RSC Advances

Shi, Cheng-Cheng; Chen, Tian-Ran; Zhang, Qi-Hua; Wei, Ling-Hua; Huang, Chao; Zhu, Ya-Di; Liu, Hai-Bin; Bai, Ya-Kun; Wang, Fang-Jun; Guo, Wen-Zhi; Zhang, Li-Rong; Ge, Guang-Bo

doi: 10.1039/c9ra09203jpmid: 35492646

Thrombin inhibition therapy is a practical strategy to reduce thrombotic and cardiovascular risks via blocking the formation of blood clots. This study aimed to identify naturally occurring thrombin inhibitors from licorice (one of the most popular edible herbs), as well as to investigate their inhibitory mechanisms. Among all tested licorice constituents, licochalcone A was found as the most efficacious agent against human thrombin (IC50 = 7.96 μM). Inhibition kinetic analyses demonstrated that licochalcone A was a mixed inhibitor against thrombin-mediated Z-Gly-Gly-Arg-AMC acetate hydrolysis, with a Ki value of 12.23 μM. Furthermore, mass spectrometry-based chemoproteomic assays and molecular docking simulations revealed that licochalcone A could bind to human thrombin at both exosite I and the catalytic site. In summary, our findings demonstrated that the chalcones isolated from licorice were a new class of direct thrombin inhibitors, also suggesting that licochalcone A was a promising lead compound for developing novel anti-thrombotic agents.

Müller, Henry A.; Joshi, Yug; Hadjixenophontos, Efi; Peter, Claudia; Csiszár, Gábor; Richter, Gunther; Schmitz, Guido

doi: 10.1039/c9ra10125jpmid: 35492640

Recent investigations of layered, rock salt and spinel-type manganese oxides in composite powder electrodes revealed the mutual stabilization of the Li–Mn–O compounds during electrochemical cycling. A novel approach of depositing such complex compounds as an active cathode material in thin-film battery electrodes is demonstrated in this work. It shows the maximum capacity of 226 mA h g−1 which is superior in comparison to that of commercial LiMn2O4 powder as well as thin films. Reactive ion beam sputtering is used to deposit films of a Li2MnO3−δ composition. The method allows for tailoring of the active layer's crystal structure by controlling the oxygen partial pressure during deposition. Electron diffractometry reveals the presence of layered monoclinic and defect rock salt structures, the former transforms during cycling and results in thin films with extraordinary electrochemical properties. X-ray photoelectron spectroscopy shows that a large amount of disorder on the cation sub-lattices has been incorporated in the structure, which is beneficial for lithium migration and cycle stability.

Hossain, Sayed Muktar; Prakash, Ved; Mamidi, Prabhudutta; Chattopadhyay, Soma; Singh, Akhilesh Kumar

doi: 10.1039/c9ra09376apmid: 35492648

A pyrene-appended bipyridine hydrazone-based ligand, HL, was synthesized and characterized by spectroscopic methods. Upon complexation with Cu(ii), HL formed a hexanuclear paddlewheel metal–organic macrocycle (MOM) via self-assembly with a high association constant with the molecular formula of [Cu6L6(NO3)6]. Intermolecular and intramolecular π–π interactions were demonstrated in this hexanuclear Cu(ii) complex. Further, it was observed that HL had the potential to detect a trace level of Cu(ii) ion selectively among a wide range of biologically relevant metal ions in aqueous medium at physiological pH. Using HL, it was feasible to sense copper(ii) ions in living cells due to its good cell permeability and high solubility under physiological conditions along with its high IC50 value. The low detection limit, high sensitivity and good reproducibility make this Cu–sensor very promising. The complex (MOM) formed between the ligand and Cu(ii) was found to be 1 : 1 on the basis of fluorescence titrations and was confirmed by ESI-MS. Moreover, single-crystal study of the hexanuclear self-assembled fluorescent species provided better insight into its chemistry, e.g. coordination environment and binding mode, unlike most of the metal sensors due to the lack of a single-crystal structure of the metal sensor complex. Cytotoxicity assay and bioimaging were performed in living cells (Vero cells), giving green fluorescent images. Fluorescence lifetime measurements and theoretical calculations were carried out. The morphology and topographic details on the surface of the metal–organic macrocycle (MOM) were studied by field-emission scanning electron microscopy (FESEM).

