Relevant aspects of piranha passivation in Ti6Al4V alloy dental meshes

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.Peer ReviewedPostprint (published version

Mechanical properties of CoCr dental-prosthesis restorations made by three manufacturing processes. Influence of the microstructure and topography

The aim of this study is to compare the mechanical properties of three different dental restorations’ manufacturing processes (CADCAM milling, casting and laser sintering) generated by only one laboratory scanner focusing on marginal fit analysis and their mechanical properties. A chrome-cobalt (Cr-Co) alloy from the same batch was used for three different methods to make an implant abutment. This simulates a maxillary right first molar that was fixed in a hemi-maxillary stone model. Five scans were performed by each tested framework. Nine frameworks were manufactured for each manufacture procedure. Field-Emission Scanning Electron Microscope (FE-SEM) direct vision was used to marginal gap measurement in five critical points for each specimen. In order to fix the samples in the microscope chamber, the restorations were submitted at a compression load of 50 N. The samples always have the same orientation and conditions. The resolution of the microscope is 4 nm and it is equipped by J image software. The microstructure of the samples was also determined with the FE-SEM equipped with EDS-microanalysis. Roughness parameters were measured using White Light Interferometry (WLI). The arithmetical mean for the Ra and Rq of each sample was calculated. The samples were mechanically characterized by means of microhardness and flexural testing. Servo-hydraulic testing machine was used with cross-head rate of 1 mm/min. Two-way ANOVA statistical analysis was performed to determine whether the marginal discrepancies and mechanical properties were significantly different between each group (significance level p < 0.05). The overall mean marginal gap values were: from 50.53 ± 10.30 µm for the samples produced by CADCAM to 85.76 ± 22.56 µm for the samples produced by the casting method. Laser sintering presents a marginal gap of 60.95 ± 20.66 µm. The results revealed a statistically significant difference (p-value < 0.005) in the mean marginal gap between the CADCAM systems studied. The higher flexure load to fracture for these restorations were for CADCAM restoration and the lower was for the casting samples. For these restorations, CADCAM Restoration yielded a higher flexure load to fracture and Casting ones yielded the lower. Porosity and microstructure play a very important role in the mechanical properties.Peer ReviewedPostprint (published version

Experimental study of an evanescent-field biosensor based on 1D photonic bandgap structures

