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The nature of the electronic ground state of the Ti2C MXene is unambiguously determined by making use of density functional theory-based calculations including hybrid functionals together with a stringent computational setup providing numerically converged results up to 1 meV. All the explored density functionals (i.e., PBE, PBE0, and HSE06) consistently predict that the Ti2C MXene has a magnetic ground state corresponding to antiferromagnetic (AFM)-coupled ferromagnetic (FM) layers. A spin model, with one unpaired electron per Ti center, consistent with the nature of the chemical bond emerging from the calculations, is presented in which the relevant magnetic coupling constants are extracted from total energy differences of the involved magnetic solutions using an appropriate mapping approach. The use of different density functionals enables us to define a realistic range for the magnitude of each of the magnetic coupling constants. The intralayer FM interaction is the dominant term, but the other two AFM interlayer couplings are noticeable and cannot be neglected. Thus, the spin model cannot be reduced to include nearest-neighbor interactions only. The Néel temperature is roughly estimated to be in the 220 ± 30 K, suggesting that this material can be used in practical applications in spintronics and related fields.

Additive manufacturing (AM) enables fully dense biomimetic implants in the designed geometries from preferred materials such as titanium and its alloys. Titanium aluminum vanadium (Ti6Al4V) is one of the pioneer metal alloys for bone implant applications, however, the reasons for eliminating the toxic effects of Ti6Al4V and maintaining adequate mechanical strength have increased the potential of commercially pure titanium (cp-Ti) to be used in bone implants. This literature review aims to evaluate the production of cp-Ti and Ti6Al4V biomedical implants with laser powder bed fusion (L-PBF) technology, which has a very high level of technological matureness and industrialization level. The optimization of L-PBF manufacturing parameters and post-processing techniques affect the obtained microstructure leading to various mechanical, corrosion and biological behaviors of the manufactured titanium. All of the features are considered in the light of specifications and needs of bone implant applications. The most critical disadvantages of the L-PBF technology, such as residual stresses and leading deformations are introduced and the potential solutions are discussed. Moreover, the manufacturability of porous bone implants that causes benefit and harm in L-PBF applications are assessed. Peer Reviewed Objectius de Desenvolupament Sostenible::3 - Salut i Benestar

The synthesis, properties, and reactivity of monocyclopentadienyltitanium(III) complexes stabilized by hydridoborato (BH3R)(-) ligands are reported. The reactions of the titanium(IV) trichlorides [Ti(eta(5)-C5H5-nMen)Cl-3] with excess LiBH3R (R = H, Me) afford dimeric [{Ti(eta(5)-C5H5-nMen)(BH4)(mu-BH4)}(2)] (n = 5 (1), 4 (2), 0 (3)) or monomeric [Ti(eta(5)-C5Me5)(BH3Me)(2)] (4) titanium(III) derivatives. Compound 3 is a thermally unstable oil and decomposes at room temperature forming a mixedvalence Ti-II/Ti-III tetrametallic species [{Ti(eta(5)-C5H5)(BH4)}(2){(mu(3)-B2H6)Ti(eta(5)-C5H5)}(2)] (5) with dianionic diborane(6) ligands in a rare mu(3)-kappa(2):kappa(2):kappa(2)-B2H6 coordination mode. Density functional theory (DFT) calculations for 5 agree with a triplet ground state with two inner titanium(II) atoms bonded by a single bond and two outer titanium(III) centers. In contrast to 3, the monomeric tetrahydrofuran adduct derivative [Ti(eta(5)-C5H5)(BH4)(2)(thf)] (6) is a stable solid. Dimeric 1-3 react with 2,6-lutidinium salts (LutH)X (X = BPh4, OSO2CF3) to afford ion pairs, [Ti(eta(5)-C5H5-nMen)(BH4)L-2](BPh4) (L = thf, n = 5 (7), 4 (8), 0 (9); L = py, n = 5 (10)), or molecular aggregates, [{Ti(eta(5)-C5Me5)(BH4)(mu-O2SOCF3)}(2)] (11) and [{Ti(eta 5C5H5-nMen)(mu-O2SOCF3)(2)} x] (n = 5, x = 3 (12); n = 4, x = 4 (13)), via formation of H-2 and (Lut)BH3. Diamagnetic titanium(II) derivatives [{Ti(eta(5)-C5Me5)(mu-H)}(2){(mu-H)(2)Al(BH3R)(thf)}(2)] (R = H (14), Me (15)) were isolated in reactions of complexes 1 and 4 with LiAlH4 in tetrahydrofuran., Spanish Structures of Excellence María de Maeztu, Ministerio de Ciencia, Innovación y Universidades, Universidad de Alcalá

The surface topography of titanium dental implants has a great influence on osseointegration. In this work, we try to determine the osteoblastic behavior and gene expression of cells with different titanium surfaces and relate them to the physicochemical properties of the surface. For this purpose, we have used commercial titanium discs of grade 3: as-received corresponds to machined titanium without any surface treatment (MA), chemically acid etched (AE), treated via sand blasting with Al2O3 particles (SB) and a sand-blasting treatment with acid etching (SB+AE). The surfaces have been observed using scanning electron microscopy (SEM) and the roughness, wettability and surface energy with dispersive and polar components have been characterized. Osteoblastic cultures were performed with SaOS-2 osteoblastic cells determining cell viability as well as alkaline phosphatase levels for 3 and 21 days, and osteoblastic gene expression was determined. The roughness values of the MA discs was 0.02 μm, which increases to 0.3 μm with acid attack and becomes the maximum for the sand-blasted samples, reaching values of 1.2 μm for SB and SB+AE. The hydrophilic behavior of the MA and AE samples with contact angles of 63° and 65° is superior to that of the rougher samples, being 75° for SB and 82° for SB+AE. In all cases, they show good hydrophilicity. GB and GB+AE surfaces present a higher polar component in the surface energy values, 11.96 and 13.18 mJ/m2, respectively, than AE and MA, 6.64 and 9.79 mJ/m2, respectively. The osteoblastic cell viability values at three days do not show statistically significant differences between the four surfaces. However, the viability of the SB and SB+AE surfaces at 21 days is much higher than that of the AE and MA samples. From the alkaline phosphatase studies, higher values were observed for those treated with sand blasting with and without acid etching compared to the other two surfaces, indicating a greater activity in osteoblastic differentiation. In all cases except in the Osterix (Ostx) —osteoblast-specific transcription factor—a decrease in gene expression is observed in relation to the MA samples (control). The most important increase was observed for the SB+AE condition. A decrease in the gene expression of Osteoprotegerine (OPG), Runt-related transcription factor 2 (Runx2), Receptor Activator of NF-κB Ligand (RANKL) and Alkaline Phosphatase (Alp) genes was observed in the AE surface.

