title: Size-dependent cytotoxicity of silver nanoparticles in human neutrophils assessed by multiple analytical approaches.
abstract: OBJECTIVE
  Silver nanoparticles (AgNPs) have emerged as an important class of nanomaterials with a wide range of industrial and medical applications. The assessment of AgNPs' biological effects in the human organism is therefore essential to evaluate the impact of these nanomaterials in public health and reassure the ratio benefit/risk. In the present study, the effect of polyvinyl pyrrolidone (PVP)-coated AgNPs with distinct sizes (10 and 50nm) on neutrophils' oxidative burst and toxicity were tested.
  
  
  METHODS
  The effect of AgNPs on human neutrophils viability was evaluated by trypan blue, neutral red and propidium iodide methods. The measurement of neutrophils' oxidative burst was performed using the probe dihydrorhodamine 123. The cytomorphological alterations of human neutrophils exposed to AgNPs were evaluated by optical microscopy and transmission electron microscopy.
  
  
  RESULTS
  It was observed that PVP-coated AgNPs are toxic to human neutrophils being the 10nm AgNPs more toxic than the 50nm AgNPs. The smallest AgNPs lead to membrane damage, impaired lysosomal activity and induce neutrophils' oxidative burst. Despite the production of reactive species, the toxicity of AgNPs is not NADPH oxidase-dependent.
  
  
  CONCLUSIONS
  These data indicate that AgNPs are toxic to human neutrophils in concentration-, time- and size-dependent manner, but independent of NADPH oxidase activation.
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal.
authors.forename: Tânia
authors.initials: T
authors.lastname: Soares
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal.
authors.forename: Daniela
authors.initials: D
authors.lastname: Ribeiro
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal.
authors.forename: Carina
authors.initials: C
authors.lastname: Proença
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal.
authors.forename: Renan Campos
authors.initials: RC
authors.lastname: Chisté
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal.
authors.forename: Eduarda
authors.initials: E
authors.lastname: Fernandes
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal. Electronic address: marisafreitas@ff.up.pt.
authors.forename: Marisa
authors.initials: M
authors.lastname: Freitas
mesh_terms: D002470:Cell Survival / Q000187:drug effects*; D002478:Cells, Cultured; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D019255:NADPH Oxidases / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects; D010316:Particle Size; D012834:Silver / Q000737:chemistry / Q000633:toxicity*
chemical_list: D012834:Silver; D019255:NADPH Oxidases
keywords: Cell viability; Necrosis; Neutral red; Oxidative burst; Propidium iodide