Fluorescence quenching in β-cyclodextrin vesicles: membrane confinement and host-guest interactions

Abstract

Fluorescent β-cyclodextrin vesicles (β-CDV) that display host cavities available for host-guest interactions at the vesicle surface were prepared by incorporation of the hydrophobic spirobifluorene-based dye 1 into the membrane of unilamellar vesicles. Fluorescence quenching of dye 1 was observed in the presence of different quenchers. Methyl viologen 2 does not quench dye 1 because it does not bind to β-CDV. 4-Nitrophenol 3 and 4-nitrophenol covalently connected to adamantane 4 quench the fluorescence of dye 1 in neutral solution, but by different mechanisms according to lifetime measurements. The quenching efficiency of 3 is pH dependent due to the presence of the phenolate form. Competition experiments with excess host and guest showed that 3 is likely to diffuse in and out of the membrane, while 4 forms an inclusion complex with β-CDV leading to close contact and efficient quenching. Our findings confirm that this dynamic supramolecular system is a versatile model to investigate quenching and recognition processes in bilayer membranes.

Fluorescent Amorphous Distyrylnaphthalene-Based Polymers: Synthesis, Characterization and Thin-Film Nanomolar Sensing of Nitroaromatics in Water

“…Therefore, the increase of the optical density either by changing the excitation wavelength or the path-length of the excitation beam results in an upward curvature. In principle, amplified quenching observed in extended conjugated systems [9], or combined quenching that occurs in environments where the fluorophores are confined in a membrane [35], could lead to positive deviations from linearity. In our case, amplified quenching can be ruled out due to the segmented nature of the conjugated system of the polymer P26 that prevents exciton mobility along the polymer backbone.…”

Twisted Push‐Pull Probes with Turn‐On Sulfide Donors

“…Cyclodextrins (CDs) are macrocyclic oligomers of α ‐1,4 glucopyranosides obtained from the enzymatic degradation of amylose . Guest inclusion in their hydrophobic interior is used extensively to solubilize hydrophobic compounds in water.…”

“…Guest inclusion in their hydrophobic interior is used extensively to solubilize hydrophobic compounds in water. Moreover, molecular recognition within cyclodextrins has been applied to catalysis, transport and the self‐assembly into higher‐order architectures including multilayers on solid surfaces, vesicles as well as pseudorotaxanes and rotaxanes, particularly polyrotaxanes, in many variations …”

CH3NH3PbBr3 Perovskite Nanocrystals as Efficient Light‐Harvesting Antenna for Fluorescence Resonance Energy Transfer

“…Interestingly, the SV plot of PNC/Rh101 showed a non‐linear behavior with an upward curvature (Figure b). The positive deviation from linearity implies the presence of both static and dynamic components in the fluorescence quenching process . The following adjusted Stern–Volmer equation was used to separate the dynamic ( K D ) and static ( K S ) quenching components. …”