title: Surface defects on plate-shaped silver nanoparticles contribute to its hazard potential in a fish gill cell line and zebrafish embryos.
abstract: We investigated and compared nanosize Ag spheres, plates, and wires in a fish gill epithelial cell line (RT-W1) and in zebrafish embryos to understand the mechanism of toxicity of an engineered nanomaterial raising considerable environmental concern. While most of the Ag nanoparticles induced N-acetyl cysteine sensitive oxidative stress effects in RT-W1, Ag nanoplates were considerably more toxic than other particle shapes. Interestingly, while Ag ion shedding and bioavailability failed to comprehensively explain the high toxicity of the nanoplates, cellular injury required direct particle contact, resulting in cell membrane lysis in RT-W1 as well as red blood cells (RBC). Ag nanoplates were also considerably more toxic in zebrafish embryos in spite of their lesser ability to shed Ag into the exposure medium. To elucidate the "surface reactivity" of Ag nanoplates, high-resolution transmission electron microscopy was performed and demonstrated a high level of crystal defects (stacking faults and point defects) on the nanoplate surfaces. Surface coating with cysteine was used to passivate the surface defects and demonstrated a reduction of toxicity in RT-W1 cells, RBC, and zebrafish embryos. This study demonstrates the important role of crystal defects in contributing to Ag nanoparticle toxicity in addition to the established roles of Ag ion shedding by Ag nanoparticles. The excellent correlation between the in vitro and in vivo toxicological assessment illustrates the utility of using a fish cell line in parallel with zebrafish embryos to perform a predictive environmental toxicological paradigm.
authors.affiliation: Department of Medicine, Division of NanoMedicine, University of California, Los Angeles, Los Angeles, California 90095, USA.
authors.forename: Saji
authors.initials: S
authors.lastname: George
authors.forename: Sijie
authors.initials: S
authors.lastname: Lin
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Ji
authors.forename: Courtney R
authors.initials: CR
authors.lastname: Thomas
authors.forename: LinJiang
authors.initials: L
authors.lastname: Li
authors.forename: Mathew
authors.initials: M
authors.lastname: Mecklenburg
authors.forename: Huan
authors.initials: H
authors.lastname: Meng
authors.forename: Xiang
authors.initials: X
authors.lastname: Wang
authors.forename: Haiyuan
authors.initials: H
authors.lastname: Zhang
authors.forename: Tian
authors.initials: T
authors.lastname: Xia
authors.forename: J Nathan
authors.initials: JN
authors.lastname: Hohman
authors.forename: Shuo
authors.initials: S
authors.lastname: Lin
authors.forename: Jeffrey I
authors.initials: JI
authors.lastname: Zink
authors.forename: Paul S
authors.initials: PS
authors.lastname: Weiss
authors.forename: André E
authors.initials: AE
authors.lastname: Nel
mesh_terms: D000818:Animals; D002460:Cell Line; D005880:Gills / Q000166:cytology*; D013058:Mass Spectrometry; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D012834:Silver / Q000737:chemistry*; D013499:Surface Properties; D015027:Zebrafish / Q000196:embryology*
chemical_list: D012834:Silver