A Structural Comparison of Ordered and Non-Ordered Ion Doped Silicate Bioactive Glasses

One of the key benefits of sol-gel-derived glasses is the presence of a mesoporous structure and the resulting increase in surface area. This enhancement in textural properties has a significant e ect on the physicochemical properties of the materials. In this context the aim of this study was to investigate how sol-gel synthesis parameters can influence the textural and structural properties of mesoporous silicate glasses. We report the synthesis and characterization of metal ion doped sol-gel derived glasses with di erent dopants in the presence or absence of a surfactant (Pluronic P123) used as structure-directing templating agent. Characterization was done by several methods. Using a structure directing agent led to larger surface areas and highly ordered mesoporous structures. The chemical structure of the non-ordered glasses was modified to a larger extent than the one of the ordered glasses due to increased incorporation of dopant ions into the glass network. The results will help to further understand how the properties of sol-gel glasses can be controlled by incorporation of metal dopants, in conjunction with control over the textural properties, and will be important to optimize the properties of sol-gel glasses for specific applications, e.g., drug delivery, bone regeneration, wound healing, and antibacterial materials.European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 643050, project “HyMedPoly

Sinergías en la investigación en STEM

La Universidad, como centro de educación Superior, tiene objetivo la formación específica en cada rama del conocimiento, así como la generación y transferencia de conocimientos. Para estar en la vanguardia del conocimiento, la investigación es uno de los pilares fundamentales; la creación de nuevos conocimientos es el soporte científico y técnico necesario para la innovación y el avance. En este contexto, la Escuela Politécnica Superior (EPS) de la Universidad de Sevilla trata de promocionar la investigación a través de diversas actividades como son las Jornadas de Investigación, Desarrollo e Innovación, que en el curso 2021/22 han alcanzado su octava edición. En este evento, se presentan los avances en investigación en diversas ramas de la Ciencia y la Ingeniería, con participación de estudiantes de todos los niveles, así como del personal docente e investigador no solo de este centro, sino que contribuyen participantes de más de 8 países. El carácter multidisciplinar conlleva a establecer sinergias entre grupos de investigación de diferentes disciplinas, compaginando el conocimiento científico desde la investigación básica con la aplicada, además de aprovechar las diferentes instalaciones de investigación. La ciencia fundamental ayuda a comprender los fundamentos fenomenológicos, mientras que la ciencia aplicada se centra en los productos y desarrollos tecnológicos, destacando la necesidad de realizar una transferencia de conocimiento a la sociedad y los sectores industriales. Este libro recoge alguno de los trabajos presentados en las diversas ramas de conocimiento (Materiales y Ciencias para la Ingeniería, Proyectos de Química Industrial y Ambiental, Sistemas Inteligentes y Desarrollo de Productos, y Sistemas Industriales computarizados, robóticos y neuromórficos)

Incorporation of Calcium Containing Mesoporous (MCM-41-Type) Particles in Electrospun PCL Fibers by Using Benign Solvents

The electrospinning technique is a versatile method for the production of fibrous scaffolds able to resemble the morphology of the native extra cellular matrix. In the present paper, electrospinning is used to fabricate novel SiO2 particles (type MCM-41) containing poly(epsilon-caprolactone) (PCL) fibers. The main aims of the present work are both the optimization of the particle synthesis and the fabrication of composite fibers, obtained using benign solvents, suitable as drug delivery systems and scaffolds for soft tissue engineering applications. The optimized synthesis and characterization of calcium-containing MCM-41 particles are reported. Homogeneous bead-free composite electrospun mats were obtained by using acetic acid and formic acid as solvents; neat PCL electrospun mats were used as control. Initially, an optimization of the electrospinning environmental parameters, like relative humidity, was performed. The obtained composite nanofibers were characterized from the morphological, chemical and mechanical points of view, the acellular bioactivity of the composite nanofibers was also investigated. Positive results were obtained in terms of mesoporous particle incorporation in the fibers and no significant differences in terms of average fiber diameter were detected between the neat and composite electrospun fibers. Even if the Ca-containing MCM-41 particles are bioactive, this property is not preserved in the composite fibers. In fact, during the bioactivity assessment, the particles were released confirming the potential application of the composite fibers as a drug delivery system. Preliminary in vitro tests with bone marrow stromal cells were performed to investigate cell adhesion on the fabricated composite mats, the positive obtained results confirmed the suitability of the composite fibers as scaffolds for soft tissue engineerin

