π-Conjugated polymer anisotropic organogel nanofibrous assemblies for thermoresponsive photonic switches

Optical properties of quadrupolar and bi-quadrupolar dyes: intra and inter chromophoric interactions

In this work we present the synthesis, characterization and theoretical investigation of three boron-difluoride-curcuminoid derivatives and their covalent homodimers chemically linked through a polymethylenic chain. Low-lying electronic excited states and photophysical properties of the monomeric species have been described as the convolution of different donor-acceptor intramolecular excitations. Covalent dimers in solution can present open or folded structural conformations. Analysis of absorption profiles and computational results allow to identify the factors that control the relative stability of the two forms and rationalize its dependence with the solvent polarity. Interestingly, the strong electronic coupling in the folded forms results in low-lying excitations with sizable mixings of intra- and inter-chromophoric contributions, which cannot be described by means of the Kasha model of interacting chromophores. Our study demonstrates how decomposition of the computed excitations in terms of diabatic states can be extremely valuable in order to identify and quantify the nature of electronic transitions in the presence of several electron donor and acceptor fragments.

π-Conjugated Chromophore Incorporated Polystyrene Nanobeads as Single Optical Agent for Three-Channel Fluorescent Probe in Bioimaging Application

Fluorescent polystyrene (PS) nanobeads in the size range ∼70-120 nm incorporating perylene bisimide (PBI-PS) and/or oligo(p-phenylenevinylene) (OPV-PS) was developed by miniemulsion polymerization technique. A dye loading content (DLC) of <3% was sufficient to impart high fluorescence emission capability to the PS beads. OPV-PS exhibited emission in the range 400-550 nm with peak emission at 450 nm (λ_ex = 350 nm; ϕ_FL = 26%); PBI-PS showed emission from 520-650 nm with peak emission at 545 nm (λ_ex = 490 nm; ϕ_FL = 9.7%) in 1× PBS buffer, whereas OPV(PBI)-PS nanobeads incorporating both the fluorophores exhibited multicolor emission capabilities (λ_ex from 350 to 490 nm). The nanoparticles were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS) for size and zeta potential for surface charge. For bioimaging applications, the PS nanoparticles were incubated with HeLa cells. Cell viability analysis involving HeLa cells showed more than 90% cell viability confirming the biocompatibility of the PS beads. The cellular uptake of the nanoparticles was confirmed by flow cytometry analysis and confocal laser scanning microscopy (CLSM) images. The subcellular localization of the nanoparticles in the cytoplasm could be precisely established by their simultaneous multicolor emission. The PS-based single optical agent presented here that can function as three-channel fluorescent probe to meet the requirements for multicolor bioimaging is advantageous.

Photocurrent generation of nanofibers constructed using a complex of a gelator and a fullerene derivative

Two-component xerogel film constructed by a carboxylic acid derivative and fullerene derivative could generate large photocurrent under light irradiation.

Supramolecular association of 2D alumino-siloxane aquagel building blocks to 3D porous cages and its efficacy for topical and injectable delivery of fluconazole, an antifungal drug

A fascinating 2D architecture of an alumino-siloxane gel self-assembled into a well-defined 3D porous aquagel cage. It is identified to be an excellently mechanically stable, injectable and non-cytotoxic medium for drug delivery applications.