Preventing bacterial adhesion on scaffolds for bone tissue engineering

Bone implant infection constitutes a major sanitary concern which is associated to high morbidity and health costs. This manuscript focused on overviewing the main research efforts committed up to date to develop innovative alternatives to conventional treatments, such as those with antibiotics. These strategies mainly rely on chemical modifi-cations of the surface of biomaterials, such as providing it of zwitterionic nature, and tailoring the nanostructure surface of metal implants. These surface modifications have successfully allowed inhibition of bacterial adhesion, which is the first step to implant infection, and preventing long-term biofilm formation compared to pristine materials. These strate-gies could be easily applied to provide three-dimensional (3D) scaffolds based on bioceramics and metals, of which its manufacture using rapid prototyping techniques was reviewed. This opens the gates for the design and development of advanced 3D scaffolds for bone tissue engineering to prevent bone implant infections. Keywords: Antibacterial adhesion, biofilm formation, zwitterionic surfaces, nanostructured surfaces, rapid prototyping 3D scaffolds, bone tissue engineering

Prevention of Bacterial Adhesion to Zwitterionic Biocompatible Mesoporous Glasses

Novel materials, based on Mesoporous Bioactive Glasses(MBGs) in the ternary system SiO2-CaO-P2O5, decorated with (3-aminopropyl)triethoxysilane (APTES) and subsequently with amino acid Lysine (Lys), by post-grafting method on the external surface of the glasses (named MBG-NH2 and MBG-Lys), are reported. The surface functionalization with organic groups did not damage the mesoporous network and their structural and textural properties were also preserved despite the high solubility of MBG matrices. The incorporation of Lys confers a zwitterionic nature to these MBG materials due to the presence of adjacent amine and carboxylic groups in the external surface. At physiologic pH, this coexistence of basic amine and carboxilic acid groups from anchored Lys provided zero surface charge named zwitterionic effect. This behaviour could give rise to potential applications of antibacterial adhesion. Therefore, in order to assess the influence of zwitterionic nature in in vitro bacterial adhesion, studies were carried out with Staphylococcus aureus. It was demonstrated that the efficient interaction of these zwitterionic pairs onto the MBG surfaces reduced bacterial adhesion up to 99.9% compared to bare MBGs. In order to test the suitability of zwitterionic MBGs materials as bone grafts, their cytocompatibility was investigated in vitro with MC3T3-E1 preosteoblasts. These findings suggested that the proposed surface functionalization strategy provided MBG materials with notable antibacterial adhesion properties, hence making these materials promising candidates for local bone infection therapy

Mesoporous core-shell silica nanoparticles with anti-fouling properties for ovarian cancer therapy

Mesoporous silica nanoparticles (MSNPs) have many potential applications in biomedical fields. However, when MSNPs are exposed to plasma, protein adsorption leads to opsonization and decreases blood circulation time. A new multifunctional nanodevice based on polyethylenimine (PEI) coated core-shell Fe⁠3O⁠4@SiO⁠2 MSNPs with a zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) surface was designed to minimize unspecific protein adhesion. Particle size measurements demonstrated an excellent non-fouling capacity in solutions containing Bovine Serum Albumin (BSA) and Fetal Bovine Serum (FBS) plasma proteins. The system was used in this study to co-deliver two different cargos: siRNA and daunorubicin. Anti-TWIST siRNA plays critical role in modulating knockdown of TWIST and sensitizing cells to chemotherapeutics such as daunorubicin for ovarian cancer therapy. The drug was released in response to externally controlled oscillating magnetic fields (OMF). siRNA (siGFP) silenced expression of green fluorescence protein (GFP) in Ovcar8 cancer cells, demonstrating the incorporation of core shell MSNPs into cells and siGFP delivery. The synergistic effect of the co-release of anti-TWIST-siRNA loaded in the PEI and daunorubicin loaded in NPs’ pores caused increased cytotoxicity in Ovcar8 of up to 50% from both zwitteronic and non-zwitteronic NPs. The system is the first example of silencing by anti-TWITS-siRNA/daunorubicin co-delivered using zwitterionic core-shell nanoparticles with low-fouling adsorption. This engineered multifunctional approach may provide therapeutic potential for the treatment of currently incurable ovarian cáncer

Synthesis of HA/beta-TCP bioceramic foams from natural products

A novel technology for the preparation of bioceramic foams (BF) using a simple and economic procedure is presented. This technology combines two conventional methods to produce a tridimensional macroporous structure by using a sol-gel route, submitted afterward to a microwave treatment and thermal annealing. The use of agri-waste products on this procedure, such as egg shell and white egg recycle, represents an interesting way for waste management while developing potential commercial biomaterials. The use of egg shell as eco-compatible reactant instead of commercial ones and the egg white as foaming agent to produce a tridimensional macroporous structures has been optimized by using a sol-gel route. The crystalline phase and quantitative phase composition has been studied by Rietveld refinement and the optimization of the foaming process and determination of interconnected porosity by scanning electron microscopy, Hg porosimetry and X-ray micro-CT imaging. Our results show that BF samples showed a composition of 60 wt% HA (hydroxyapatite) and 40 wt% beta-TCP (beta-tricalcium phosphate) with a total porosity of approx. 70 % and a porosity ranging from 5 to 300 mu m. These features indicate that BF samples are ideal for bone regeneration, and they are produced in an easy and environmental friendly viable process

