title: Cytotoxicity of phenol red in toxicity assays for carbon nanoparticles.
abstract: To explore the novel properties of carbon nanoparticles (CNPs) in nanotoxicity assays, the adsorption of phenol red (a pH indicator for culture medium) by multi-walled carbon nanotubes (MWNTs) and three kinds of carbon blacks (CBs) with nanosize, and its effects on cytotoxicity were studied. Results indicated that the phenol red adsorbed and delivered into cells by CBs was responsible for the toxicity to Hela cells in the medium without serum. The cellular uptake of phenol red was verified using 125I-labeling techniques. The size-dependent cytotoxicity of CBs was found to closely correlate to adsorption of phenol red, cellular uptake of phenol red-CB complexes and the amount of phenol red delivered into the cells by CBs. Although the CBs were either nontoxic or slightly toxic, as vehicles of phenol red, they played an essential role in the cytotoxicity induced by phenol red. However, MWNTs showed an intrinsic cytotoxicity independent of phenol red. The implications associated with these findings are discussed.
authors.affiliation: Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China. zhuying@sinap.ac.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhu
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Zhang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhu
authors.forename: Qunfen
authors.initials: Q
authors.lastname: Zhao
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Li
authors.forename: Wenxin
authors.initials: W
authors.lastname: Li
authors.forename: Chunhai
authors.initials: C
authors.lastname: Fan
authors.forename: Qing
authors.initials: Q
authors.lastname: Huang
mesh_terms: D000327:Adsorption; D002470:Cell Survival / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D007457:Iodine Radioisotopes / Q000737:chemistry; D007553:Isotope Labeling; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*; D010316:Particle Size; D010637:Phenolsulfonphthalein / Q000737:chemistry / Q000633:toxicity; D053260:Soot / Q000737:chemistry; D018675:Toxicity Tests
chemical_list: D007457:Iodine Radioisotopes; D037742:Nanotubes, Carbon; D053260:Soot; D010637:Phenolsulfonphthalein