[EN] A photonic bandgap (PBG) biosensor has been developed for the label-free detection of proteins. As the sensing in this type of structures is governed by the interaction between the evanescent field going into the cladding and the target analytes, scanning near-field optical microscopy has been used to characterize the profile of that evanescent field. The study confirms the strong exponential decrease of the signal as it goes into the cladding. This means that biorecognition events must occur as close to the PBG structure surface as possible in order to obtain the maximum sensing response. Within this context, the PBG biosensor has been biofunctionalized with half-antibodies specific to bovine serum albumin (BSA) using a UV-induced immobilization procedure. The use of half-antibodies allows one to reduce the thickness of the biorecognition volume down to ca. 2.5 nm, thus leading to a higher interaction with the evanescent field, as well as a proper orientation of their binding sites towards the target sample. Then, the biofunctionalized PBG biosensor has been used to perform a direct and real-time detection of the target BSA antigen.This research was funded by the European Commission through the Horizon 2020 Programme (PHC-634013-PHOCNOSIS project) and by the Spanish Ministry of Economy and Competitiveness (TEC2015-63838-C3-1-R-OPTONANOSENS project and FJCI-2015-27228 grant).Sabek, J.; Díaz-Fernández, FJ.; Torrijos-Morán, L.; Díaz-Betancor, Z.; Maquieira Catala, A.; Bañuls Polo, M.; Pinilla-Cienfuegos, E.... (2019). Experimental study of an evanescent-field biosensor based on 1D photonic bandgap structures. Beilstein Journal of Nanotechnology. 10:967-974. https://doi.org/10.3762/bjnano.10.97S96797410Wu, J., Dong, M., Santos, S., Rigatto, C., Liu, Y., & Lin, F. (2017). Lab-on-a-Chip Platforms for Detection of Cardiovascular Disease and Cancer Biomarkers. Sensors, 17(12), 2934. doi:10.3390/s17122934Qavi, A. J., Washburn, A. L., Byeon, J.-Y., & Bailey, R. C. (2009). Label-free technologies for quantitative multiparameter biological analysis. Analytical and Bioanalytical Chemistry, 394(1), 121-135. doi:10.1007/s00216-009-2637-8Luan, E., Shoman, H., Ratner, D., Cheung, K., & Chrostowski, L. (2018). Silicon Photonic Biosensors Using Label-Free Detection. Sensors, 18(10), 3519. doi:10.3390/s18103519Washburn, A. L., & Bailey, R. C. (2011). Photonics-on-a-chip: recent advances in integrated waveguides as enabling detection elements for real-world, lab-on-a-chip biosensing applications. The Analyst, 136(2), 227-236. doi:10.1039/c0an00449aIqbal, M., Gleeson, M. A., Spaugh, B., Tybor, F., Gunn, W. G., Hochberg, M., … Gunn, L. C. (2010). Label-Free Biosensor Arrays Based on Silicon Ring Resonators and High-Speed Optical Scanning Instrumentation. IEEE Journal of Selected Topics in Quantum Electronics, 16(3), 654-661. doi:10.1109/jstqe.2009.2032510Huertas, C. S., Fariña, D., & Lechuga, L. M. (2016). Direct and Label-Free Quantification of Micro-RNA-181a at Attomolar Level in Complex Media Using a Nanophotonic Biosensor. ACS Sensors, 1(6), 748-756. doi:10.1021/acssensors.6b00162Baker, J. E., Sriram, R., & Miller, B. L. (2015). Two-dimensional photonic crystals for sensitive microscale chemical and biochemical sensing. Lab on a Chip, 15(4), 971-990. doi:10.1039/c4lc01208aPhaner-Goutorbe, M., Dugas, V., Chevolot, Y., & Souteyrand, E. (2011). Silanization of silica and glass slides for DNA microarrays by impregnation and gas phase protocols: A comparative study. Materials Science and Engineering: C, 31(2), 384-390. doi:10.1016/j.msec.2010.10.016Díaz-Fernández, F. J., Pinilla-Cienfuegos, E., García-Meca, C., Lechago, S., Griol, A., & Martí, J. (2019). Characterisation of on-chip wireless interconnects based on silicon nanoantennas via near-field scanning optical microscopy. IET Optoelectronics, 13(2), 72-76. doi:10.1049/iet-opt.2018.507

Immobilization strategies to functionalize tantalum surfaces with cell-adhesive peptides: physicochemical and biological characterization

Postprint (published version

Cell Models and Their Application for Studying Adipogenic Differentiation in Relation to Obesity: A Review

Over the last several years, the increasing prevalence of obesity has favored an intense study of adipose tissue biology and the precise mechanisms involved in adipocyte differentiation and adipogenesis. Adipocyte commitment and differentiation are complex processes, which can be investigated thanks to the development of diverse in vitro cell models and molecular biology techniques that allow for a better understanding of adipogenesis and adipocyte dysfunction associated with obesity. The aim of the present work was to update the different animal and human cell culture models available for studying the in vitro adipogenic differentiation process related to obesity and its co-morbidities. The main characteristics, new protocols, and applications of the cell models used to study the adipogenesis in the last five years have been extensively revised. Moreover, we depict co-cultures and three-dimensional cultures, given their utility to understand the connections between adipocytes and their surrounding cells in adipose tissue

Evaluación basada en el método del gradiente de las propiedades elásticas de tejidos humanos in vivo

