Development of insulator base pairs for the drastic enhancement of quantum yield

2011 ◽  
Author(s):  
Hiromu Kashida ◽  
Koji Sekiguchi ◽  
Hiroyuki Asanuma
Keyword(s):  
Quantum Yield ◽  
Base Pairs

Detection of the Glanzmann's Thrombasthenia Mutations in Arab and Iraqi-Jewish Patients by Polymerase Chain Reaction and Restriction Analysis of Blood or Urine Samples

1991 ◽  
Vol 66 (04) ◽  
pp. 500-504 ◽  
Author(s):  
H Peretz ◽  
U Seligsohn ◽  
E Zwang ◽  
B S Coller ◽  
P J Newman
Keyword(s):  
Polymerase Chain Reaction ◽  
Base Pair ◽  
Restriction Analysis ◽  
Urine Samples ◽  
Chain Reaction ◽  
Base Pairs ◽  
Glanzmann’S Thrombasthenia ◽  
Glanzmann's Thrombasthenia ◽  
Base Pair Deletion ◽  
Polymerase Chain

SummarySevere Glanzmann's thrombasthenia is relatively frequent in Iraqi-Jews and Arabs residing in Israel. We have recently described the mutations responsible for the disease in Iraqi-Jews – an 11 base pair deletion in exon 12 of the glycoprotein IIIa gene, and in Arabs – a 13 base pair deletion at the AG acceptor splice site of exon 4 on the glycoprotein IIb gene. In this communication we show that the Iraqi-Jewish mutation can be identified directly by polymerase chain reaction and gel electrophoresis. With specially designed oligonucleotide primers encompassing the mutation site, an 80 base pair segment amplified in healthy controls was clearly distinguished from the 69 base pair segment produced in patients. Patients from 11 unrelated Iraqi-Jewish families had the same mutation. The Arab mutation was identified by first amplifying a DNA segment consisting of 312 base pairs in controls and of 299 base pairs in patients, and then digestion by a restriction enzyme Stu-1, which recognizes a site that is absent in the mutant gene. In controls the 312 bp segment was digested into 235 and 77 bp fragments, while in patients there was no change in the size of the amplified 299 bp segment. The mutation was found in patients from 3 out of 5 unrelated Arab families. Both Iraqi-Jewish and Arab mutations were detectable in DNA extracted from blood and urine samples. The described simple methods of identifying the mutations should be useful for detection of the numerous potential carriers among the affected kindreds and for prenatal diagnosis using DNA extracted from chorionic villi samples.

Size-dependent emission of a dipole coupled to a metal nanoparticle

MRS Advances ◽  
2020 ◽  
Vol 5 (62) ◽  
pp. 3315-3325
Author(s):  
Viktoriia Savchuk ◽  
Arthur R. Knize ◽  
Pavlo Pinchuk ◽  
Anatoliy O. Pinchuk
Keyword(s):  
Numerical Analysis ◽  
Quantum Yield ◽  
Electric Dipole ◽  
Incident Radiation ◽  
Metal Nanoparticle ◽  
Plasmonic Nanoparticle ◽  
Size Dependent ◽  
Emission Enhancement ◽  
Electric Dipoles

AbstractWe present a systematic numerical analysis of the quantum yield of an electric dipole coupled to a plasmonic nanoparticle. We observe that the yield is highly dependent on the distance between the electric dipole and the nanoparticle, the size and permittivity of the nanoparticle, and the wavelength of the incident radiation. Our results indicate that enhancement of the quantum yield is only possible for electric dipoles coupled to a nanoparticle with a radius of 20 nm or larger. As the size of the nanoparticle is increased, emission enhancement occurs at wavelengths dependent on the coupling distance.

Highly Fluorescent Au25-xAgx Nanoclusters Protected with Poly(ethylene glycol) - and Zwitterion-Modified Thiolate Ligands

2018 ◽  
Author(s):  
Dinesh Mishra ◽  
Sisi Wang ◽  
Zhicheng Jin ◽  
Eric Lochner ◽  
Hedi Mattoussi
Keyword(s):  
Quantum Yield ◽  
Near Infrared ◽  
Small Diameter ◽  
Binding Energies ◽  
Thiolate Ligands ◽  
Nir Emission ◽  
Thiolate Complexes ◽  
Long Lifetime ◽  
Poly Ethylene

<p>We describe the growth and characterization of highly fluorescing, near-infrared-emitting nanoclusters made of bimetallic Au<sub>25-x</sub>Ag<sub>x</sub> cores, prepared using various monothiol-appended hydrophobic and hydrophilic ligands. The reaction uses well-defined triphenylphosphine-protected Au<sub>11</sub> clusters (as precursors), which are reacted with Ag(I)-thiolate complexes. The prepared nanoclusters are small (diameter < 2nm, as characterized by TEM) with emission peak at 760 nm and long lifetime (~12 µs). The quantum yield measured for these materials was 0.3 - 0.4 depending on the ligand. XPS measurements show the presence of both metal atoms in the core, with measured binding energies that agree with reported values for nanocluster materials. The NIR emission combined with high quantum yield, small size and ease of surface functionalization afforded by the coating, make these materials suitable to implement investigations that address fundamental questions and potentially useful for biological sensing and imaging applications.<br></p>

Synthesis and Characterization of ROSA Dye - A Rhodamine B-type Fluorophore, Suitable for Bioconjugation and Fluorescence Studies in Live Cells