The rapid integration in the bone tissue and the prevention of bacterial infection are key for the success of the implant. In this regard, a silver (Ag)-doped thermochemical treatment that generate an Ag-doped calcium titanate layer on titanium (Ti) implants was previously developed by our group to improve the bone-bonding ability and provide antibacterial activity. In the present study, the biological and antibacterial potential of this coating has been further studied. In order to prove that the Ag-doped layer has an antibacterial effect with no detrimental effect on the bone cells, the behavior of osteoblast-like cells in terms of cell adhesion, morphology, proliferation and differentiation was evaluated, and the biofilm inhibition capacity was assessed. Moreover, the competition by the surface between cell and bacteria was carried out in two different co-culture methods. Finally, the treatment was applied to porous Ti implants to study in vivo osteointegration. The results show that the incorporation of Ag inhibits the biofilm formation and has no effect on the performance of osteoblast-like cells. Therefore, it can be concluded that the Ag-doped surface is capable of preventing bone bacterial infection and providing suitable osseointegration.

[ES] Las aleaciones de Titanio (Ti) tienen una gran importancia en numerosas industrias. En particular, son los metales más utilizados para aplicaciones biomédicas. La aleación más común, Ti6Al4V tiene desventajas de toxicidad y elevado modulo elástico. Para superarlas se usan cada vez más como aleantes el Niobio (Nb) y Molibdeno (Mo). Son elementos estabilizantes de fase β que tiene el módulo elástico más reducido y además son biocompatibles y poco tóxicos. El estaño (Sn) es un elemento neutro (no βestabilizante), no refractario que también es biocompatible y se utiliza mucho como aleante en biomateriales. La obtención de las aleaciones por el método pulvimetalurgico (PM) es una alternativa más económica al método convencional de colada, que además permite obtener formas de componentes difíciles de obtener por otras rutas. Sin embargo, las aleaciones obtenidas por PM presentan un problema de porosidad elevada que reduce la resistencia a compresión y corrosión. Se pretende reducir esta porosidad realizando tratamientos superficiales, uno de los cuales es la refusión con láser. En este tratamiento se funde una pequeña capa del material aportando calor con el rayo del láser a velocidad y potencia determinadas. Al solidificar se forma una capa superficial que puede mejorar las propiedades mecánicas de las piezas. En este trabajo se estudian algunas propiedades mecánicas y la microestructura de las muestras de 30x12x5 mm3 de aleaciones Ti-35Nb-2Sn y Ti-27Nb-8Mo obtenidas por PM después de la refusión superficial con cinco condiciones (potencia y velocidad del láser). En primer lugar, se analiza la porosidad y densidad relativa obtenidas por el método de Arquímedes. Se obtiene el módulo elástico utilizando la técnica de excitación por impulso. Se realiza el ensayo a flexión a cuatro puntos para obtener el módulo elástico a flexión, resistencia máxima y deformación. Se estudian las dimensiones de las zonas refundidas en las imágenes obtenidas mediante microscopia óptica. Mediante las imágenes de microscopia electrónica de barrido se analiza la microestructura tanto de los cordones de refusión como de las superficies refundidas y fracturas. Se evalúa la geometría de las superficies refundidas con un perfilómetro y finalmente se realiza el ensayo de nanoindentación de los cordones de refusión y la ZAC (zona afectada por el calor) para determinar la evolución de la dureza y el módulo de indentación a lo largo de ellos. Analizando los resultados de dichos ensayos podemos concluir que para las aleaciones en cuestión obtenidas por PM se consigue una mejora de algunas propiedades mecánicas superficiales gracias a la refusión superficial con el láser y se establecen algunas correlaciones entre los parámetros del láser y las mejoras. Sin embargo, habría que estudiar el comportamiento químico de las aleaciones para asegurar que no presenten problemas de corrosión. Este trabajo encuadra en los siguientes ODS (objetivos del desarrollo sostenible): -ODS 3, Salud y bienestar: ya que los implantes de las aleaciones estudiadas podrían ayudar a salvar las vidas, por ejemplo, de las víctimas de accidentes de tráfico, como lo propone la meta 3.6 - ODS 4, Educación de calidad: ya que el hecho de que la autora de este trabajo está realizando sus estudios demuestra el acceso igualitario de todos los hombres y las mujeres a una formación técnica, como lo propone la meta 4.3 -ODS 9, Industria, innovación e infraestructuras: ya que aporta a la investigación científica y mejora la capacidad tecnológica del sector industrial, como se propone en la meta 9.5, [CAT] Els aliatges de Titani (Ti) tenen una gran importància en nombroses indústries. En particular, són els metalls més utilitzats per a aplicacions biomèdiques. L'aliatge més comú, Ti6Al4V té desavantatges de toxicitat i elevat mòdul elàstic. Per superar-les usen cada vegada més com a aleants el Niobi (Nb) i Molibdè (Mo). Són elements estabilitzants de fase β que té el mòdul elàstic més reduït i a més són biocompatibles i poc tòxics. L'estany (Sn) és un element neutre (no β-estabilitzant), no refractari que també és biocompatible i s'utilitza molt com a aliant en biomaterials. La obtenció dels aliatges pel mètode pulvimetal·lúrgic (PM) és una alternativa més econòmica al mètode convencional de colada, que a més permet obtenir formes de components difícils d'obtenir per altres rutes. No obstant això, els aliatges obtinguts per PM presenten un problema de porositat elevada que redueix la resistència a compressió i corrosió. Es pretén reduir