Synthesis, solid state characterization, theoretical and experimental spectroscopic studies of the new lanthanide complexes.

Three new complexes Na[Ln(pic)4]ּ⋅2.5H2O (Ln = Tb, Eu or Gd; pic = picolinate) were synthesized and characterized by infrared spectroscopy, powder X-ray diffraction and thermogravimetric analyses. The molecular structures of the complexes have been determined by single-crystal X-ray diffraction. The three isostructural lanthanide complexes crystalize in the hexagonal system with space group P6122 to Eu complex and Gd complex and space group P6522 to Tb complex. In each of the complexes, the picolinate ligands are bonded to Ln3+ and Na+ ions by different coordination modes promoting polymeric structures. The photoluminescent properties of complexes were studied and combined with theoretical studies using the density functional theory (DFT: B3LYP, PBE1PBE) and the semiempirical method AM1/Sparkle from the single crystal X-ray diffraction structures to assign a suitable model for describing the system. The B3LYP DFT functional was considered the most adequate for providing structural properties of the compounds and for describing luminescence properties. The excited triplet states (T1) and excited singlet states (S1) of the ligand were determined theoretically using Time-dependent DFT calculations (TD-DFT: B3LYP, CAM-B3LYP and LC-wPBE) and INDO/S-CIS, with the best agreement with experimental values obtained from the LC-wPBE DFT functional. The photoluminescent spectra of the complexes and their lifetime measurements were determined indicating that the Eu complex and Tb complex display different intramolecular energy transfer mechanisms with higher efficiency to ligand-to-terbium energy transfer. In addition, the experimental and theorical Judd-Ofelt intensity parameters and quantum yields of the complexes were also determined and discussed besides to a proposed 9-state diagram to describe the luminescence properties of the Eu complex. The low value of emission quantum efficiency of 5D0 emitting level of Eu(III) ion was explained by the presence of the ligand-to-metal charge transfer state (LMCT) evidenced experimentally and theoretically. A good agreement was obtained between the proposed kinetic model and experimental results showing the consistency of the set of rate equations assumed and the intramolecular pathways proposed.

Graphene quantum dots decorated with imatinib for leukemia treatment.

The use of graphene quantum dots as biomedical device and drug delivery system has been increasing. This nanoplatform of pure carbon has showed unique properties and showed to be safe for human use. The imatinib is a molecule designed to specifically inhibit the tyrosine kinase, used for leukemia treatment. In this study, we successfully decorated the graphene quantum dots (GQDs@imatinb) by a carbodiimide crosslinking reaction. The GQDs@imatinb were characterized by FTIR and AFM. The nanoparticles' in vitro behaviors were evaluated by cellular trafficking (internalization) assay and cell viability and apoptosis assays in various cancer cell lines, including suspension (leukemia) cells and adherent cancer cells. The results showed that the incorporation of the imatinib on the surface of the graphene quantum dots did not change the nanoparticles' morphology and properties. The GQDs@imatinb could be efficiently internalized and kill cancer cells via the induction of apoptosis. The data indicated that the prepared GQDs@imatinb might be a great drug nano-platform for cancer, particularly leukemia treatments.

Green synthesis of silver indium telluride nanocrystals: characterization and photothermal analyses.

Here, we report the preparation and characterization of stable AgIn5Te8 (AITe) nanocrystals (NCs) and their respective AITe-ZnS and AITe-ZnSe alloys. A green route of synthesis is described by using an aqueous electrochemical method in a cavity cell. The elemental ratio modulation of the NCs was investigated to determine the ideal improvement of the structural and electronic properties. The AITe NCs presented an emission band at 889 nm and hypsochromic shifts when coated with ZnS and ZnSe seeds. Photothermal analyses point to theranostic applications.

Radioactive polymeric nanoparticles for biomedical application.

