Synthesis, characterization and functionalization of magnetic particles for patogen detection : study of mesoporous SiO2 functionalization

[Resumen] En este Trabajo de Fin de Grado se han preparado nanopartículas magnéticas estabilizadas con sílice y se ha comenzado su funcionalización para ser utilizadas en detección de patógenos. Para la caracterización de los productos sintetizados se han utilizado técnicas de difracción de rayos X de polvo cristalino (DRX), espectroscopia infrarroja (IR), análisis termogravimétrico (ATG), microscopia electrónica de transmisión (MET) y dispersión de luz dinámica (DLS). Por una parte se sintetizaron nanopartículas magnéticas (MNP) de Fe3O4 con morfología relativamente esférica, diámetros entre 10-20 nm (rango ideal para presentar comportamiento superparamagnético) y tendencia a formar aglomerados. Estas MNPs se recubrieron posteriormente por un material biocompatible (sílice), disminuyendo su tendencia a aglomerarse, y fueron funcionalizadas exitosamente con un aminosilano (APTES). Por otra parte se llevó a cabo la síntesis de sílice mesoporosa (MCM-41), obteniendo partículas con morfología esférica cuyos diámetros se encuentran entre 100-250 nm, y con poros de diámetro en torno a 3 nm. Se modificaron las condiciones de reacción para comprobar el efecto de éstas sobre el tamaño de las partículas obtenidas, dando como resultado una gran dispersión en el diámetro y la morfología de las mismas. Se hicieron reaccionar las esferas mesoporosas de este material con las nanopartículas magnéticas, obteniendo composites Fe3O4-SiO2 mesoporoso viables para la funcionalización con APTES en una etapa posterior.[Resumo] No presente Traballo de Fin de Grado preparáronse nanopartículas magnéticas estabilizadas con sílice e comezouse a súa funcionalización para seren empregadas na detección de patóxenos. Para a caracterización dos produtos obtidos, empregáronse as técnicas de difracción de raios X de po cristalino (DRX), espectroscopia infravermella (IR), análise termogravimétrico (ATG), microscopia electrónica de transmisión (MET) e dispersión de luz dinámica (DLS). Por una parte sintetizáronse nanopartículas magnéticas (MNP) de Fe3O4 con morfoloxía relativamente esférica, diámetros entre 10-20 nm (rango ideal para presentar comportamento superparamagnético) e tendencia a formar aglomerados. Estas MNPs foron recubertas posteriormente por un material biocompatible (sílice), diminuindo a súa tendencia a aglomerarse, e foron funcionalizadas exitosamente cun aminosilano (APTES). Por outra parte levouse a cabo a síntese de sílice mesoporosa (MCM-41), obtendo nanopartículas con morfoloxía esférica cuxos diámetros se encontran entre 100-250 nm, presentando poros de diámetro en torno a 3 nm. Modificáronse as súas condicións de reacción para comprobar o efecto destas sobre o tamaño das nanopartículas obtidas, dando como resultado una gran dispersión no diámetro e morfoloxía das mesmas. Fixéronse reaccionar as esferas mesoporosas deste material coas nanopartículas magnéticas, obtendo composites Fe3O4-SiO2 mesoporoso viables para a súa funcionalización con APTES nunha etapa posterior.[Abstract] In this TFG we have prepared magnetic nanoparticles of magnetite (Fe3O4) stabilized with silica (SiO2), and we have started their functionalization for the use in pathogen detection. Powder X-Ray Diffraction (XRD), Infrared Spectroscopy (IR), Thermogravimetric Analysis (TGA), Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) were used for their characterization. The synthesized Fe3O4 magnetic nanoparticles (MNP) show relatively spherical morphology, diameters of 10-20 nm (ideal for exhibit superparamagnetic behavior) and a certain tendency to form agglomerates. These MNPs were coated by a biocompatible material (silica), reducing its tendency to agglomerate, and they were successfully functionalized with the aminosilane APTES, allowing its availability for their use in a pathogen detection method. Synthesis of a mesoporous silica (MCM-41) was carried out, giving particles with spherical morphology, diameters between 100-250 nm and pores of about 3 nm of diameter. Reaction conditions were modified to test their effect on the particle size, resulting in an undesired increase of the size dispersion. We have prepared Fe3O4-Mesoporous SiO2 composites by heating a mixture of both particles in a closed vessel. Those composites form quite stable suspensions and are viable for functionalization with APTES at a later stage.Traballo fin de grao (UDC.CIE). Química. Curso 2015/201