aquesta porositat fent tractaments superficials, un dels quals és la refusió amb làser. En aquest tractament es fon una petita capa del material aportant calor amb el raig del làser a velocitat i potència determinades. En solidificar es forma una capa superficial que pot millorar les propietats mecàniques de les peces. En aquest treball s'estudien algunes propietats mecàniques i la microestructura de les mostres de 30x12x5 mm3 d'aliatges Ti-35Nb-2Sn i Ti-27Nb-8Mo obtingudes per PM després de la refusió superficial amb cinc condicions (potència i velocitat del làser). A primer lloc, s'analitza la porositat i la densitat relativa obtingudes pel mètode d'Arquimedes. S'obté el mòdul elàstic utilitzant la tècnica d'excitació per impuls. Es realitza l'assaig a flexió a quatre punts per obtenir el mòdul elàstic a flexió, resistencia màxima i deformació. S'estudien les dimensions de les zones refoses a les imatges obtingudes mitjançant microscòpia òptica. Mitjançant les imatges de microscòpia electrònica d'escombrada s'analitza la microestructura tant dels cordons de refusió com de les superfícies refoses i les seues fractures. S'avalua la geometria de les superfícies refoses amb un perfilòmetre i finalment es realitza el assaig de nanoindentació dels cordons de refusió i la ZAC (zona afectada per la calor) per determinar l'evolució de la duresa i el mòdul d'indentació al llarg d'ells. Analitzant els resultats d'aquests assaigs podem concloure que per els aliatges en qüestió obtinguts per PM s'aconsegueix una millora de algunes propietats mecàniques superficials gràcies a la refusió superficial amb el làser i s'estableixen algunes correlacions entre els paràmetres del làser i les millores. No obstant això, caldria estudiar el comportament químic dels aliatges per assegurar que no presenten problemes de corrosió. Aquest treball s'enquadra en els següents ODS (objectius del desenvolupament sostenible): -ODS 3, Salut i benestar: ja que els implants dels aliatges estudiades podrien ajudar a salvar les vides, per exemple, de les víctimes d'accidents de trànsit, com ho proposa la meta 3.6. - ODS 4, Educació de qualitat: ja que el fet que l'autora de aquest treball està fent els estudis demostra l'accés igualitari de tots els homes i les dones a una formación tècnica, com ho proposa la meta 4.3 -ODS 9, Indústria, innovació i infraestructures: ja que aporta resultats a la investigació científica i millora la capacitat tecnològica del sector industrial, com es proposa a la meta 9.5., [EN] The Titanium (Ti) alloys are important for many industries because of their unique properties. In particular, they are the most used metals for biomedical applications. The most common alloy, Ti6Al4V, has the disadvantages of toxicity and high elastic modulus. In order to overcome these disadvantages, the Nb (Niobium) and Mo (Molybdenum) are used as alloying elements in the recent years. They are stabilizing elements of the β phase, the one that offers the lowest elastic modulus. The tin (Sn) is a neutral element (not β-stabilizing) and non-refractory, which also presents great biocompatibility and is commonly used in biomaterials. The powder metallurgy (PM) is a cheaper alternative method of alloy fabrication which also allows creating components with shapes that are hard to achieve by other methods. On the other hand, the components created by PM have the problem of high porosity which leads to poor compression and corrosion resistance. This porosity can be reduced by applying superficial treatments. One of them is laser surface modification, in which a small layer of the material is melted with the laser beam with given power and speed. After solidification, a layer with improved mechanical properties is formed. In this work, some of mechanical properties and microstructure of Ti-35Nb-2Sn and Ti27Nb-8Mo alloys, obtained by PM and treated with laser, are studied. The samples of alloys of 30x12x5 mm3 and five laser conditions (sets of power and speed of the laser) were used. In the first place, the porosity and density obtained with the Archimedes method are analyzed. The elastic modulus is obtained using the pulse excitation technique. The, the four-point flexure test is performed to determine the elastic flexural modulus, resistance and deformation. The dimensions of the remelted zones are studied using the optical microscopy and with electron microscopy images are used to analyze the remelted surfaces as well as the fractures. To study the geometry of the surface, perfilometry is used. And finally, nanoindentation tests of the remelted zones and HAZ (head affected zones) are performed to determine the evolution of the microhardness and nanoindentation modulus. Analyzing the results of the tests described above, the conclusion is, the laser surface modification improves some of the mechanical surface properties of the studied alloys obtained by PM. In addition, the correlations of these improvements with the laser conditions are established. However, the chemical analysis of the alloys should be performed to make sure they do not present significant corrosion problems. This work could be framed in the following SDG (sustainable development goals): -SDG 3, Good health and well-being: as the implants made of the studied alloys could save lives, for example, of the traffic accident victims, as the target 3.6 suggests. - SDG 4, Quality education: as the fact that the author of this work is carrying out her studies demonstrates the equal access opportunities to technical degrees for men and women, as it is stated in the target 4.3. -SDG 9, Industry, innovation and infrastructures: as it contributes to the scientific investigation and improves the technological capacity in the industrial sector, as it is is proposed in the target 9.5.