Suchánková, Petra; Kukleva, Ekaterina; Štamberg, Karel; Nykl, Pavel; Vlk, Martin; Kozempel, Ján

doi: 10.1039/c9ra08953epmid: 35492660

The mechanism of 223Ra uptake on hydroxyapatite and titanium dioxide nanoparticles was studied as a function of pH. Both materials are widely used in food industry and medicine. They offer properties suitable for labelling with medicinal radionuclides, particularly for targeted radionuclide therapy. The selected isotope, 223Ra, is an alpha emitter widely used in targeted alpha particle therapy due to high-dose delivery in very small tissue volume, nevertheless the results are applicable for any radium isotope including 226Ra. The study was performed in the pH range 4.5 to 12 for hydroxyapatite nanoparticles and 2 to 12 for titanium dioxide nanoparticles in Britton–Robinson buffer solution. Both nanomaterials at pH 6 and higher showed that over 95% of the radium has been sorbed. According to the applied chemical equilibrium model, the most important species playing a role in sorption on the edge-sites were RaCO3, RaPO4−, RaHPO4 and Ra(Ac−)2, and Ra2+ and RaH2PO4+ on layer-sites. All experiments were conducted under free air conditions and no negative impact of CO2 was found. The surface complexation model was found suitable for describing radium uptake by the studied hydroxyapatite and titanium dioxide nanomaterials.

Cuixia, Yan; Yingming, Xu; Lin, Wang; Xuefeng, Liang; Yuebing, Sun; Hongtao, Jia

doi: 10.1039/c9ra08199bpmid: 35492654

Biochar derived from chicken manure, as an effective metal adsorbent, was prepared through a pyrolysis method at different pyrolytic temperatures (200, 400, 600, and 800 °C). The physicochemical characteristics of chicken manure biochar (CMB) and its lead (Pb2+) adsorption mechanisms were studied by batch adsorption experiments, DTA/TGA, XRD, SEM-EDS, FTIR and an analysis of the composition of their mineral ash. Results showed that the best-fit for the Pb2+ adsorption data was achieved using a Langmuir isotherm and a pseudo-second-order model. The maximum adsorption capacities of Pb2+ increased with increasing of pyrolytic temperatures of the CMB, being 180.21, 200.80, 239.59, and 242.57 mg g−1, respectively, for CMB-200, CMB-400, CMB-600 and CMB-200. Although Pb2+ adsorption on CMB revealed that adsorption was controlled by multiple mechanisms, (e.g. surface complexation, ion exchange, surface precipitation, electrostatic attraction, physical adsorption, and co-precipitation), the ion exchange and surface precipitation played a dominant role in Pb2+ sorption. Using CMB for the removal of Pb from water is proposed as an effective, environmentally protective, novel approach.

Hekal, Mohamed H.; El-Naggar, Abeer M.; Abu El-Azm, Fatma S. M.; El-Sayed, Wael M.

doi: 10.1039/c9ra09016apmid: 35492649

Background and aim: The current study reports the synthesis and biological evaluation of two novel series of 4-(5-mercapto-1,3,4-oxadiazol-2-yl)phthalazin-1(2H)-one derivatives. Methods: The synthetic reactions were carried out under both conventional and ultrasonic irradiation conditions. The anti-proliferative activity of the newly synthesized compounds against two human epithelial cell lines; liver (HepG2) and breast (MCF-7) in addition to normal fibroblasts (WI-38) was investigated. In addition to molecular docking studies, the possible mechanism(s) of action were also explored. Results: In general, an improvement in synthetic rates and yields was observed when reactions were carried out under sonication compared with classical conditions. The structures of the products were established based on analytical and spectral data. Derivatives 2e and 7d, in addition to compound 1, had significant and selective anti-proliferative activity against liver and breast cancer cell lines without harming normal fibroblasts. These derivatives arrested the cell cycle progression and/or induced apoptosis. This has been manifested by the elevation in the expression of p53 and caspase 3, down-regulation of cdk1, and a reduction in the concentrations of MAPK and Topo II at submicromolar concentrations. The latter results confirmed the molecular docking study. Conclusions: Compound 1 had the best profile on the gene and protein levels (arresting cell cycle and inducing apoptosis). The ability of compounds 1 and 2e to inhibit both MAPK and Topo II nominates these derivatives as potential candidates for further anticancer and antitumor studies.

