The search for sensitive and rapid analytical techniques for the determination of natural antioxidants is an area in constant growth due, among other aspects, to the complexity of plant matrices. In this study, silver nanoparticles prepared with the aqueous extract of Mimosa albida leaves were used to assess their polyphenolic content and antioxidant capacity. Silver nanoparticles were characterized by different techniques. As a result, nanoparticles of 6.5 ± 3.1 nm were obtained. The total phenolic content in the extract was 1320.4 ± 17.6 mg of gallic acid equivalents GAE· 100 g⁻¹ and in the nanoparticles 257.3 ± 5.1 mg GAE· 100 g⁻¹. From the phenolic profile analyzed by ultra high-performance liquid chromatography (UPLC) with a diode-array detector (DAD), the presence of apigenin and luteolin in the plant extract is postulated. The antioxidant capacity measured by oxygen radical absorbance capacity ORAC-fluorescein assay was 86917 ± 6287 and 7563 ± 967 µmol ET g⁻¹ in the extract and nanoparticles respectively. Electrochemical analysis by cyclic voltammetry (CV) confirmed the effective reduction capacity of the Mimosa albida leaves extract to reduce Ag ions to AgNPs and differential pulse voltammetry (DPV) suggested the presence of two main reducing agents in the extract. From this study, it was concluded that the aqueous extract of Mimosa albida contains reducing agents capable of synthesizing silver nanoparticles, which can be used in the phytochemical industry.

In this study, the ability of CF₃ groups to bind to the electron-rich side chains and backbone groups of proteins has been investigated by combining a Protein Data Bank (PDB) survey and ab initio quantum mechanics calculations. More precisely, an inspection of the PDB involving organic ligands containing a CF₃ group and electron-rich atoms (A = N, O and S) in the vicinity revealed 419 X-ray structures exhibiting CF₃⋯A tetrel bonds (TtBs). In a posterior stage, those hits that exhibited the most relevant features in terms of directionality and intermolecular distance were selected for theoretical calculations at the RI-MP2/def2-TZVPD level of theory. Also, Hammett's regression plots of several TtB complexes involving meta- and para-substituted benzene derivatives were computed to shed light on the substituent effects. Moreover, the TtBs were characterized through several state-of-the-art computational techniques, such as the Quantum Theory of Atoms in Molecules (QTAIM) and Noncovalent Interactions plot (NCIplot) methodologies. We believe that the results gathered from our study will be useful for rational drug design and biological communities as well as for further expanding the role of this interaction to biomedical applications.

We report the fast (three minutes) synthesis of green nanoparticles based on nanoparticles coated with the natural organic receptor phytate for the recognition and capture of ⁹⁰Sr, ⁹⁰Y, and (UO₂₎²⁺. The new material shows excellent retention for (UO₂)²⁺, 97%; these values were 73% and 100% for ⁹⁰Sr and ⁹⁰Y, respectively. Recovery of the three radioactive metal ions occurs through a non-competitive process. The new hybrid material is harmless, easy to prepare, and immobilizes these radioactive contaminants in water with great efficiency.

The search for new strategies to curb the spread of the SARS-CoV-2 coronavirus, which causes COVID-19, has become a global priority. Various nanomaterials have been proposed as ideal candidates to inactivate the virus; however, because of the high level of biosecurity required for their use, alternative models should be determined. This study aimed to compare the effects of two types of nanomaterials gold (AuNPs) and silver nanoparticles (AgNPs), recognized for their antiviral activity and affinity with the coronavirus spike protein using PhiX174 and enveloped Phi6 bacteriophages as models. To reduce the toxicity of nanoparticles, a species known for its intermediate antiviral activity, Solanum mammosum L. (Sm), was used. NPs prepared with sodium borohydride (NaBH₄) functioned as the control. Antiviral activity against PhiX174 and Phi6 was analyzed using its seed, fruit, leaves, and essential oil; the leaves were the most effective on Phi6. Using the aqueous extract of the leaves, AuNPs-Sm of 5.34 ± 2.25 nm and AgNPs-Sm of 15.92 ± 8.03 nm, measured by transmission electron microscopy, were obtained. When comparing NPs with precursors, both gold(III) acetate and silver nitrate were more toxic than their respective NPs (99.99% at 1 mg ml⁻¹). The AuNPs-Sm were less toxic, reaching 99.30% viral inactivation at 1 mg ml⁻¹, unlike the AgNPs-Sm, which reached 99.94% at 0.01 mg ml⁻¹. In addition, cell toxicity was tested in human adenocarcinoma alveolar basal epithelial cells (A549) and human foreskin fibroblasts. Gallic acid was the main component identified in the leaf extract using high performance liquid chromatography with diode array detection (HPLC-DAD). The FT-IR spectra showed the presence of a large proportion of polyphenolic compounds, and the antioxidant analysis confirmed the antiradical activity. The control NPs showed less antiviral activity than the AuNPs-Sm and AgNPs-Sm, which was statistically significant; this demonstrates that both the S. mammosum extract and its corresponding NPs have a greater antiviral effect on the surrogate Phi bacteriophage, which is an appropriate model for studying SARS-CoV-2.

In this work four different iron oxide nanoparticles for the delivery of antitumoral drugs into cancer cells were synthesized and characterized. The antifolates raltitrexed, pemetrexed and methotrexate were bound to iron oxide nanoparticles by two different methods: covalent bonding or non-covalent interactions, such as electrostatic and H-bonding. For the covalent bonding of antifolates to the surface of nanoparticles an appropriate linker (3-aminopropyltriethoxysilane) was used, while the non-covalent interaction was achieved using nanoparticles functionalized in one step with squaramides and meso-2,3-dimercaptosuccinic acid. To evaluate the efficacy of the antifolate-derivatized nanoparticles, their cytotoxicity was assayed in A549 human lung adenocarcinoma cells. Only administration of the covalent antifolate-functionalized nanoparticles strongly inhibited the viability of these cancer cells, whereas the delivery of antifolates bound to nanoparticles through non-covalent interactions did not exhibit significant cytotoxic effects. The present results suggest that covalent antifolate-functionalized nanoparticles could be a potential delivery system for certain cancer cells.