[ES] El grabado láser consiste en provocar, mediante un haz de luz alta energía, una oxidación controlada en la superficie de una pieza metálica. El empleo de sistemas de diseño y fabricación asistido por ordenador (CAD / CAM) permite generar geometrías y caracteres en la pieza a grabar. Este estudio se centrará en el grabado láser de piezas de titanio aleado Ti6Al4V ELI, siendo este un material de uso muy extendido en la industria biomédica. Durante la realización de este proyecto se estudia el proceso de grabado láser en piezas de Ti6Al4V ELI dentro de un proyecto de transferencia de producción de un proveedor externo a fabricación interna. Además, se contextualiza este proceso de grabado láser en un contexto de gestión de riesgos y un sistema de calidad mediante el uso de PFMEA y la validación estadística del proceso de grabado láser y los resultados que este produce en la pieza final. Se estudia, además, dos alternativas de parametrización y realización del proceso de grabado láser con el objetivo de obtener las mejores condiciones de grabado teniendo en cuenta todo el flujo de fabricación de las piezas. A estas piezas se realizan los análisis superficiales pertinentes y las inspecciones de acuerdo con los criterios de inspección alineados con el plano de la pieza final con el objetivo de conseguir unos parámetros óptimos de grabado láser, que permitan obtener un acabado negro intenso que no se delamine tras los procesos de limpieza y que tenga los mínimos efectos posibles en el paciente final., [CAT] El gravat làser consisteix en provocar, mitjançant un fes de llum d’alta energia, una oxidació controlada en la superfície d’una peça metàl·lica. La utilització de sistemes de disseny i fabricació per ordinador (CAD/CAM) permet generar geometries i caràcters en la peça a gravar. Este estudi es centrarà en el gravat làser de peces de titani aliat Ti6Al4V ELI, sent aquest un material d’us molt estès en l’industria biomèdica. Durant la realització d’aquest projecte s’estudia el procés de gravat làser en peces de Ti6Al4V ELI en un projecte de transferència de producció de un proveïdor extern a fabricació interna. A més, es contextualitza aquest procés de gravat làser en un context de gestió de riscs i un sistema de qualitat mitjançant l’ús d’un PFMEA i la validació estadística del procés de gravat làser i els resultats que aquest procés produeix en la peça final. S’estudia, a demés, dues alternatives de parametrització i realització de del procés de gravat làser amb l’objectiu d’obtenir les millors condicions de gravat tenint en compte tot el fluix de fabricació de les peces. Amb aquestes peces es realitzaran els anàlisis superficials necessaris i les inspeccions d’acord amb els criteris d’inspecció alineats amb el pla de la peça final amb l’objectiu d’obtenir uns paràmetres òptims per al gravat làser que permeten obtenir un acabat negre intens que no es del·lamine després dels procesos de neteja i que causi els mínims efectes possibles en el pacient final., [EN] The laser marking process consists in inducing, using a high energy beam of light, a controlled oxidation of a metallic part¿s surface. This process, combined with the use of computer assisted design and manufacturing systems (CAD/CAM), allows for the generation of geometries and alphanumerical symbols. This study will be centered around laser marking on alloyed titanium Ti6Al4V ELI parts, because of the widespread use of this material on the biomedical industry. During the realization of this project the laser marking process on Ti6Al4V parts isstudied in the context of a transfer project from an external supplier to internal manufacturing. This laser marking process is contextualized within a risk management and quality management system by using a PFMEA. The laser marking process will also be statistically validated and the results of this process in the part will be studied. With the goal of obtaining the best laser marking conditions and considering all the manufacturing flow, two different alternatives for parametrization will be studied. The parts surface will be analyzed, and the parts will be inspected according to the inspection criteria aligned with the parts drawing. This will be performed with the objective of obtaining the optimal laser marking parameters that will allow for the obtention of a clear black mark that will not delaminate after the cleaning process and that is harmless to the final patient

Titanium mini-implants are used as anchorage for orthodontic tooth movements. However, these implants present problems due to the infection of surrounding tissues. The aim of this work was to obtain a polyethylene glycol (PEG) layer by plasma in order to achieve a bacteriostatic surface. Titanium surfaces were activated by argon plasma and, after, by PEG plasma with different powers (100, 150 and 200 W) for 30 and 60 min. The roughness was determined by white light interferometer microscopy and the wettability was determined by the contact angle technique. Surface chemical compositions were characterized by X-ray photoelectron spectroscopy (XPS) and cytocompatibility and cell adhesion studies were performed with fibroblast (hFFs) and osteoblast (SAOS-2) cells. Bacterial cultures with Spectrococcus Sanguinis and Lactobacillus Salivarius were performed, and bacterial colonization was determined. The results showed that plasma treatments do not affect the roughness. Plasma makes the surfaces more hydrophilic by decreasing the contact angles from 64.2° for titanium to 5.2° for argon-activated titanium, with values ranging from 12° to 25° for the different PEG treatments. The plasma has two effects: the cleaning of the surface and the formation of the PEG layer. The biocompatibility results were, for all cases, higher than 80%. The polymerization treatment with PEG reduced the adhesion of hFFs from 7000 to 6000 and, for SAOS-2, from 14,000 to 6500, for pure titanium and those treated with PEG, respectively. Bacterial adhesion was also reduced from 600 to 300 CFU/mm2 for Spetrococcuns Sanguinis and from 10,000 to 900 CFU/mm2 for Lactobacillus Salivarius. The best bacteriostatic treatment corresponded to PEG at 100 W and 30 s. As a consequence, the PEG coating would significantly prevent the formation of bacterial biofilm on the surface of titanium mini-implants. info:eu-repo/semantics/publishedVersion