[EN] Nowadays the computational simulation of the mechanical behaviour of human tissues in the medical context is a field which has aroused a great interest in the scientific community. The study of the behaviour of those tissues carries a great difficulty, in part, due to the fact that the behaviour of those tissues is different from one patient to another and, in general, it is no possible to make empirical experiments with the tissue to determine its elastic properties. In order to circumvent this issue, in this work we propose a method to evaluate these properties assuming a Mooney-Rivlin constitutive model. The proposed method is based on the information provided by medical images and two different deformation states of the organ and, by using a gradient-based optimization process we accurately obtain the elastic properties of the constitutive model. The numerical experiments show the validity of the method for the example used.[ES] En la actualidad la simulación numérica del comportamiento mecánico de tejidos humanos en el campo de la medicina es un ámbito de estudio que ha despertado gran interés en la comunidad científica. El estudio del comportamiento de dichos tejidos conlleva una gran dificultad, en parte, atribuida al hecho de que su comportamiento cambia de paciente a paciente y en numerosas ocasiones no es posible realizar experimentos directos sobre el tejido para determinar sus propiedades elásticas. Para tal fin, en el presente trabajo se propone un método para hallar dichas propiedades asumiendo un modelo constitutivo de Mooney-Rivlin. Dicho método se basa en la información proporcionada por imágenes médicas en dos situaciones de deformación del órgano y, mediante un proceso de optimización basado en el gradiente se obtienen, con precisión, las propiedades elásticas del modelo constitutivo. Los experimentos numéricos realizados demuestran la validez del método para el ejemplo utilizado, tras comprobar que las propiedades del modelo constituvo de referencia son obtenidas por el método propuesto.Nadal, E.; Rupérez Moreno, MJ.; Martinez-Sanchis, S.; Monserrat Aranda, C.; Tur Valiente, M.; Fuenmayor Fernández, FJ. (2017). Evaluación basada en el método del gradiente de las propiedades elásticas de tejidos humanos in vivo. Revista UIS Ingenierías. 16(1):15-22. doi:10.18273/revuin.v16n1-2017002S152216

Análisis multidisciplinar de la aplicación de técnicas de evaluación continua formativa

El presente trabajo presenta las actividades realizas para la mejora del proceso de aprendizaje en sesiones de prácticas mediante distintas estrategias de evaluación continua formativa por parte de un grupo de innovación educativa de la Universidad Politécnica de Valencia. Se ha estudiado el uso de cuestionarios temporizados realizados antes y al finalizar la práctica mediante el uso de una plataforma de e-learning así como el uso de rúbricas para la valoración del trabajo del alumno y las memorias de prácticas. La eficacia de las distintas estrategias ha sido establecida a partir de datos cualitativos y cuantitativos recogidos mediante observación durante su aplicación, calificaciones obtenidas y realizando un sondeo de opinión. La aplicación de estas metodologías ha sido llevada a cabo en 10 asignaturas de diferentes áreas de conocimiento (Teoría de la Señal y Comunicaciones, Química, Ingeniería Química y Economía) impartidas en diferentes carreras técnicas, por lo que se obtiene una visión multidisciplinar del efecto de las innovaciones

Eplerenone attenuated cardiac steatosis, apoptosis and diastolic dysfunction in experimental type-II diabetes

