Search

In the field of tissue engineering (TE), cells are recruited with scaffolds and soluble factors to make artificial tissues. The scaffolds aim to re-create the native extracellular matrix (ECM) for the cells in vitro, regulating various cellular behaviors, such as proliferation, migration, and differentiation. Biomaterials have widely been used as the tissue scaffolds providing multiple functions, such as the substrate for cells, control on the mechanics, morphology, and three-dimensional (3D) structure of tissues, and encapsulation and release of different biomolecules, such as growth factors and drugs. Biomaterials can generally be divided into two categories: natural and synthetic. Major characteristics of natural biomaterials are their biocompatibility, cell-binding affinity, and degradation, while synthetic biomaterials often provide high mechanical properties as well as tunable chemistry and physical structure. This chapter reviews the characteristics and applications of the commonly used biomaterials in the TE field. 2017 WILEY-VCH Verlag GmbH & Co. KGaA. Scopus

In this paper, a Bayesian method for piecewise regression is adapted to handle counting processes data distributed as Poisson. A numerical code in Mathematica is developed and tested analyzing simulated data. The resulting method is valuable for detecting breaking points in the count rate of time series for Poisson processes., 6 pages, 4 figures

Animal models have been the main resources for drug discovery and prediction of drugs’ pharmacokinetic responses in the body. However, noticeable drawbacks associated with animal models include high cost, low reproducibility, low physiological similarity to humans, and ethical problems. Engineered tissue models have recently emerged as an alternative or substitute for animal models in drug discovery and testing and disease modeling. In this review, we focus on skeletal muscle and cardiac muscle tissues by first describing their characterization and physiology. Major fabrication technologies (i.e., electrospinning, bioprinting, dielectrophoresis, textile technology, and microfluidics) to make functional muscle tissues are then described. Finally, currently used muscle tissue models in drug screening are reviewed and discussed

Le but de cet article est de proposer une relecture de la genèse de l’ultramontanisme moderne. L’idée de persécution religieuse et son pessimisme sous-jacent ont longtemps masqué l’impact positif de la période révolutionnaire dans la réaffirmation du pouvoir pontifical et plus généralement dans les dynamiques catholiques au XIXe siècle. L’affermissement de l’autorité papale bénéficia du bouleversement des structures féodales et épiscopales par les révolutions, du charisme acquis par des papes « martyrs » et de l’association d’idées d’une part entre défense de la papauté et défense de l’ordre établi, et d’autre part entre gallicanisme et/ou l’épiscopalisme et Révolution française. Par ailleurs, l’effondrement de l’empire espagnol conduisit l’Église à se penser en termes globaux et, par conséquent, participa à sa “reglobalisation”. The aim of this paper is to propose a reinterpretation of modern ultramontanism’s genesis. The idea of religious persecution and its underlying pessimism have obscured the positive impact of the revolutionary period in the reassertion of papal power and more generally in the dynamic of Catholicism in the 19th century. The strengthening of papal authority benefitted from the overthrow of feudal and episcopal structures, the charisme of martyrdomand the association of ideas between on one hand, defending the papacy and the established order, and the other, between Gallicanism/Episcopalism and the French Revolution. Finally, the collapse of the Spanish Empire led the Church to think in global terms and, therefore, to a process of reglobalisation. Este trabajo se propone ofrecer una nueva lectura de la génesis del ultramontanismo. Partimos de la constatación de que la idea de persecución religiosa, con su pesimismo subyacente, ha ocultado durante largo tiempo el impacto, paradójicamente positivo, que el periodo revolucionario tuvo en la reafirmación del poder pontificio durante el siglo XIX. La consolidación de la autoridad pontificia fue acompañada de la alteración de las estructuras feudales y episcopales durante las revoluciones, de la atribución de cierto carisma a los papas « mártires » y de la asociación de ideas que ligaba, por una parte, la defensa del papado a la defensa del orden establecido y, por la otra, el galicanismo y/o el episcopalismo con la Revolución francesa. Estos procesos fueron concomitantes a otro no menos importante : el derrumbe del imperio español, que condujo a la Iglesia a pensarse a sí misma en términos más globales.

Actualmente la causa principal de las enfermedades en el mundo es la falta de agua potable y de saneamiento. Para afrontar esta situación, se han desarrollado una gran variedad de filtros para potabilizar agua de entre los que destacan los cerámicos. El objetivo de este proyecto ha sido el de analizar y estudiar los diseños existentes, con el fin de simplificar su proceso de fabricación y mejorar su eficiencia. Para ello, por medio de ensayos con prototipos se han estudiado los parámetros más influyentes con el fin de optimizarlos. Como resultado se ha obtenido un diseño en el que ya no es necesario el uso de una prensa para dar forma al filtro manteniendo las especificaciones en cuanto a eficiencia.