Perfil social y económico de los pacientes diagnosticados con trastornos del humor del Hospital Departamental Psiquiátrico Universitario del Valle, Cali

The aim of this article is to provide a social, economic and demographic profile of the population registered with SISBÉN at the Hospital Departamental Psiquiátrico Universitario del Valle (HDPUV) between 2009 and 2018, whose diagnosis is within the group of mood disorders, (corresponding to the spectrum of ICD- 10 codes ranging from F30 to F39, manic episode, bipolar disorder, depressive episode, recurrent depressive disorder, persistent mood disorder, other mood disorders, mood disorder without specification). We opted for a study in which we complemented the information between the Cali SISBÉN and HDPUV databases to deepen in data on poverty and vulnerability of people who are potential beneficiaries of state social programs. We identified 5,280 patients diagnosed with mood disorders, mostly women (70.4%) in conditions of economic, social and access to health services vulnerability, which represent yet another risk factor for their mental health.El objetivo de este artículo consiste en dar a conocer un perfil social, económico y demográfico de la población registrada con SISBÉN en el Hospital Departamental Psiquiátrico Universitario del Valle (HDPUV) entre el 2009 y el 2018, cuyo diagnóstico se encuentra dentro del grupo de los trastornos del humor (correspondiente al espectro de códigos del CIE-10 que va desde F30 a F39, episodio maníaco, trastorno bipolar, episodio depresivo, trastorno depresivo recurrente, trastorno del humor persistente, otros trastornos del humor,  trastorno del humor sin especificación). Se optó por un trabajo en el que se complementó la información entre las bases de datos del SISBÉN de Cali y la del HDPUV para profundizar en datos sobre pobreza y vulnerabilidad de las personas que son potenciales beneficiarios de programas sociales estatales. Se identificaron 5.280 pacientes diagnosticados con trastornos del humor, en su mayoría mujeres (70,4 %) en condiciones de vulnerabilidad económicas, sociales y de acceso a servicios de salud, que representan otro factor más de riesgo para su salud mental

Modelo predictivo del índice de anisotropía del semicoque a partir de las propiedades de los carbones de la Cordillera Oriental de Colombia

This study developed a theoretical model for the determination of the Coke Anisotropy Quotient (CAQ) of semi-coke from the properties of its precursor coal. This is an useful parameter to define the resistance and reactivity of semi-coke in the blast furnace. For 36 semi-coke samples, a textural analysis was performed alongside a fluidity test to determine the real CAQ. The main textures observed were: isotropic and circular for high volatile bituminous coals (HVB); lenticular and fine ribbons for the medium volatile bituminous coals (MVB); and medium and thick ribbons for the low volatile bituminous coals (LVB). The CAQ varied in a range from 1 to 11. A principal component analysis (PCA) and multiple regression allowed to discriminated the importance of certain coal properties, in determining the CAQ to be recognized and to estimate parameters of the mathematical model. The statistical analysis suggested that CAQ can be best predicted from the fluidity, volatile matter, and Ro of the parent coals. The veracity of this model result was then tested using a second dataset from Poland. This work optimizes the usefulness of standard datasets in the prediction of CAQ's offering a means of quality control that could be implemented in Colombian coke production.En esta investigación se desarrolló un modelo teórico para la determinación del Cociente de Anisotropía del Coque (CAQ) del semicoque a partir de las propiedades de su carbón precursor. El CAQ permite definir la resistencia y la reactividad del semicoque en el alto horno. Usando material residual de las pruebas de fluidez se realizó un análisis textural para determinar el CAQ real sobre 36 muestras de semicoque. Las principales texturas observadas para los carbones bituminosos fueron: isotrópicas y circulares para los de alta volatilidad (HVB); cintas lenticulares y finas para los de media volatilidad (MVB); y cintas medias y gruesas para los de baja volatilidad (LVB). El CAQ varió en un rango de 1 a 11. Análisis de componentes principales (PCA) y regresión múltiple permitieron reconocer la importancia de ciertas propiedades del carbón para determinar el CAQ. El análisis estadístico sugirió que el CAQ puede predecirse mejor a partir de la fluidez,la materia volátil y el Ro de los carbones precursores. Este modelo fue validado a través de la comparación con datos reales de carbones de Polonia. Este trabajo proporciona un medio de control de calidad que podríaimplementarse en la producción de coque colombiano.&nbsp

La investigación como recurso formativo en el ámbito universitario

En esta ponencia se recoge una experiencia formativa realizada durante el primer cuatrimestre del curso académico 2004/05 en el ámbito universitario, en la que ha participado un grupo de alumnas de la titulación de Maestro Especialista en Audición y Lenguaje de la E.U. de Magisterio ‘Virgen de Europa’ de La Línea de la Concepción, adscrita a la Universidad de Cádiz. La experiencia se ha ido articulando a partir de la necesidad planteada en clase de conocer más profundamente cuál iba a ser la función que tendrían que desempeñar en los centros escolares. Es así, que se va diseñando toda una línea de acercamiento a la realidad educativa que va tomando la forma de una investigación que gira en torno a la vida cotidiana del aula de A. y L. y al conjunto de decisiones que deben tomar estos profesionales.Eje: Educación universitaria: Experiencias educativasRed de Universidades con Carreras en Informática (RedUNCI

