Structural evolutions in liquid tellurium (Te) are observed employing molecular dynamics simulations at various temperatures ranging from 1500 K to 300 K. Local structural variations are noticed in radial correlation functions, structure factor, bond angle distribution functions, Honeycutt-Anderson index, Voronoi tessellation, and coordination number. Upon quenching, we find that icosahedral short-range motifs dominate in a stable and supercooled liquid state. The first peak of the radial distribution function at 970 K and 722 K shows excellent agreement with the findings of neutron diffraction. The transformation to a super-cooled liquid state with distorted icosahedral patterns is observed at 600 K and to a body-centred cubic cluster after 600 K. Finally, we also show that near the melting point diffusion coefficient of liquid tellurium is fairly consistent with the tight-binding and experimental purposed models. We assume that our findings not only replicate all the remarkable characteristic but also predict useful transition mechanisms through the use of the well-known Stillinger-Weber potential.

ZnO is an attractive semiconductor material due to its potential application in various fields such as solar cells, antibiotics, gas sensors, organic pollutant degradation, etc. For this purpose, researchers are trying to synthesize ZnO by using a different method such as sol-gel, electrodeposition, mechanochemical, sonochemical, and chemical vapor deposition. However, it is still required to improve the economical method for synthesizing ZnO. In the present study, we synthesized ZnO nanoparticles (ZnO-NPs) by a thermal method. The process is environmentally safer than other methods because it does not involve more chemicals or a catalyst, acid, or base source. We used methylene blue for photocatalytic and Escherichia coli for antibacterial activity tests. The results found that an outstanding degradation percentage (⁓99%) for the photocatalytic experiment. Besides, the antibacterial activity was tested at different concentrations, and the minimum inhibitory concentration (MIC) of the ZnO-NPs was 30⁓50 μg/mL. Our synthesized ZnO-NPs were found to be more effective than previously described ZnO-NPs prepared via other methods.

We have designed a nanocomposite of silver nanoparticle and carbon nanospheres (AgNPs/CNSs) as a catalyst for the rapid degradation of organic pollutants. The photocatalytic performance of the nanocomposite was examined by evaluating the degradation of methylene blue (MB) under UV light irradiation. The degradation percentages of the pollutant dye (MB) are: AgNPs/CNSs (~90.82%), AgNPs (~80.18%) under UV irradiation for 60 min. Furthermore, stability performance is studied by recycling the AgNPs/CNSs composite. It is found that the photocatalytic activity of AgNPs/CNSs composite is slightly decreased even after five cycles. In a nutshell, this novel composite AgNPs/CNSs exhibit time-dependent remarkable catalytic activity under UV light irradiation.

Metal nanoclusters (MNCs) have become one of the most promising nanomaterials in the analytical chemistry area due to their optoelectronic properties and the possibility of bioconjugation to different type of biomolecules (e.g. antibodies). Thus, MNCs can be used as labels for the detection of specific biomolecules in biological samples (e.g. fluids, tissues or cells). MNCs have diameters smaller than 3 nm, so they can be employed to label antibodies without disrupting their recognition capabilities. Another advantage of MNCs compared to other labels is the possibility of performing multimodal detection by using fluorescence, electrochemistry, and mass spectrometry (MS). Such multimodal detection will allow both the characterization of the synthesized MNCs as well as the validation of the analytical methodologies developed for the biomolecules determination.

The synthesis of water-soluble luminescent MNCs has been thoroughly investigated in the last decade. The research has been fueled by MNCs properties, such as strong photoluminescence, large Stoke shifts, good photostability and low toxicity. Most of the studies have been devoted to AuNCs and AgNCs, although fluorescent NCs made of copper and platinum have been also reported.

In this study, the synthesis of new IrNCs and PdNCs has been tackled. MNCs have been characterized by fluorescence spectroscopy, dynamic light scattering (DLS), high-resolution transmission electron microscopy (HR-TEM) and elemental MS. The synthesized MNCs will be further used as labels for the determination of specific proteins of biomedical interest in fluids (e.g. saliva, nasal exudate and tears) and biological tissues. For such purpose, an immunoassay will be developed.