L’estudi de les variables que influeixen en la pràctica de l’activitat esportiva de les dones aporta una informació valuo­sa per desenvolupar tàctiques encaminades a incentivar l’esport entre elles. Estudis previs mostren clarament que existeixen diferències de pràctica basada en el gènere, no obstant això fins al moment les recerques sobre activitat física esportiva (AFE) s’han centrat a estudiar els motius de pràctica o no pràctica sense realitzar diferències de gènere. En aquest treball, ens centrem a conèixer el pes que tenen les causes inductores o variables analitzades en la pràctica de l’activitat física de les participants. Per obtenir els nostres resultats es realitza un contrast empíric per analitzar les varia­bles més determinants de la pràctica esportiva. Per realitzar el contrast es va utilitzar l’enquesta d’hàbits esportius del Centre de Recerques Sociològiques amb un total de 8 925 enquestats. L’anàlisi dels resultats mostra que variables com la realització d’activitats esportives pel pare o la mare, la visió de les dones sobre l’esport, les instal·lacions esportives disponibles al barri, la valoració d’instal·lacions esportives com a suficients o no, l’edat, la situació laboral, la cura de familiars i l’ús del temps lliure influeixen en la pràctica de l’activitat esportiva de les dones.

Tissue engineering (TE) aims to restore function or replace damaged tissue through biological principles and engineering. Nanofibers are attractive substrates for tissue regeneration applications because they structurally mimic the native extracellular matrix. Composite nanofibers, which are hybrid nanofibers blended from natural and synthetic polymers, represent a major advancement in TE and regenerative medicine, since they take advantage of the physical properties of the synthetic polymer and the bioactivity of the natural polymer while minimizing the disadvantages of both. Although various nanofibrous matrices have been applied to almost all the areas of TE, in this chapter we will focus on nanofiber composites scaffolds for vascular TE.

La caracterización mecánica de vigas de madera es un requerimiento práctico para el constructor. Debido a la diversidad en las propiedades tecnológicas de la madera, es necesario relativizar los parámetros de ingeniería mediante indicadores de calidad, indicadores que tienen por objeto estandarizar los valores particulares determinados experimentalmente. El objetivo de la investigación fue valorizar la madera de la especie Enterolobium cyclocarpum y mejorar su apreciación como material de ingeniería. Se determinaron el módulo de elasticidad, el factor de calidad y el índice material, derivados de pruebas de vibraciones transversales en vigas. La frecuencia natural, el módulo de elasticidad y sus indicadores de calidad fueron propios al grupo de vigas estudiadas y a la configuración de las pruebas realizadas. Los módulos de elasticidad son comparables con los descritos para vigas de madera recomendados para su uso estructural. La densidad de la madera de E. cyclocarpum es la característica que predice el módulo de elasticidad y sirve como referencia para el cálculo de los indicadores factor de calidad e índice de calidad de vigas de esta especie.

The aim of this paper is to analyze how prophecy and Apocalypse were used to interpret the events of the tumultuous period of 1793-1825. To that end, I have worked mainly with prophetic books and press. By putting in dialogue these sources with the events they interpreted, I have sought to recover the historicity of these documents to analyze the new ways they are expressed and to stress the significance of these documents to understand how political and cultural changes were perceived. To address these issues, the article focuses on four aspects showing the evolution of prophetic speeches in this period: the apocalyptic discourses about Napoleon, the prophecies looking for the restoration of the Old Regime, the anti-liberal prophecies and, finally, the dangers of prophecies for the Church. In this paper I have showed that the prophetic framework was part of the anti-liberal catholic political culture. The prophecy not only interpreted political events but also to fight the political enemy. El objetivo de este artículo es analizar cómo se recurrió al universo profético apocalíptico para interpretar los acontecimientos del convulso período 1793-1825. Para ello, se han trabajado fundamentalmente obras de inspiración profética y prensa de la época. Al poner en diálogo estas fuentes con los acontecimientos que interpretaban hemos buscado recuperar la historicidad de estos documentos, observar las nuevas formas y medios con los que se expresa el discurso profético y destacar su importancia para comprender cómo fueron percibidos los cambios políticos y culturales. Para abordar estas cuestiones, el artículo se centra en cuatro aspectos que ponen de relieve la evolución del discurso profético en el período analizado: los discursos apocalípticos en torno a Napoleón, las profecías sobre la restauración del orden, las profecías antiliberales y, finalmente, los peligros que planteaban las profecías para la Iglesia. En este artículo hemos podido ver cómo el marco profético formó parte de la cultura política católica de inspiración anti-liberal. La profecía no sólo sirvió para interpretar los acontecimientos políticos sino para combatir al enemigo político.

