Evidence of the involvement of a “cocktail”-type catalytic system in the alkyne and alkene hydrosilylation reaction in the presence of platinum on a carbon support is reported.
In this work, we have developed covalent
and low molecular weight
docetaxel delivery systems based on conjugation with N-acetyl-d-galactosamine and studied their properties related
to hepatocellular carcinoma cells. The resulting glycoconjugates have
an excellent affinity to the asialoglycoprotein receptor (ASGPR) in
the nanomolar range of concentrations and a high cytotoxicity level
comparable to docetaxel. Likewise, we observed the 21–75-fold
increase in water solubility in comparison with parent docetaxel and
prodrug lability to intracellular conditions with half-life values
from 25.5 to 42 h. We also found that the trivalent conjugate possessed
selective toxicity against hepatoma cells vs control cell lines (20–35
times). The absence of such selectivity in the case of monovalent
conjugates indicates the effect of ligand valency. Specific ASGPR-mediated
cellular uptake of conjugates was proved in vitro using fluorescent-labeled
analogues. In addition, we showed an enhanced generation of reactive
oxygen species in the HepG2 cells, which could be inhibited by the
natural ligand of ASGPR. Overall, the obtained results highlight the
potential of ASGPR-directed cytostatic taxane drugs for selective
therapy of hepatocellular carcinoma.
Water-soluble Pt complexes are the key components in medicinal chemistry and catalysis. The well-known cisplatin family of anticancer drugs and industrial hydrosylilation catalysts are two leading examples. On the molecular level, the activity mechanisms of such complexes mostly involve changes in the Pt coordination sphere. Using 195 Pt NMR spectroscopy for operando monitoring would be a valuable tool for uncovering the activity mechanisms; however, reliable approaches for the rapid correlation of Pt complex structure with 195 Pt chemical shifts are very challenging and not available for everyday research practice. While NMR shielding is a response property, molecular 3D structure determines NMR spectra, as widely known, which allows us to build up 3D structure to 195 Pt chemical shift correlations. Accordingly, we present a new workflow for the determination of lowest-energy configurational/conformational isomers based on the GFN2-xTB semiempirical method and prediction of corresponding chemical shifts with a Machine Learning (ML) model tuned for Pt complexes. The workflow was designed for the prediction of 195 Pt chemical shifts of water-soluble Pt(II) and Pt(IV) anionic, neutral, and cationic complexes with halide, NO 2 À , (di)amino, and (di)carboxylate ligands with chemical shift values ranging from À 6293 to 7090 ppm. The model offered an accuracy (normalized root-mean-square deviation/RMSD) of 1.08 %/ 145.02 ppm on the held-out test set.
Surface-enhanced Raman scattering (RS) spectroscopy is a sensitive analytical method that makes it possible to detect individual molecules. The substantial enhancement of the intensity of the signals in this method when compared to traditional Raman scattering is associated with two mechanisms, namely, electromagnetic and chemical. The first mechanism is associated with the enhancement of both the impinging and scattered radiation (electromagnetic enhancement), while the second mechanism is explained by the electron interaction between the molecule being analyzed and metal nanoparticles, namely, by the change in the polarizability of the adsorbed molecule, which results in the displacement and broadening of the electron levels of the adsorbed molecule or in the occurrence of new levels and promotes the enhancement of the signal in the Raman scattering spectrum. Graphene and material associated with it such as graphene oxide, graphite oxide, and reduced forms of graphene and graphite oxides are advanced materials for the creation of a significant chemical enhancement. Taking into account the different nature of the enhancement of the signal from the nanoparticles of noble metals and graphene and its derivatives, it is reasonable to study the effectiveness of hybrid structures on the basis of derivatives of graphene and noble metal nanoparticles in the Raman scattering spectroscopy of the analyte molecules with an aromatic structure.
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