In the field of Transition Metal Dichalcogenides (TMDCs), molybdenum disulfide (MoS₂) has attracted an outstanding interest due to several applications. MoS₂ has potentialities not yet fully realized in solution-based applications. However, the lack of knowledge of the optical properties of MoS₂, especially in the infrared range, has significantly limited his use in many exciting photonic fields. In this work, the broadband optical properties of MoS₂ films deposited by spin-coating onto Si/SiO₂ substrates were studied by means of Variable Angle Spectroscopic Ellipsometry (VASE).

The morphological and the structural properties of the samples were investigated by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Micro-Raman Spectroscopy.

Micro-Raman spectroscopy measurements reveal the presence of 2H-MoS₂ and 1T-MoS₂ phases. The optical properties of the films show a mid-gap state at 0.6 eV, not reported in an ellipsometry work before, induced by defects in the MoS₂ samples.

Lately, the optical properties of Graphene Oxide (GO) and Reduced Graphene Oxide (RGO) films have been studied in the ultraviolet and visible spectral range. However, the accurate optical properties in the extended near-infrared and mid-infrared range have not been published yet. In this work, we report a Variable Angle Spectroscopic Ellipsometry (VASE) characterization of GO thin films dip-coated on SiO₂/Si substrates and thermally reduced GO films in the [0.38-4.1] eV photon energy range. Moreover, the optical properties of RGO stabilized with poly(sodium 4-styrenesulfonate) (PSS) films dip-coated on SiO₂/Si substrates are studied in the same range for the first time. The Lorentz optical models fit well the experimental data. In addition, the morphological properties of the samples were investigated by Scanning Electron Microscopy (SEM) analysis.

The beginnings of Metal-Organic Frameworks (MOFs) chemistry were established by Yaghi et al. in the 90s. They started a new promising field for which, depending on the nature of the organic functionality and metal−ligand coordination chemistry, diversity of MOFs in terms of their structures and chemical properties is virtually endless. Since the 90s it has been reported different synthetic routes (e.g. hydro-solvothermal synthesis, microwave and ultrasound-assisted synthesis, mechanochemistry, microemulsion synthesis, continuous flow production). Nevertheless, no control on the shape and size of the crystal was achieved in a proper way. The results obtained during this work demonstrates that the surfactant plays an important role in the MOF´s synthesis protocol, in particular, in those with Zeolitic Imidazolate Framework (ZIF-8) structure, by changing the former physico-chemical properties without altering their crystalline structure. That is, variations on surfactant´s properties lead to changes both in shape and size of MOFs without altering their intrinsic properties. Thus, this work is focused on the effect of two surfactants: Sodium Dodecyl Sulfate (SDS) and Hexadecyltrimethylammonium bromide (CTAB). In this sense, for each family of surfactant the influence of the surfactant tail chain length and the nature of their head group were investigated. For these studies, dynamic laser-light scattering (DLS), scanning electron microscopy (SEM) and powder X-Ray Diffraction (PXRD) were performed in order to characterize the physicochemical properties and the morphology of the obtained MOFs.

Acknowledgements: This work was supported by Agencia Estatal de Investigación (AEI) through Project MAT2016-80266-R, and Xunta de Galicia (Grupo de Referencia Competitiva ED431C 2018/26; Agrupación Estratégica en Materiales-AEMAT ED431E 2018/08). FEDER funds are also acknowledged.

Maslinic acid (MA), a triterpene widely found in natural sources, is a gaining interest compound due to its multiple therapeutic activities and its lack of harmful effects. However, MA is practically insoluble in water, which limits its clinical application. Here, we present a solvent displacement method to produce MA Solid Lipid Nanoparticles (SLNs) as a nanoplatform to carry hydrophobic drugs. A systematic study of the experimental parameters that may have some influence on the colloidal characteristics of MA SLNs was carried out. The effect of the Aqueous/Organic phase volume ratio and the organic phase composition on the size of SLNs evidence the role of the solvent diffusivity on the colloidal characteristic of the SLNs. On the other hand, the effect of surfactant/MA ratio proved the relevance of the surfactant on stabilizing the SLNs interface, owing to the changes on the interfacial tension that it promotes. MA SLNs have proved to be highly stable over time and a wide range of pH and salinity conditions, as well as a high curcumin encapsulation efficiency. MA SLNs prepared in this work provide a starting point to develop functionalized active nanocarriers which allow stablishing synergistic relation with the loaded-drug

