Hematite nanoparticles larger than 90 nm show no sign of toxicity in terms of lactate dehydrogenase release, nitric oxide generation, apoptosis, and comet assay in murine alveolar macrophages and human lung epithelial cells.
Three hematite samples were synthesized by precipitation from a FeCl₃ solution under controlled pH and temperature conditions in different morphology and dimensions: (i) microsized (average diameter 1.2 μm); (ii) submicrosized (250 nm); and (iii) nanosized (90 nm). To gain insight into reactions potentially occurring in vivo at the particle-lung interface following dust inhalation, several physicochemical features relevant to pathogenicity were measured (free radical generation in cell-free tests, metal release, and antioxidant depletion), and cellular toxicity assays on human lung epithelial cells (A549) and murine alveolar macrophages (MH-S) were carried out (LDH release, apoptosis detection, DNA damage, and nitric oxide synthesis). The decrease in particles size, from 1.2 μm to 90 nm, only caused a slight increase in structural defects (disorder of the hematite phase and the presence of surface ferrous ions) without enhancing surface reactivity or cellular responses in the concentration range between 20 and 100 μg cm⁻².
Department of Applied Science and Technology, and INSTM-unit of Torino Politecnico, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino I-10129, Italy.
Francesca Stefania
FS
Freyria
Barbara
B
Bonelli
Maura
M
Tomatis
Mara
M
Ghiazza
Elena
E
Gazzano
Dario
D
Ghigo
Edoardo
E
Garrone
Bice
B
Fubini
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D005290:Ferric Compounds / Q000737:chemistry / Q000633:toxicity*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D016676:Macrophages, Alveolar / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity* / Q000648:ultrastructure; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism*; D010316:Particle Size; D013696:Temperature
D005290:Ferric Compounds; C000499:ferric oxide; D009569:Nitric Oxide; D007770:L-Lactate Dehydrogenase