Nowadays, emerging radiolabeled nanosystems are revolutionizing medicine in terms of diagnostics, treatment, and theranostics. These radionuclides include polymeric nanoparticles (NPs), liposomal carriers, dendrimers, magnetic iron oxide NPs, silica NPs, carbon nanotubes, and inorganic metal-based nanoformulations. Between these nano-platforms, polymeric NPs have gained attention in the biomedical field due to their excellent properties, such as their surface to mass ratio, quantum properties, biodegradability, low toxicity, and ability to absorb and carry other molecules. In addition, NPs are capable of carrying high payloads of radionuclides which can be used for diagnostic, treatment, and theranostics depending on the radioactive material linked. The radiolabeling process of nanoparticles can be performed by direct or indirect labeling process. In both cases, the most appropriate must be selected in order to keep the targeting properties as preserved as possible. In addition, radionuclide therapy has the advantage of delivering a highly concentrated absorbed dose to the targeted tissue while sparing the surrounding healthy tissues. Said another way, radioactive polymeric NPs represent a promising prospect in the treatment and diagnostics of cardiovascular diseases such as cardiac ischemia, infectious diseases such as tuberculosis, and other type of cancer cells or tumors.

Cytotoxic Activity of the Mesoionic Compound MIH 2.4Bl in Breast Cancer Cell Lines.

In this work, we report the synthesis of a new 1,3-thiazolium-5-thiolate derivative of a mesoionic compound (MIH 2.4Bl) and the characterization of its selective cytotoxicity on a panel of breast cancer cells lines. The cytotoxic effect of MIH 2.4Bl on breast cancer cell lines was determined by XTT and crystal violet assays, flow cytometry analysis, electron microscopy characterization, and terminal deoxynucleotidyl transferase (TdT) deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) apoptosis assays. As determined using XTT cell growth and survival assays, MIH 2.4Bl exhibited growth inhibition activity on most breast cancer cell lines tested, compared with normal human mammary epithelial cells. Three breast cancer cell lines (MCF-7, T-47D, and ZR-75-1) showed a more potent sensitivity index to growth inhibition by MIH 2.4Bl than the other breast cancer cell lines. Interestingly, these 3 cell lines were derived from tumors of Luminal A origin and have ER (estrogen receptor), PR (progesterone receptor), and HER2 (human epidermal growth factor receptor 2) positive expression. Additional analysis of cytotoxicity mediated by MIH 2.4Bl was performed using the MCF-7 cell line. MCF-7 cells displayed both time- and dose-dependent decreases in cell growth and survival, with a maximum cytotoxic effect observed at 72 and 96 hours. The MCF-7 cells were also characterized for cell cycle changes upon treatment with MIH 2.4Bl. Using flow cytometry analysis of cell cycle distribution, a treatment-dependent effect was observed; treatment of cells with MIH 2.4Bl increased the G2/M population to 34.2% compared with 0.1% in untreated (control) cells. Ultrastructural analysis of MFC-7 cells treated with MIH 2.4Bl at 2 different concentrations (37.5 and 75 µM) was performed by transmission electron microscopy. Cells treated with 37.5 µM MIH 2.4Bl showed morphologic changes beginning at 6 hours after treatment, while cells treated with 75 µM showed changes beginning at 3 hours after treatment. These changes were characterized by an alteration of nuclear morphology and mitochondrial degeneration consistent with apoptotic cell death. Results of a TUNEL assay performed on cells treated for 96 hours with MIH 2.4Bl supported the observation of apoptosis. Together, these results suggest that MIH 2.4Bl is a promising candidate for treating breast cancer and support further in vitro and in vivo investigation.