Objective: To present and evaluate simple, cost-effective tests to determine the amount of insecticide on treated materials. Methods: We developed and evaluated a competitive immunoassay on two different platforms: a label-free impedimetric biosensor (EIS biosensor) and a lateral flow. Both approaches were validated by gas chromatography (GC) and ELISA, gold standards for analytical methods and immunoassays, respectively. Finally, commercially available pyrethroid-treated ITN samples were analysed. Different extraction methods were evaluated. Results: Insecticide extraction by direct infusion of the ITN samples with dichloromethane and dioxane showed recovery efficiencies around 100% for insecticide-coated bednets, and >70% for insecticide-incorporated bednets. These results were comparable to those obtained with standard sonication methods. The competitive immunoassay characterisation with ELISA presented a dynamic range between 12 nm and 1.5 μm (coefficient of variation (CV) below 5%), with an IC50 at 138 nm, and a limit of detection (LOD) of 3.2 nm. EIS biosensor had a linear range between 1.7 nm and 61 nm (CV around 14%), with an IC50 at 10.4 nm, and a LOD of 0.6 nm. Finally, the lateral flow approach showed a dynamic range between 150 nm and 1.5 μm, an IC50 at 505 nm and a LOD of 67 nm. Conclusions: ELISA can replace chromatography as an accurate laboratory technique to determine insecticide concentration in bednets. The lateral flow approach developed can be used to estimate ITN insecticide concentration in the field. This new technology, coupled to the new extraction methods, should provide reliable guidelines for ITN use and replacement in the field. © 2016 John Wiley & Sons Ltd, Project funded by the CERCA Institutes Integration Program (SUMA 2013) [promoted and managed by the Secretariat for Universities and Research of the Ministry Economy and Knowledge of the Government of Catalonia (SUR), the Agency for Management of University and Research Grants (AGAUR) and the CERCA Institute]. The research performed has also count with the support of the EC-FP7 SEA-ON A CHIP project (FP7-OCEAN-2013-1-614168). The Nb4D group is a consolidated research group (Grup de Recerca) of the Generalitat de Catalunya and has support from the Departament d'Universitats, Recerca i Societat de la Informaci? de la Generalitat de Catalunya (expedient: 2014 SGR 1484). CIBER-BBN is an initiative funded by the Spanish National Plan for Scientific and Technical Research and Innovation 2013?2016, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. The authors would like to thank Professor Bruce Hammock and Shirley Gee, from the Department of Entomology of University of California Davis, for providing the immunoreagents for deltamethrin detection used in this study. Interceptor and LifeNet bednets were kindly provided by BASF and BAYER, respectively.

Nanofiber composite materials play an important role in tissue engineering (TE) and regenerative medicine, mimicking the structure and properties of the extracellular matrix at nanoscale. They serve as scaffolds for cells, as carriers for various biomolecules (e.g., drugs, genes, and soluble factors), and as injectable biomaterials in TE and regenerative medicine. Clinical and preclinical studies of nanofiber composite materials have recently emerged to further develop therapeutic applications of these materials. Topics of these studies range from tissue regeneration and wound healing to biosensing and monitoring, demonstrating the great promise of nanofiber composites for a wide variety of clinical applications. This book chapter describes the characteristics and applications of nanofiber composite materials in clinical and preclinical studies. Results of relevant research are highlighted and potential research directions are discussed.

The anisotropy feature of wood confers versatility for designing products and wood structu­res. The objective of this research was to determine the modulus of elasticity and strength by compression on the radial, tangential and longitudinal directions, for P . Michoacana , P . pringlei and P . douglasiana wood. Compression tests were performed on 39 specimens and wood moisture content and basic density were calculated. For each of the species studied, the results of an analysis of variance between radial, tangential and longitudinal directions of modulus of elasticity and strength by compression, suggest a significant difference between the mean values of the three variables grouped into elastic and strength parameters. These results confirm that the elastic and mechanical properties of wood vary according to the di­rection in which they are measured, verifying the anisotropy feature of the material.

