Using attenuated total reflection in the terahertz domain, we studied the dynamics of MDCK cells after permeabilization by saponin molecules. We developed an analytical model taking into account molecules diffusion, cell geometry, and pore dynamics.
Using attenuated total reflection (ATR) in the terahertz domain, we demonstrate non-invasive, non-staining real time measurements of cytoplasm leakage during permeabilization of live epithelial cells by saponin detergent and after electropermeabilization. The origin of the contrast observed between cells and culture medium is addressed by both experimental and theoretical approaches, and gives access to permeabilization dynamics of live cells in real time. We show that terahertz modalities are more sensitive than fluorescence microscopy which is the reference optical technique for electropermeabilization. We propose analytical models for the influx and efflux of non-permeant molecules through permeabilized cell membranes.
Using attenuated total reflection (ATR) in the terahertz domain, we demonstrate non-invasive, non-staining real time measurements of cytoplasm leakage during permeabilization of live epithelial cells by saponin, and after electropermeabilization. The origin of the contrast observed between cells and culture medium is addressed by both experimental and theoretical approaches, and gives access to permeabilization dynamics of live cells in real time. We show that terahertz modalities are more sensitive than fluorescence microscopy which is the reference optical technique for electropermeabilization. We propose analytical models for the influx and efflux of non-permeant molecules through permeabilized cell membranes.
We demonstrated the direct and noninvasive imaging of functional neurons by Ionic Contrast Terahertz (ICT)
near-field microscopy. This technique provides quantitative measurements of ionic concentrations in both the
intracellular and extracellular compartments and opens the way to direct noninvasive imaging of neurons during
electrical, toxin, or thermal stresses. Furthermore, neuronal activity results from both a precise control
of transient variations in ionic conductance and a much less studied water exchange between the extracellular
matrix and the intraaxonal compartment. The developed ICT technique associated with a full three-dimensional
simulation of the axon-aperture near-field system allows a precise measurement of the axon geometry and therefore
the direct visualization of neuron swelling induced by temperature change or neurotoxin poisoning. We
also developed Terahertz Attenuated Total Reflection (ATR) devices perfectly suited for studying cell layers.
Inserted in a terahertz time-domain system, and using a high resistivity low loss silicon prism to couple the
terahertz wave into the sample, the detection scheme is based on the relative differential spectral phase of two
orthogonal polarizations. Biological sample imaging as well as subwavelength (λ/16) longitudinal resolution are
demonstrated.
A wide-band spectral diagnostic system based on dispersion property of the Zinc Selenide prism, a crystalline
material highly dispersive in the near-to-far infrared spectral range, has been studied and developed for the laser
wakefield acceleration experiment at LOA for the measurement of few femto-seconds long electron beam. The
extensive PIC simulation studies of the colliding-beam LWFA have shown very short electron beam duration of
less than 10 femtoseconds. The prism spectrometer diagnostic with highly sensitive Mercury Cadmium Telluride
infrared detector and the diffraction-grating spectrometer with a high-resolution imaging visible camera together
have the spectral range coverage and resolution capable of detecting ultra-short Coherent Transition Radiation
(CTR) generated by interaction of bunch charges with a 100 microns thickness aluminum foil. The beam profile
of asymmetric shape then could be extracted from the CTR spectrum by inverse Fourier transformation with
Kramers-Kronig relation. The diagnostic system has been tested and calibrated for characterization of blackbody
source spectrum and spectral responsivity. The measurement of electron beam duration of few femtoseconds has
yet been convincingly shown with high resolution, and the measurements of this kind have important implication
in understanding and subsequent successful operation of the future FEL light source with a highly mono-energetic
LWFA beam source.
We demonstrated the direct and noninvasive imaging of functional neurons,1 as well as auricular heart muscle
electrical activity2 by Ionic Contrast Terahertz (ICT) near-field microscopy. This technique provides quantitative
measurements of ionic concentrations in both the intracellular and extracellular compartments and opens
the way to direct noninvasive imaging of neurons during electrical, toxin, or thermal stresses. Furthermore,
neuronal activity results from both a precise control of transient variations in ionic conductances and a much
less studied water exchange between the extracellular matrix and the intraaxonal compartment. The developed
ICT technique associated with a full three-dimensional simulation of the axon-aperture near-field system allows
a precise measurement of the axon geometry and therefore the direct visualization of neuron swelling induced by
temperature change or neurotoxin poisoning. This technique should then provide grounds for the development
of advanced functional neuroimaging methods based on diffusion anisotropy of water molecules.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.