2019 ◽  
Vol 26 (10) ◽  
pp. 758-767
Author(s):  
Vicente Rubio ◽  
Vijaya Iragavarapu ◽  
Maciej J. Stawikowski
Keyword(s):  
Quantum Yield ◽  
Cancer Cells ◽  
Fluorescent Probe ◽  
Extinction Coefficient ◽  
Rhodamine B ◽  
Solid Phase ◽  
Total Yield ◽  
Molar Extinction Coefficient ◽  
Αvβ3 Integrin ◽  
Αvβ3 Integrins

Background: Herein we report the multigram-scale synthesis, characterization and application of a rhodamine B-based fluorophore (ROSA) suitable for fluorescent studies in biological applications. This fluorophore is devoid of rhodamine spirolactone formation and furthermore characterized by a high molar extinction coefficient (ϵ=87250 ± 1630 M-1cm-1) and quantum yield (φ) of 0.589 ± 0.070 in water. Reported here is also the application of ROSA towards synthesis of a ROSA-PEG-GRGDS-NH2 fluorescent probe suitable for live cell imaging of αvβ3 integrins for in vitro assays. Objective: The main objective of this study is to efficiently prepare rhodamine B derivative, devoid of spirolactone formation that would be suitable for bioconjugation and subsequent bioimaging. Methods: Rhodamine B was transformed into rhodamine B succinimide ester (RhoB-OSu) using N-hydroxysuccinimide. RhoB-OSu was further coupled to sarcosine to obtain rhodamine Bsarcosine dye (ROSA) in good yield. The ROSA dye was then coupled to a αvβ3 integrin binding sequence using standard solid-phase conditions. Resulting ROSA-PEG-GRGDS-NH2 probe was used to image integrins on cancer cells. Results: The rhodamine B-sarcosine dye (ROSA) was obtained in multigram scale in good total yield of 47%. Unlike rhodamine B, the ROSA dye does not undergo pH-dependent spirolactone/spirolactam formation as compared with rhodamine B-glycine. It is also characterized by excellent quantum yield (φ) of 0.589 ± 0.070 in water and high molar extinction coefficient of 87250 ± 1630 M-1cm-1. ROSA coupling to the RGD-like peptide was proved to be efficient and straightforward. Imaging using standard filters on multimode plate reader and confocal microscope was performed. The αvβ3 integrins present on the surface of live WM-266-4 (melanoma) and MCF- 7 (breast cancer) cells were successfully imaged. Conclusion: We successfully derivatized rhodamine B to create an inexpensive, stable and convenient to use fluorescent probe. The obtained derivative has excellent photochemical properties and it is suitable for bioconjugation and many imaging applications.

New 2-Oxopyridine/2-Thiopyridine Derivatives Tethered to a Benzotriazole with Cytotoxicity on MCF7 Cell Lines and with Antiviral Activities

2020 ◽  
Vol 17 (2) ◽  
pp. 124-137 ◽  
Author(s):  
Adel Mahmoud Attia ◽  
Ahmed Ibrahin Khodair ◽  
Eman Abdelnasser Gendy ◽  
Mohammed Abu El-Magd ◽  
Yaseen Ali Mosa Mohamed Elshaier
Keyword(s):  
Dna Damage ◽  
Anticancer Agents ◽  
Active Compound ◽  
Docking Study ◽  
Base Pairs ◽  
Dna Base ◽  
Dna Base Pairs ◽  
Antiviral Activities ◽  
Active Methylene ◽  
Damage Study

Background:Perturbation of nucleic acids structures and confirmation by small molecules through intercalation binding is an intriguing application in anticancer therapy. The planar aromatic moiety of anticancer agents was inserted between DNA base pairs leading to change in the DNA structure and subsequent functional arrest.Objective:The final scaffold of the target compounds was annulated and linked to a benzotriazole ring. These new pharmacophoric features were examined as antiviral and anticancer agents against MCF7 and their effect on DNA damage was also assessed.Methods:A new series of fully substituted 2-oxopyridine/2-thioxopyridine derivatives tethered to a benzotriazole moiety (4a-h) was synthesized through Michael cyclization of synthesized α,β- unsaturated compounds (3a-e) with appropriate active methylene derivatives. The DNA damage study was assessed by comet assay. In silico DNA molecular docking was performed using Open Eye software to corroborate the experimental results and to understand molecule interaction at the atomic level.Results:The highest DNA damage was observed in Doxorubicin, followed by 4h, then, 4b, 4g, 4f, 4e, and 4d. The docking study showed that compound 4h formed Hydrogen Bonds (HBs) as a standard ligand with GSK-3. Compound 4h was the most active compound against rotavirus Wa, HAVHM175, and HSV strains with a reduction of 30%, 40%, and 70%, respectively.Conclusion:Compound 4h was the most active compound and could act as a prospective lead molecule for anticancer agent.

On the change of the order od stability of DNA base pairs as a result of the methylation of guanine

1988 ◽  
Vol 53 (9) ◽  
pp. 1943-1945
Author(s):  
Pavel Hobza ◽  
Camille Sandorfy
Keyword(s):  
Ab Initio ◽  
Base Pairs ◽  
Dispersion Energy ◽  
Dna Base ◽  
Dna Base Pairs

The interaction of the 6-O methylguanine cation with cytosine and thymine was studied using the ab initio SCF method in combination with a London type expression for dispersion energy. The structure of the complex formed with cytosine differs from that found previously with guanine itself.

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