title: The influence of Citrate or PEG coating on silver nanoparticle toxicity to a human keratinocyte cell line.
abstract: Surface coating of silver nanoparticles may influence their toxicity, in a way yet to decipher. In this study, human keratinocytes (HaCaT cells) were exposed for 24 and 48h to well-characterized 30nm AgNPs coated either with citrate (Cit30 AgNPs) or with poly(ethylene glycol) (PEG30 AgNPs), and assessed for cell viability, reactive oxygen species (ROS), cytokine release, apoptosis and cell cycle dynamics. The results showed that Cit30 AgNPs and PEG30 AgNPs decreased cell proliferation and viability, the former being more cytotoxic. The coating molecules per se were not cytotoxic. Moreover, Ag(+) release and ROS production were similar for both AgNP types. Cit30 AgNPs clearly induced apoptotic death, while cells exposed to PEG30 AgNPs appeared to be at an earlier phase of apoptosis, supported by changes in BAX, BCL2 and CASP-3 expressions. Concerning the impact on cell cycle dynamics, both Cit30 and PEG30 AgNPs affected cell cycle regulation of HaCaT cells, but, again, citrate-coating induced more drastic effects, showing earlier downregulation of cyclin B1 gene and cellular arrest at the G2 phase. Overall, this study has shown that the surface coating of AgNPs influences their toxicity by differently regulating cell-cycle and cell death mechanisms.
authors.affiliation: CESAM & Laboratory of Biotechnology and Cytomics, Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: V
authors.initials: V
authors.lastname: Bastos
authors.affiliation: CESAM & Laboratory of Biotechnology and Cytomics, Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: J M P
authors.initials: JM
authors.lastname: Ferreira de Oliveira
authors.affiliation: School of Life sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK.
authors.forename: D
authors.initials: D
authors.lastname: Brown
authors.affiliation: School of Life sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK.
authors.forename: H
authors.initials: H
authors.lastname: Jonhston
authors.affiliation: CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Aveiro, Portugal.
authors.forename: E
authors.initials: E
authors.lastname: Malheiro
authors.affiliation: CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Aveiro, Portugal.
authors.forename: A L
authors.initials: AL
authors.lastname: Daniel-da-Silva
authors.affiliation: CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Aveiro, Portugal.
authors.forename: I F
authors.initials: IF
authors.lastname: Duarte
authors.affiliation: CESAM & Laboratory of Biotechnology and Cytomics, Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal; Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, Porto, Portugal. Electronic address: csantos@fc.up.pt.
authors.forename: C
authors.initials: C
authors.lastname: Santos
authors.affiliation: CESAM & Laboratory of Biotechnology and Cytomics, Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: H
authors.initials: H
authors.lastname: Oliveira
mesh_terms: D017304:Annexin A5 / Q000032:analysis; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019343:Citric Acid / Q000494:pharmacology*; D016207:Cytokines / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000633:toxicity*; D011092:Polyethylene Glycols / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012834:Silver / Q000633:toxicity*
chemical_list: D017304:Annexin A5; D016207:Cytokines; D017382:Reactive Oxygen Species; D019343:Citric Acid; D012834:Silver; D011092:Polyethylene Glycols
keywords: Apoptosis; Cell cycle; Citrate-coating; Cytokines; Nanotoxicology; PEG-coating; ROS; Silver nanoparticles