Quitosana, óxido de zinco e óleo essencial de pimenta rosa: propriedades e potencialidades de aplicações / Chitosan, zinc oxide and pink pepper essential oil: potential properties and applications

Objetivo: descrever propriedades e aplicações potenciais da quitosana, óxido de zinco e óleo essencial de pimenta rosa. Método: estudo descritivo, tipo informativo, mediante o levantamento do universo da produção científica. Resultados: a quitosana é um polímero que possui características tais como biodegrabilidade, biocompatibilidade, atoxicidade, baixo custo, produto natural e existe em grande quantidade na natureza. É suscetível de ser manipulada nos formatos de lâminas, filmes, fibras e géis. É uma molécula extremamente funcional exercendo ação mucoadesiva, anticoagulante, imunoestimulante, cicatrizante, antitumoral, hemostática, hipolipêmica, antimicrobiana, dentre outras. O óxido de zinco é um antimicrobiano com extraordinária eficácia bactericida e fungicida. Estudos têm investigado o óleo essencial da pimenta rosa e identificado que ele possui atividade diurética, adstringente, antidiarreica, anti-inflamatória, cicatrizante, bactericida, antiviral, analgésica, sedativa, expectorante, antipirética, vermífuga e antisséptica. Conclusão: a quitosana, o óxido de zinco e o óleo essencial de pimenta rosa apresentam, individualmente ou em conjunto, potencialidades para aplicações em áreas tais como embalagens ativas, tratamento de água, curativos e outras, em consequência da competência para minimizar ou erradicar a proliferação de micro-organismos patógenos.(AU)

Characterization and application of a lanthanide-based metal-organic framework in the development and validation of a matrix solid-phase dispersion procedure for pesticide extraction on peppers (Capsicum annuum L.) with gas chromatography-mass spectrometry.

The metal-organic framework [(La0.9 Sm0.1 )2 (DPA)3 (H2 O)3 ]∞ was synthetized and characterized by X-ray diffractometry, differential thermogravimetric analysis, and infrared spectroscopy. The material was tested for the development and validation of a matrix solid-phase dispersion procedure for extraction of atrazine, bifenthrin, bromuconazole, clofentezine, fenbuconazole, flumetralin, procymidone, and pirimicarb, from peppers, with analysis using gas chromatography with mass spectrometry in the selected ion monitoring mode. The method developed was linear over the range tested (50.0-1000.0 µg/kg for procymidone and 200.0-1000.0 µg/kg for all other pesticides), with correlation coefficients ranging from 0.9930 to 0.9992. Experiments were carried out at 250.0, 500.0, and 1000.0 µg/kg fortification levels, and resulted in recoveries in the range of 52.7-135.0%, with coefficient of variation values between 5.2 and 5.4%, respectively, for [(La0.9 Sm0.1 )2 (DPA)3 (H2 O)3 ]∞ sorbent. Detection and quantification limits ranged from 16.0 to 67.0 µg/kg and from 50.0 to 200.0 µg/kg, respectively, for the different pesticides studied. The results were compared with literature data. The developed and validated method was applied to real samples. The analysis detected the presence of residues of pesticides procymidone, fenbuconazole, flumetralin, clofentezine, atrazine, and bifenthrin.

Evaluation of a novel metal-organic framework as an adsorbent for the extraction of multiclass pesticides from coconut palm (Cocos nucifera L.): An analytical approach using matrix solid-phase dispersion and liquid chromatography.

