Fluorescence emission quenching of RdB fluorophores in attendance of various blood type RBCs based on Stern-Volmer formalism

2021 ◽  
Vol 248 ◽  
pp. 119237
Author(s):  
S. Seyedi ◽  
P. Parvin ◽  
A. Jafargholi ◽  
A. Abbasian ◽  
M. Mehdinejad ◽  
...  
Keyword(s):  
Fluorescence Emission ◽  
Blood Type ◽  
Emission Quenching

A perylene monoimide probe based fluorescent micelle sensor for the selective and sensitive detection of picric acid

2020 ◽  
Vol 12 (44) ◽  
pp. 5353-5359
Author(s):  
Weiqing Li ◽  
Huipeng Zhou ◽  
Muhammad Azhar Hayat Nawaz ◽  
Niu Niu ◽  
Na Yang ◽  
...  
Keyword(s):  
Picric Acid ◽  
Fluorescence Emission ◽  
Sensitive Detection ◽  
Quenching Mechanism ◽  
Excimer Fluorescence ◽  
Emission Quenching ◽  
Triton X

A PMI-OH@Triton X-100 micelle sensor based on the perylene probe excimer fluorescence emission quenching mechanism has been developed for the detection of picric acid (PA).

Evaluating Mitochondrial Membrane Potential in Cells

2007 ◽  
Vol 27 (1-3) ◽  
pp. 11-21 ◽  
Author(s):  
Giancarlo Solaini ◽  
Gianluca Sgarbi ◽  
Giorgio Lenaz ◽  
Alessandra Baracca
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Large Population ◽  
Fluorescence Emission ◽  
High Sensitivity ◽  
Biological Phenomena ◽  
Sensitive Tool ◽  
Emission Quenching ◽  
Fluorescent Molecules

Permeant cationic fluorescent probes are widely employed to monitor mitochondrial transmembrane potential and its changes. The application of such potential-dependent probes in conjunction with both fluorescence microscopy and fluorescence spectroscopy allows the monitoring of mitochondrial membrane potential in individual living cells as well as in large population of cells. These approaches to the analysis of membrane potential is of extremely high value to obtain insights into both the basic energy metabolism and its dysfunction in pathologic cells. However, the use of fluorescent molecules to probe biological phenomena must follow the awareness of some principles of fluorescence emission, quenching, and quantum yield since it is a very sensitive tool, but because of this extremely high sensitivity it is also strongly affected by the environment. In addition, the instruments used to monitor fluorescence and its changes in biological systems have also to be employed with cautions due to technical limits that may affect the signals. We have therefore undertaken to review the most currently used analytical methods, providing a summary of practical tips that should precede data acquisition and subsequent analysis. Furthermore, we discuss the application and feasibility of various techniques and discuss their respective strength and weakness.

scholarly journals A Pentapeptide with Tyrosine Moiety as Fluorescent Chemosensor for Selective Nanomolar-Level Detection of Copper(II) Ions

2020 ◽  
Vol 21 (3) ◽  
pp. 743 ◽  
Author(s):  
Krzysztof Żamojć ◽  
Dominik Kamrowski ◽  
Magdalena Zdrowowicz ◽  
Dariusz Wyrzykowski ◽  
Wiesław Wiczk ◽  
...  
Keyword(s):  
Metal Ion ◽  
Limit Of Detection ◽  
Fluorescence Emission ◽  
Peptide Sequence ◽  
Fluorescence Emission Spectrum ◽  
Tyrosine Residue ◽  
Metal Ion Binding ◽  
Time Resolved ◽  
Selective Ligand ◽  
Emission Quenching

Herein, we have investigated principally with the use of UV and fluorescence (steady-state and time-resolved) spectroscopy the interactions between selected pentapeptides with tyrosine residue (EYHHQ, EHYHQ, EHHQY, and KYHHE) and various metal ions (Cu2+, Mn2+, Co2+, Ni2+, Zn2+, Cr3+, Cd2+, Ag+, Pb2+, Sr2+, Ba2+, Ca2+, Mg2+, Al3+, Fe2+, and Ga3+) in order to establish the relationship between the position of a tyrosine residue in the peptide sequence and the metal ion-binding properties. Among the peptides studied, EHYHQ was evaluated as an efficient and selective ligand for developing a chemosensor for the detection of copper(II) ions. While significant fluorescence emission quenching was observed for that peptide in the presence of Cu2+ cations, other metal cations used at the same and at considerably higher concentrations caused a negligible change of the fluorescence emission spectrum, indicating a high selectivity of EHYHQ for Cu2+ ions. Under optimum conditions, fluorescence intensity was inversely proportional to the concentration of Cu2+ ions. The limit of detection of Cu2+ ions with the use of EHYHQ was determined at the level of 26.6 nM. The binding stoichiometry of the complexes of the studied peptides with Cu2+ ions was evaluated spectrophotometrically and fluorimetrically (as in the case of EHYHQ confirmed by mass spectrometry) and found to be 1:2 (Cu2+-peptide) for all the investigated systems. Furthermore, the stability constant (K) values of these complexes were determined. The reversibility of the proposed Cu2+ ions sensor was confirmed, the pH range where the sensor acts was determined, while its analytical performance was compared with some other reported recently fluorescent sensors. The mechanism of the interactions between EHYHQ and Cu2+ was proposed on the basis of NMR spectroscopy investigations.

