title: Adsorption of lactate dehydrogenase enzyme on carbon nanotubes: how to get accurate results for the cytotoxicity of these nanomaterials.
abstract: Carbon nanotube (CNT) cytotoxicity is frequently investigated using in vitro classical toxicology assays. However, these cellular tests, usually based on the use of colorimetric or fluorimetric dyes, were designed for chemicals and may not be suitable for nanosized materials. Indeed, because of their unique physicochemical properties CNT can interfere with the assays and bias the results. To get accurate data and draw reliable conclusions, these artifacts should be carefully taken into account. The aim of this study was to evaluate qualitatively and quantitatively the interferences occurring between CNT and the commonly used lactate dehydrogenase (LDH) assay. Experiments under cell-free conditions were performed, and it was clearly demonstrated that artifacts occurred. They were due to the intrinsic absorbance of CNT on one hand and the adsorption of LDH at the CNT surface on the other hand. The adsorption of LDH on CNT was modeled and was found to fit the Langmuir model. The K(ads) and n(eq) constants were defined, allowing the correction of results obtained from cellular experiments to get more accurate data and lead to proper conclusions on the cytotoxicity of CNT.
authors.affiliation: †Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS, Saint-Etienne, France.|‡LINA, EA4624, Saint-Etienne, France.|§SFR IFRESIS, Saint-Etienne, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Forest
authors.affiliation: ‡LINA, EA4624, Saint-Etienne, France.|§SFR IFRESIS, Saint-Etienne, France.|∥Ecole Nationale Supérieure des Mines de Saint-Etienne, SPIN, CNRS: UMR 5307, LGF, Saint-Etienne, France.
authors.forename: Agathe
authors.initials: A
authors.lastname: Figarol
authors.affiliation: ‡LINA, EA4624, Saint-Etienne, France.|§SFR IFRESIS, Saint-Etienne, France.|⊥Faculté de Médecine J. Lisfranc, Université Jean Monnet, Saint-Etienne, France.|#PRES Lyon, France.|∇CHU, Saint-Etienne, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Boudard
authors.affiliation: ‡LINA, EA4624, Saint-Etienne, France.|§SFR IFRESIS, Saint-Etienne, France.|⊥Faculté de Médecine J. Lisfranc, Université Jean Monnet, Saint-Etienne, France.|#PRES Lyon, France.|∇CHU, Saint-Etienne, France.
authors.forename: Michèle
authors.initials: M
authors.lastname: Cottier
authors.affiliation: ∥Ecole Nationale Supérieure des Mines de Saint-Etienne, SPIN, CNRS: UMR 5307, LGF, Saint-Etienne, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Grosseau
authors.affiliation: †Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS, Saint-Etienne, France.|‡LINA, EA4624, Saint-Etienne, France.|§SFR IFRESIS, Saint-Etienne, France.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Pourchez
mesh_terms: D000327:Adsorption; D000818:Animals; D016477:Artifacts; D007770:L-Lactate Dehydrogenase / Q000737:chemistry* / Q000378:metabolism*; D051379:Mice; D008958:Models, Molecular; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000633:toxicity*; D000067996:RAW 264.7 Cells; D013499:Surface Properties; D018675:Toxicity Tests
chemical_list: D037742:Nanotubes, Carbon; D007770:L-Lactate Dehydrogenase