Biomedical Engineering Reference
In-Depth Information
(A)
(B)
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Phase signal
Calcium signal
Glutamate
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Phase signal
Calcium signal
Glutamate
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m
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Time (min)
Time (min)
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Figure 5.5
(A) Phase signal monitoring and calcium imaging through Fluo-4 measurement in the case of
(left) a calcium regulation, linked with a rapid recovery of the phase signal and (right) a calcium
deregulation linked with the strong phase signal decrease. (B) Image of neuron cells after a
glutamate stimulation, shown in phase (top). The image can be linked with the fluorescence
signal detected from propidium iodide (bottom), where a clear staining can be identified on
several cells. Source: Modified from Ref.
[157]
.
the development of real time and high-resolution DHM-based optical diffraction
tomography, would avoid these potential interpretation difficulties of the phase signal by
having direct access to the 3D map of refractive index
[158
160]
. Obtaining a high-
resolution 3D map of the intracellular refractive index could provide invaluable information
about cytoarchitecture and the emerging concept of the functional compartmentalization of
cytoplasm, which plays a critical role in many fundamental cell mechanisms, including
proteins synthesis. See Sections 4.1 and 4.2 of Chapter 4 for more information about the
recent development of optical diffraction tomography.
On the other hand, promising future directions involve integrating DHM into a multimodal
microscope able to provide various different types of information on the cell state, a
necessary step to obtain a comprehensive understanding of cell dynamics. For instance,
DHM will benefit from the specificity of fluorescent dyes to correlate cell morphology with
specific protein or ion localization and dynamics
[32,37,161]
. Furthermore, information
concerning transmembrane current obtained from electrophysiological recording combined
with phase signal allows us to pave the way for studying the involvement of specific
receptors or cotransporters in the physiological and/or pathological cellular processes
[155]
.
Acknowledgments
The authors would like to thank the people of the Microvision and Microdiagnostic group at the EFPL and those
at Lync´e Tec (
www.lynceetec.com
) for fruitful discussions during the writing of this chapter.
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