benzoates; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D037742:Nanotubes, Carbon; D011092:Polyethylene Glycols; D004317:Doxorubicin; C053198:4-hydrazinobenzoic acid