Reaction of [TiCp*Cl-3] (Cp*=eta(5)-C5Me5) with one equivalent of magnesium in tetrahydrofuran at room temperature affords the paramagnetic trinuclear complex [{TiCp*(mu-Cl)}(3)(mu(3)-Cl)], which reacts with dinitrogen under ambient conditions to give the diamagnetic derivative [{TiCp*(mu-Cl)}(3)(mu(3)-eta(1) : eta(2) : eta(2)-N-2)] and the titanium(III) dimer [{TiCp*Cl(mu-Cl)}(2)]. The structure of the trinuclear mixed-valence complexes has been studied by experimental and theoretical methods and the latter compound represents the first well-defined example of the mu(3)-eta(1) : eta(2) : eta(2) coordination mode of the dinitrogen molecule. The reaction of [{TiCp*(mu-Cl)}(3)(mu(3)-eta(1) : eta(2) : eta(2)-N-2)] with excess HCl in tetrahydrofuran results in clean NH4Cl formation with regeneration of the starting material [TiCp*Cl-3]. Therefore, a cyclic ammonia synthesis under ambient conditions can be envisioned by alternating N-2/HCl atmospheres in a [TiCp*Cl-3]/Mg(excess) reaction mixture in tetrahydrofuran., Ministerio de Ciencia, Innovación y Universidades, Universidad de Alcalá, Spanish Structures of Excellence María de Maeztu

The influence of the surface topography of dental implants has been studied to optimize titanium surfaces in order to improve osseointegration. Different techniques can be used to obtain rough titanium, however, their effect on wettability, surface energy, as well as bacterial and cell adhesion and differentiation has not been studied deeply. Two-hundred disks made of grade 4 titanium were subjected to different treatments: machined titanium (MACH), acid-attacked titanium (AE), titanium sprayed with abrasive alumina particles under pressure (GBLAST), and titanium that has been treated with GBLAST and then subjected to AE (GBLAST + AE). The roughness of the different treatments was determined by confocal microscopy, and the wettability was determined by the sessile drop technique; then, the surface energy of each treatment was calculated. Osteoblast-like cells (SaOs-2) were cultured, and alkaline phosphatase was determined using a colorimetric test. Likewise, bacterial strains S. gordonii, S. oralis, A. viscosus, and E. faecalis were cultured, and proliferation on the different surfaces was determined. It could be observed that the roughness of the GBLAST and GBLAS + AE was higher, at 1.99 and 2.13 μm of Ra, with respect to the AE and MACH samples, which were 0.35 and 0.20 μm, respectively. The abrasive treated surfaces showed lower hydrophilicity but lower surface energy. Significant differences could be seen at 21 days between SaOS-2 osteoblastic cell adhesion for the blasted ones and higher osteocalcin levels. However, no significant differences in terms of bacterial proliferation were observed between the four surfaces studied, demonstrating the insensitivity of bacteria to topography. These results may help in the search for the best topographies for osteoblast behavior and for the inhibition of bacterial colonization. info:eu-repo/semantics/publishedVersion

Osseointegration capacity and good mechanical behavior are key to the success of the dental implant. In many investigations, comparisons of properties are made using different dental implant designs and therefore the results can be influenced by the macrodesign of the dental implant. In this work, studies were carried out with the same dental implant model using different roughness and different materials—commercially pure titanium (grade 4) and zirconia. For this purpose, 80 smooth passivated titanium (Ti), 80 smooth zirconia (ZrO2), and 80 rough passivated titanium (Ti-R) dental implants were used. The samples were characterized by their roughness, wettability, surface energy, residual stresses, and fatigue behavior. The implants were implanted in minipigs for 4 and 12 weeks. The animals were sacrificed, and histological studies were carried out to determine the osseointegration parameters for each of the implantation times. Ti and ZrO2 dental implants have very similar wettability and surface energy properties. However, the roughness causes a decrease in the hydrophilic character and a decrease of the total surface energy and especially the dispersive component, while the polar component is higher. Due to the compressive residual stresses of alumina sandblasting, the rough dental implant has the best fatigue behavior, followed by Ti and due to the lack of toughness and rapid crack propagation the ZrO2 implants have the worst fatigue behavior. The bone index contact (BIC) values for 4 weeks were around 25% for Ti, 32% for ZrO2, and 45% for Ti-R. After 12 weeks the Ti dental implants increased to 42%, for Ti, 43% for ZrO2, and an important increase to 76% was observed for Ti-R implants. In vivo results showed that the key factor that improves osseointegration is roughness. There was no significant difference between ZrO2 and Ti implants without sandblasting. info:eu-repo/semantics/publishedVersion

Background: The objective of this study was to evaluate the accumulation of ions in blood and organs caused by Ti metal particles in a mandibular defect in rats, together with a description of the local reaction of oral tissues to these titanium alloy debris. Methods: Twenty Sprague-Dawley rats were randomly distributed into three groups: an experimental group with a mandibular bone defect filled with metallic debris obtained by implantoplasty; a positive control group; and a negative control group. Thirty days after surgery, the rats were euthanized and perilesional tissue surrounding the mandibular defect was removed, together with the lungs, spleen, liver and brain. Two blood samples were collected: immediately before surgery and before euthanasia. The perilesional tissue was histologically analyzed using hematoxylin-eosin staining, and titanium, aluminum and vanadium ion concentrations in blood and organs were measured by TQ-ICP-MS. Descriptive and bivariate analyses of the data were performed. Results: All rats with implanted metal debris showed metal particles and a bone fracture callus on the osseous defect. The metal particles were surrounded by a foreign body reaction characterized by the presence of histiocytes and multinucleated giant cells. The experimental group had a significant higher concentration of Ti ions in all studied organs except lung tissue (p < 0.05). In addition, there were more V ions in the brain in the experimental group (p = 0.008). Conclusions: Although further studies are required to confirm the clinical relevance of these results, Ti metal particles in the jaw might increase the concentration of metal ions in vital organs and induce a foreign body reaction. This article is protected by copyright. All rights reserved. Keywords: Ion release; Ti6Al4V; implantoplasty; metal particles; peri-implantitis; titanium.

