Two-photon-excited fluorescence from silicate glass containing tantalum ions pumped by a near-infrared femtosecond pulsed laser

2006 ◽  
Vol 31 (19) ◽  
pp. 2867 ◽  
Author(s):  
Xiangeng Meng ◽  
Katsuhisa Tanaka ◽  
Shunsuke Murai ◽  
Koji Fujita ◽  
Kiyotaka Miura ◽  
...  
Keyword(s):  
Silicate Glass ◽  
Near Infrared ◽  
Pulsed Laser ◽  
Two Photon ◽  
Femtosecond Pulsed Laser

scholarly journals Two-photon microscopy-guided femtosecond-laser photoablation of avian cardiogenesis: noninvasive creation of localized heart defects

2010 ◽  
Vol 299 (5) ◽  
pp. H1728-H1735 ◽  
Author(s):  
Huseyin C. Yalcin ◽  
Akshay Shekhar ◽  
Nozomi Nishimura ◽  
Ajinkya A. Rane ◽  
Chris B. Schaffer ◽  
...  
Keyword(s):  
Heart Defects ◽  
Pulsed Laser ◽  
Genetic Mutation ◽  
Cardiac Morphogenesis ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Myocardial Wall ◽  
Heart Formation ◽  
Arterial Constriction ◽  
Femtosecond Pulsed Laser

Embryonic heart formation is driven by complex feedback between genetic and hemodynamic stimuli. Clinical congenital heart defects (CHD), however, often manifest as localized microtissue malformations with no underlying genetic mutation, suggesting that altered hemodynamics during embryonic development may play a role. An investigation of this relationship has been impaired by a lack of experimental tools that can create locally targeted cardiac perturbations. Here we have developed noninvasive optical techniques that can modulate avian cardiogenesis to dissect relationships between alterations in mechanical signaling and CHD. We used two-photon excited fluorescence microscopy to monitor cushion and ventricular dynamics and femtosecond pulsed laser photoablation to target micrometer-sized volumes inside the beating chick hearts. We selectively photoablated a small (∼100 μm radius) region of the superior atrioventricular (AV) cushion in Hamburger-Hamilton 24 chick embryos. We quantified via ultrasound that the disruption causes AV regurgitation, which resulted in a venous pooling of blood and severe arterial constriction. At 48 h postablation, quantitative X-ray microcomputed tomography imaging demonstrated stunted ventricular growth and pronounced left atrial dilation. A histological analysis demonstrated that the laser ablation produced defects localized to the superior AV cushion: a small quasispherical region of cushion tissue was completely obliterated, and the area adjacent to the myocardial wall was less cellularized. Both cushions and myocardium were significantly smaller than sham-operated controls. Our results highlight that two-photon excited fluorescence coupled with femtosecond pulsed laser photoablation should be considered a powerful tool for studying hemodynamic signaling in cardiac morphogenesis through the creation of localized microscale defects that may mimic clinical CHD.

scholarly journals Photo-Induced Cell Damage Analysis for Single- and Multifocus Coherent Anti-Stokes Raman Scattering Microscopy

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Takeo Minamikawa ◽  
Yoshinori Murakami ◽  
Naokazu Matsumura ◽  
Hirohiko Niioka ◽  
Shuichiro Fukushima ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Cell Viability ◽  
Near Infrared ◽  
Cell Damage ◽  
Pulsed Laser ◽  
Excitation Scheme ◽  
Two Photon ◽  
Two Photon Fluorescence ◽  
Anti Stokes ◽  
Photon Fluorescence

In this study, we investigated photo-induced damage to living cells during single- and multifocus excitations for coherent anti-Stokes Raman scattering (CARS) imaging. A near-infrared pulsed laser (709 nm) was used to induce cell damage. We compared the photo-induced cell damage in the single- and the multifocus excitation schemes with the condition to obtain the same CARS signal in the same frame rate. For the evaluation of cell viability, we employed 4′,6-diamidino-2-phenylindole (DAPI) fluorophores that predominantly stained the damaged cells. One- and two-photon fluorescence of DAPI fluorophores were, respectively, excited by an ultraviolet light source and the same near-infrared light source and were monitored to evaluate the cell viability during near-infrared pulsed laser irradiation. We found lower uptake of DAPI fluorophores into HeLa cells during the multifocus excitation compared with the single-focus excitation scheme in both the one- and the two-photon fluorescence examinations. This indicates a reduction of photo-induced cell damage in the multifocus excitation. Our findings suggested that the multifocus excitation scheme is expected to be suitable for CARS microscopy in terms of minimal invasiveness.

