A study of the spectral behaviour of Eosin dye in three states of metallosurfactants: Monomeric, micelles and metallosomes

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2021-02, Vol.610, p.125697, Article 125697
• Main Authors: Garg, Preeti, Kaur, Baljinder, Kaur, Gurpreet, Saini, Sakshi, Chaudhary, Ganga Ram
• Format: Article
• Language: English
• Subjects: Bacteria; Eosin yellow; Metallomicelle; Metallosome; Metallosurfactant
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2020.125697

[Display omitted] •Spectral properties of EY in different environments of metallosurfactants (monomeric, metallomicellar and metallosomal) were studied.•Clarified the mechanism of ion-pair formation between metallosurfactants (in monomeric state) and EY.•Enhanced fluorescence quantum yield of EY with its solubilisation in the peripheral layer of metallomicelles.•A much better encapsulation efficiency of EY was observed with formulated metallosomes and visualized by confocal microscopy.•Analysed the antimicrobial nature of utilized metallosurfactants towards gram positive and gram negative bacteria. Eosin Yellow (EY) is one of the most prominent synthetic dyes used for the histological stain but it is prone to fading under the influence of the surrounding environment. This article describes the better understanding of spectral characteristics of EY in three different environments (aggregates) of metallosurfactants i.e. monomeric, metallomicellar and metallosomal solution in phosphate buffer pH = 7. This study also compares photophysics of EY with four different transition metal ion (Fe, Co, Ni and Cu) based metallosurfactants, which is beneficial in biomedical applications. It was observed that the addition of EY provoked the formation of metallomicelles at the lower concentration of metallosurfactants. Absorption and fluorescence spectroscopy clarify the mechanism of ion-pair formation associated with electrostatic interaction between cationic metallosurfactants (in the monomeric state) and anionic EY, which become stronger due to the presence of metal ion that acts as an electrolyte to increase the solvation of EY. Further, metallomicelles leads to solubilize the EY at their Stern layer. The Stern-Volmer study indicates the static quenching of EY with metallosurfactants occurred at two binding sites. This interaction also quantified the enhanced fluorescence quantum yield. In the case of the third type of aggregates i.e. metallosomes, we observed a high encapsulation efficiency (75 %) of EY in metallosomes which is supported by confocal microscopy. Along with, the antimicrobial activity of metallosurfactants was evaluated against gram-negative and gram-positive bacteria.