Anionic liposomes (AL) are very attractive for nanomedicine and some formulations have already been launched for clinical development. Despite the excellent potential, their application presents two ...major challenges: laborious production methods and rapid degradation and elimination from blood by the immune system. In this work, we optimized the production of AL and its stealth form (SAL) using a onestep microfluidic process. We obtained unilamellar and near-monodisperse (< 10%) AL composed by the commercial composition (DMPC:DMPG) with mean size small as 53.7 nm, which is optimized for application in drug delivery. We also obtained SAL with similar characteristics using the microfluidic technique, overcoming the limitation of conventional methods where SAL presents high polydispersity (> 30%). This study demonstrates the great potential of the microfluidic technique for one-step production of stealth anionic nanoliposomes with controlled sizes and reproducible characteristics.
A multifunctional smart supramolecular platform based on a lanthanide-organic hydrogel is presented. This platform, which provides unique biocompatibility and tunable optical properties, is ...synthesized by a simple, fast, and reproducible eco-friendly microwave-assisted route. Photoluminescent properties enable the production of coated light-emitting diodes (LED), unique luminescent barcodes dependent on the excitation wavelength and thin-films for use in tamper seals. Moreover, piroxicam entrapped in hydrogel acts as a transdermal drug release device efficient in inhibiting edemas as compared to a commercial reference.
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.
Rare-earth three-dimensional hydroxide frameworks ((Yb1-xLnx)3O(OH)6Cl.2H2O) were synthesized according to a previously published procedure, without modifications. The study of the structural ...behavior of these compounds against doping with Eu3+ ions showed that the replacement of 20% of Yb3+ by Eu3+ led to the formation of a lamellar structure. The maximum percentage of Eu3+ that can be included in the doping of the three-dimensional structure is 19%. Isophthalate was used as a luminescence sensitizer for the compounds and increased the quantum yield to 107 and 46% for the starting samples, doped with 10 and 20% of Eu3+, respectively. The lifetimes were adjusted to second order exponential decays for all samples, indicating the existence of two emitting centers. Samples were tested as adsorbents for methylene blue and methyl orange dyes in water. None of the samples showed positive results for the adsorption of methylene blue. For methyl orange, the lamellar sample showed promise. In preliminary tests, 10 mg of this sample managed to adsorb 70% of the dye present in 10 mL of a 10 mg L−1 methyl orange solution.
•Rare-earth three-dimensional hydroxide frameworks doped with Eu3+ ions were obtained.•The 3D structure is converted to lamellar when 20% Eu3+ ions are inserted.•Isophthalate was used as a luminescence sensitizer.•Isophthalate increased the quantum yield by 107% and 46% for the starting samples.•Lamellar rare-earth hydroxide is promising for adsorption of methyl orange.
The application of computer-aided drug discovery (CADD) approaches has enabled the discovery of new antimicrobial therapeutic agents in the past. The high prevalence of ...methicillin-resistantStaphylococcus aureus(MRSA) strains promoted this pathogen to a high-priority pathogen for drug development. In this sense, modern CADD techniques can be valuable tools for the search for new antimicrobial agents. We employed a combination of a series of machine learning (ML) techniques to select and evaluate potential compounds with antibacterial activity against methicillin-susceptible S. aureus (MSSA) and MRSA strains. In the present study, we describe the antibacterial activity of six compounds against MSSA and MRSA reference (American Type Culture Collection (ATCC)) strains as well as two clinical strains of MRSA. These compounds showed minimal inhibitory concentrations (MIC) in the range from 12.5 to 200 μM against the different bacterial strains evaluated. Our results constitute relevant proven ML-workflow models to distinctively screen for novel MRSA antibiotics.
Display omitted
•Most intense reduction process of metal oxides under laser ablation.•High visible absorbance.•Photothermal conversion with higher efficiency.•Simple, fast and safe methodology.
In ...this work, reduced Titania (TiO2−x) was obtained by laser ablation of commercial rutile TiO2 powder dispersed in N,N-dimethyl formamide (DMF) using a pulsed Nd:YAG (Neodymium-doped Yttrium Aluminium Garnet) laser (532 nm, 10 ns, 10 Hz). It was observed that DMF solvent was able to promote change in the optical band gap of commercial TiO2 (P25). The Ultraviolet–Visible (UV–vis) absorption measurement showed a shoulder in the infrared region with maximum at 690 nm, characteristic of reduced metal oxide. The electron paramagnetic resonance (EPR) measurements confirmed the presence of oxygen vacancies by the characteristic signal in g = 2.002 g and more intense than water-reduced oxide commonly obtained in other works. The X-ray diffraction (XRD) results show the same crystalline phase to P25 and small shifts due to presence of vacancy’s distorting the TiO2 structure. Scanning electron microscopy (SEM) image have shown surface coalesced particles in comparison to commercial P25, agreeing with nitrogen adsorption measurements which indicated a decrease in the surface area from 10.6 to 6.9 m2/g. The photothermal conversion properties was investigated and the reduced TiO2 samples showed higher temperatures when excited with a laser 785 nm wavelength in function of the strong absorption band and higher vacancy’s concentration.