scholarly journals New insights into the nature of the Cibacron brilliant red 3B-A – Chitosan interaction

2016 ◽  
Vol 88 (9) ◽  
pp. 891-904 ◽  
Author(s):  
Stefan Hoffmann ◽  
Juan Pablo Fuenzalida Werner ◽  
Ignacio Moreno-Villoslada ◽  
Francisco M. Goycoolea
Keyword(s):  
Fluorescence Emission ◽  
Pharmaceutical Formulations ◽  
Charge Ratio ◽  
Amino Groups ◽  
Linear Charge ◽  
Band Shift ◽  
Chiral Structure ◽  
Linear Charge Density ◽  
Emission Quenching ◽  
Absorbance Band

AbstractCibacron brilliant red 3B-A (CBR) has been introduced to determine chitosan (CS) concentrations in solution, and several studies applied it to measure chitosan content in pharmaceutical formulations. So far, studies have relied on the absorbance band shift to 570 nm to determine the extent of the CBR – CS interaction. In this study, we show that CBR forms micro- to nanometer sized aggregates with CS, depending on their charge ratio and that other photophysical changes in CBR are induced by this interaction. We found that, besides the bathochromic band shift, aggregation induces emission at 600 nm and emission quenching at 360 nm. We compared changes CS induced in absorbance and fluorescence emission of CBR with the CS monomer glucosamine and poly(allylamine) hydrochloride, which both contain amino groups, and found that similar but less intense photophysical changes also occur. Furthermore, CS-induced circular dichroism in CBR suggests a twisted, chiral structure of these aggregates that should match with the previously published in silico simulations of the structure of CS in solution. The low linear charge density of CS and its chiral conformation are considered responsible for the enhanced photophysical response of CBR interacting with the polycation.

scholarly journals Paper Sensors Based on Fluorescence Changes of Carbon Nanodots for Optical Detection of Nanomaterials

2021 ◽  
Vol 13 (21) ◽  
pp. 11896
Author(s):  
Evie L. Papadopoulou ◽  
Giulia Biffi ◽  
Anitha Senthamizhan ◽  
Beatriz Martín-García ◽  
Riccardo Carzino ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Fluorescence Emission ◽  
Carbon Nanodots ◽  
Practical Applications ◽  
Quenching Mechanisms ◽  
Uv Lamp ◽  
Emission Quenching ◽  
Cellulosic Paper ◽  
Paper Sensor ◽  
Pl Quenching

A paper sensor was designed in order to detect the presence of nanomaterials, such as ZnO and silica nanoparticles, as well as graphene nanoplatelets (GnP), based on fluorescence changes of carbon nanodots. Paper strips were functionalized with carbon nanodots using polyvinyl alcohol (PVA) as binder. The carbon nanodots were highly fluorescent and, hence, rendered the (cellulosic) paper stripes emissive. In the presence of silica and ZnO nanoparticles, the fluorescence emission of the carbon nanodots was quenched and the emission decay was shortened, whereas in the presence of GnP only emission quenching occurred. These different photoluminescence (PL) quenching mechanisms, which are evident from lifetime measurements, convey selectivity to the sensor. The change in fluorescence of the carbon dot-functionalized paper is also evident to the naked eye under illumination with a UV lamp, which enables easy detection of the nanomaterials. The sensor was able to detect the nanomaterials upon direct contact, either by dipping it in their aqueous dispersions, or by sweeping it over their powders. The use of the proposed optical sensor permits the detection of nanomaterials in a straightforward manner, opening new ways for the development of optical sensors for practical applications.

