Coumarin Xanthene Combined Probe for the Multi-Color Detection of Metal Ions and Electrospun Fibers Developed for Real-Time Monitoring.

A coumarin-rhodamine (RhBC)-fused colorimetric/fluorescent probe was designed and synthesized. The probe is effective in Cu2+/Hg2+ ion sensing. With the added Cu2+ to RhBC in water: N, N-dimethyl formamide (8:2, v/v), the cyclic form of RhBC, is converted into the open ring form and shows a clear color change from yellow to red. In the presence of additional participating cations, this moiety shows effectiveness for Cu2+ and Hg2+ ions. The RhBC's detection limit by the UV-visible spectral method was 8.81 × 10-6 M for Cu2+ ions and 2.26 × 10-5 M for Hg2+ ions. The detection limit in the fluorescence titration spectra was 2.02 × 10-7 M for Cu2+ ions and 6.11 × 10-8 M for Hg2+ ions. A 1:1 stoichiometric ratio was validated between the probe and copper/mercury ions by the method of the job plot. Moreover, RhBC-combined polyurethane electrospun nanofibers were synthesized. These nanofibers could detect Cu2+ in real samples with no complications, with an instinctive color difference from yellow to red and a weak orange color for mercury ions.

Vascular inflammation exposes perivascular cells to SARS-CoV-2 infection

Pericytes stabilize blood vessels and promote vascular barrier function. However, vessels subjected to pro-inflammatory conditions have impaired barrier function, which has been suggested to potentially expose perivascular cells to SARS-CoV-2. To test this hypothesis, we engineered pericyte-supported vascular capillaries on-a-chip, and determined that the extravasation and binding of spike protein (S1) on perivascular cells of inflamed vessels to be significantly higher that in healthy controls, indicating a potential target to understand COVID-19 vascular complications.

Facile synthesis of 2-azaspiro[3.4]octane.

Our annulation strategy utilized for the synthesis of 2-azaspiro[3.4]octane is explained. Three successful routes for the synthesis were developed. One of the approaches involved annulation of the cyclopentane ring and the remaining two approaches involved annulation of the four membered ring. All three approaches employ readily available starting materials with conventional chemical transformations and minimal chromatographic purifications to afford the title compound. The merits and limitations of the three approaches are also discussed.