This study proposes a novel approach to improve the performance of third-generation solar cells, particularly perovskite solar cells (PSCs), by employing zinc oxide (ZnO) nanoparticles (NPs). The ZnO ...NPs are dispersed on the upper surface of the device, acting as nanodiffusers. This reduces reflection and increases solar radiation absorption in the photovoltaic active layer, enhancing the light pathway within the device. To analyze the impact of ZnO nanodiffusers on solar cell performance, computer simulations using the finite element method (FEM) and experimental analysis were conducted. Green synthesis methods were employed to synthesize ZnO nanoparticles with an average size of 160 nm, which were subsequently characterized. Thin films of ZnO NPs were deposited on the transparent indium tin oxide (ITO) electrode using spin coating, and their optical response was evaluated. This study proposes methodologies for optical and electrical modeling of third-generation photovoltaic cells using ZnO NPs. Optical computational modeling results evidence that ZnO nanospheres with a diameter of 160 nm predominantly scatter solar radiation in the forward direction. The incorporation of ZnO NPs (160 nm in diameter) reduces device reflectance, resulting in efficient light coupling and increased absorbance in the active layer. The integrated effects of light trapping and anti-reflective properties enhance photocurrent generation, leading to an increase in short-circuit current density. Experimental verification with ZnO NP deposition on PSCs confirms a 23.5% enhancement in photovoltaic device efficiency, increasing from 10.6 to 13.1% in an 11.68 cm
2
perovskite cell. The study presents the optical benefits of ZnO nanostructures, including anti-reflective effects and light scattering, when integrated into devices containing thin films as active material.
Display omitted
•Gadolinium Complex, Terbium Complex and Europium Complex.•Structure of Lanthanide Coordination Polymers.•Photoluminescence: lifetime, Judd-Ofelt intensity parameters, quantum yield ...and LMCT.•Molecular Modeling of structural and luminescent properties, Kinetic Model, DFT.
Three new complexes NaLn(pic)4ּ⋅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.
Display omitted
•Experimental parameters were studied to optimize the synthesis of Cu(IDA)(H2O)2;•Cu/Mn bimetallic compounds were obtained with different molar ratio;•Materials were investigated as ...new catalysts for the Baylis-Hillman reaction.
This work reports the influence of experimental parameters (pH and counter-ion) in the synthesis of the 1D coordination polymer Cu(IDA)(H2O)2n (IDA = iminodiacetate), named here Cu-IDA. Copper-manganese bimetallic coordination polymers were also obtained by isomorphic replacement into Cu-IDA structure, with different molar ratio of Cu2+ and Mn2+ ions, denoted here as Cu/Mn-IDA (0.9/0.1; 0.7/0.3 and 0.5/0.5). New coordination polymers are isostructural to Cu-IDA and amounts of manganese atoms inserted into crystalline structure were evaluated by single-crystal X-ray diffraction and Rietveld refinement. All coordination polymers obtained were also characterized by infrared absorption spectroscopy and thermogravimetric analysis. Homometallic and bimetallic compounds were evaluated as catalysts for Baylis-Hillman reaction with yields and reaction times comparable or superior to those in the literature. Compounds containing manganese cations shows higher catalytic performance, especially Cu/Mn-IDA (0.9/0.1) with yield 91% in 5 h of reaction. Results also indicate an important role played by the metallic centre in the catalytic mechanism.
We report the synthesis, characterization, and application of Zn(1,4‐benzenedicarboxylate)(H2O)2n, Zn(1,4‐benzenedicarboxylate)0.99(NH2‐1,4‐benzenedicarboxylate)0.01(H2O)2n, ...Zn(1,4‐benzenedicarboxylate)0.95(NH2‐1,4‐benzenedicarboxylate)0.05(H2O)2n, and Zn(1,4‐benzenedicarboxylate)0.9(NH2‐1,4‐benzenedicarboxylate)0.1(H2O)2n 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)(H2O)2n, Zn(1,4‐benzenedicarboxylate)0.99(NH2‐1,4‐benzenedicarboxylate)0.01(H2O)2n, Zn(1,4‐benzenedicarboxylate)0.95(NH2‐1,4‐benzenedicarboxylate)0.05(H2O)2n, and Zn(1,4‐benzenelate)0.95(NH2‐1,4‐benzenedicarboxylate)0.05(H2O)2n, and Zn(1,4‐benzenedicarboxylate)0.9(NH2‐1,4‐benzenedicarboxylate)0.1(H2O)2n, 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(H2O)2n with the commercially available neutral alumina showed that Zn(1,4‐benzenedicarboxylate)0.9(NH2‐1,4‐benzenedicarboxylate)0.1(H2O)2n was a similar extracting phase for the pesticides investigated.
PDF