RNA interference (RNAi) has emerged as a promising therapeutic approach for the treatment of a wide range of disorders. Small interfering RNAs (siRNAs), i.e. non-coding double-stranded RNA molecules, have been mainly used for RNAi. Because siRNA is susceptible for enzymatic degradation and is rapidly cleared from the bloodstream, the success of RNAi is strongly related to the design of efficient delivery technologies. Among auspicious carriers for siRNA, polymeric micelles self-assembled by polyion complexation between block ionomers and siRNA have attracted much attention due to their well-defined size, efficient complexation and potential for delivery in vivo. In this regard, we have recently demonstrated that the polycation flexibility influences the complexation with single stranded RNA molecules, affecting the delivery capability of the resulting micelles. On the other hand, the effects of the catiomer flexibility on micelles loading double stranded siRNA remains unknown. Thus, herein, we studied the effects of the polycation backbone flexibility on siRNA-loaded polyion complex (PIC) micelles by using complementary block copolymers, i.e. the relatively flexible poly(ethylene glycol)-poly(glycidylbutylamine) (PEG-PGBA) and the more rigid PEG-poly(L-lysine) (PEG-PLL). By mixing these polymers with siRNA at different N/P ratios, we found that PEG-PGBA effectively promoted self-assembly of PIC micelles at lower N/P ratios and lower siRNA concentrations than PEG-PLL. Computational studies of siRNA binding with polycations and PEG-polycations further supported the favorable binding process of flexible polycations with siRNA. The micelles based on PEG-PGBA were stable in physiological conditions and promoted effective intracellular delivery of siRNA for efficient gene knockdown. Our results indicate the importance of polycation flexibility on the assembly of PIC micelles with siRNA, and its potential for developing innovative carrier systems.

Obesity and glioblastoma multiforme (GB) are two unmet medical needs where effective therapies are lacking. Carnitine palmitoyl transferase 1 (CPT1), an enzyme catalyzing the rate-limiting step in fatty acid oxidation (FAO), is a viable target for both diseases . C75, a FAS inhibitor, forms an adduct with CoA to form C75-CoA, which is a strong competitive inhibitor to CPT1 that is selective in its target. However, it is polar and charged, having low cell membrane permeability, and therefore needing a delivery system for intracellular transport.

(±)-C75-CoA and its enantio-separated forms (+)- and (-)-C75-CoA were used to form PIC micelles with the cationic block co-polymer PEG-PAsp(DET). The drug and polymer were mixed in a 1:1 anion/cation ratio to give 50-70-nm micelles with a unimodal size profile and narrow polydispersity. Size was maintained upon introduction of physiological saline. Micellar (±)-, (+)-, and (-)-C75-CoA were all significantly more cytotoxic compared to the respective free drugs in U87MG. We examined whether C75-CoA inhibits FAO by measuring ATP concentrations in U87MG and GT1-7. ATP generation was found to be hampered after adding C75-CoA in both cell types, with micelle-treated cells producing significantly lower ATP than those treated with free drug, suggesting that the effective intracellular delivery of C75-CoA leads to a more-pronounced FAO inhibition. A fluorescent CoA derivative, Fluor-CoA, also yielded monodisperse micelles similar to C75-CoA. Micellar internalization was significantly greater than that of the free dye. Uptake of both increased with time, with this effect is more pronounced in U87MG than GT1-7. The %Fluor-CoA+ cells were also expressively higher for the micelle across cell lines. From this data, it can be convincingly concluded that neuronal and glioma cellular uptake of micelles is superior to that of the free dye, validating the need for cellular delivery systems for anionic, CoA-type molecules.

The micellar form neutralized the negative charge of the cargo, promoting transport into the cell. These outcomes strongly support the effectiveness of using a PIC micelle-type system to deliver anionic small molecules into glioma cells and neurons meant to inhibiting enzymes such as CPT1, for future applications in diseases like obesity and cancer.