Naphthalene anhydride triphenylamine as a viscosity-sensitive molecular rotor for liquid safety inspection

A viscosity-sensitive molecular rotor, DPPBQD, was synthesized through the Suzuki coupling reaction successfully. This molecular rotor was constructed by the naphthalene anhydride and triphenylamine moieties, formed into a typical twisted...

Two ‘braking mechanisms’ for Tin phthalocyanine molecular rotor on dipolar oxide iron surface

Manipulation of artificial molecular rotors/motors is a key issue in the field of molecular nanomachine. Here we assemble non-planar SnPc molecules on FeO film to form two kinds of rotors...

The Role of Plasma Membrane Viscosity in the Response and Resistance of Cancer Cells to Oxaliplatin

Maintenance of the biophysical properties of membranes is essential for cell survival upon external perturbations. However, the links between a fluid membrane state and the drug resistance of cancer cells remain elusive. Here, we investigated the role of membrane viscosity and lipid composition in the responses of cancer cells to oxaliplatin and the development of chemoresistance. Plasma membrane viscosity was monitored in live colorectal cancer cells and tumor xenografts using two-photon excited fluorescence lifetime imaging microscopy (FLIM) using the fluorescent molecular rotor BODIPY 2. The lipid profile was analyzed using time-of-flight secondary ion mass spectrometry (ToF-SIMS). It was found that the plasma membrane viscosity increased upon oxaliplatin treatment, both in vitro and in vivo, and that this correlated with lower phosphatidylcholine and higher cholesterol content. The emergence of resistance to oxaliplatin was accompanied by homeostatic adaptation of the membrane lipidome, and the recovery of lower viscosity. These results suggest that maintaining a constant plasma membrane viscosity via remodeling of the lipid profile is crucial for drug resistance in cancer.

SPECTRAL PROPERTIES OF A BENZOTHIAZOLE DYE MODIFIED WITH POLYETHYLENE GLYCOL

The spectral properties of a new benzothiazole dye modified with polyethylene glycol have been investigated. A strong dependence of the fluorescence quantum yield on the viscosity and polarity of the medium has been shown, i.e. the conjugation of the dye with polyethylene glycol does not lead to the loss of the properties of the molecular rotor, while significantly reduces its aggregation. When incorporated into amyloid fibrils, the quantum yield of the dye increases by more than 40 times; the new dye can be regarded as an efficient fluorescent probe for amyloid fibrils detection and research. In this case, not only the intensity, but also the position of the absorption spectrum can be used as a sensitive parameter. The presence of blood plasma proteins (albumins) in the solution has practically no effect on the position of the absorption spectrum and has little effect on the fluorescence intensity of the probe.

An expanded palette of fluorogenic HaloTag probes with enhanced contrast for targeted cellular imaging

We report on new fluorogenic HaloTag probes based on a molecular rotor design. Thanks to their viscosity-sensitive emission, the probes light-up upon reaction with the protein self-labeling tag HaloTag. The palette of probes cover an emission range from green to red and exhibit remarkably low non-specific signal that enabled wash-free targeted imaging of intracellular organelles and proteins with good contrast in live Hela cells.

Probing a Local Viscosity Change at the Nematic-Isotropic Liquid Crystal Phase Transition by a Ratiometric Flapping Fluorophore

Local viscosity change in the thermal phase transition of a nematic liquid crystal, 5CB, has been analyzed by doping fluorescent viscosity probes, flapping fluorophores (FLAP) as well as a molecular rotor BODIPY-C12. As a result, only flapping anthraceneimide has successfully monitored a small viscosity change (corresponding to a few cP (centipoise) change in shear viscosity around 25 cP) in the nematic-to-isotropic phase transition by ratiometric spectroscopy. In addition, analysis of fluorescence anisotropy indicates that the emissive species (planarized flapping anthraceneimides) are aligned parallel to the director of 5CB in the nematic phase.