A lack of primary stability and osteointegration in metallic implants may result in implant loosening and failure. Adding porosity to metallic implants reduces the stress shielding effect and improves implant performance, allowing the surrounding bone tissue to grow into the scaffold. However, a bioactive surface is needed to stimulate implant osteointegration and improve mechanical stability. In this study, porous titanium implants were produced via powder sintering to create different porous diameters and open interconnectivity. Two strategies were used to generate a bioactive surface on the metallic foams: (1) an inorganic alkali thermochemical treatment, (2) grafting a cell adhesive tripeptide (RGD). RGD peptides exhibit an affinity for integrins expressed by osteoblasts, and have been reported to improve osteoblast adhesion, whereas the thermochemical treatment is known to improve titanium implant osseointegration upon implantation. Bioactivated scaffolds and control samples were implanted into the tibiae of rabbits to analyze the effect of these two strategies in vivo regarding bone tissue regeneration through interconnected porosity. Histomorphometric evaluation was performed at 4 and 12 weeks after implantation. Bone-to-implant contact (BIC) and bone in-growth and on-growth were evaluated in different regions of interest (ROIs) inside and outside the implant. The results of this study show that after a long-term postoperative period, the RGD-coated samples presented higher quantification values of quantified newly formed bone tissue in the implant’s outer area. However, the total analyzed bone in-growth was observed to be slightly greater in the scaffolds treated with alkali thermochemical treatment. These results suggest that both strategies contribute to enhancing porous metallic implant stability and osteointegration, and a combination of both strategies might be worth pursuing. info:eu-repo/semantics/publishedVersion

[ES] En el presente trabajo se plantea realizar inicialmente un análisis del estado de arte sobre la evolución de la bicicleta según diferentes modalidades y usos, los componentes que la forman y materiales empleados, así como los procesos de fabricación. Con ello, se propone como objetivo principal del diseño, cálculo y selección de materiales para un cuadro de bicicleta de carretera a partir de los requerimientos funcionales determinados. En una primera fase, se plantea establecer una geometría básica sobre la que poder realizar la hipótesis de carga mediante el empleo del método de los elementos finitos que originaría un ciclista de forma estática y en movimiento. Esta etapa puede sufrir diferentes iteraciones hasta lograr optimizar la geometría del cuadro. A partir del análisis de fuerzas a las que el cuadro está sometido, se podrá en una segunda etapa estudiar los distintos materiales seleccionados con ayuda del software GRANTA CES Edupack. Se tendrá en cuenta también en esta fase, aspectos relacionados con los procesos de fabricación y acabado superficial. Finalmente, se propone un estudio económico en el que se incluyan los diferentes requisitos del proceso de diseño llevado a cabo., [CAT] En aquest treball es planteja realitzar inicialment una anàlisi de l'estat d'art sobre l'evolució de la bicicleta segons diferents modalitats i usos, els components que la formen i els materials emprats, així com els processos de fabricació. Amb això, es proposa com a objectiu principal del disseny, càlcul i selecció de materials per a un quadre de bicicleta de carretera a partir dels requeriments funcionals determinats. En una primera fase, es planteja establir una geometria bàsica sobre la qual poder fer la hipòtesi de càrrega mitjançant l'ús del mètode dels elements finits que originaria un ciclista de forma estàtica i en moviment. Aquesta etapa pot patir diferents iteracions fins aconseguir optimitzar la geometria del quadre. A partir de l'anàlisi de forces a què el quadre està sotmès, es podrà en una segona etapa estudiar els diferents materials seleccionats amb ajuda del programari GRANTA CES Edupack. Es tindrà en compte també en aquesta fase aspectes relacionats amb els processos de fabricació i acabat superficial. Finalment, es proposa un estudi econòmic en què s'incloguin els diferents requisits del procés de disseny dut a terme., [EN] In the present work, it is proposed to initially carry out an analysis of the state of the art on the evolution of the bicycle according to different modalities and uses, the components that form it and the materials used, as well as the manufacturing processes. With this, it is proposed as the main objective of the design, calculation and selection of materials for a road bicycle frame based on the determined functional requirements. In a first phase, it is proposed to establish a basic geometry on which to carry out the load hypothesis by using the finite element method that a static and moving cyclist would originate. This stage can undergo different iterations until the geometry of the frame is optimized. From the analysis of the forces to which the frame is subjected, it will be possible in a second stage to study the different materials selected with the help of the GRANTA CES Edupack software. In this phase, aspects related to manufacturing processes and surface finishing will also be taken into account. Finally, an economic study is proposed in which the different requirements of the process are included, both from the point of view of the material and the manufacturing process of a road bicycle frame.

The augmentation of the alveolar crest after the loss of one or several teeth can be carried out using different bone augmentation techniques. These techniques include bone distraction, ridge expansion, bone block grafts, etc. Guided bone regeneration is an alternative to increase the volume of the hard tissues for the subsequent placement of the implants in the optimal three-dimensional position. The objective of this paper is to show a case report of the use of customized titanium mesh for posterior vertical bone regeneration. Case report and Results: A 59-year-old woman comes to rehabilitate edentulous spaces with implants. After taking the anamnesis and the intra and extraoral exploration, a vertical and horizontal bone defect is observed in the third quadrant. After the radiological study with CBCT, a bone height of 6.04 mm to the inferior alveolar nerve and a width of the bone crest of 3.95 mm was observed. It was decided to carry out a regeneration with a preformed titanium mesh (Avinent®, Santpedor, Spain) and four microscrews (Avinent®, Santpedor, Spain). The flap was closed without tension. Regular check-ups were performed without complications. At 7 months, the mesh was removed and two osteoingrated implants (Avinent®, Santpedor, Spain) were placed with a torque greater than 45 N/cm and an ISQ of 82 and 57 N/cm, respectively. The bone gain obtained was 1.84 and 1.92 mm in width and 4.2 and 3.78 mm in height for positions 3.5 and 3.6. The newly formed bone, obtained by trephine, was well-structured and histologically indistinguishable from the previous bone. Conclusion: The use of a customized pre-formed titanium mesh together with the mixture of autologous bone and xenograft is a feasible and predictable technique for vertical bone regeneration.