Diagnostico financiero y análisis bursátil Cementos Argos S.A

El sector cementerio en nuestro país tiene gran importancia, ya que se constituye en este sector como el principal proveedor de materias primas en el sector de la construcción, el cual es fundamental y esenciales para el desarrollo económico de la nación. Para el año 2021, Grupo Inversiones Argos, con sus filiales Cementos Argos, Concretos Argos y Zona Franca Argos, se consolida como líder en la industria del cemento, seguido de Cemex y otras empresas del sector. En cuanto a la elaboración de cemento Gris en Colombia actualmente se encuentra en un rango de 1.140.8 miles de toneladas. Los índices de crecimiento de este sector son evidentes y demuestra ser un mercado rentable. Cementos Argos SA se posesiona como líder en Centroamérica, incursionando en mercados internacionales con bastante fuerza, por lo que nos despierta el interés de estudiar y recopilar datos con el fin de explorar sus principales Estados Financieros, sus informes de sostenibilidad (Objetivos de la OCDE) y su comportamiento en el mercado bursátil. Al realizar este estudio se analizan a profundidad los indicadores financieros más relevantes, con el fin de obtener evidencia argumentada en base a cálculos precisos para medir el nivel de rentabilidad, apalancamiento, endeudamiento y otros indicadores agrupados para determinar la ubicación de esta importante empresa en el mercado cementero.El cement industry in Colombia is of great importance as it constitutes one of the main raw materials in the construction sector, which is essential for the nation's economic growth. In 2021, Grupo Inversiones Argos, along with its subsidiaries Cementos Argos, Concretos Argos, and Zona Franca Argos, consolidates its position as a leader in the cement industry, followed by Cemex and other companies in the sector. Regarding the production of gray cement in Colombia, it currently stands at a range of 1,140.8 thousand tons. The growth rates in this sector are evident, demonstrating its profitability as a market. Cementos Argos SA positions itself as a leader in Central America, making strong inroads into international markets. Therefore, there is an interest in analyzing and studying its main Financial Statements, sustainability reports (OECD goals), and its behavior in the stock market. This research work thoroughly analyzes the main financial indicators in order to obtain evidence-based arguments based on precise calculations to measure the level of profitability, leverage, debt, and other grouped indicators to determine the company's positioning in the cement market

Exploiting the Redox Activity of MIL-100(Fe) Carrier Enables Prolonged Carvacrol Antimicrobial Activity

The design of efficient food contact materials that maintain optimal levels of food safety is of paramount relevance to reduce the increasing number of foodborne illnesses. In this work, we develop a smart composite metal-organic framework (MOF)-based material that fosters a unique prolonged antibacterial activity. The composite is obtained by entrapping a natural food preserving molecule, carvacrol, into a mesoporous MIL-100(Fe) material following a direct and biocompatible impregnation method, and obtaining particularly high payloads. By exploiting the intrinsic redox nature of the MIL-100(Fe) material, it is possible to achieve a prolonged activity against Escherichia coli and Listeria innocua due to a triggered two-step carvacrol release from films containing the carvacrol@MOF composite. Essentially, it was discovered that based on the underlying chemical interaction between MIL-100(Fe) and carvacrol, it is possible to undergo a reversible charge-transfer process between the metallic MOF counterpart and carvacrol upon certain chemical stimuli. During this process, the preferred carvacrol binding site was monitored by infrared, Mössbauer, and electron paramagnetic resonance spectroscopies, and the results are supported by theoretical calculations

Sustained proliferation in cancer: mechanisms and novel therapeutic targets

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression

Metal-organic frameworks as non-innocent scaffolds for the encapsulation of active biomolecules

