title: Cytotoxic evaluation of nanostructured zinc oxide (ZnO) thin films and leachates.
abstract: Nanostructured ZnO films have potential use as coatings on medical devices and food packaging due to their antimicrobial and UV-protection properties. However, their influence on mammalian cells during clinical use is not fully understood. This study investigated the potential cytotoxicity of ZnO thin films in RAW 264.7 macrophages. ZnO thin films (∼96nm thick with a 50nm grain) were deposited onto silicon wafers using pulsed laser deposition. Cells grown directly on ZnO thin film coatings exhibited less toxicity than cells exposed to extracts of the coatings. Cells on ZnO thin films exhibited a 43% and 68% decrease in cell viability using the MTT and 7-AAD/Annexin V flow cytometry assays, respectively, after a 24-h exposure as compared to controls. Undiluted 100% 24- and 48-h extracts decreased viability by 89%, increased cell death by LDH release to 76% 24h after treatment, and increased ROS after 5-24h of exposure. In contrast, no cytotoxicity or ROS were observed for 25% and 50% extracts, indicating a tolerable concentration. Roughly 24 and 34μg/m(2) Zn leached off the surfaces after 24 and 48h of incubation, respectively. ZnO coatings may produce gradual ion release which becomes toxic after a certain level and should be evaluated using both direct exposure and extraction methods.
authors.affiliation: Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD 20993, USA; Joint Dept of Biomedical Engineering, Univ of North Carolina-Chapel Hill and North Carolina State Univ, Raleigh, NC 27695, USA.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Petrochenko
authors.affiliation: Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD 20993, USA.
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Intel Corporation, IMO-SC, SC2, Santa Clara, CA 95052, USA.
authors.forename: Reza
authors.initials: R
authors.lastname: Bayati
authors.affiliation: Joint Dept of Biomedical Engineering, Univ of North Carolina-Chapel Hill and North Carolina State Univ, Raleigh, NC 27695, USA.
authors.forename: Shelby A
authors.initials: SA
authors.lastname: Skoog
authors.affiliation: Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD 20993, USA.
authors.forename: K Scott
authors.initials: KS
authors.lastname: Phillips
authors.affiliation: Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD 20993, USA.
authors.forename: Girish
authors.initials: G
authors.lastname: Kumar
authors.affiliation: Joint Dept of Biomedical Engineering, Univ of North Carolina-Chapel Hill and North Carolina State Univ, Raleigh, NC 27695, USA.
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Narayan
authors.affiliation: Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD 20993, USA. Electronic address: Peter.Goering@fda.hhs.gov.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Goering
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D051379:Mice; D049329:Nanostructures / Q000737:chemistry / Q000633:toxicity*; D009336:Necrosis; D015034:Zinc Oxide / Q000737:chemistry / Q000633:toxicity*
chemical_list: D015034:Zinc Oxide
keywords: Macrophage; Metal leaching; Nanoroughness; Pulsed laser deposition; Surface toxicity; Zinc oxide (ZnO)