Hydrophilic Tetraphenylethene-Based Tetracationic Cyclophanes: NADPH Recognition and Cell Imaging With Fluorescent Switch

Construction of a Reversible Solid-state Fluorescence Switching Via Photochromic Diarylethene and Si-ZnO Quantum Dots

Developing fluorescence switching as functional system is highly desirable for potential applications in the fields of light-responsive materials or devices. Attempt to construct fluorescence switching system tend to focus on the high fluorescence modulation efficiency, especially in solid state. Herein, a photo-controlled fluorescence switching system was constructed with photochromic diarylethene and trimethoxysilane modified zinc oxide quantum dots (Si-ZnO QDs) successfully. It was verified by the measurement of modulation efficiency, fatigue resistance as well as theoretical calculation. Upon irradiation with UV/Vis lights, the system exhibited excellent photochromic property and photo-controlled fluorescence switching performance. Furthermore, the excellent fluorescence switching characters could also be realized in solid state and the fluorescence modulation efficiency was determined to be 87.4%. The results will provide new strategies to the construction of reversible solid-state photo-controlled fluorescence switching for the application in the fields of optical data storage and security labels.

Cataleptogenic Effect of Haloperidol Formulated in Water-Soluble Calixarene-Based Nanoparticles

In this study, a water-soluble form of haloperidol was obtained by coaggregation with calix[4]resorcinol bearing viologen groups on the upper rim and decyl chains on the lower rim to form vesicular nanoparticles. The formation of nanoparticles is achieved by the spontaneous loading of haloperidol into the hydrophobic domains of aggregates based on this macrocycle. The mucoadhesive and thermosensitive properties of calix[4]resorcinol–haloperidol nanoparticles were established by UV-, fluorescence and CD spectroscopy data. Pharmacological studies have revealed low in vivo toxicity of pure calix[4]resorcinol (LD50 is 540 ± 75 mg/kg for mice and 510 ± 63 mg/kg for rats) and the absence of its effect on the motor activity and psycho-emotional state of mice, which opens up a possibility for its use in the design of effective drug delivery systems. Haloperidol formulated with calix[4]resorcinol exhibits a cataleptogenic effect in rats both when administered intranasally and intraperitoneally. The effect of the intranasal administration of haloperidol with macrocycle in the first 120 min is comparable to the effect of commercial haloperidol, but the duration of catalepsy was shorter by 2.9 and 2.3 times (p < 0.05) at 180 and 240 min, respectively, than that of the control. There was a statistically significant reduction in the cataleptogenic activity at 10 and 30 min after the intraperitoneal injection of haloperidol with calix[4]resorcinol, then there was an increase in the activity by 1.8 times (p < 0.05) at 60 min, and after 120, 180 and 240 min the effect of this haloperidol formulation was at the level of the control sample.

Tetraphenylethene Derivatives Modulate the RNA Hairpin-G-quadruplex Conformational Equilibria in Proto-Oncogenes

RNA G-quadruplexes (GQs) sequence in 5' UTRs of certain proto-oncogenes colocalize with hairpin (Hp) forming sequence resulting in intramolecular Hp-GQ conformational equilibria which is suggested to regulate cancer development and progression. Thus, regulation of Hp-GQ equilibria with small molecules is an attractive but less explored therapeutic approach. Herein, two tetraphenylethenes (TPE) derivatives TPE-Py and TPE-MePy were synthesized and their effect on Hp-GQ equilibrium was explored. The FRET, CD and molecular docking experiments suggested that cationic TPE-MePy shifts the Hp-GQ equilibrium significantly towards the GQ conformer mainly through π-π stacking and van der waals interaction. In presence of TPE-MePy the observed rate constant values for first and second folding step was increased up to 14.6 and 2.6-fold respectively. The FRET melting assay showed a strong stabilizing ability of TPE-MePy (ΔTm = 4.36 °C). Notably, the unmethylated derivative TPE-Py did not alter the Hp-GQ equilibrium. Subsequently, the luciferase assay demonstrated that the TPE-MePy derivatives suppressed the translation efficiency by ∼5.7-fold by shifting the Hp-GQ equilibrium toward GQ conformers in 5' UTR of TRF2. Our data suggest that HpGQ equilibria could be selectively targeted with small molecules to modulate translation for therapy.