Richaud, Arlette; López, María J.; Mojica, Martha; Alonso, Julio A.; Méndez, Francisco

doi: 10.1039/c9ra09804fpmid: 35492679

The chemical synthesis of C60 fullerene in the laboratory is still a challenge. In order to achieve this goal, we propose a synthetic route based on the dimerization between two pentacyclopentacorannulene (C30H10) fragments employing the Diels–Alder cycloaddition reaction. Density functional calculations indicate that a step wise non-concerted dimerization mechanism of C30H10 is favored over a one stage dimerization. The step wise dimerization implies the sequential formation of 2, 4, 6, and 10 new C–C bonds between the two fragments. This leads to the formation of the Diels–Alder cycloadduct C60H20. The results then suggest the synthesis of C60H20 as a precursor for C60. The synthesis of the analogue C60F20 has already been reported.

Motlochová, Monika; Slovák, Václav; Pližingrová, Eva; Lidin, Sven; Šubrt, Jan

doi: 10.1039/c9ra08737kpmid: 35492627

In this work, we report on the efficient removal of heavy metal ions with nanostructured lithium, sodium and potassium titanates from simulated wastewater. The titanates were obtained via a fast, easy and cost effective process based on extraction of sulfate ions from the crystals of titanyl sulfate and their replacement with hydroxyl groups of NaOH, LiOH and KOH solutions leaving the Ti–O framework intact. The as-prepared titanates were carefully examined by scanning and transmission electron microscopy. Furthermore, the effect of contact time, pH, annealing temperature, together with adsorption in real conditions including competitive adsorption and reusability were studied. It was found that the maximum adsorption capacity, as calculated from the Langmuir adsorption model, is up to 3.8 mmol Pb(ii) per g, 3.6 mmol Cu(ii) per g and 2.3 mmol Cd(ii) per g. Based on the characterization results, a possible mechanism for heavy metal removal was proposed. This work provides a very efficient, fast and convenient approach for exploring promising materials for water treatment.

Marieeswaran, Muppidathi; Panneerselvam, Perumal

doi: 10.1039/c9ra08274cpmid: 35492667

A novel fluorescent biosensor has been designed and synthesized comprising a magnetic nanoscale metal–organic framework (MNMOF) functionalized with fluorescein amidite (FAM)-labeled ssDNA. It exhibits good sensitivity and selectivity for Hg(ii) cations over other co-existing metal ions. MNMOF was fabricated by a one-pot synthetic method and it was successfully characterized with various techniques such as UV-visible spectroscopy, fluorescence spectroscopy, Fourier-transform infrared (FT-IR) spectrometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The FAM-labeled ssDNA was adsorbed onto the surface of MNMOF through π–π stacking and electrostatic interactions, which resulted in the partial quenching of its fluorescence intensity (65%). Upon the subsequent addition of Hg(ii) ions, the fluorescence intensity was further quenched at 52%, due to the re-adsorption of dsDNA onto the surface of MNMOF. Thus, the FAM-labeled ssDNA showed a drastic decrease in fluorescence intensity with Hg(ii). This quenching–quenching mechanism led to a linear response in the fluorescence intensity to Hg(ii) concentration (R2 = 0.934) with a low detection limit of 8 nM. The specific merits of MNMOF make it an ideal platform for mercury sensor applications.

Wang, Yang; Rong, Zhihao; Tang, Xincun; Cao, Shan

doi: 10.1039/d0ra90005bpmid: 35503675

Correction for ‘The synthesis of calcium arsenate@iron arsenate coating materials and their application for arsenic-containing wastewater treatment’ by Yang Wang et al., RSC Adv., 2020, 10, 719–723.