La investigación como recurso formativo en el ámbito universitario

En esta ponencia se recoge una experiencia formativa realizada durante el primer cuatrimestre del curso académico 2004/05 en el ámbito universitario, en la que ha participado un grupo de alumnas de la titulación de Maestro Especialista en Audición y Lenguaje de la E.U. de Magisterio ‘Virgen de Europa’ de La Línea de la Concepción, adscrita a la Universidad de Cádiz. La experiencia se ha ido articulando a partir de la necesidad planteada en clase de conocer más profundamente cuál iba a ser la función que tendrían que desempeñar en los centros escolares. Es así, que se va diseñando toda una línea de acercamiento a la realidad educativa que va tomando la forma de una investigación que gira en torno a la vida cotidiana del aula de A. y L. y al conjunto de decisiones que deben tomar estos profesionales.Eje: Educación universitaria: Experiencias educativasRed de Universidades con Carreras en Informática (RedUNCI

Antibacterial effect of 3D printed mesoporous bioactive glass scaffolds doped with metallic silver nanoparticles

The development of new biomaterials for bone tissue regeneration with high bioactivity abilities and antibacterial properties is being intensively investigated. We have synthesized nanocomposites formed by mesoporous bioactive glasses (MBGs) in the ternary SiO2, CaO and P2O5 system doped with metallic silver nanoparticles (AgNPs) that were homogenously embedded in the MBG matrices. Ag/MBG nanocomposites have been directly synthesized and silver species were spontaneously reduced to metallic AgNPs by high temperatures (700ºC) obtained of last MBG synthesis step. Three-dimensional silver-containing mesoporous bioactive glass scaffolds were fabricated showing uniformly interconnected ultrapores, macropores and mesopores. The manufacture method consisted of a combination of a single-step sol-gel route in the mesostructure directing agent (P123) presence and a biomacromolecular polymer such as (hydroxypropyl)methyl cellulose (HPMC) as the macrostructure template, followed by rapid prototyping (RP) technique. Biological properties of Ag/MBG nanocomposites were evaluated by MC3T3-E1 preosteoblastic cells culture tests and bacterial (E. coli and S. aureus) assays. The results showed that the MC3T3-E1 cells morphology was not affected while preosteoblastic proliferation decreased when the presence of silver increased. Antimicrobial assays indicated that bacterial growth inhibition and biofilm destruction were directly proportional to the increased presence of AgNPs in the MBG matrices. Furthermore, in vitro co-culture of MC3T3- E1 cells and S. aureus bacteria confirmed that AgNPs presence was necessary for antibacterial activity, and AgNPs slightly affected cell proliferation parameters. Therefore, 3D printed scaffolds with hierarchical pore structure and high antimicrobial capacity have potential applications in bone tissue regeneration

Effects of immobilized VEGF on endothelial progenitor cells cultured on silicon substituted and nanocrystalline hydroxyapatites

Vascular endothelial growth factor (VEGF) plays an essential role in angiogenesis and vascular homeostasis. Endothelial progenitor cells (EPCs) are primitive bone marrow cells participating in neovascularization and revascularization processes, which also promote bone regeneration. Synthetic hydroxyapatite (HA) has been widely used in bone repair and implant coatings. In HA-based materials, small levels of ionic substitution by silicon (Si) have significant effects on osteoclastic and osteoblastic responses. Moreover, nanocrystalline hydroxyapatites (nano-HA) display enhanced bioreactivity and beneficial effects in bone formation. In this work, the angiogenic potential of VEGF-121 adsorbed on crystalline and nanocrystalline HAs with different Si proportion is evaluated with endothelial-like cells derived from EPCs cultured on nano-HA, nano-SiHA0.25, nano-SiHA0.4, HA, SiHA0.25 and SiHA0.4 disks. The Si amount incorporated for x ¼ 0.25 is enough to yield changes in the textural parameters and surface charge without decomposing the HA phase. Si substitution for x ¼ 0.4 does not result in pure Si-substituted apatites. Si probably remains at the grain boundaries as amorphous silica in nano-SiHA0.4 and SiHA0.4 is decomposed in a-TCP and HA after 1150 �C treatment. Immobilized VEGF on nano-HA, nano-SiHA0.25, nano-SiHA0.4, HA, SiHA0.25 and SiHA0.4 maintains its function exerting a local regulation of the cell response. The crystallite size and topography of nanocrystalline HAs could produce insufficient and weak contacts with endothelial-like cells triggering anoikis. Concerning Si proportion, the best results are obtained with SiHA0.25/VEGF and nano- SiHA0.25/VEGF disks. All these results suggest the potential utility of SiHA0.25/VEGF and nano-SiHA0.25/VEGF for bone repair and tissue engineering by promoting angiogenesis