[eng] This thesis consists in the development of a new methodology of α-alkylation of carbonyl compounds and its application to the synthesis of small molecules with therapeutic interest. In this context, the alkylation of carbonyl compounds is usually achieved by alkylation of nucleophilic metal enolates with alkyl halides through a SN2 substitution mechanism. This approach entails a limited scope in terms of alkylating agent since the alkyl halide should be activated enough to undergo such substitution. In this thesis, a radical alternative which uses titanium(IV) enolates is presented. In fact, titanium enolates are found in equilibrium between a nucleophilic species, the titanium(IV) enolate, and a biradical species, the titanium(III). This equilibrium is the result of a valence tautomerism that lies in an electron transfer from the ligand (the enolate) to the metal center (titanium), which is reduced to titanium(III). As a consequence of this redox process, the enolate becomes an open shell species with three electrons in the acyl moiety instead of four, which grants the enolate with radical reactivity. In chapter one, this reactivity is exploited to achieve the radical alkylation of titanium(IV) enolates from chiral N-acyl oxazolidinones with diacyl peroxides. When mixed with the enolate, these species break homolytically to give an acyloxy radical, which upon decarboxylation, generates an alkyl radical that recombines with the titanium enolate to give a single diastereomer of the alkylated product. The high reactivity of alkyl radicals permits us to perform the alkylation with deactivated primary and secondary alkyl groups, a transformation that is difficult to achieve by other established methodologies. A broad scope of primary and secondary diacyl peroxides including different functional groups such as unsaturations, phenyl or esters is described. In addition, the alkylation can be performed on a vast range of titanium enolates, which can also include such functionalities as well as an oxygen, nitrogen or chlorine in the α position. This methodology is finally applied to the straightforward synthesis of arundic acid. In chapter two, the total synthesis of umuravumbolide, a substituted pyrone extracted from a medicinal plant, is described. The synthesis includes the abovementioned alkylation of a titanium enolate derived from glycolic acid to furnish the stereocenter in the side chain. Other key steps are the formation of a Z double bond and an asymmetric allylation of a sensitive aldehyde intermediate. Chapter three describes an analogous alkylation procedure to that one investigated in the first chapter, only this time, tert-butyl peresters are used instead of diacyl peroxides. This change allows the alkylation of titanium enolates derived from chiral N-acyl oxazolidinones with secondary and even tertiary alkyl groups, a transformation that is rarely reported in the literature. A broad scope of secondary and tertiary peresters is described for this transformation. And similarly to chapter one, different titanium enolates including functional groups such as esters, unsaturations or heteroatoms can be used for such alkylation procedure. Finally, in chapter four other alkylating agents that are able to render an alkyl radical are investigated. However, the alkylation product is not obtained in any of the examples tested against titanium enolates. Therefore, the substitution of titanium for another metal that can render biradical enolates but at the same time can be used in catalytic amounts is attempted. For that, a screening of different metals in various oxidation states is performed. In this case, TEMPO is used to trap a putative biradical enolate., [cat] Aquesta tesi es basa en el desenvolupament d’una metodologia d’α-alquilació de compostos carbonílics i l’aplicació d’aquesta a la síntesis de petites molècules orgàniques d’interès terapèutic. La característica més rellevant d’aquesta nova metodologia és el seu mecanisme radicalari, que es manifesta gràcies a l’ús d’enolats de titani(IV). De fet, aquests enolats es troben en equilibri a través d’un procés de tautomeria de valència entre una espècie de caràcter nucleòfil, l’enolat de titani(IV), i una espècie biradicalaria, l’enolat de titani(III). En el primer capítol, s’estudia l’alquilació d’enolats de titani derivats de N-acil oxazolidinones quirals amb peròxids de diacil. L’escissió d’aquests últims dona lloc a un radical aciloxi que, després d’un procés de descarboxilació, forma un radical alquil que reacciona amb l’enolat de titani per donar lloc al producte d’alquilació com a únic diastereòmer. Aquest procediment permet l’alquilació amb un ampli ventall de peròxids de diacil que contenen grups d’alquil primaris i secundaris amb diversos grups funcionals, tals com dobles i triples enllaços, fenils o esters. A més a més, també permet alquilar diversos enolats amb funcionalitats semblants, fins i tot, amb oxigen, nitrogen i clor en posició alfa. Aquesta metodologia s’aplica a la síntesis directa de l’àcid arúndic. En el segon capítol, es duu a terme la síntesis total de la umuravumbolida, una pirona substituïda que s’extreu d’una planta medicinal. En aquesta síntesi es fa servir l’alquilació anteriorment descrita per formar l’estereocentre de la cadena lateral de la umuravumbolida. En el tercer capítol es desenvolupa una alquilació d’enolats de titani anàloga a la del primer capítol, aquest cop, però, emprant perèsters de tert-butil. Aquest canvi permet l’alquilació amb grups secundaris i terciaris, una transformació que normalment és difícil d’aconseguir. Com en el primer capítol, l’alquilació també permet l’ús de diferents enolats de titani amb funcionalitats diverses. Finalment, en el quart capítol es busquen altres agents alquilants que formin radicals alquil. No obstant, no s’aconsegueix l’alquilació de l’enolat de titani en cap dels casos. Per tant, es fa un canvi d’objectiu i es busca trobar un metall substitut del titani que també pugui formar enolats amb activitat radicalària però de manera catalítica.

