title: Carboxylation of multiwalled carbon nanotube enhanced its biocompatibility with L02 cells through decreased activation of mitochondrial apoptotic pathway.
abstract: Modification of carbon nanotubes (CNTs) with carboxyl group is one of the widely used strategies to increase their water dispersibility. Various molecules can be further coupled to the surface of carboxylated CNTs for the desired applications. However, the effect of carboxylation of CNTs on their cytotoxicity is far from being completely understood. In this study, the impact of carboxylated multiwalled CNT (MWCNT-COOH) on human normal liver cell line L02 was studied and compared with pristine multiwalled CNT (p-MWCNT). The data accumulated in this study revealed that modification with carboxyl group reduced the toxicity of MWCNT on L02 cells, probably due to the decreased activation of mitochondria mediated apoptotic pathway. Both p-MWCNT and MWCNT-COOH, when reaching to certain concentration, induced significant decrease in the mitochondrial membrane potential, enhanced release of cytochrome c from the mitochondria to cytoplasm as well as activation of caspase-9, and -3. However, the changes induced by MWCNT-COOH were significantly milder than that by p-MWCNT. Our observation suggests that carboxylated MWCNTs might be safer for in vivo application as compared with p-MWCNT.
authors.affiliation: Laboratory of Bioengineering, Tianjin Key Laboratory of Biomedical Materials, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, 300192, People's Republic of China; Department of Pharmaceutics, School of Pharmaceutical Sciences, Central South University, Changsha, 410013, Hunan Province, People's Republic of China.
authors.forename: Zhenbao
authors.initials: Z
authors.lastname: Liu
authors.forename: Xia
authors.initials: X
authors.lastname: Dong
authors.forename: Liping
authors.initials: L
authors.lastname: Song
authors.forename: Hailing
authors.initials: H
authors.lastname: Zhang
authors.forename: Lanxia
authors.initials: L
authors.lastname: Liu
authors.forename: Dunwan
authors.initials: D
authors.lastname: Zhu
authors.forename: Cunxian
authors.initials: C
authors.lastname: Song
authors.forename: Xigang
authors.initials: X
authors.lastname: Leng
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001672:Biocompatible Materials / Q000737:chemistry* / Q000633:toxicity; D002264:Carboxylic Acids / Q000737:chemistry* / Q000633:toxicity; D002460:Cell Line; D006801:Humans; D008099:Liver / Q000166:cytology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000633:toxicity
chemical_list: D001672:Biocompatible Materials; D002264:Carboxylic Acids; D037742:Nanotubes, Carbon
keywords: L02 cells; apoptosis; carboxylation; mitochondria; multiwalled carbon nanotubes