Stem cells are a key element in tissue engineering and regenerative medicine. However, they require a suitable microenvironment to grow and regenerate. Carbon nanotubes (CNTs) have attracted much attention as promising materials for stem cell research due to their extraordinary properties, such as their extracellular matrix-like structure, high mechanical strength, optical properties, and high electrical conductivity. Of particular interest is the use of CNTs as biomimetic substrates to control the differentiation of stem cells. CNTs have also been combined with commonly used scaffolds to fabricate functional scaffolds to direct stem cell fate. CNTs can also be used for stem cell labeling due to their high optical absorbance in the near-infrared regime. In this paper, we review and discuss the applications of CNTs in stem cell research along with CNT toxicity issues.

We propose a novel application of dielectrophoresis (DEP) to make three-dimensional (3D) methacrylated gelatin (GelMA) hydrogels with gradients of micro- and nanoparticles. DEP forces were able to manipulate micro- and nanoparticles of different sizes and materials (i.e., C2C12 myoblasts, polystyrene beads, gold microparticles, and carbon nanotubes) within GelMA hydrogels in a rapid and facile way and create 3D gradients of these particles in a microchamber. Immobilization of drugs, such as fluorescein isothiocyanate-dextran (FITC-dextran) and 6-hydroxydopamine (6-OHDA), on gold microparticles allowed us to investigate the high-throughput release of these drugs from GelMA-gold microparticle gradient systems. The latter gradient constructs were incubated with C2C12 myoblasts for 24h to examine the cell viability through the release of 6-OHDA. The drug was released from the microparticles in a gradient manner, inducing a cell viability gradient. This novel approach to create 3D chemical gradients within hydrogels is scalable to any arbitrary length scale. It is useful for making anisotropic biomimetic materials and high-throughput platforms to investigate cell-microenvironment interactions in a rapid, simple, cost-effective, and reproducible manner.

Dielectrophoresis (DEP) approach was employed to achieve highly aligned multi-walled carbon nanotubes (MWCNTs) within the gelatin methacrylate (GelMA) hydrogels in a facile, rapid, inexpensive, and reproducible manner. This approach enabled us to make different CNTs alignments (e.g., vertical or horizontal alignments) within the GelMA hydrogel using different electrode designs or configurations. Anisotropically aligned GelMA-CNTs hydrogels showed considerably higher conductivity compared to randomly distributed CNTs dispersed in the GelMA hydrogel and the pristine and non-conductive GelMA hydrogel. Adding 0.3 mg/mL CNTs to the GelMA hydrogel led to a slight increase in the mechanical properties of the GelMA and made it to behave as a viscoelastic material. Therefore, it can be used as a suitable scaffold for soft tissues, such as skeletal muscle tissue. 3D microarrays of skeletal muscle myofibers were then fabricated based on the GelMA and GelMA-CNTs hydrogels and they were characterized in terms of gene expressions related to the muscle cell differentiation and contraction. Owing to high electrical conductivity of aligned GelMA-CNTs hydrogels, the engineered muscle tissues cultivated on these materials demonstrated superior maturation and functionality particularly after applying the electrical stimulation (voltage 8 V, frequency 1 Hz, and duration 10 ms for 2 days) compared to the corresponding tissues obtained on the pristine GelMA and randomly distributed CNTs within the GelMA hydrogel.

Tissue engineering (TE) is a multidisciplinary research area that combines medicine, biology, and material science. In recent decades, microtechnology and nanotechnology have also been gradually integrated into this field and have become essential components of TE research. Tissues and complex organs in the body depend on a branched blood vessel system. One of the main objectives for TE researchers is to replicate this vessel system and obtain functional vascularized structures within engineered tissues or organs. With the help of new nanotechnology and microtechnology, significant progress has been made. Achievements include the design of nanoscale-level scaffolds with new functionalities, development of integrated and rapid nanotechnology methods for biofabrication of vascular tissues, discovery of new composite materials to direct differentiation of stem and inducible pluripotent stem cells into the vascular phenotype. Although numerous challenges to replicating vascularized tissue for clinical uses remain, the combination of these new advances has yielded new tools for producing functional vascular tissues in the near future.

In this manuscript, we demonstrate the rapid formation of three-dimensional (3D) embryonic stem cell (ESC) aggregates with controllable sizes and shapes in hydrogels using dielectrophoresis (DEP). The ESCs encapsulated within a methacrylated gelatin (GelMA) prepolymer were introduced into a DEP device and, upon applying an electric field and crosslinking of the GelMA hydrogel, formed 3D ESC aggregates. Embryoid bodies (EBs) fabricated using this method showed high cellular viability and pluripotency. The proposed technique enables production of EBs on a large scale and in a high-throughput manner for potential cell therapy and tissue regeneration applications.

