Enhanced Multiplexing of Immunofluorescence Microscopy Using a Long‐Stokes‐Shift Fluorophore

2021 ◽  
Vol 1 (8) ◽  
Author(s):  
Sydney J. Reitz ◽  
Andrew D. Sauerbeck ◽  
Terrance T. Kummer
Author(s):  
J. H. Hayden

In a previous study, Allen video-enhanced constrast/differential interference constrast (AVEC-DIC) microscopy was used in conjunction with immunofluorescence microscopy to demonstrate that organelles and vesicle move in either direction along linear elements composed of microtubules. However, this study was limited in that the number of microtubules making up a linear element could not be determined. To overcome this limitation, we have used AVEC-DIC microscopy in conjunction with whole mount electron microscopy.Keratocytes from Rana pipiens were grown on glass coverslips as described elsewhere. Gold London Finder grids were Formvar- and carbon coated, and sterilized by exposure to ultraviolet light. It is important to select a Formvar film that gives a grey reflection when it is floated on water. A silver film is too thick and will detract from the image in the light microscope.


2019 ◽  
Author(s):  
Young-Kwang Jung ◽  
Joaquin Calbo ◽  
Ji-Sang Park ◽  
Lucy D. Wahlley ◽  
Sunghyun Kim ◽  
...  

Cs<sub>4</sub>PbBr<sub>6 </sub>is a member of the halide perovskite family that is built from isolated (zero-dimensional) PbBr<sub>6</sub><sup>4-</sup> octahedra with Cs<sup>+</sup> counter ions. The material exhibits anomalous optoelectronic properties: optical absorption and weak emission in the deep ultraviolet (310 - 375 nm) with efficient luminescence in the green region (~ 540 nm). Several hypotheses have been proposed to explain the giant Stokes shift including: (i) phase impurities; (ii) self-trapped exciton; (iii) defect emission. We explore, using first-principles theory and self-consistent Fermi level analysis, the unusual defect chemistry and physics of Cs<sub>4</sub>PbBr<sub>6</sub>. We find a heavily compensated system where the room-temperature carrier concentrations (< 10<sup>9</sup> cm<sup>-3</sup>) are more than one million times lower than the defect concentrations. We show that the low-energy Br-on-Cs antisite results in the formation of a polybromide (Br<sub>3</sub>) species that can exist in a range of charge states. We further demonstrate from excited-state calculations that tribromide moieties are photoresponsive and can contribute to the observed green luminescence. Photoactivity of polyhalide molecules is expected to be present in other halide perovskite-related compounds where they can influence light absorption and emission. <br>


Author(s):  
Young-Kwang Jung ◽  
Joaquin Calbo ◽  
Ji-Sang Park ◽  
Lucy D. Wahlley ◽  
Sunghyun Kim ◽  
...  

Cs<sub>4</sub>PbBr<sub>6 </sub>is a member of the halide perovskite family that is built from isolated (zero-dimensional) PbBr<sub>6</sub><sup>4-</sup> octahedra with Cs<sup>+</sup> counter ions. The material exhibits anomalous optoelectronic properties: optical absorption and weak emission in the deep ultraviolet (310 - 375 nm) with efficient luminescence in the green region (~ 540 nm). Several hypotheses have been proposed to explain the giant Stokes shift including: (i) phase impurities; (ii) self-trapped exciton; (iii) defect emission. We explore, using first-principles theory and self-consistent Fermi level analysis, the unusual defect chemistry and physics of Cs<sub>4</sub>PbBr<sub>6</sub>. We find a heavily compensated system where the room-temperature carrier concentrations (< 10<sup>9</sup> cm<sup>-3</sup>) are more than one million times lower than the defect concentrations. We show that the low-energy Br-on-Cs antisite results in the formation of a polybromide (Br<sub>3</sub>) species that can exist in a range of charge states. We further demonstrate from excited-state calculations that tribromide moieties are photoresponsive and can contribute to the observed green luminescence. Photoactivity of polyhalide molecules is expected to be present in other halide perovskite-related compounds where they can influence light absorption and emission. <br>


2020 ◽  
Vol 6 (2) ◽  
pp. 134-146 ◽  
Author(s):  
Kehkashan Arshad Qamar ◽  
Ahsana Dar Farooq ◽  
Bina S. Siddiqui ◽  
Nurul Kabir ◽  
Sabira Begum

Aims: The aim of the current study was to identify active compound(s) responsible for the antiproliferative effects of O. basilicum and explore their underlying mechanism/s. Background: Plants have been the source of medicines for the treatment of various diseases since ancient times. Ocimum basilicum (Sweet Basil, Bobai Tulsi) has been used in the folk medicine for the treatment of human liver, spleen and stomach cancers. Background: Plants have been the source of medicines for the treatment of various diseases since ancient times. Ocimum basilicum (Sweet Basil, Bobai Tulsi) has been used in the folk medicine for the treatment of human liver, spleen and stomach cancers. Objective: To emphasize the importance of O. basilicum as a potential novel non-toxic alternative to the conventional anticancer therapy. Method: O. basilicum (aerial parts) methanolic extract and fractions were screened against HT-144, MCF-7, NCI-H460 and SF-268 human cancer cell lines using sulforhodamine B assay. The more active Petroleum Ether Insoluble (PEI) fraction was fractionated into six sub-fractions (OB-1 to OB-6). Four pure compounds (3-O-methyl ursolic acid, oleanolic acid, 3-epi-ursolic acid and ursolic acid) were isolated from the more potent sub-fraction OB- 6. Triple channel immunofluorescence microscopy was employed to observe the effects of methanolic extract, PEI fraction, sub-fractions OB-5 and OB-6, 3-epi-ursolic acid and oleanolic acid on the cytoskeleton and nuclei of MCF-7 cells. Result: The methanolic extract and the PEI fraction exhibited selectively greater growth inhibition against MCF-7 cell line (TGI: 56 and 36.2 µg/ml, respectively). By using triple channel immunofluorescence microscopy, it was observed that the methanolic extract, PEI fraction, sub-fraction OB-5 and 3-epi-ursolic acid induced irregular mitotic spindle formation and slowing of mitotic progression in MCF-7 cells while sub-fraction OB-6 induced mitotic arrest in the prophase stage. F-actin aggregation was also visible in PEI fraction, subfraction OB-5 and 3-epi-ursolic acid treated MCF-7 cells. Conclusion: These results emphasize the importance of O. basilicum as a potential novel non-toxic alternative to the conventional anticancer therapy and suggest that it inhibits the growth of MCF-7 cancer cells via multiple mechanisms such as interaction with the microtubules and mitotic spindle apparatus, and F-actin aggregation.


2021 ◽  
Author(s):  
Jiahui Du ◽  
Bing Zhao ◽  
Wei Kan ◽  
Haochun Yin ◽  
Tianshu Song ◽  
...  

Development of highly sensitive and selective fluorescent sensors toward Cu2+ has gained considerable attention in view of its application of environmental and biological fields. However, the strategy of sensing by...


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