Titanium dental meshes have a wide application in order to ensure the retention of calcium phosphate-based biomaterials to regenerate bone tissue. These meshes are temporary and must grow a soft tissue to prevent bacterial colonization and provide stability. In this work, we aimed to optimize the roughness of the meshes to obtain a good biological seal while maintaining a behavior that did not favor bacterial colonization. To this end, six types of surfaces were studied: machined as a control, polished, sandblasted with three different alumina sizes and sintered. The roughness, contact angles and biological behavior of the samples using fibroblast cultures at 7, 24 and 72 h were determined as well as cytotoxicity studies. Cultures of two very common bacterial strains in the oral cavity were also carried out: Streptococcus sanguinis and Lactobacillus salivarius. The results showed that the samples treated with alumina particles by sandblasting at 200 micrometers were the ones that performed best with fibroblasts and also with the number of bacterial colonies in both strains. According to the results, we see in this treatment a candidate for the surface treatment of dental meshes with an excellent performance. info:eu-repo/semantics/publishedVersion

The techniques used in oral implantology to remove bacterial biofilm from the surface of implants by machining the titanium surface (implantoplasty) or by placing rough dental implants through friction with the cortical bone generate a large release of particles. In this work, we performed a simulation of particle generation following clinical protocols. The particles were characterized for commercially pure titanium with particle sizes of 5, 10, 15, and 30 μm. The aim was to determine the effect of particle size and chemical composition of the implant on the immune response. For this purpose, their morphology and possible contamination were characterized by scanning electron microscopy and X-ray microanalysis. In addition, the granulometry, specific surface area, release of metal ions into the medium, and studies of cytocompatibility, gene expression, and cytokine release linked to the inflammatory process were studied. The release of ions for titanium particles showed levels below 800 ppb for all sizes. Smaller particle sizes showed less cytotoxicity, although particles of 15 μm presented higher levels of cytocompatibility. In addition, inflammatory markers (TNFα and Il-1β) were higher compared to larger titanium. Specifically, particles of 15 μm presented a lower proinflammatory and higher anti-inflammatory response as characterized by gene expression and cytokine release, compared to control or smaller particles. Therefore, in general, there is a greater tendency for smaller particles to produce greater toxicity and a greater proinflammatory response. info:eu-repo/semantics/publishedVersion

Treballs Finals de Grau d'Enginyeria Biomèdica. Facultat de Medicina i Ciències de la Salut. Universitat de Barcelona. Curs: 2021-2022. Director: Javier Fernández González. Tutora: Raisha Lorena García Cadme., Increased life expectancy leads to the increasing use of metallic prostheses. Titanium and its alloys are the most widely used materials for metallic prostheses thanks to their biocompatibility, but further work still necessary to improve bioactivity and reduce osseointegration problems. Developing nanostructured titanium dioxide (TiO2) coatings increases the biocompatibility of titanium prostheses. Using the electrolytic anodizing process, nanostructures can be achieved easily and economically. This project aims to optimize the voltage and anodizing time conditions to obtain titanium dioxide nanotubes on the surface of Ti-6Al-7Nb alloy, as well as to propose ideas for industrial implementation of the project. To this purpose, a market study, a project implementation plan and a technical and economic feasibility analysis were carried out. An electron microscope image processing method and a rigorous statistical analysis have been studied to obtain an average pore diameter quantify the effect of the studied variables. Potentials of 15, 30 and 60 volts and anodizing times of 15 and 30 minutes were studied. The effect of the concentration of fluoride ions and the type of cathode used in anodizing has also been studied. The optimum conditions for the smallest pore size we have found are anodizing at 15V and 15 minutes, with a grid cathode. With these conditions, an average pore diameter of 0,48 ± 0,05 μm was obtained.

Passivation of titanium alloy dental meshes cleans their surface and forms a thin layer of protective oxide (TiO2) on the surface of the material to improve resistance to corrosion and prevent release of ions to the physiological environment. The most common chemical agent for the passivation process of titanium meshes is hydrochloric acid (HCl). In this work, we introduce the use of Piranha solution (H2SO4 and H2O2) as a passivating and bactericidal agent for metallic dental meshes. Meshes of grade 5 titanium alloy (Ti6Al4V) were tested after different treatments: as-received control (Ctr), passivated by HCl, and passivated by Piranha solution. Physical-chemical characterization of all treated surfaces was carried out by scanning electron microscopy (SEM), confocal microscopy and sessile drop goniometry to assess meshes’ topography, elemental composition, roughness, wettability and surface free energy, that is, relevant properties with potential effects for the biological response of the material. Moreover, open circuit potential and potentiodynamic tests were carried out to evaluate the corrosion behavior of the differently-treated meshes under physiological conditions. Ion release tests were conducted using Inductively Coupled Plasma mass spectrometry (ICP-MS). The antibacterial activity by prevention of bacterial adhesion tests on the meshes was performed for two different bacterial strains, Pseudomonas aeruginosa (Gram-) and Streptococcus sanguinis (Gram+). Additionally, a bacterial viability study was performed with the LIVE/DEAD test. We complemented the antibacterial study by counting cells attached to the surface of the meshes visualized by SEM. Our results showed that the passivation of titanium meshes with Piranha solution improved their hydrophilicity and conferred a notably higher bactericidal activity in comparison with the meshes passivated with HCl. This unique response can be attributed to differences in the obtained nanotextures of the TiO2 layer. However, Piranha solution treatment decreased electrochemical stability and increased ion release as a result of the porous coating formed on the treated surfaces, which can compromise their corrosion resistance. Framed by the limitations of this work, we conclude that using Piranha solution is a viable alternative method for passivating titanium dental meshes with beneficial antibacterial properties that merits further validation for its translation as a treatment applied to clinically-used meshes. info:eu-repo/semantics/publishedVersion