Five historical full-size wood structural beams of Picea abies were tested with ultrasound. The speed of ultrasound, the modulus of elasticity, the moisture content and the wood density were measured for each specimen. The speed of the ultrasound waves in the radial, tangential and longitudinal directions was 1,769 m/s, 1,599 and 5,713 m/s respectively. The modulus of elasticity in the radial, tangential and longitudinal directions was 1,353 MPa, 1,069 MPa and 13,863 MPa respectively. The moisture content was on average 11.92% and the density was on average 422 kg/m3. Wood parameters such as density and orthotropic directions had influence in ultrasound measurements. In spite of local weakness in the beams, they had enough strength to be considered full structural members.

La madera laminada es la tendencia en ingenieria de la madera para sustituir a la madera solida. El conocimiento de su reaccion al fuego tiene aplicacion en el diseno arquitectural y en el calculo para edificar con madera. El objetivo de la investigacion fue determinar la disminucion de la resistencia mecanica de la madera laminada ocasionada por su exposicion al fuego. Se fabricaron piezas de madera laminada de Pinus pseudostrobus y se desarrollo un protocolo de laboratorio especifico para medir la disminucion de la masa por el fuego, asi como para estimar la variacion de los modulos de elasticidad estatico y de ruptura determinados en pruebas de flexion estatica. Se calcularon la densidad y el contenido de humedad de la madera. Para fines del diseno experimental, el factor de variacion fue el tiempo de exposicion al fuego. Las variables estudiadas fueron: la perdida de masa, el modulo de elasticidad y el modulo de ruptura. Los parametros determinados correlacionan estadisticamente de manera importante con el tiempo durante el periodo medido. Los resultados mostraron que la perdida de masa aumento con la exposicion al fuego. En contraste, los modulos de elasticidad y de ruptura de la madera disminuyeron a medida que el tiempo aumento.

Fil: Ferragut, Javier Ramón Antonio. Universidad Nacional de Misiones. Facultad de Humanidades y Ciencias Sociales. Programa de Posgrado en Antropología Social; Argentina. La tesis reseñada posee, ante todo, una originalidad empírica: revela la presencia histórica de las mujeres en la cosecha de yerba mate en Misiones y la mutación de la que ha sido objeto la percepción de su trabajo a lo largo de la historia.

The design of products and wooden structures requires information concerning the effect of protective substances on the mechanical properties of wood. The goal of the research was to impregnate Guazuma ulmifolia, Spathodea campanulata and Abies religiosa with boron salts and to assess the effect of the retention of the salts on the density, speed of stress waves, and dynamic modulus of elasticity. A boron salt solution was prepared and a hot-cold bath method of impregnation was applied. Wood density, speed of stress waves and modulus of elasticity were assessed for standard specimens before and after treatment. Each of the woods: G. ulmifolia, S. campanulata and A. religiosa retains a different quantity of boron salts and they all retained a larger quantity of the salts than the amount recommended by international standards. The retention of boron salts did not significantly affect the physical and mechanical characteristics of the G. ulmifolia wood. In contrast, the retention of the salts affected the wood density, speed of the stress wave, and dynamic modulus of elasticity of S. campanulata and A. religiosa woods

Memoria ID-0202. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2015-2016.

Ramon Solans analyzes the Spanish reception of Lourdes and the role it played in the creation of a mass devotional model. Focusing on the modernization of the Shrine of the Virgin of el Pilar, the chapter also draws attention to the first mass demonstrations in the Shrine of el Pilar within the context of a culture war in Spain. Apart from analyzing the role the Virgin played in the struggle against secularization, the author explores the project to transform her shrine into a center for miraculous cures. “A New Lourdes in Spain” concludes with a reflection on the horizontal Romanization of the Catholic Church.

