Intrinsic Turn‐On Response of Thioflavin T in Complexes

Abstract

The fluorescence enhancement (“turn‐on”) response of the amyloid‐sensing dye thioflavin T (ThT) is examined in vacuo, where solvent interactions are absent. Upon the complexation of ThT with a derivatized β‐cyclodextrin, heptakis‐[6‐deoxy‐6‐(3‐sulfanylpropanoic acid)]‐β‐cyclodextrin, turn‐on responses in both the gas phase and solution phase were observed. In contrast, turn‐on response was not detected when ThT was bound to gaseous cucurbit[7]uril or human telomeric DNA 22AG, whereas clear turn‐on response occurs in solution. The observed difference in turn‐on response in the gas phase emphasizes the key interplay between chromophore, host and solvent and demonstrates the utility of gas‐phase spectroscopy to tease out the balance among intermolecular forces driving the behavior of important chromophores in solution.

Structural Deformation to β‐Cyclodextrin Due to Strong π‐Stacking in the Self‐Assembly of Inclusion Complex

“…The distortions are not transitory in nature and lead to formation of assemblies which are stable even at high temperatures. The structure and properties of cyclodextrins continue to inspire chemists [39–46] . In this context the understanding that CD structures are not inflexible may lead to design of novel molecular architectures in the future.…”

“…The structure and properties of cyclodextrins continue to inspire chemists. [39][40][41][42][43][44][45][46] In this context the understanding that CD structures are not inflexible may lead to design of novel molecular architectures in the future. Structural deformation of cyclodextrin is subject to several theoretical studies, but none of the studies have considered large deformations to its structure.…”

Breaking the Brightness Barrier: Design and Characterization of a Selected-Ion Fluorescence Measurement Setup with High Optical Detection Efficiency

“…Figure 2 shows the fluorescence excitation and emission spectra acquired with the setup over a wide range of wavelengths and for analytes of different mass, fluorescence emission maxima, quantum yields, and polarity. To demonstrate the high fluorescence collection efficiency of the setup, we acquired fluorescence emission spectra of the two dyes fluorescein and thioflavin T (Figure 2 (b)), both of which have been posited [21,25] to have low quantum yields in the gas phase. Fluorescein mono anions were stored in the trap and due to high photofragmentation, low laser power (0.5 mW) was used.…”

“…When comparing the spectra of low quantum yield dyes, thioflavin T and fluorescein, acquired in similar conditions, this setup produces a much higher S/N spectrum for dyes for which only very weak fluorescence signals were reported earlier. [21,25] To further optimize the transfer of fluorescence emission to the detectors, ray tracing of the setup is currently in progress. However, lower fluorescence collection time for a bright dye like rhodamine 6G and high S/N for low quantum yield dyes within fluorescence collection time in minutes, clearly validate the high fluorescence detection efficiency of the setup.…”

“…[2,[15][16][17][18][19] To collect fluorescence from trapped ions in the ICR cell, one of the cell plates was replaced with a wire mesh and an adjoining lens collected the fluorescence from the trapped ions. Time-dependent decay in fluorescence was also observed for rhodamine 575 in a modified QIT by Cline et al [20] The Jockusch group presented another iteration of a modified QIT with high-end detection systems for fluorescence studies and has published extensively on fluorescence studies on gaseous dye ions, [3,[21][22][23] host-guest complexes, [24,25] FRET from biomolecules [26,27] and ion imaging [9].…”