Supramolecular Strategies To Construct Biocompatible and Photoswitchable Fluorescent Assemblies (original) (raw)
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Chemistry – A European Journal
HBDI‐like chromophores represent a novel set of biomimetic switches mimicking the fluorophore of the green fluorescent protein that are currently studied with the hope to expand the molecular switch/motor toolbox. However, until now members capable of absorbing visible light in their neutral (i. e. non‐anionic) form have not been reported. In this contribution we report the preparation of an HBDI‐like chromophore based on a 3‐phenylbenzofulvene scaffold capable of absorbing blue light and photoisomerizing on the picosecond timescale. More specifically, we show that double‐bond photoisomerization occurs in both the E‐to‐Z and Z‐to‐E directions and that these can be controlled by irradiating with blue and UV light, respectively. Finally, as a preliminary applicative result, we report the incorporation of the chromophore in an amphiphilic molecule and demonstrate the formation of a visible‐light‐sensitive nanoaggregated state in water.
Angewandte Chemie International Edition, 2007
Variations in the radiative properties of fluorescent dyes through the formation of supramolecular host-guest assemblies or association with biomacromolecules such as proteins and oligonucleotides enable sensor applications and improve the understanding of the factors governing molecular recognition. [1] Macrocyclic hosts impose a structural confinement of the included chromophoric guest molecules, increase their thermal and photochemical stability, and isolate them from the bulk water, which together improves their radiative properties. The radiative lifetimes of triphenylmethane (TPM) dyes, for example, are very short (< 1 ps) in lowviscosity solvents, but increase substantially upon binding with biomolecules as a consequence of altered photophysical characteristics. [2] These increases are accompanied by variations in the electron-transfer properties of the excited states, [2b, 3] which are also relevant for their use as drugs in photodynamic therapy. [4] Furthermore, TPM dyes have been used as aptamer-based fluorescence sensors to assay the formation, location, or break down of RNA. [1d, 5] We now demonstrate that the photophysical properties of the antimicrobial TPM dye Brilliant Green (BG) and its binding
This paper describes a facile and reproducible protocol for the preparation of a supramolecular photodynamic therapeutic agent mediated by host-guest encapsulation in the absence of inorganic matrix. Two distinct approaches were explored to modulate the size and morphology of supramolecular nanoparticles (SNPs). One approach is through changing the guest integration components of biviologen derivatives during the self-assembly process. It provides the opportunity to modulate the morphology (from amorphous to spherical) and the size of the self-assemblies (from 100 to 600 nm) by simply adjusting the length of the guest components. The other approach is a facile oil-in-water emulsionphase method to synthesize high-quality supramolecular photodynamic therapeutic agents with good dispersion and uniform morphology in aqueous solution. In particular, photosensitizing efficiency was compared and the results revealed that this kind of particles exhibited higher photo-oxidation efficiency than the pure porphyrin derivative at the same concentration. Furthermore, the confocal microscopic images revealed the SNPs can be successfully endocytosed by Hela cell at various concentrations. In addition, the MTT assay indicated cell viability was not hindered by the concentration of SNPs up to 3.2 mg mL À1 before light irradiation, thereby revealing good biocompatibility and remarkably low cytotoxicity of SNPs in vitro. Importantly, the cell viability was significantly attenuated to $20% after light irradiation (633 nm) for 1 hour. These SNPs would thus be promising materials as supramolecular photodynamic therapeutic agents in the treatment of cancer.
Photoactivatable BODIPYs Designed to Monitor the Dynamics of Supramolecular Nanocarriers
Journal of the American Chemical Society, 2015
Self-assembling nanoparticles of amphiphilic polymers can transport hydrophobic molecules across hydrophilic media and, as a result, can be valuable delivery vehicles for a diversity of biomedical applications. Strategies to monitor their dynamics noninvasively and in real time are, therefore, essential to investigate their translocation within soft matrices and, possibly, rationalize the mechanisms responsible for their diffusion in biological media. In this context, we designed molecular guests with photoactivatable fluorescence for these supramolecular hosts and demonstrated that the activation of the fluorescent cargo, under optical control, permits the tracking of the nanocarrier translocation across hydrogel matrices with the sequential acquisition of fluorescence images. In addition, the mild illumination conditions sufficient to implement these operating principles permit fluorescence activation within developing Drosophila Melanogaster embryos and enable the monitoring of t...
Small photoactivatable molecules for controlled fluorescence activation in living cells
Bioorganic & Medicinal Chemistry, 2011
The search for chemical probes which allow a controlled fluorescence activation in living cells represent a major challenge in chemical biology. To be useful, such probes have to be specifically targeted to cellular proteins allowing thereof the analysis of dynamic aspects of this protein in its cellular environment. The present paper describes different methods which have been developed to control cellular fluorescence activation emphasizing the photochemical activation methods known to be orthogonal to most cellular components and, in addition, allowing a spatio-temporal controlled triggering of the fluorescent signal.
Macromolecules, 2017
We describe a facile strategy, involving bioinspired noncovalent molecular recognition, for fabricating water-dispersible luminescent polymer dots without any ionic groups. We first synthesized the thymine-functionalized conjugated polymers PC-T and PTC-T through conventional Suzuki coupling polymerization and copper(I)-catalyzed alkyne/azide cycloaddition (CuAAC). These multiple-hydrogen-bonding materials exhibited distinct luminescent properties in protic and aprotic solvents as well as attractive thermal properties and stabilities; most importantly, they had the ability to pair with complementary base units. Next, we prepared the hydrophilic polymer PEG-A and examined its molecular recognition with PC-T and PTC-T through DNA-like adenine−thymine (A−T) base pairing. We used transmission electron microscopy (TEM) and dynamic light scattering (DLS) to determine the size distributions and dispersibilities of the resulting supramolecular micelles, which appeared as polymeric dots with high signal-to-background ratios through fluorescence microscopy. The PEG shells of these micelles functioned as biomimetic surfaces that sustained the biocompatibility for practical usage. Our results suggest that supramolecular self-assembly through specific nucleobase recognition appears to be a reliable process with which to apply conjugated polymers into, for example, modern biological analysis.