Co-expression of recombinant single chain variable fragment recognizing blood antigen fused with sumo and chaperones in Escherichia coli

2018 ◽  
Vol 40 (4) ◽  
Author(s):  
Dang Thi Ngoc Ha ◽  
Le Thi Thu Hong ◽  
Truong Nam Hai
Keyword(s):  
Recombinant Antibody ◽  
Blood Type ◽  
Soluble Form ◽  
Supernatant Fraction ◽  
Blood Group Antigens ◽  
Single Chain ◽  
E Coli ◽  
Recombinant Scfv ◽  
Single Chain Variable Fragments

Single chain variable fragments (scFv) have widely been used in research, diagnosis and treatment, but the scFv is considered as difficult protein for expression in E. coli. In previous studies, we expressed a construction of recombinant single chain variable fragments again antigen specific for blood type A (antiA-scFv) individually or fused with Trx or SUMO. However, soluble fraction was low abandant and only approximately 40% when fused with Trx, the other cases were expressed in form of inclusion body. Therefore, it was difficult for purification, refolding and activity assesment. In thispaper, we demonstrated a suitable construction for soluble production of antiA-scFv fused with SUMO (SM/antiA-scFv) in presence of chaparones. Under fermentation with 0.1 mM IPTG at 20oC, the SM/antiA-scFv was entirely expressed in soluble form. Importantly, after cleavage from SUMO with SUMOprotease, antiA-scFv was still maintained in the supernatant fraction. Therefore, it can help ensure bioactivity and is useful for purification process. To the best of our knowledge, this is the first report showing soluble recombinant scFv fused with SUMO in presence of chaperone for determination of blood group antigens. Thus, this result facilitates the optimal study of soluble expression, purification and bioactivity determination of the antiA-scFv recombinant antibody. 

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.

Enhanced-Fluorescence of a Dye on DNA- assembled Gold Nano-Dimers Discriminated by Lifetime Correlation Spectroscopy

2017 ◽  
Author(s):  
Pedro M. R. Paulo ◽  
David Botequim ◽  
Agnieszka Jóskowiak ◽  
Sofia Martins ◽  
Duarte M. F. Prazeres ◽  
...  
Keyword(s):  
Single Molecule ◽  
Fluorescence Emission ◽  
Directed Assembly ◽  
Plasmon Mode ◽  
Correlation Spectroscopy ◽  
Enhanced Fluorescence ◽  
Detection Volume ◽  
Relaxation Component ◽  
Good Agreement ◽  
Confocal Detection

<div> <div> <div> <p>We have employed DNA-directed assembly to prepare dimers of gold nanoparticles and used their longitudinally coupled plasmon mode to enhance the fluorescence emission of an organic red-emitting dye, Atto-655. The plasmon- enhanced fluorescence of this dye using dimers of 80 nm particles was measured at single molecule detection level. The top enhancement factors were above 1000-fold in 71% of the dimers within a total of 32 dimers measured, and, in some cases, they reached almost 4000-fold, in good agreement with model simulations. Additionally, fluorescence lifetime correlation analysis enabled the separation of enhanced from non-enhanced emission simultaneously collected in our confocal detection volume. This approach allowed us to recover a short relaxation component exclusive to enhanced emission that is attributed to the interaction of the dye with DNA in the interparticle gaps. </p> </div> </div> </div>

Low-Cost Hardware Implementation of Human Blood Identification Device Using Feed-Forward Artificial Neural Network on FPGA

2018 ◽  
Author(s):  
Rizki Eka Putri ◽  
Denny Darlis
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Low Cost ◽  
Image Resolution ◽  
Blood Type ◽  
Feed Forward ◽  
Testing Facility ◽  
System Input ◽  
Artificial Neural ◽  
Short Time

This article was under review for ICELTICS 2018 -- In the medical world there is still service dissatisfaction caused by lack of blood type testing facility. If the number of tested blood arise, a lot of problems will occur so that electronic devices are needed to determine the blood type accurately and in short time. In this research we implemented an Artificial Neural Network on Xilinx Spartan 3S1000 Field Programable Gate Array using XSA-3S Board to identify the blood type. This research uses blood sample image as system input. VHSIC Hardware Discription Language is the language to describe the algorithm. The algorithm used is feed-forward propagation of backpropagation neural network. There are 3 layers used in design, they are input, hidden1, and output. At hidden1layer has two neurons. In this study the accuracy of detection obtained are 92%, 92%, 92%, 90% and 86% for 32x32, 48x48, 64x64, 80x80, and 96x96 pixel blood image resolution, respectively.

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