Picosecond Single-Photon and Femtosecond Two-Photon Pulsed Laser Stimulation for IC Characterization and Failure Analysis

2009 ◽  
Author(s):  
V. Pouget ◽  
E. Faraud ◽  
K. Shao ◽  
S. Jonathas ◽  
D. Horain ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Single Photon ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Laser Stimulation ◽  
Two Photon ◽  
Resolution Improvement ◽  
Ultrashort Laser

Abstract This paper presents the use of pulsed laser stimulation with picosecond and femtosecond laser pulses. We first discuss the resolution improvement that can be expected when using ultrashort laser pulses. Two case studies are then presented to illustrate the possibilities of the pulsed laser photoelectric stimulation in picosecond single-photon and femtosecond two-photon modes.

Lysosomal targeted NIR photosensitizer for photodynamic therapy and two-photon fluorescent imaging

2021 ◽  
Author(s):  
Ruiyuan Liu ◽  
Yuping Zhou ◽  
Di Zhang ◽  
Genghan He ◽  
Chuang Liu ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Fluorescence Imaging ◽  
Near Infrared ◽  
Fluorescent Imaging ◽  
High Fidelity ◽  
Design And Synthesis ◽  
Two Photon ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence

Design and synthesis of near-infrared (NIR) emissive fluorophore for imaging of organelle and photodynamic therapy has received enormous attention. Hence, NIR emissive fluorophore of high-fidelity lysosome targeting, two-photon fluorescence imaging,...

scholarly journals Femtosecond pulsed laser microscopy: a new tool to assess the in vitro delivered dose of carbon nanotubes in cell culture experiments

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Dominique Lison ◽  
Saloua Ibouraadaten ◽  
Sybille van den Brule ◽  
Milica Todea ◽  
Adriana Vulpoi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Cell Culture ◽  
Pulsed Laser ◽  
Lung Fibroblasts ◽  
Laser Microscopy ◽  
Cell Responses ◽  
The Impact ◽  
Delivered Dose ◽  
Femtosecond Pulsed Laser

Abstract Background In vitro models are widely used in nanotoxicology. In these assays, a careful documentation of the fraction of nanomaterials that reaches the cells, i.e. the in vitro delivered dose, is a critical element for the interpretation of the data. The in vitro delivered dose can be measured by quantifying the amount of material in contact with the cells, or can be estimated by applying particokinetic models. For carbon nanotubes (CNTs), the determination of the in vitro delivered dose is not evident because their quantification in biological matrices is difficult, and particokinetic models are not adapted to high aspect ratio materials. Here, we applied a rapid and direct approach, based on femtosecond pulsed laser microscopy (FPLM), to assess the in vitro delivered dose of multi-walled CNTs (MWCNTs). Methods and results We incubated mouse lung fibroblasts (MLg) and differentiated human monocytic cells (THP-1) in 96-well plates for 24 h with a set of different MWCNTs. The cytotoxic response to the MWCNTs was evaluated using the WST-1 assay in both cell lines, and the pro-inflammatory response was determined by measuring the release of IL-1β by THP-1 cells. Contrasting cell responses were observed across the MWCNTs. The sedimentation rate of the different MWCNTs was assessed by monitoring turbidity decay with time in cell culture medium. These turbidity measurements revealed some differences among the MWCNT samples which, however, did not parallel the contrasting cell responses. FPLM measurements in cell culture wells revealed that the in vitro delivered MWCNT dose did not parallel sedimentation data, and suggested that cultured cells contributed to set up the delivered dose. The FPLM data allowed, for each MWCNT sample, an adjustment of the measured cytotoxicity and IL-1β responses to the delivered doses. This adjusted in vitro activity led to another toxicity ranking of the MWCNT samples as compared to the unadjusted activities. In macrophages, this adjusted ranking was consistent with existing knowledge on the impact of surface MWCNT functionalization on cytotoxicity, and might better reflect the intrinsic activity of the MWCNT samples. Conclusion The present study further highlights the need to estimate the in vitro delivered dose in cell culture experiments with nanomaterials. The FPLM measurement of the in vitro delivered dose of MWCNTs can enrich experimental results, and may refine our understanding of their interactions with cells.

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