Porous titanium substrates coated with a bilayer of bioactive glasses

Porous titanium substrates coated by dripping-sedimentation technique with a novel bilayer of (45S5 / 1393) bioactive glasses are proposed to overcome some limitations of the use of titanium for implants, such as the stress shielding and the poor osseointegration. Composition, thickness, roughness and micromechanical behavior (P-h curves) of the coating and the influence of the porous titanium substrates have been characterized. Best results were found for the substrate with 30 vol.% of porosity and a range size of 355 ‒ 500 μm, since it enhanced the mechanical and biofunctional behavior, due to the good adhesion of the 1393 bioglass to the substrate and the greater bioactivity of the 45S5 bioglass, which would be in contact with the bone.Junta de Andalucía–FEDER (Spain) US-1259771M.E.C. (Spain) 2004/00001203 (RYC-2004-001497

Biofunctional and Tribo-mechanical Behavior of Porous Titanium Substrates Coated with a Bioactive Glass Bilayer (45S5 ‒ 1393)

Porous substrates of commercially pure titanium have been coated with a novel bilayer of bioactive glasses, 45S5 and 1393, to improve the osseointegration and solve the stress-shielding phenomenon of titanium partial implants. The porosity of the substrates, the scratch resistance and bioactivity of the coating have been evaluated. Results are discussed in terms of stiffness and yield strength of the substrates, as well as the chemical composition, thickness and design of the bioglass coating (monolithic vs. bilayer). The role of the pores was a crucial issue in the anchoring of the coating, both in porosity percentage (30 and 60 vol. %) and pore range size (100 – 200 and 355 ‒ 500 μm). The study was focused on the adhesion and infiltration of a 1393 bioglass layer (in contact with a porous titanium substrate), in combination with the biofunctionality of the 45S5 bioglass layer (surrounded by the host bone tissue), as 1393 bioglass enhances the adherence, while 45S5 bioglass promotes higher bioactivity. This bioactivity of the raw powder was initially estimated by nuclear magnetic resonance, through the evaluation of the chemical environments, and confirmed by the formation of hydroxyapatite, when immersed in simulated body fluid. Results revealed that the substrate with 30 vol. % of porosity and a range of 355 ‒ 500 μm pore size, coated with this novel bioactive glass bilayer, presented the best combination in terms of mechanical and biofunctional properties.Junta de Andalucía–FEDER (Spain) Project Ref. US-1259771Ministerio de Ciencia y Educación (Spain) Project 2004/00001203 (RYC-2004-001497

Porous Titanium surfaces to control bacteria growth: mechanical properties and sulfonated polyetheretherketone coating as antibiofounling approaches

Here, titanium porous substrates were fabricated by a space holder technique. The relationship between microstructural characteristics (pore equivalent diameter, mean free-path between pores, roughness and contact surface), mechanical properties (Young’s modulus, yield strength and dynamic micro-hardness) and bacterial behavior are discussed. The bacterial strains evaluated are often found on dental implants: Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. The colony-forming units increased with the size of the spacer for both types of studied strains. An antibiofouling synthetic coating based on a sulfonated polyetheretherketone polymer revealed an effective chemical surface modification for inhibiting MRSA adhesion and growth. These findings collectively suggest that porous titanium implants designed with a pore size of 100–200 µm can be considered most suitable, assuring the best biomechanical and bifunctional anti-bacterial properties.University of Seville VI Plan Propio de Investigación y Transferencia—US 2018, I.3A

Balancing porosity and mechanical properties of titanium samples to favor cellular growth against bacteria

Two main problems limit the success of titanium implants: bacterial infection, which restricts their osseointegration capacity; and the stiffness mismatch between the implant and the host cortical bone, which promotes bone resorption and risk of fracture. Porosity incorporation may reduce this difference in stiffness but compromise biomechanical behavior. In this work, the relationship between the microstructure (content, size, and shape of pores) and the antibacterial and cellular behavior of samples fabricated by the space-holder technique (50 vol % NH4HCO3 and three ranges of particle sizes) is established. Results are discussed in terms of the best biomechanical properties and biofunctional activity balance (cell biocompatibility and antibacterial behavior). All substrates achieved suitable cell biocompatibility of premioblast and osteoblast in adhesion and proliferation processes. It is worth to highlighting that samples fabricated with the 100–200 μm space-holder present better mechanical behavior—in terms of stiffness, microhardness, and yield strength—which make them a very suitable material to replace cortical bone tissues. Those results exposed the relationship between the surface properties and the race of bacteria and mammalian cells for the surface with the aim to promote cellular growth over bacteria.University of Seville (Spain) VI Plan Propio de Investigación y Transferencia—US 2018, I.3A