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Monitoring Local pH of Membranous Aggregates via Ratiometric Color Changing Response

Jha, Satadru and Kumari, Namita and Chettri, Bimal and Dey, Nilanjan (2022) Monitoring Local pH of Membranous Aggregates via Ratiometric Color Changing Response. In: ChemPhysChem .

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Official URL: https://doi.org/10.1002/cphc.202200208


A series of oxidized di(indolyl)arylmethanes (DIAM) with polyaromatic signaling moieties have been designed for monitoring local pH at the interfacial region of surfactant aggregates, such as micelles and vesicles. The oxidized DIAMs show changes in solution color from red to yellow when incorporated in cationic surfactants (at pH 7.4) and yellow to reddish pink when exposed to negatively-charged surfactants (at pH 5.0). The changes in surface charge can influence the interfacial pH (distinct from bulk pH of the medium) of the surfactant aggregates. The mechanistic studies indicate that the red-shifted absorption maxima observed in the presence of anionic amphiphiles (acidic local pH) originated from the protonated species. On the contrary, maxima in the blue region, triggered by positively charged amphiphiles (basic local pH), is attributed to the zwitterionic species. Such prototropic equilibrium affects charge transfer states of the molecules along with their self-assembly properties. Thus, it is evident that probes can predict as well as quantify the local pH change using the pseudophase ion exchange formalism. Also, the probes can detect the presence of anionic amphiphiles even when bound to phospholipid membranes.

Item Type: Journal Article
Publication: ChemPhysChem
Publisher: John Wiley and Sons Inc
Additional Information: The copyright for this article belongs to the John Wiley and Sons Inc.
Keywords: bisindolyl probes; charge transfer; membranous aggregates; microenvironment; ratiometric response
Department/Centre: Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited: 27 May 2022 05:45
Last Modified: 27 May 2022 05:45
URI: https://eprints.iisc.ac.in/id/eprint/72757

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