Rapid synthesis of cesium lead halide perovskite nanocrystals by l-lysine assisted solid-phase reaction at room temperature.

Nowadays, there are many ways to obtain cesium lead halide perovskite nanocrystals. In addition to the synthesis methods carried out in solution, the solid-phase synthesis was reported involving grinding and milling. In this paper, we synthesized luminescent CsPbBr3/Cs4PbBr6 perovskite nanocrystals (PNCs) by three solid-phase synthesis methods (grinding, knocking, stirring) using l-lysine as a ligand. This is the first attempt to use an amino acid for assisting the solid phase synthesis of perovskite and to study the difference in the products obtained by the three solid phase synthesis methods. The results show that the productivity of the solid-phase synthesis methods can be greatly improved by adding l-lysine and the perovskites obtained by the methods are more resistant to water due to the addition of l-lysine. The simplicity of the synthesis process expanded the use of solid-phase synthesis to obtain more perovskites and provided potential applications of perovskite in analytical detection and sensing in aqueous solution.

Virtual screening of B-Raf kinase inhibitors: A combination of pharmacophore modelling, molecular docking, 3D-QSAR model and binding free energy calculation studies.

B-Raf kinase has been identified as an important target in recent cancer treatment. In order to discover structurally diverse and novel B-Raf inhibitors (BRIs), a virtual screening of BRIs against ZINC database was performed by using a combination of pharmacophore modelling, molecular docking, 3D-QSAR model and binding free energy (ΔGbind) calculation studies in this work. After the virtual screening, six promising hit compounds were obtained, which were then tested for inhibitory activities of A375 cell lines. In the result, five hit compounds show good biological activities (IC50<50µM). The present method of virtual screening can be applied to find structurally diverse inhibitors, and the obtained five structurally diverse compounds are expected to develop novel BRIs.

Novel water-soluble fisetin/cyclodextrins inclusion complexes: Preparation, characterization, molecular docking and bioavailability.

Novel water-soluble inclusion complexes for fisetin (FIT) were developed by introducing ß-cyclodextrin (ß-CD) and γ-CD. Properties of the obtained complexes, as well as the interactions between each component, were systematically investigated in both solution and solid states by means of ESI-MS, NMR, FT-IR, XRD, DSC, SEM etc. All characterization information demonstrated that FIT/CDs inclusion complexes were formed, and exhibited different spectroscopic features and properties from FIT. A complex with 1:1 stoichiometry of FIT and CDs was confirmed with Job's method. Meanwhile, as supported by molecular modeling calculations, we suggested that phenyl group (C ring) of FIT molecule was included in the CDs cavity from the wide side. Moreover, the water solubility of FIT/CDs was successfully improved from 2.8 mg/mL (in ethanol aqueous solution) to 4.5 mg/mL (FIT/ß-CD complex) and 7.8 mg/mL (FIT/γ-CD complex), and higher thermal stability results were shown by thermal analysis for those complexes. Notably, the inclusion complexes displayed almost two times higher cytotoxicity compared to free FIT against Hela and MCF-7 cells. These results suggested that FIT/CDs complexes could be potentially useful in food industry and healthcare area.

Preparation, spectroscopy and molecular modelling studies of the inclusion complex of cordycepin with cyclodextrins.

The inclusion complexes of cordycepin with cyclodextrins (CDs) were prepared, the resultant complexes were characterised by UV-vis, FTIR, DSC, SEM, XRD, ESI-MS and proton nuclear magnetic resonance spectroscopy ((1)H NMR). The stoichiometry was established using a Job plot and the inclusion mechanism was clarified using molecular dynamic simulations. Molecular modelling calculations have been carried out to rationalise the experimental findings and predict the stable molecular structure of the inclusion complex. The stability of the inclusion complexes were confirmed by energetic and thermodynamic properties (ΔE, ΔH, ΔG and ΔS) and HOMO, LUMO orbital. The 1:1 binding model of complexes were visually proved by ESI-MS experiment. Our results showed that the purine group of cordycepin molecule was deeply inserted into the cavity of CDs.

Phosphate ion targeted colorimetric and fluorescent probe and its use to monitor endogeneous phosphate ion in a hemichannel-closed cell.

Fluorescent probe 1, the first inorganic phosphate (Pi) targeted colorimetric and fluorescent probe to detect endogenous Pi in hemichannel-closed cells, has been developed. Probe 1 undergoes a unique Pi induced hydrolytic reaction in DMSO-HEPES (V/V = 9:1) buffered (0.02 M, pH 7.4) solutions that produces a colorimetric change associated with a 62 nm red-shift in the UV-vis absorption maximum and up to a 780-fold enhancement in the fluorescence intensity. The mechanistic proposal that these spectroscopic changes are associated with reaction Pi with 1 to form coumarin gains support from the results of theoretical calculations and mass spectrometry studies. Observations made in fluorescence imaging studies with HeLa cells and C. elegans show that 1 can be employed to monitor Pi production in vivo caused by apyrase-catalyzed ATP hydrolysis. Moreover, probe 1 was utilized to show that apoptosis of hemichannel-closed Sf9 cells is caused by Inx3 promoted dephosphorylation of Akt (RAC serine/threonine-protein kinase), leading to an elevation of the concentration of Pi. Overall, the study has produced the first fluorescent sensor 1 for endogenous inorganic phosphate. Moreover, the utility of 1 for measuring Pi release in vitro has been demonstrated and utilized to elucidate the mechanism of Inx3 action in hemichannel-closed Sf9 cells.

Preparation, characterisation and bioactivity evaluation of the inclusion complex formed between picoplatin and γ-cyclodextrin.

The inclusion complex of picoplatin with γ-cyclodextrin (γ-CD) was prepared and characterised by different analytical methods, including NMR, FTIR, TGA, phase solubility as well as SEM. All of these approaches indicated that picoplatin was able to form an inclusion complex with γ-CD, and that the picoplatin/γ-CD inclusion compounds exhibited different spectroscopic features and properties from free picoplatin. The stoichiometry of the complex was 1:1; the pyridine group of picoplatin was deeply inserted into the cavity of γ-CD and the amine platinum group of picoplatin was near the narrower rim of γ-CD. The calculated apparent stability constant of the complex was 10,318M(-1). Moreover, the water solubility of picoplatin was significantly improved, according to phase-solubility studies. The complex maintained its anticancer activity, as shown by an in vitro cell-survival assay on A549 and MCF-7 cancer cell lines. All of these results showed that inclusion complexation may be a promising strategy to design a novel formulation of picoplatin as an anticancer therapy.

A pyrene derivative for Hg(2+) -selective fluorescent sensing and its application in in vivo imaging.

An Hg(2+) -selective fluorescent sensor (1) bearing pyrene as a fluorophore was synthesized. A sandwich-stacking binding mode was formed during the binding process, which increased the excimer fluorescence 22-fold at 490 nm. Compound 1 was successfully applied in in vivo imaging to trace the enrichment and distribution of mercury in the nervous system, digestive system, and reproductive system of Caenorhabditis elegans, as well as the organs of zebrafish.