IR/Raman imaging in vitro for investigation of cell/fiber interaction
Yao Seydou
Université de Bordeaux, CNRS UMR 5248 CBMN, 14 Allée Geoffroy St-Hillaire, 33600 Pessac, France
Abstract:
Amphiboles caused cohorts of deaths in exposed workers, leading to some of the largest class
actions in the industry. Once inhaled, these inorganic fibers are thought to be both chemically and
morphologically toxic, and their biopersistence in lungs over decades lead to progressive
pathologies, mesothelioma and asbestosis. However, this exceptionally long chronicity for human
pathologies suggests that chemical toxicity is certainly low, making that morphological
parameters could be more relevant in the pathology. Here, we developed a 3D Raman/optical
imaging methodology in vitro to characterize both morphological and chemical parameters of
cell/fiber interactions. We determined that lung cells could vesiculate amphiboles with length
below 5 µm (figure 1) or could embed those not exceeding 15 µm in their fibrous extracellular
matrix. Lung cells can thus develop defense strategies for handling the biopersistence of
inorganic species, which may thus have major impact for biosafety issues related to
nanomaterials. We also propose to use ATR-FTIR imaging of live cells for analyzing the
interface formed by lung cell ECM and amphiboles when fibers have length between 5 and 15
µm. The methodology for in vitro FTIR imaging will be presented with analytical performances
obtained on a new ATR objective designed for this purpose. The analytical potential of this
multimodal vibrational spectroscopy imaging resource will be discussed.
Figure:
A) Visible image the target of cell
B) combined image of the cell (in
blue), the fiber (in white) and a
vesicle (in red); z=1.5µm C)
Spectra of each component from
(B): cell spectrum in blue, fiber
spectrum in black and the vesicle
spectrum in red. Integration
values (a.u., average ± standard
deviation) from the lipids and
asbestos fiber spectral region for
each class of spectra are above
the colored arrow. The red box
corresponds to the Raman
microscopy area of interest.