Ensuring the safety and quality of food is one of the main focuses of the field of food industry. Different active materials are currently being studied to extend the useful life of food products. Metal–Organic Framework (MOF) materials have emerged in the last years as a promising alternative owing to their excellent porosity, high loading capacity, controlled release ability and ease of surface modification. The main motivation of this thesis is to evaluate the possible use of different MOFs, their miniaturization and processing, and their use as encapsulating agents of active molecules of natural origin, with the aim of developing intelligent hybrid materials of interest in the food and disinfection industry. The objectives of this thesis are summarized in four points: (1) Systematic evaluation of the feasibility of nanoMOFs as essential oil carrier agents following a direct impregnation methodology. (2) Incorporation of a composite biomolecule@MOF material into biopolymeric films and evaluation of the MOF ability to stabilize and govern the release of the bioactive molecule. (3) Obtention of a series of biomolecule@MOF biocomposites and study of their fungicidal effect after integration into biopolymeric films. (3) Synthesis and characterization of Mixed-Metal MUV-2 analogues (MM-MUV-2), as well as suitability determination of the materials as macrobiomolecule carriers. The thesis is divided into five chapters. Chapter 1 corresponds to a general introduction to the field of MOFs and their biorelated applications, from drug delivery, biomedicine, cosmetics, and remediation to their implementation into food industry, presenting the importance of essential oils and its derivatives in this later field, and discussing the MOF candidates for encapsulation employed throughout this Thesis. Chapter 2 presents a systematic study in which the suitability of MOFs as essential oil encapsulating agents is determined. Furthermore, a direct impregnation method is developed, where it was found that biomolecule encapsulation was favoured under aqueous-alcoholic mixtures (in which these molecules are poorly soluble), this parameter resulting key for a successful encapsulation. In total, twelve new biocomposites were obtained and analysed. The presence of the biomolecules in the composites was evidenced for each encapsulation product. Considering the analysed results, MIL-100(Fe) and ZIF-8 are presented as the most promising carrier agents for their great loading capacity, the affordability and availability of their precursors, and their greener synthetic protocol. After selecting the best performing scaffolds, in Chapter 3 the implementation of a biomolecule@MOF composite into biopolymeric films and its antibacterial activity are studied, thoroughly elucidating the chemical interactions between the guest molecule and the host framework. In this chapter, a carvacrol@MIL-100(Fe) biocompatible composite containing considerable payloads of active agent is prepared following a direct impregnation method. In addition to provide chemical stability to the active molecule, MIL-100(Fe) scaffold endorses an unprecedented retained and remarkable sustained delivery of the antimicrobial agent when processed in polymeric biofilms, because of its unique redox responsiveness that promotes effective interactions with the active agent. Mossbauer spectroscopy supported by theoretical calculations revealed a successful reversible interaction of the carvacrol molecules with the redox-active MIL-100(Fe) scaffold, thus enabling a prolonged delivery. The released carvacrol dose was enough to fight bacterial pathogens, with an improved activity against E. Coli and L. innocua in comparison with an equivalent “free” carvacrol dosage. The combination of a direct preparation, the facile processing and the scaffold-mediated delivery performance that enables prolonged carvacrol bactericide activity, make the obtained carvacrol@MIL-100(Fe) composite a promising candidate for food packaging applications. Chapter 4 concerns the obtention of a series of biomolecule@MOF composites with enhanced antifungal properties. Four ZIF-8-based biocomposites containing benzaldehyde, salicylaldehyde, methyl anthranilate or guaiacol, are obtained adapting the direct infiltration method previously developed and described in chapter 2. The encapsulation kinetics were evaluated, resulting in a surprisingly fast encapsulation process, where the infiltration of the biomolecule occurs almost immediately with effective loadings of ca. 20-30 %. Of the four obtained composites, Bz@ZIF-8 and MA@ZIF-8 were employed in antifungal activity essays. The released benzaldehyde and methyl anthranilate dose was enough to oppose fungal growth, with an improved activity against Penicilium expansum in comparison with the “free” biomolecule after integration in biopolymeric films. The prepared bimolecule@ZIF-8 composites are potential options for food packaging applications due to their direct preparation and simple processing, and a scaffold-mediated performance that permits an enhanced antifungal action. Finally, in Chapter 5, the encapsulation of macrobiomolecules is targeted by synthetizing mixed-metal hierarchical mesoporous MOFs following a green chemistry route. Two new Mixed-Metal MOF derivatives of MUV-2(Fe) with empirical formula (TTFTB)3[(Fe2MIIO)(H2O)2]2 (MII = Co, Ni), are obtained in this chapter. The synthetized materials are isostructural with the crystalline MUV-2 (as confirmed by their diffraction patterns) and present and analogous breathing behaviour upon solvent exposure. The development of a green synthesis approach replaces the harmful DMF solvent preliminary used with the aim to move towards environment friendly methodologies and scalable processes. Taking advantage of the hierarchical mesoporous nature of the framework, the performance of these materials as larger bioactive molecule carriers was evaluated. Preliminary results showcase composites with high estimated lysozyme loadings (up to 40 %) following an infiltration methodology

