Polyanion-induced circular dichroism of Thioflavin T

Fedunova, Diana; Huba, Peter; Bágeľová, Jaroslava; Antalı́k, Marián

doi:10.4149/gpb_2013020

Cited by 7 publications

(8 citation statements)

References 30 publications

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“…The excitonic coupling between neighboring molecules in aggregates is distinctly revealed in electronic circular dichroism (CD) spectra where two successive absorption bands of opposite signs characterize the excitonic interaction. , To characterize this aspect, we have performed the electronic CD measurements for the PMA–SCD complex and the results have been presented in Figure S6 (Supporting Information). It is evident that the CD spectrum changes from a negative to positive cotton effect at the PMA-aggregate absorption band, therefore constituting a clear bi-signate CD signal, suggesting the existence of excitonic interactions in the present system, whereas only PMA or only SCD remains spectroscopically silent in the CD spectra in the same wavelength region.…”

Section: Resultsmentioning

confidence: 99%

Stimulus-Responsive Supramolecular Host–Guest Assembly of a Cationic Pyrene Derivative with Sulfated β-Cyclodextrin

Singh

2019

Langmuir

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In general, aggregation-prone organic molecules are prevented from self-aggregation in the presence of macrocyclic hosts like β-cyclodextrin because of their preference for the formation of inclusion complex with guest molecules. On the contrary, sulfate-laced β-cyclodextrin has been recently reported to induce the aggregation of some of the non-aggregation-prone organic dyes, which have been subsequently utilized for biosensing applications. In the present contribution, we report the interaction of a cationic organic probe molecule, 1-pyrene methyl amine (PMA), which belongs to one of the most useful families of organic fluorescent probes, that is, pyrene, with a sulfated β-cyclodextrin derivative (SCD). Interaction of a cationic probe with a βcyclodextrin derivative was studied using a variety of photophysical methods such as ground-state absorption, steady-state emission, and time-resolved emission techniques. Detailed photophysical investigations have revealed that SCD induces the ground-state association of PMA molecules. This SCD-induced aggregation of PMA molecules has been attributed to the charge neutralization of the cationic probe by negatively charged sulfate groups, which subsequently lead to their association because of the close proximity on the rims of cyclodextrin. This monomer−dimer equilibrium of the PMA−SCD system is found to be extremely responsive to external chemical stimuli like temperature, pH, ionic strength of the medium, and organic solvent (dimethyl sulfoxide), which projects them as potential platforms for various sensing applications including bioanalytes. The supramolecular assembly has been demonstrated to sense arginine.

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Section: Resultsmentioning

confidence: 99%

Stimulus-Responsive Supramolecular Host–Guest Assembly of a Cationic Pyrene Derivative with Sulfated β-Cyclodextrin

Singh

2019

Langmuir

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“…The excitonic interaction between the ThT molecules in the aggregated form is further confirmed by electronic circular dichroism (CD) measurements, which displays a clear bisignate CD signal in the absorption region of ThT chromophores (Figure A). The bisignate feature is characteristic of the aggregates, and can be assigned to excitonic coupling between transition dipole moments of ThT. , With an aim to establish that the enhanced fluorescence of ThT, in the presence of heparin, arises from ThT H-aggregates, the excitation spectrum was measured for the red-shifted emission band of 560 nm. The excitation spectra (Figure S1) displays a maximum at 393 nm which matches quite nicely with the absorption maximum (∼393 nm) collected for ThT H-aggregates, clearly suggesting that the increased fluorescence band at 560 nm correspond to H-aggregate.…”

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confidence: 99%

Emissive H-Aggregates of an Ultrafast Molecular Rotor: A Promising Platform for Sensing Heparin

Mudliar

Singh

2016

ACS Appl. Mater. Interfaces

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Constructing "turn on" fluorescent probes for heparin, a most widely used anticoagulant in clinics, from commercially available materials is of great importance, but remains challenging. Here, we report the formation of a rarely observed emissive H-aggregate of an ultrafast molecular rotor dye, Thioflavin-T, in the presence of heparin, which provides an excellent platform for simple, economic and rapid fluorescence turn-on sensing of heparin. Generally, H-aggregates are considered as serious problem in the field of biomolecular sensing, owing to their poorly emissive nature resulting from excitonic interaction. To the best of our knowledge, this is the first report, where contrastingly, the turn-on emission from the H-aggregates has been utilized in the biomolecule sensing scheme, and enables a very efficient and selective detection of a vital biomolecule and a drug with its extensive medical applications, i.e., heparin. Our sensor system offers several advantages including, emission in the biologically advantageous red-region, dual sensing, i.e., both by fluorimetry and colorimetry, and most importantly constructed from in-expensive commercially available dye molecule, which is expected to impart a large impact on the sensing field of heparin. Our system displays good performance in complex biological media of serum samples. The novel Thioflavin-T aggregate emission could be also used to probe the interaction of heparin with its only clinically approved antidote, Protamine.

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“…For metmyoglobin complex formation with heparin has been established by absorbance and fluorescence spectroscopy as well as differential scanning microcalorimetry in a pH‐dependent manner, but no binding affinities are reported. Ovalbumin exhibited no heparin affinity in mass spectrometry analysis .…”

Section: Resultsmentioning

confidence: 97%

“…In order to determine the binding behavior of P‐selectin and ascertain whether it was a typical or unusual behavior, we have investigated five model proteins, namely human serum albumin (HSA) , bovine serum albumin (BSA) , beta Lactoglobulin (Beta‐LG), myoglobin and ovalbumin , and an additional protein namely vitronectin for their binding behavior with heparinoids. An overview of the main properties of the proteins is summarized in Table .…”

Section: Resultsmentioning

confidence: 99%

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Using affinity capillary electrophoresis and computational models for binding studies of heparinoids with p‐selectin and other proteins

et al. 2017

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A fast and precise affinity capillary electrophoresis (ACE) method has been developed and applied for the investigation of the binding interactions between P-selectin and heparinoids as potential P-selectin inhibitors in the presence and absence of calcium ions. Furthermore, model proteins and vitronectin were used to appraise the binding behavior of P-selectin. The normalized mobility ratios (∆R/R ), which provided information about the binding strength and the overall charge of the protein-ligand complex, were used to evaluate the binding affinities. It was found that P-selectin interacts more strongly with heparinoids in the presence of calcium ions. P-selectin was affected by heparinoids at the concentration of 3 mg/L. In addition, the results of the ACE experiments showed that among other investigated proteins, albumins and vitronectin exhibited strong interactions with heparinoids. Especially with P-selectin and vitronectin, the interaction may additionally induce conformational changes. Subsequently, computational models were applied to interpret the ACE experiments. Docking experiments explained that the binding of heparinoids on P-selectin is promoted by calcium ions. These docking models proved to be particularly well suited to investigate the interaction of charged compounds, and are therefore complementary to ACE experiments.

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Polyanion-induced circular dichroism of Thioflavin T

Cited by 7 publications

References 30 publications

Stimulus-Responsive Supramolecular Host–Guest Assembly of a Cationic Pyrene Derivative with Sulfated β-Cyclodextrin

Stimulus-Responsive Supramolecular Host–Guest Assembly of a Cationic Pyrene Derivative with Sulfated β-Cyclodextrin

Emissive H-Aggregates of an Ultrafast Molecular Rotor: A Promising Platform for Sensing Heparin

Using affinity capillary electrophoresis and computational models for binding studies of heparinoids with p‐selectin and other proteins

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