Timing, hosts and locations of (grouped) events of NanoImpactNet

High Resolution Electron Microscopy image of ZnO particles
2) Single Photon Emission Computed Tomography (SPECT)
and Positron Emission Tomography (PET) for the
analysis of the uptake, distribution and release of NPs in
vivo.
At the organism level, we propose the novel use of methodologies
such as Single Photon Emission Computed Tomography (SPECT)
and Positron Emission Tomography (PET). Both techniques allow
for the three dimensional mapping or imaging of organs and
functional processes in the body through the detection of
radioactive species. SPECT and PET will be used to directly follow
the uptake, distribution and release of the particles in animal
models by different ingestion ways. To perform this task, special
NPs have to be designed with tracers of gamma radiation (SPECT)
or positron emitters (PET). This complicated task requires the
fabrication and stabilization of these particles under conditions of
hot chemistry, taking into account the limited decay time. Wholebody
analysis using direct imaging techniques of potentially toxic
NP distribution and kinetics has been accomplished.
Image sequence of PET scanning for g-Al218O3 NPs by IV route
NanoSafetyCluster - Compendium 2012
3) Quantification and distribution studies at cellular level,
by Ion Beam Microscopy (IBM), Electron Microscopy
(EM) and Confocal Laser Scanning (CLSM).
There is a profound lack of knowledge concerning the amount of
NPs present in a cell for an applied NP dose. In other words, a
quantitative relation between dose and uptake of NPs at both
organ and cellular level is missing. The particle uptake depends on
the activity of the cells, as well as the size, shape and physicochemical
properties of the nanomaterial. Therefore, the absence of
dose-effect relationships represents a serious drawback for proper
risk evaluation of special intracellular developed effects. At cellular
level, the localization and quantification of metal and metal oxide
NPs will be performed by Ion Beam Microscopy (IBM), Electron
Microscopy (EM) and Confocal Laser Scanning Microscopy (CLSM
or LSCM).
A) Confocal laser scanning microscopy image of HepG2 cells after
being incubated with CeO2 NPs for 24hrs. (B) HepG2 cells without
exposure to NPs as control.
IBM is a unique and very powerful technique capable of localizing
and quantifying these particles as well as performing elemental
map distributions inside cells. It does not require particle labelling
and relatively thick specimens can be investigated. The IBM
technique is based on the targeting of a sample with high
energetic ions (with approximately 2-3 MeV energy), which
penetrate the targeted sample interacting with the electrons and
nuclei present. This leads to an excitation of electron shells, which
rearrange themselves under emission of electromagnetic radiation
(X-rays and light).
PIXE elemental mapping of A549 cells treated during 72 h with
various NPs: A- ZnO; B – CeO2; C – TiOx; D - FeOx . Left images
demonstrate the P distribution (yellow is maximum, black is
minimum) and right images – overlapping of two elements in the
cells: S (green) and NPs metal (Zn, Ce, Ti, and Fe) (purple).
Compendium of Projects in the European NanoSafety Cluster 37