Exploiting directed self-assembly and disassembly for off-to-on fluorescence responsive live cell imaging.

A bio-responsive nanoparticle was formed by the directed self-assembly (DSA) of a hydrophobic NIR-fluorophore with poloxamer P. Fluorophore emission was switched off when part of the nanoparticle, however upon stimulus induced nanoparticle dis-assembly the emission switched on. The emission quenching was shown to be due to fluorophore hydration and aggregation within the nanoparticle and the turn on response attributable to nanoparticle disassembly with embedding of the fluorophore within lipophilic environments.

Biocompatible and Photostable Photoacoustic Contrast Agents as Nanoparticles Based on Bodipy Scaffold and Polylactide Polymers: Synthesis, Formulation, and Evaluation.

We have designed a new Bodipy scaffold for efficient photoacoustic (PA) imaging of nanoparticles commonly used as drug nanovectors. The new dye has an optimized absorption band in the near-infrared window in biological tissue and a low fluorescence quantum yield that leads to a good photoacoustic generation efficiency. After Bodipy-initiated ring-opening polymerization of lactide, the polylactide-Bodipy was formulated into PEGylated nanoparticles (NPs) by mixing with PLA-PEG at different concentrations.

Selective population of triplet excited states in heavy-atom-free BODIPY-C based molecular assemblies.

Photophysical studies on a BODIPY-fullerene-distyryl BODIPY triad (BDP-C-DSBDP) and its reference dyads (BODIPY-fullerene; BDP-C and distyryl BODIPY-fullerene; DSBDP-C) are presented herein. In the triad, the association of the two chromophore units linked by a fullerene moiety leads to strong near UV-Visible light absorption from 300 to 700 nm. The triplet-excited state was observed upon visible excitation in all these assemblies, and shown to be localized on the C or BODIPY moieties.

"CinNapht" dyes: a new cinnoline/naphthalimide fused hybrid fluorophore. Synthesis, photo-physical study and use for bio-imaging.

Six-membered-diaza ring of cinnoline has been fused on naphthalimide dye to give a donor-acceptor system called CinNapht. This red shifted fluorophore, that can be synthesised in gram scale, exhibits a large Stoke shift and a fluorescence quantum yield up to 0.33.

FRET-mediated quenching of BODIPY fluorescent nanoparticles by methylene blue and its application to bacterial imaging.

High resolution and a good signal to noise ratio are a requirement in cell imaging. However, after labelling with fluorescent entities, and after several washing steps, there is often an unwanted fluorescent background that reduces the images resolution. For this purpose, we developed an approach to remove the signal from extra-cellular fluorescent nanoparticles (FNPs) during bacteria imaging, without the need for any washing steps.