Microscopic Insights into the Mechanism of White Light Generation by Disruptive Interaction between Human Serum Albumin Amyloid Fibrils and Surfactant-AIEgen Nanorods

Abstract

Dimethyl-2,5-bis­[4-(methoxyphenyl)­amino] terephthalate (DBMPT) exhibits aggregation-induced enhancement of emission with Tween 40 and formation of nanorods with strong orange fluorescence. These nanorods disrupt fibrils of human serum albumin and lead to partial refolding of the protein, as monitored by circular dichroism and thioflavin T (ThT) fluorescence. The resultant milieu emits white light, the mechanism of which is explored in this study. It is established that direct excitation of the acceptor plays a significant role, even though Förster resonance energy transfer (FRET) is found to be operative to some extent. A decrease in the fluorescence intensity and lifetime of ThT with progressive addition of DBMPT, which is often used as the sole indicator of FRET, is ascribed to the disruption of the fibrils by the nanorods.

Fluorescence correlation spectroscopy and fluorescence lifetime imaging microscopy for deciphering the morphological evolution of supramolecular self-assembly

“…60 Generally, the lifetime of the emissive aggregates or the self-assembled structures can vary due to spontaneous or stimuli-responsive morphological transformation. 85–90 Hence, FLIM images, along with fluorescence lifetime histograms and in situ lifetime profiles, provide a clear idea about the evolution dynamics of self-assembled structures. 88,90…”

“…85–90 Hence, FLIM images, along with fluorescence lifetime histograms and in situ lifetime profiles, provide a clear idea about the evolution dynamics of self-assembled structures. 88,90…”

“…The variation in microheterogeneity during morphological evolution was delineated through the lifetime histograms. 90 Schanze and co-workers revealed the phase heterogeneity in the self-assembled metal–organic framework structure using FLIM. 89 Thus, the above discussion emphasizes the promising scope of lifetime imaging to unravel the impact of microenvironments on dynamic self-assembly processes.…”

“…60 Generally, the lifetime of the emissive aggregates or the self-assembled structures can vary due to spontaneous or stimuli-responsive morphological transformation. [85][86][87][88][89][90] Hence, FLIM images, along with fluorescence lifetime histograms and in situ lifetime profiles, provide a clear idea about the evolution dynamics of self-assembled structures. 88,90 Cienfuegos and co-workers probed the early-stage selfassembly process leading to the evolution of supramolecular nanofibers of fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF), a short peptide, in the presence of metal salts of Ca 2+ (Fmoc-FF Ca 2+ ) and Cs + (Fmoc-FF Cs + ).…”

“…[85][86][87][88][89][90] Hence, FLIM images, along with fluorescence lifetime histograms and in situ lifetime profiles, provide a clear idea about the evolution dynamics of self-assembled structures. 88,90 Cienfuegos and co-workers probed the early-stage selfassembly process leading to the evolution of supramolecular nanofibers of fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF), a short peptide, in the presence of metal salts of Ca 2+ (Fmoc-FF Ca 2+ ) and Cs + (Fmoc-FF Cs + ). 52 The formation of fibers was observed at a higher concentration (Z5 mM) of the metal ions.…”