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

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.