Enhanced two-photon absorption and fluorescence upconversion in Thioflavin T micelle-type aggregates in glycerol/water solution

Donnelly, Julie; Vesga, Yuly; Hernández, Florencio E.

doi:10.1016/j.chemphys.2016.08.010

Cited by 6 publications

(5 citation statements)

References 42 publications

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“…Khurana et al [29] show that ThT has a critical micelle concentration of approximately 4 µM, in good agreement with our observations that ThT becomes self-fluorescent at or above 5 µM. Formation of ThT micelles was also demonstrated by Sabaté et al [30] and Donnelly et al [31]. To be clear, however, our results do not imply, nor are we suggesting, that ThT binds to amyloid in the form of micelles.…”

Section: Resultssupporting

confidence: 92%

See 1 more Smart Citation

Thioflavin T as an amyloid dye: fibril quantification, optimal concentration and effect on aggregation

Xue¹,

Lin²,

Chang³

et al. 2017

R. Soc. open sci.

569

428

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Formation of amyloid fibrils underlies a wide range of human disorders, including Alzheimer's and prion diseases. The amyloid fibrils can be readily detected thanks to thioflavin T (ThT), a small molecule that gives strong fluorescence upon binding to amyloids. Using the amyloid fibrils of Aβ40 and Aβ42 involved in Alzheimer's disease, and of yeast prion protein Ure2, here we study three aspects of ThT binding to amyloids: quantification of amyloid fibrils using ThT, the optimal ThT concentration for monitoring amyloid formation and the effect of ThT on aggregation kinetics. We show that ThT fluorescence correlates linearly with amyloid concentration over ThT concentrations ranging from 0.2 to 500 µM. At a given amyloid concentration, the plot of ThT fluorescence versus ThT concentration exhibits a bell-shaped curve. The maximal fluorescence signal depends mostly on the total ThT concentration, rather than amyloid to ThT ratio. For the three proteins investigated, the maximal fluorescence is observed at ThT concentrations of 20–50 µM. Aggregation kinetics experiments in the presence of different ThT concentrations show that ThT has little effect on aggregation at concentrations of 20 µM or lower. ThT at concentrations of 50 µM or more could affect the shape of the aggregation curves, but this effect is protein-dependent and not universal.

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Section: Resultssupporting

confidence: 92%

“…[ 30 ] and Donnelly et al . [ 31 ]. To be clear, however, our results do not imply, nor are we suggesting, that ThT binds to amyloid in the form of micelles.…”

Section: Resultsmentioning

confidence: 99%

Thioflavin T as an amyloid dye: fibril quantification, optimal concentration and effect on aggregation

Xue¹,

Lin²,

Chang³

et al. 2017

R. Soc. open sci.

569

428

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“…The less intense band predicted by theory at around 640 nm corresponds to the second and fourth excited-state transitions for 1b and 1c,r espectively.T he band was measurable for 1b and detectable for 1c.H owever,t he sharp increase in the experimental TPAb elow 600 nm, attributable to enhancement due to linear absorption, likely explains why the 640 nm peak was not resolved for 1c.Asecond important observation is that, in the case of 1c,t he predicted cross-sections are larger than those observed experimentally.A lthough it is difficult to explain this difference, considering that all measurements were made in the femtosecond regime, whereby excited-state absorption is negligible, [26,27] it is ac ommono bservation in theoretical-experimental studies. [8,[22][23][24][28][29][30] However,i n the case of 1b,t he experimentalc ross-sections are almost exactly as predicted. The experimentald ifferences could be attributed to the increased degree of symmetry in 1c compared to 1b.The differencebetween the calculated and experimental cross-sectionso f1c is more difficult to explain;i tm ay be that solventeffects are more importantin1c than in 1b due to the quadrupolarI CT path.…”

Section: Tpas Pectroscopysupporting

confidence: 53%

“…A second important observation is that, in the case of 1 c , the predicted cross‐sections are larger than those observed experimentally. Although it is difficult to explain this difference, considering that all measurements were made in the femtosecond regime, whereby excited‐state absorption is negligible, it is a common observation in theoretical‐experimental studies . However, in the case of 1 b , the experimental cross‐sections are almost exactly as predicted.…”

Section: Resultsmentioning

confidence: 95%

Helicenes Grafted with 1,1,4,4‐Tetracyanobutadiene Moieties: π‐Helical Push–Pull Systems with Strong Electronic Circular Dichroism and Two‐Photon Absorption

Bouvier

Durand

Favereau

et al. 2018

Chemistry A European J

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Enantiopure P- and M-carbo[6]helicenes substituted with one or two tetracyanobutadiene moieties at positions 2 and 15 have been prepared. Grafting of these electron-accepting groups onto the π-helical core resulted in strong charge-transfer effects, which greatly affected the UV/Vis, electronic circular dichroism (ECD), and two-photon absorption (TPA) responses. The ECD signal was found to be reversibly switched by applying a redox stimulus.

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“…Indeed, ThT can also detect keratin, elastin fiber, and nucleic acids [43]. Furthermore, different conformational and oligomeric states are not properly detected and ThT self-aggregates in micelles starting from 4µM concentrations [44]. Due to the positively charged quaternary heterocyclic nitrogen of the benzothiazolium, ThT is not suitable to cross the blood-brain barrier (BBB) and the charged nature of the molecule limits its use in neutral, basic conditions [45].…”

Section: Fl Extrinsic Dyes and Imaging Technology Of Amyloid Fibersmentioning

confidence: 99%

Fluorescence Phenomena in Amyloid and Amyloidogenic Bionanostructures

et al. 2020

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Nanoscale optical labeling is an advanced bioimaging tool. It is mostly based on fluorescence (FL) phenomena and enables the visualization of single biocells, bacteria, viruses, and biological tissues, providing monitoring of functional biosystems in vitro and in vivo, and the imaging-guided transportation of drug molecules. There is a variety of FL biolabels such as organic molecular dyes, genetically encoded fluorescent proteins (green fluorescent protein and homologs), semiconductor quantum dots, carbon dots, plasmonic metal gold-based nanostructures and more. In this review, a new generation of FL biolabels based on the recently found biophotonic effects of visible FL are described. This intrinsic FL phenomenon is observed in any peptide/protein materials folded into β-sheet secondary structures, irrespective of their composition, complexity, and origin. The FL effect has been observed both in natural amyloid fibrils, associated with neurodegenerative diseases (Alzheimer’s, Parkinson’s, and more), and diverse synthetic peptide/protein structures subjected to thermally induced biological refolding helix-like→β-sheet. This approach allowed us to develop a new generation of FL peptide/protein bionanodots radiating multicolor, tunable, visible FL, covering the entire visible spectrum in the range of 400–700 nm. Newly developed biocompatible nanoscale biomarkers are considered as a promising tool for emerging precise biomedicine and advanced medical nanotechnologies (high-resolution bioimaging, light diagnostics, therapy, optogenetics, and health monitoring).

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Enhanced two-photon absorption and fluorescence upconversion in Thioflavin T micelle-type aggregates in glycerol/water solution

Cited by 6 publications

References 42 publications

Thioflavin T as an amyloid dye: fibril quantification, optimal concentration and effect on aggregation

Thioflavin T as an amyloid dye: fibril quantification, optimal concentration and effect on aggregation

Helicenes Grafted with 1,1,4,4‐Tetracyanobutadiene Moieties: π‐Helical Push–Pull Systems with Strong Electronic Circular Dichroism and Two‐Photon Absorption

Fluorescence Phenomena in Amyloid and Amyloidogenic Bionanostructures

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