A New Coumarin-Acridone Compound as a Fluorescence Probe for Fe3+ and Its Application in Living Cells and Zebrafish

A novel [1, 2, 4]triazolo[5,1-b]quinazoline derivative as a fluorescent probe for highly selective detection of Fe3+ ions

A novel [1, 2, 4]triazolo[5,1-b]quinazoline fluorescent probe (VIi) for Fe3+ was developed, featuring with rapid response (< 5 s) and specific selectivity to Fe3+, low detection limit (1.3 × 10-5 M), as well as the ability to resist interference of chelating agent (e.g. EDTA). VIi-based fluorescent test paper can quickly recognize Fe3+ under irradiation at the wavelength of 365 nm. The fluorescence probe VIi has potential application prospects for the detection of Fe3+ in real circumstance.

A water-soluble naphthalimide fluorescent probe for Cr2O72- and Fe3+ based on inner filter effect

A probe 3 (2-ethoxy-N-(2-(2-(2-hydroxyethoxy)ethyl)-1,3-dioxo-2,3-dihydro-1H-benzo[de] isoquinolin-6-yl)benzamide) that could selectively respond to Cr₂O₇^2- and Fe³⁺ was reported in this paper. The selectivity, pH titration, concentration titration, detection limit, time dependence, quenching constant and recognition mechanism of probe 3 for Cr₂O₇^2- and Fe³⁺ were studied in CH₃CN/HEPES buffer solution. The results showed that Cr₂O₇^2- and Fe³⁺ could rapidly quench the fluorescence of probe 3 through the inner filter effect (IFE). The quenching kept constant after 30 s, and the quenching constants were 7.99 × 10³ L^.mol^-1 and 4.13 × 10³ L^.mol^-1, respectively. The detection limits of probe 3 for Cr₂O₇^2- and Fe³⁺ were 1.15 μmol^.L^-1 and 1.95 μmol^.L^-1, respectively, which were lower than the maximum allowable concentrations in drinking water stipulated by EPA. The determination results of Cr₂O₇^2- and Fe³⁺ in water samples indicated that probe 3 could be used as a potential detection tool in practical applications.

Design, synthesis and biological evaluation of novel dual-targeting fluorescent probes for detection of Fe3+ in the lysosomes of hepatocytes mediated by galactose-morpholine moieties

In this work, novel dual-targeting probes composed of galactose and morpholine were designed and synthesized for monitoring Fe³⁺ levels in the lysosome of hepatocyte. MP-Gal-1, MP-Gal-2 and MP-Gal-3 showed good selectivity and sensitivities toward Fe³⁺ with the detection limits of 9.40 × 10^-8 M, 7.68 × 10^-8 M and 7.10 × 10^-8 M, respectively. 1:2 stoichiometry is the most likely recognition mode between probe and Fe³⁺. Low toxic MP-Gal-1, MP-Gal-2 and MP-Gal-3 exhibited favorable hepatic targeting effect in both cell and tissue levels, which was because the galactose group of probe could be recognized by ASGPR overexpressed on the hepatocytes. The hepatocyte-targeting capacity followed MP-Gal-1 < MP-Gal-2 < MP-Gal-3 trend, which was attributed to the galactose cluster effect. MP-Gal-1, MP-Gal-2 and MP-Gal-3 also displayed good lysosomes-targeting capacities, because the basic morpholine moiety of probes could be easily attracted by the acidic lysosome. Therefore, MP-Gal-1, MP-Gal-2 and MP-Gal-3 have good dual targeting capacities (liver and lysosome) and could be used to detect lysosomal Fe³⁺ in the liver, which is great significant for precise diagnosis and treatment of liver lysosomal iron-related diseases.

Nanodispersions of Polyelectrolytes Based on Humic Substances: Isolation, Physico-Chemical Characterization and Evaluation of Biological Activity

Natural polyelectrolytes, including in the form of complexes with colloidal particles, are increasingly used in pharmacy due to the possibility of regulated attachment of medicinal substances and their targeted delivery to the target organ. However, the formation, stability, and molecular-mass characteristics of polyelectrolyte nanodispersions (ND) vary depending on the nature and composition of the medium of their origin. This is due to the lack of standardized approaches to quality control and regulatory documentation for most natural ND. In this paper, we first introduced the isolation, followed by investigations into their physico-chemical properties and bioactivity. Using the dried droplet method, we were able to detect the “coffee ring effect”. Fractographic studies of the surface structure of EHA and FA dried samples using SEM showed its heterogeneity and the presence of submicron particles encapsulated in the internal molecular cavities of polyelectrolyte. FTIR spectroscopy revealed the ND chemical structure of benzo-α-pyron and benzo-γ-pyron, consisting of nanoparticles and a branched frame part. The main elements detected by X-ray fluorescence in humic substance extract and fulvic acid include Si, P, S, K, Ca, Mn, Fe, Cu, Zn, whereas Fe is in high concentrations. The UV-spectra and fluorescent radiation demonstrated the possibility of studying the effect of the fulvate chromone structure on its optical properties. It is shown that dilution of the initial solutions of polyelectrolytes 1:10 contributes to the detection of smaller nanoparticles and an increase in the absolute value of the negative ζ-potential as a factor of ND stability. A study of the EHS effect on the SARS-CoV-2 virus infectious titer in the Vero E6 cell showed the effective against virus both in the virucidal scheme (the SI is 11.90–22.43) and treatment/prevention scheme (the SI is 34.85–57.33). We assume that polyelectrolyte ND prevent the binding of the coronavirus spike glycoprotein to the receptor. Taking into account the results obtained, we expect that the developed approach can become unified for the standardization of the ND natural polyelectrolytes complex, which has great prospects for use in pharmacy and medicine as a drug with antiviral activity.