Formation of a planar biomimetic membrane with a novel zwitterionic polymer for nanopore sequencing

Biological membranes containing transmembrane channels play a crucial role in numerous cellular processes, and mimicking of cell membranes has garnered significant interest in various biomedical applications, particularly nanopore sequencing technology, where remarkable progress has been made with nanopore membranes. Considering the fragility of biomimetic membranes formed by artificial lipids and the limited mimicry of those formed by common block copolymers, this study developed a novel amphiphilic polymer by covalently linking hydrophilic heads of phospholipids to the ends of hydrophobic poly(dimethyl siloxane) (PDMS) chains. The absence of hydrophilic blocks allowed for good control over the polydispersity of this polymer within a narrow range. The high flexibility of PDMS chains, combined with relatively uniform molecular weights, would confer enhanced stability and robustness to polymeric membranes. Dynamic light scattering measurements and microdroplet formation tests demonstrated good amphipathic properties of these novel polymers when maintaining an appropriate hydrophilic-hydrophobic ratio. Moreover, the high similarity between the hydrophilic heads and natural phospholipids makes this polymer more compatible with biomolecules. A successful protein insertion experiment confirmed both the stability of this polymeric membrane and its compatibility with membrane proteins. As a result, this novel amphiphilic polymer exhibits great potential for biomembrane mimicking and paves a new path for material design in biomedical applications.

New Functional Alkoxysilanes and Silatranes: Synthesis, Structure, Properties, and Possible Applications

The aza-Michael reaction of 3-aminopropyltriethoxysilane (1) and -silatrane (2) with acrylates affords functionalized silyl-(3-8) and silatranyl-(9-14) mono- and diadducts with up to a 99% yield. Their structure has been proved with IR and NMR spectroscopies, mass spectrometry and XRD analysis. The hydrolytic homo-condensation of triethoxysilanes 3-5 gives siloxanes 3a-5a, which form complexes with Ag, Cu, and Ni salts. They are also able to adsorb these metals from solutions. The hetero-condensation reaction of silanes 4-8 with OH groups of zeolite (Z), silica gel (S) and glass (G) delivers the modified materials (Z4, S7, G4, G5, G7, G8, etc.), which can adsorb ions of noble metal (Au, Rh, Pd: G4 + Au, G5 + Pd, G7 + Rh). Thus, the synthesized Si-organic polymers and materials turned out to be promising sorbents (enterosorbents) of noble, heavy, toxic metal ions and can be applied in industry, environment, and medicine.

New 3-Aminopropylsilatrane Derivatives: Synthesis, Structure, Properties, and Biological Activity

The biologically active compound 3-aminopropylsilatrane (a compound with a pentacoordinated silicon atom) underwent an aza-Michael reaction with various acrylates and other Michael acceptors. Depending on the molar ratio, the reaction yielded Michael mono- or diadducts (11 examples) containing functional groups (silatranyl, carbonyl, nitrile, amino, etc.). These compounds were characterized via IR and NMR spectroscopy, mass spectrometry, X-ray diffraction, and elemental analysis. Calculations (using in silico, PASS, and SwissADMET online software) revealed that the functionalized (hybrid) silatranes were bioavailable, druglike compounds that exhibited pronounced antineoplastic and macrophage-colony-stimulating activity. The in vitro effect of silatranes on the growth of pathogenic bacteria (Listeria, Staphylococcus, and Yersinia) was studied. It was found that the synthesized compounds exerted inhibitory and stimulating effects in high and low concentrations, respectively.

Recent advances in the asymmetric synthesis of pharmacology-relevant nitrogen heterocycles via stereoselective aza-Michael reactions

In this review, recent applications of a stereoselective aza-Michael reaction for asymmetric synthesis of naturally occurring N-containing heterocyclic scaffolds and their usefulness to pharmacology are summarized.