Cardiac steatosis and apoptosis are key processes in diabetic cardiomyopathy, but the underlying mechanisms have not been elucidated, leading to a lack of effective therapy. The mineralocorticoid receptor blocker, eplerenone, has demonstrated anti-fibrotic actions in the diabetic heart. However, its effects on the fatty-acid accumulation and apoptotic responses have not been revealed. Methods: Non-hypertensive Zucker Diabetic Fatty (ZDF) rats received eplerenone (25 mg/kg) or vehicle. Zucker Lean (ZL) rats were used as control (n = 10, each group). After 16 weeks, cardiac structure and function was examined, and plasma and hearts were isolated for biochemical and histological approaches. Cultured cardiomyocytes were used for in vitro assays to determine the direct effects of eplerenone on high fatty acid and high glucose exposed cells. Results: In contrast to ZL, ZDF rats exhibited hyperglycemia, hyperlipidemia, insulin-resistance, cardiac steatosis and diastolic dysfunction. The ZDF myocardium also showed increased mitochondrial oxidation and apoptosis. Importantly, eplerenone mitigated these events without altering hyperglycemia. In cultured cardiomyocytes, high-concentrations of palmitate stimulated the fatty-acid uptake (in detriment of glucose assimilation), accumulation of lipid metabolites, mitochondrial dysfunction, and apoptosis. Interestingly, fatty-acid uptake, ceramides formation and apoptosis were also significantly ameliorated by eplerenone. Conclusions: By blocking mineralocorticoid receptors, eplerenone may attenuate cardiac steatosis and apoptosis, and subsequent remodelling and diastolic dysfunction in obese/type-II diabetic ratsThis work was supported by national grants from Ministerio de Educación y Ciencia (SAF2009-08367), Comunidad de Madrid (CCG10-UAM/BIO-5289), FISS (PI10/00072), and a grant from by Pfizer (NY, USA), Spanish Ministry of Economy and Competitiveness (MINECO) CTQ2011-23562. These grants were used to provide consumables and animals required. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. AF received funding from the European Union Seventh Framework Programme [FP7/2007-2013] under grant agreement nº 26486

Relationship between Physical Activity, Oxidative Stress, and Total Plasma Antioxidant Capacity in Spanish Children from the GENOBOX Study

The World Health Organization has recommended performing at least 60 min a day of moderate-to-vigorous physical activity (MVPA) and reducing sedentarism in children and adolescents to offer significant health benefits and mitigate health risks. Physical fitness and sports practice seem to improve oxidative stress (OS) status during childhood. However, to our knowledge, there are no data regarding the influence of objectively-measured physical activity (PA) and sedentarism on OS status in children and adolescents. The present study aimed to evaluate the influence of moderate and vigorous PA and sedentarism on OS and plasma total antioxidant capacity (TAC) in a selected Spanish population of 216 children and adolescents from the GENOBOX study. PA (light, moderate, and vigorous) and sedentarism (i.e., sedentary time (ST)) were measured by accelerometry. A Physical Activity-Sedentarism Score (PASS) was developed integrating moderate and vigorous PA and ST levels. Urinary 8-hydroxy-20-deoxyguanosine (8-OHdG) and isoprostane F2 (F2-IsoPs), as markers of OS, were determined by ELISA; and TAC was estimated by colorimetry using an antioxidant kit. A higher PASS was associated with lower plasma TAC and urinary 8-OHdG and F2-IsoPs, showing a better redox profile. Reduced OS markers (8-OHdG and F2-IsoPs) in children with higher PASS may diminish the need of maintaining high concentrations of antioxidants in plasma during rest to achieve redox homeostasis.Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (I + D + I), Instituto de Salud Carlos III-Health Research Funding (FONDOS FEDER) PI11/02042 PI11/02059 PI11/01425 PI16/00871 PI16/01301 PI16/01205RETIC (Redes temáticas de investigación cooperativa) Red SAMID RD12/0026/0015Instituto de Salud Carlos III European Commission IFI17/00048Research Plan of the Vice-Rectorate of Research and Transfer of the University of Granada, Spai

Friction coefficients and wear rates of different orthodontic archwires in artificial saliva

The aim of this paper is to analyze the influence of the nature of the orthodontic archwires on the friction coefficient and wear rate against materials used commonly as brackets (Ti–6Al–4V and 316L Stainless Steel). The mate- rials selected as orthodontic archwires were ASI304 stainless steel, NiTi, Ti, TiMo and NiTiCu. The array archwire’s materials selected presented very similar roughness but different hardness. Materials were chosen from lower and higher hardness degrees than that of the brackets. Wear tests were carried out at in artificial saliva at 37 C. Results show a linear relationship between the hardness of the materials and the friction coefficients. The material that showed lower wear rate was the ASI304 stainless steel. To prevent wear, the wire and the brackets have high hardness values and in the same order of magnitude.Peer ReviewedPostprint (published version