We report the synthesis, characterization, and application of [Zn(1,4-benzenedicarboxylate)(H2 O)2 ]n , Zn(1,4-benzenedicarboxylate)0.99 (NH2 -1,4-benzenedicarboxylate)0.01 (H2 O)2 ]n , [Zn(1,4-benzenedicarboxylate)0.95 (NH2 -1,4-benzenedicarboxylate)0.05 (H2 O)2 ]n , and [Zn(1,4-benzenedicarboxylate)0.9 (NH2 -1,4-benzenedicarboxylate)0.1 (H2 O)2 ]n as sorbents for the extraction of multiclass pesticides from coconut palm. Liquid chromatography with ultraviolet diode array detection was used as the analysis technique, and the experiments were performed at one fortification level (0.1 µg/g). The recoveries were 47-67, 51-70, 58-72, and 64-76% for [Zn(1,4-benzenedicarboxylate)(H2 O)2 ]n , Zn(1,4-benzenedicarboxylate)0.99 (NH2 -1,4-benzenedicarboxylate)0.01 (H2 O)2 ]n , [Zn(1,4-benzenedicarboxylate)0.95 (NH2 -1,4-benzenedicarboxylate)0.05 (H2 O)2 ]n , and [Zn(1,4-benzenelate)0.95 (NH2 -1,4-benzenedicarboxylate)0.05 (H2 O)2 ]n , and [Zn(1,4-benzenedicarboxylate)0.9 (NH2 -1,4-benzenedicarboxylate)0.1 (H2 O)2 ]n , respectively, with relative standard deviation ranging from 1 to 7% (n = 3). Detection and quantification limits were 0.01-0.05 and 0.05-0.2 µg/g, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.01-10.0 µg/g) with r2  > 0.9991. A direct comparison of [Zn(1,4-benzenedicarboxylate)0.9 (NH2 -1,4-benzenedicarboxylate)0.1 (H2 O)2 ]n with the commercially available neutral alumina showed that [Zn(1,4-benzenedicarboxylate)0.9 (NH2 -1,4-benzenedicarboxylate)0.1 (H2 O)2 ]n was a similar extracting phase for the pesticides investigated.

New Composites LnBDC@AC and CB[6]@AC: From Design toward Selective Adsorption of Methylene Blue or Methyl Orange.

New porous composites LnBDC@AC (AC = Activated carbon, Ln = Eu and Gd and BDC = 1,4-benzenedicaboxylate) and CB[6]@AC (CB[6] = Cucurbit[6]uril) were obtained using hydrothermal route. The LnBDC and CB[B] are located inside the pore of the carbon materials as was observed in SEM-EDS, XRPD and FT-IR analysis. Porosimetry analysis showed values typically between AC and LnBDC material, with pore size and surface area, respectively, 29,56 Å and 353.98 m2g-1 for LnBDC@AC and 35,53 Å and 353.98 m2g-1 for CB[6]@AC. Both materials showed good absorptive capacity of metil orange (MO) and methylene blue (MB) with selectivity as a function of pH. For acid pH, both materials present selectivity by MB and alkaline pH for MO, with notable performance for CB[6]@AC. Additionally, europium luminescence was used as structural probe to investigate the coordination environment of Eu3+ ions in the EuBDC@AC composite after adsorption experiment.

Adsorption in a Fixed-Bed Column and Stability of the Antibiotic Oxytetracycline Supported on Zn(II)-[2-Methylimidazolate] Frameworks in Aqueous Media.

A metal-organic framework, Zn-[2-methylimidazolate] frameworks (ZIF-8), was used as adsorbent material to remove different concentrations of oxytetracycline (OTC) antibiotic in a fixed-bed column. The OTC was studied at concentrations of 10, 25 and 40 mg L(-1). At 40 mg L(-1), the breakthrough point was reached after approximately 10 minutes, while at 10 and 25 mg L(-1) this point was reached in about 30 minutes. The highest removal rate of 60% for the 10 mg L(-1) concentration was reached after 200 minutes. The highest adsorption capacity (28.3 mg g(-1)) was attained for 25 mg L(-1) of OTC. After the adsorption process, a band shift was observed in the UV-Vis spectrum of the eluate. Additional studies were carried out to determine the cause of this band shift, involving a mass spectrometry (MS) analysis of the supernatant liquid during the process. This investigation revealed that the main route of adsorption consisted of the coordination of OTC with the metallic zinc centers of ZIF-8. The materials were characterized by thermal analysis (TA), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and infrared spectroscopy (IR) before and after adsorption, confirming the presence of OTC in the ZIF-8 and the latter's structural stability after the adsorption process.