ZIF-8 encapsulation improves the antifungal activity of benzaldehyde and methyl anthranilate in films

Two ZIF-8-based biocomposites are obtained by entrapping antifungal benzaldehyde and methyl anthranilate biomolecules via direct impregnation with high payloads. Enhanced antifungal activity against Penicilium expansum is shown after their integration in biopolymeric films

ZIF-8 encapsulation improves the antifungal activity of benzaldehyde and methyl anthranilate in films

In this work, two ZIF-8-based biocomposites were obtained by entrapping the biomolecules benzaldehyde and methyl anthranilate via direct impregnation with fast encapsulation kinetics and high molecule payloads were achieved. The obtained biocomposites exhibit an enhanced antifungal activity against Penicilium expansum after integration in biopolymeric zein films in comparison with the action of free molecules, making these biomaterials promising candidates for food preservation and packaging applications.This work has been supported by grants TED2021-132729A-I00, PID2020-118564GA-I00, PID2021-123077OB-I00 and CEX2019-000919-M, funded by MCIN/AEI/10.13039/501100011033, EU NextGenerationEU/PRTR and by Generalitat Valenciana (PROMETEO CIPROM/2022/48). M. G.-M. thanks MICINN for a Ramón y Cajal (RYC2019-027902-I), K. C. for a PRE2018-083355 grant included in Project MAT2017-89993-R funded by “ERDF A way of making Europe”.Peer reviewe

Exploiting redox activity of MIL-100(Fe) carrier enables carvacrol prolonged antimicrobial activity

The design of efficient food contact materials that maintain optimal levels of food safety is of paramount relevance to reduce the increasing foodborne illnesses. In this work, we develop a smart composite MOF-based material that fosters a unique prolonged antibacterial activity. The composite is obtained by entrapping a natural preserving food molecule, carvacrol, into the mesoporous MIL-100(Fe) material following a direct and biocompatible impregnation method and obtaining particularly high payloads. By exploiting the intrinsic redox nature of MIL-100(Fe) material it is possible to achieve a prolonged activity against E. coli bacteria due to a triggered two-step carvacrol release of films containing the carvacrol@MOF composite. Essentially, it was discovered that based on the underlying chemical interaction among MIL-100(Fe) and carvacrol, it is possible to undergo a reversible charge transfer process between the metallic MOF counterpart and the carvacrol upon certain physical stimuli. During this process, the preferred carvacrol binding site has been monitored by IR, Mössbauer and EPR spectroscopies and is supported by theoretical calculations

A thermally/chemically robust and easily regenerable anilato-based ultramicroporous 3D MOF for CO2 uptake and separation

The combination of a properly designed organic linker, 3,6-N-ditriazolyl-2,5-dihydroxy-1,4-benzoquinone (trz2An), with CoII ions results in a novel 3D ultramicroporous MOF with high CO2 uptake capacity and separation efficiency, with particular attention to CO2/N2 and CO2/CH4 gas mixtures. This material consists of 1D chains of octahedrally coordinated CoII ions linked through anilato ligands at the equatorial positions and triazole substituents from two neighbouring chains at the two axial positions. This leads to a 3D microporous structure with voids with an affinity for CO2 molecules and channels that enable the selective entry of CO2 but not of molecules with larger kinetic diameters such as N2 or CH4. Adsorption studies revealed that (i) the MOF presents a remarkable carbon dioxide uptake, above 20% in weight; (ii) CO2 adsorptive separation is successfully performed in CO2:N2 and CO2:CH4 gas mixtures, exhibiting high selectivity in a large operation range; (iii) regeneration is easily achieved under mild conditions