Photophysical Characterization of 1,8 Naphthalimide in Micelle‐diblock Copolymer Nano‐composite: A Case of Morphological Transformation and Vesicle Formation

Abstract

This paper reports a morphological transition of the spherical colloidal structures of the sodium dodecyl sulfate-polyethylene-bpolyethylene glycol (SDS-PE-b-PEG) complex and anionic micelle (SDS) to ''rod-shaped'' colloidal structures induced by a charge transfer dye, 1,8-naphthalimide (NAPMD) (forms anions in aqueous solution by intermolecular charge transfer). The distinct steady-state results of NAPMD in the above two media point toward the formation of a new microenvironment. SDS and SDS-PE-b-PEG form unilamellar (ULV) and multilamellar vesicles (MLV), respectively, along with the rod-shaped colloidal structures as observed from transmission electron microscopy (TEM) images. This dye causes a variation in the hydrophilic ⁄ hydrophobic ratio and forms a hydrogen bond with the copolymer in the SDS-PE-b-PEG complex and subjected to electrostatic interaction with the SDS micelle in aqueous solution, which causes this morphological transformation. These vesicles show complete encapsulation of a hydrophobic dye in its interior as evident from the TEM images. ULV get ruptured at low pH, pointing toward their lower stability over MLV at low pH value. The formation of these vesicles with complete idea of its mechanism, encapsulation of bioactive molecules and its rupture at lower pH raise hope as a potential nanoscale vehicle for biologically relevant compounds and their release at low pH medium.

Modification of a Styryl Dye Binding Mode with Calf Thymus DNA in Vesicular Medium: From Minor Groove to Intercalative

“…In an earlier communication Sahoo et al established that the block-copolymer polyethylene- b -polyethylene glycol (PE-b-PEG) on interaction with an anionic surfactant sodium dodecyl sulfate (SDS) forms a water tight microenvironment due to the entanglement of the block-copolymer with the surfactant chains. Interestingly, interaction of a charge transfer dye 1,8 naphthalimide (NAPMD) (forms anion in aqueous solution by intermolecular charge transfer) with the above-mentioned block copolymer-micelle nanocomposite in aqueous solution gives some vesicle-like structures . In another communication we have demonstrated the nanocaging of DASPMI by these vesicles and its pH sensitive release from the vesicle interior on the basis of varying fluorescence resonance energy transfer (FRET) between DASPMI and NAPMD sitting on the surface of vesicular wall.…”

“…Interestingly, interaction of a charge transfer dye 1,8 naphthalimide (NAPMD) (forms anion in aqueous solution by intermolecular charge transfer) with the above-mentioned block copolymer-micelle nanocomposite in aqueous solution gives some vesicle-like structures. 25 In another communication 26 we have demonstrated the nanocaging of DASPMI by these vesicles and its pH sensitive release from the vesicle interior on the basis of varying fluorescence resonance energy transfer (FRET) between DASPMI and NAPMD sitting on the surface of vesicular wall. Normally vesicles are very similar to modern cellular membranes 27 so these vesicular systems were considered to be an interesting medium to study their effect on the DASPMI-DNA binding properties in it vis-a-vis that in aqueous medium.…”

Role of block copolymer-micelle nanocomposites in dye–bovine serum albumin binding: a combined experimental and molecular docking study

“…The diblock copolymer polyethylene-b-polyethylene glycol (PE-b-PEG) is found to form a nanocomposite (NC) 14 by intercalating with the anionic surfactant sodium dodecyl sulphate (SDS), and the structure of this NC changes to some vesicle-like structures 15 in aqueous solution by interacting with the charge transfer dye 1,8-naphthalimide (NAPMD). Protein-surfactant interaction has ample applications, including drug delivery, cosmetics, foods etc.…”

Exploring the fluorescence switching phenomenon of curcumin encapsulated niosomes: in vitro real time monitoring of curcumin release to cancer cells

“…The abrupt increase in this anisotropy constant suggests the presence of a more confined medium with motional restrictions on the CU molecules inside the niosome. 35 The process of fluorescence switching is clearly visualized through fluorescence microscopy images and the corresponding solutions are depicted as insets in Fig. 3.…”