PULSED PHOTOACOUSTIC DETERMINATION OF ABSOLUTE FLUORESCENT QUANTUM YIELD OF THE LASER DYE RHODAMINE B

1996 ◽  
Vol 10 (22) ◽  
pp. 1103-1110 ◽  
Author(s):  
C.V. BINDHU ◽  
S.S. HARILAL ◽  
RIJU C. ISSAC ◽  
V.P.N. NAMPOORI ◽  
C.P.G. VALLABHAN
Keyword(s):  
Quantum Yield ◽  
Rhodamine B ◽  
Accurate Method ◽  
Rapid Decrease ◽  
Power Dependence ◽  
Laser Dye ◽  
Fluorescent Quantum Yield ◽  
532 Nm ◽  
Absolute Fluorescence

Pulsed photoacoustic technique which is found to be a very convenient and accurate method, is used for the determination of absolute fluorescence quantum yield of laser dye rhodamine B. Concentration and power dependence of quantum yield of rhodamine B in methanol for excitation at 532 nm is reported here. Results show that a rapid decrease in quantum yield as the concentration is increased and finally it reaches the limit corresponding to fluorescence quenching.

scholarly journals Development and validation of HPLC-PDA method for the simultaneous determination of Auramine O and Rhodamine B in foodstuffs

2019 ◽  
Vol 16 (6) ◽  
pp. 16
Author(s):  
Phan Thi Ngoc Trinh ◽  
Nguyen Thanh Thoi ◽  
Huynh Thi Nhan ◽  
Nguyen Ngoc Hung ◽  
Nguyen Thi Tuyet Nhung ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Rhodamine B ◽  
Accurate Method ◽  
Food Samples ◽  
Limits Of Detection ◽  
Basic Dyes ◽  
Auramine O ◽  
Development And Validation ◽  
Detection And Quantification

HPLC-PDA method was used to determine two basic dyes, Auramine O and Rhodamine B in food samples. The limits of detection and quantification of Auramine O (AO) and Rhodamine B (RB) were both 0.02 mg/L and 0.05 mg/L, respectively. The recoveries of AO and RB in matrices ranged from 83.00% to 105.91% with the concentration 0.5 µg/g, 1.0 µg/g and 1.5 µg/g. This is a simple and accurate method which can be applied to quantify of dyes in foodstuffs.

Measurement of the absolute fluorescence quantum yield of rhodamine B solution using a dual-beam thermal lens technique

1996 ◽  
Vol 29 (4) ◽  
pp. 1074-1079 ◽  
Author(s):  
C V Bindhu ◽  
S S Harilal ◽  
Geetha K Varier ◽  
Riju C Issac ◽  
V P N Nampoori ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Rhodamine B ◽  
Thermal Lens ◽  
Fluorescence Quantum Yield ◽  
Dual Beam ◽  
The Absolute ◽  
Absolute Fluorescence

Determination of the absolute fluorescence quantum yield of rhodamine 6G with optical and photoacoustic methods – Providing the basis for fluorescence quantum yield standards

Talanta ◽  
2012 ◽  
Vol 90 ◽  
pp. 30-37 ◽  
Author(s):  
Christian Würth ◽  
Martín G. González ◽  
Reinhard Niessner ◽  
Ulrich Panne ◽  
Christoph Haisch ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Rhodamine 6G ◽  
The Absolute ◽  
Absolute Fluorescence

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.

Development of an HPLC-UV Method for Quantification of Stattic

2019 ◽  
Vol 15 (6) ◽  
pp. 568-573
Author(s):  
Soheil Sedaghat ◽  
Ommoleila Molavi ◽  
Akram Faridi ◽  
Ali Shayanfar ◽  
Mohammad Reza Rashidi
Keyword(s):  
High Performance ◽  
Accurate Method ◽  
Plasma Samples ◽  
Promising Target ◽  
Relative Standard ◽  
Dimerization Inhibitor ◽  
Oncogenic Protein ◽  
First Time ◽  
Transcription 3

Background: Signal transducer and activator of transcription 3 (STAT3), an oncogenic protein found constitutively active in many types of human malignancies, is considered to be a promising target for cancer therapy. Objective: In this study for the first time, a simple and accurate method has been developed for the determination of a STAT3 dimerization inhibitor called stattic in aqueous and plasma samples. Methods: A reverse-phase high-performance liquid chromatography (RP-HPLC) composed of C18 column as stationary phase, and the mixture of acetonitrile (60%) and water (40%) as mobile phase with a UV detection at 215 nm were applied for quantification of stattic. The developed method was validated by Food and Drug Administration (FDA) guideline. Results: The method provided a linear range between 1-40 and 2.5-40 µg mL-1 for aqueous and plasma samples, respectively, with a correlation coefficient of 0.999. The accuracy (as recovery) of the developed method was found to be between 95-105% for aqueous medium and 85-115% for plasma samples. The precision (as relative standard deviation) for aqueous and plasma samples was less than 6% and 15%, respectively. The sensitivity of the developed method based on FDA guideline was 1 µg mL-1 for aqueous and 2.5 µg mL-1 for plasma samples. Conclusion: These results show that the established method is a fast and accurate quantification for stattic in aqueous and plasma samples.

Is it necessary to calculate Young’s modulus in AFM nanoindentation experiments regarding biological samples?

2020 ◽  
Vol 12 ◽  
Author(s):  
S.V. Kontomaris ◽  
A. Malamou ◽  
A. Stylianou
Keyword(s):  
Young’S Modulus ◽  
Biological Samples ◽  
Young's Modulus ◽  
Reference Sample ◽  
Nonlinear Behavior ◽  
Accurate Method ◽  
Accurate Solution ◽  
Hertz Model ◽  
Work Done

Background: The determination of the mechanical properties of biological samples using Atomic Force Microscopy (AFM) at the nanoscale is usually performed using basic models arising from the contact mechanics theory. In particular, the Hertz model is the most frequently used theoretical tool for data processing. However, the Hertz model requires several assumptions such as homogeneous and isotropic samples and indenters with perfectly spherical or conical shapes. As it is widely known, none of these requirements are 100 % fulfilled for the case of indentation experiments at the nanoscale. As a result, significant errors arise in the Young’s modulus calculation. At the same time, an analytical model that could account complexities of soft biomaterials, such as nonlinear behavior, anisotropy, and heterogeneity, may be far-reaching. In addition, this hypothetical model would be ‘too difficult’ to be applied in real clinical activities since it would require very heavy workload and highly specialized personnel. Objective: In this paper a simple solution is provided to the aforementioned dead-end. A new approach is introduced in order to provide a simple and accurate method for the mechanical characterization at the nanoscale. Method: The ratio of the work done by the indenter on the sample of interest to the work done by the indenter on a reference sample is introduced as a new physical quantity that does not require homogeneous, isotropic samples or perfect indenters. Results: The proposed approach, not only provides an accurate solution from a physical perspective but also a simpler solution which does not require activities such as the determination of the cantilever’s spring constant and the dimensions of the AFM tip. Conclusion: The proposed, by this opinion paper, solution aims to provide a significant opportunity to overcome the existing limitations provided by Hertzian mechanics and apply AFM techniques in real clinical activities.

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