Astrocyte sensitivity to pulsed infrared light: molecular, physiological, and mechanistic insights (Conference Presentation)

2020 ◽  
Author(s):  
Wilson R. Adams ◽  
Ana I. Borrachero-Conejo ◽  
Emanuela Saracino ◽  
Manqing Wang ◽  
Tamara Posati ◽  
...  
Keyword(s):  
Infrared Light

Fluorescent proteins for in vivo imaging, where's the biliverdin?

2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez
Keyword(s):  
Hydrogen Peroxide ◽  
In Vivo Imaging ◽  
Near Infrared ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Fluorescent Imaging ◽  
Infrared Light ◽  
Red Fluorescent Protein ◽  
Color Palette

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.

Quantum fountain infrared light sources based on intersubband emissions in quantum wells

1999 ◽  
Vol 09 (PR2) ◽  
pp. Pr2-161
Author(s):  
F. H. Julien ◽  
P. Boucaud ◽  
S. Sauvage ◽  
O. Gauthier-Lafaye ◽  
Z. Moussa
Keyword(s):  
Quantum Wells ◽  
Infrared Light ◽  
Light Sources

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

2020 ◽  
Author(s):  
Alex Stafford ◽  
Dowon Ahn ◽  
Emily Raulerson ◽  
Kun-You Chung ◽  
Kaihong Sun ◽  
...  
Keyword(s):  
Near Infrared ◽  
Transient Absorption ◽  
Reaction Times ◽  
Infrared Light ◽  
Structure Property ◽  
Light Emitting ◽  
Structure Property Relationships ◽  
Nir Light ◽  
Light Intensities ◽  
Emission Quenching

Driving rapid polymerizations with visible to near-infrared (NIR) light will enable nascent technologies in the emerging fields of bio- and composite-printing. However, current photopolymerization strategies are limited by long reaction times, high light intensities, and/or large catalyst loadings. Improving efficiency remains elusive without a comprehensive, mechanistic evaluation of photocatalysis to better understand how composition relates to polymerization metrics. With this objective in mind, a series of methine- and aza-bridged boron dipyrromethene (BODIPY) derivatives were synthesized and systematically characterized to elucidate key structure-property relationships that facilitate efficient photopolymerization driven by visible to NIR light. For both BODIPY scaffolds, halogenation was shown as a general method to increase polymerization rate, quantitatively characterized using a custom real-time infrared spectroscopy setup. Furthermore, a combination of steady-state emission quenching experiments, electronic structure calculations, and ultrafast transient absorption revealed that efficient intersystem crossing to the lowest excited triplet state upon halogenation was a key mechanistic step to achieving rapid photopolymerization reactions. Unprecedented polymerization rates were achieved with extremely low light intensities (< 1 mW/cm<sup>2</sup>) and catalyst loadings (< 50 μM), exemplified by reaction completion within 60 seconds of irradiation using green, red, and NIR light-emitting diodes.

An ordered copper nanowell-array film with near-perfect broadband absorption from ultraviolet to near-infrared light

2020 ◽  
Vol 59 (11) ◽  
pp. 110906
Author(s):  
Juan Shen ◽  
Yong Ren ◽  
Xinxin Zhu ◽  
Min Mao ◽  
Quan Zhou ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Broadband Absorption

Use of indocianine green fluorescence in acute mesenteric ischemia

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Jaime Bonnín-Pascual
Keyword(s):  
Indocyanine Green ◽  
Terminal Ileum ◽  
Mesenteric Ischemia ◽  
Intestinal Anastomosis ◽  
Acute Mesenteric Ischemia ◽  
Left Colon ◽  
Infrared Light ◽  
High Morbidity ◽  
Green Fluorescence ◽  
Clinical Cases

Introduction: Acute mesenteric ischemia has a high morbidity and mortality and constitutes an intraoperative challenge in the management of ischemic areas. In this context, we analyze the use of indocyanine green fluorescence to assess intestinal vascularization through 3 clinical cases. Case presentation: we present 3 clinical cases operated for acute mesenteric ischemia. Evaluation of intestinal viability is performed under infrared light after intravenous infusion of 25 mg of indocyanine green. Case 1 is a 42-year-old male with multiple antecedents of severe vascular disease, presenting with a massive acute mesenteric ischemia involving multiple intestinal segments. Fluorescence allows two adjusted bowel resections with double intestinal anastomosis. Case 2 is a 74-year-old woman with a history of non-anticoagulated atrial fibrillation who is decided to perform an urgent surgery when an esophageal, gastric and portal system pneumatosis is observed, as indirect signs of ischemia, in urgent CT. During the surgical act there is an ischemia of the terminal ileum and right colon without clear signs of involvement at the esophageal-gastric level. The assessment after administration of ICG discriminates the clear ischemic involvement from terminal ileum to ascending colon and patched in the transverse and left colon, without esophageal or gastric involvement. Case 3 is a 49-year-old woman with aortoiliac and visceral Takayasu disease and revascularization surgery of the celiac trunk. Given the increase in abdominal pain, a new CT scan demonstrates colonic pneumatosis. Urgent laparotomy shows necrosis at the level of the left colon and hypoperfusion of the cecum. The administration of ICG finds a lack of uptake of the entire colon. A subtotal colectomy with ileostomy and mucous fistula is performed. Introduction: Acute mesenteric ischemia has a high morbidity and mortality and constitutes an intraoperative challenge in the management of ischemic areas. In this context, we analyze the use of indocyanine green fluorescence to assess intestinal vascularization through 3 clinical cases. Case presentation: we present 3 clinical cases operated for acute mesenteric ischemia. Evaluation of intestinal viability is performed under infrared light after intravenous infusion of 25 mg of indocyanine green. Case 1 is a 42-year-old male with multiple antecedents of severe vascular disease, presenting with a massive acute mesenteric ischemia involving multiple intestinal segments. Fluorescence allows two adjusted bowel resections with double intestinal anastomosis. Case 2 is a 74-year-old woman with a history of non-anticoagulated atrial fibrillation who is decided to perform an urgent surgery when an esophageal, gastric and portal system pneumatosis is observed, as indirect signs of ischemia, in urgent CT. During the surgical act there is an ischemia of the terminal ileum and right colon without clear signs of involvement at the esophageal-gastric level. The assessment after administration of ICG discriminates the clear ischemic involvement from terminal ileum to ascending colon and patched in the transverse and left colon, without esophageal or gastric involvement. Case 3 is a 49-year-old woman with aortoiliac and visceral Takayasu disease and revascularization surgery of the celiac trunk. Given the increase in abdominal pain, a new CT scan demonstrates colonic pneumatosis. Urgent laparotomy shows necrosis at the level of the left colon and hypoperfusion of the cecum. The administration of ICG finds a lack of uptake of the entire colon. A subtotal colectomy with ileostomy and mucous fistula is performed. Conclusions: The fluorescence with ICG provides a better visualization of the intestinal vascularization in the AMI, and allows to determine the limits of the affected tissue to perform adjusted resections.

Robust fibers for delivering infrared light

SPIE Newsroom ◽  
2014 ◽  
Author(s):  
Guangming Tao ◽  
Ayman F. Abouraddy
Keyword(s):  
Infrared Light
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