SCIENTIFIC REPORts | (2018) 8:4408 | DOI:10.1038/s41598-018-21862-4
Multi-scale X-ray computed
tomography to detect and localize
metal-based nanomaterials in lung
tissues of in vivo exposed mice
, Wei Liu
, Daniel Borschneck
, Clément Levard
, Mélanie Auan
, Blanche Collin
, Isabelle Kieer
, Sophie Lanone
, Jérôme Rose
In this methodological study, we demonstrated the relevance of 3D imaging performed at various
scales for the ex vivo detection and location of cerium oxide nanomaterials (CeO
-NMs) in mouse lung.
X-ray micro-computed tomography (micro-CT) with a voxel size from 14 µm to 1 µm (micro-CT) was
combined with X-ray nano-computed tomography with a voxel size of 63 nm (nano-CT). An optimized
protocol was proposed to facilitate the sample preparation, to minimize the experimental artifacts and
to optimize the contrast of soft tissues exposed to metal-based nanomaterials (NMs). 3D imaging of
the NMs biodistribution in lung tissues was consolidated by combining a vast variety of techniques in
a correlative approach: histological observations, 2D chemical mapping and speciation analysis were
performed for an unambiguous detection of NMs. This original methodological approach was developed
following a worst-case scenario of exposure, i.e. high dose of exposure with administration via intra-
tracheal instillation. Results highlighted both (i) the non-uniform distribution of CeO
-NMs within the
entire lung lobe (using large eld-of-view micro-CT) and (ii) the detection of CeO
-NMs down to the
individual cell scale, e.g. macrophage scale (using nano-CT with a voxel size of 63 nm).
In the past years, nanotechnology has undergone rapid development because of the enhanced or modied prop-
erties (e.g. magnetic, electronic, optic, surface chemical reactivity, etc.) of nanomaterials (NMs) compared to
their bulk counterpart. Among others, cerium oxide NMs (CeO
-NMs) gained interest in many dierent elds
including industrial applications beneting from their catalytic activities (semiconductor, fuel combustion) and
applications in nanomedicine (novel therapeutics for cancer or Alzheimer’s disease) beneting from their anti-
. Conversely, such properties can also induce toxic eects both in vitro and in vivo. Moreover,
a recent study
showed that NMs may exhibit dierent biological kinetics in vivo according to their size, coating
or targeting. To go further in the understanding of the toxicity mechanisms in vivo, analytical developments are
required to thoroughly study the biodistribution and biotransformation of the NMs in organisms, tissue and even
Bio-imaging (in vivo or ex vivo, 2D or 3D) is an expanding eld with the development of state-of-the art
techniques such as electron microscopy (SEM, TEM)
, atomic force microscopy (AFM)
, confocal uorescence
, or positron emission tomography/computed tomography
. To date, the challenge in nanotoxicol-
ogy is to detect and locate small objects as NMs and NMs aggregates in so organs, tissues and biological cells.
is required the use of bio-imaging techniques with high spatial resolution and sucient contrast. e highest
resolution of biological structures is generally achieved using optical or transmission electron microscopy e.g.
but requires destructive manipulation of the 3D tissue structures. Indeed this method entails extensive tissue
Aix Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, Aix-en-Provence, France.
Univ Avignon, Inst
Mediterraneen Biodiversite & Ecol Marine & C, Aix Marseille Univ, CNRS, IRD, Marseille, France.
AP HM La
Conception, CECOS, Lab Reprod Biol, Dept Gynecol Obstet & Reprod Med, Pole Femmes Parents Enfants, Marseille,
International Consortium for the Environmental Implications of Nanotechnology iCEINT, CNRS–Duke
University, Aix en Provence, France.
INSERM, Equipe 04, U955, Creteil, France.
Univ Paris Est Creteil, IMRB, Fac
Med, DHU A TVB, Creteil, France.
OSUG-FAME, UMS 832 CNRS-Univ. Grenoble Alpes, F-38041, Grenoble, France.
Correspondence and requests for materials should be addressed to P.C. (email: firstname.lastname@example.org)
Received: 23 August 2017
Accepted: 9 February 2018
Published: xx xx xxxx