La velocidad del ultrasonido en la madera y el módulo de elasticidad, siguen un patrón anisotrópico, que se infiere mediante un modelo teórico. El objetivo de la investigación fue determinar la variación de la velocidad del ultrasonido y del módulo de elasticidad en el plano longitudinal-tangencial en la madera de Thuja plicata y Acer saccharum. Se estudiaron 32 probetas de cada especie diseñadas específicamente para la investigación. Se calcularon la velocidad del ultrasonido y el módulo de elasticidad en diez posiciones en el plano longitudinal-tangencial. Los resultados experimentales se contrastaron con las previsiones del modelo de anisotropía propuesto. Para la madera de T. plicata y A. saccharum, las velocidades de ultrasonido fueron para la dirección longitudinal 5610 m/s y 5935 m/s y para la dirección tangencial 1198 m/s y 1372 m/s. Los módulos de elasticidad en la dirección longitudinal fueron 11126 MPa y 24688 MPa y para la dirección tangencial 530 MPa y 1320 MPa. The ultrasound speed and the modulus of elasticity of the wood material follow an anisotropic behavior predicted by a theoretical model. The goal of the research was to determine the variation of the ultrasound speed and the modulus of elasticity over the longitudinal-tangential plane of Thuja plicata and Acer saccharum wood. For each species, 32 wood specimens were tested. The ultrasound speed and the modulus of elasticity were calculated in ten positions over the longitudinal-tangential plane. Experimental results were contrasted with the predictions of the proposed anisotropy model. For the T. plicata and A. saccharum woods, the ultrasound speeds were, for the longitudinal direction 5610 m/s and 5935 m/s, and for the tangential direction 1198 m/s y 1372 m/s. The moduli of elasticity were, for the longitudinal direction 11126 MPa and 24688 MPa, and for the tangential direction 530 MPa and 1320 MPa.

En este trabajo se analiza la posibilidad de confeccionar una nueva versión digital del catálogo Córdoba Durchmusterung. Para estimar la misma, se aborda una zona del cielo que comprende alrededor de 18000 estrellas de este catálogo. Se parte de la actual versión digital, disponible en la base de datos VizieR como catálogo I/114, y se corrigen errores de transcripción. Esto se logra generando automáticamente una lista de registros con posibles errores y luego, manualmente, se comparan estos registros del catálogo digital con la versión impresa del mismo. Además, se incorpora información existente en la versión impresa que actualmente no está en la versión digital. Finalmente, se propone un algoritmo que realiza una identificación cruzada entre este catálogo y uno moderno (Positions and Proper Motions eXtended). La particularidad de este algoritmo respecto a los presentes en la literatura es que permite crear referencias cruzadas de estrellas dobles adecuadamente. Fil: Severin, Daniel Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura. Escuela de Ciencias Básicas; Argentina Fil: Sevilla, Diego Javier Ramón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura. Escuela de Ciencias Básicas; Argentina

In this work, we designed a new immunodevice that combines competitive immunoreactions on the microparticles, accumulation of these particles by negative dielectrophoresis (n-DEP), and their subsequent capture through hybridization among single-stranded DNAs (ssDNAs). Two widely used pesticides, atrazine and bromopropylate, were used as target molecules to test the resulting simultaneous detection system. For sensing, we prepared two different sets of microparticles: one modified with atrazine-conjugated bovine serum albumin (BSA-2d) and ssDNA-J1(up) and the other with bromopropylate-conjugated aminodextran (AD-155) and ssDNA-J2(up). The microparticles were incubated in a mixture of analyte-specific antibody and analyte at different concentrations to trap the unreacted antibodies prior to being labeled with antibodies conjugated with a fluorescence molecule. A suspension containing both types of microparticles was introduced into an n-DEP device consisting of an interdigitated microarray (IDA) electrode and channel modified with ssDNA-J1(down) and ssDNA-J2(down), which are complementary to ssDNA-J1(up) and ssDNA-J2(up), respectively. The n-DEP force generated by applying AC voltage to the IDA electrode displaced the microparticles toward the encoded areas, causing them to rapidly accumulate on the upper surfaces. Hybridization allowed us to distinguish the microparticles and sense multiple analytes by spatial recognition in the DNA-encoded areas. The fluorescence intensity of the captured particles, which depends on analyte concentrations, was measured selectively by focusing on specific areas. The strategy is advantageous for sensitivity due to the equivalent trapping efficiency by DNA hybridization and large surface area of the microparticle for immunoreactions. The rapidity and simplicity were still supported by particle manipulation. Using this concept, we detect atrazine and bromopropylate simultaneously with limits of detection (LODs) of 0.2 μg·L(-1), which covered the maximum residue level (MRL) in food samples established the European Union (EU) and Japan Ministry of Health, Labor and Welfare (MHLW).

New biocompatible materials have enabled the direct 3D printing of complex functional living tissues, such as skeletal and cardiac muscle. Gelatinmethacryloyl (GelMA) is a photopolymerizable hydrogel composed of natural gelatin functionalized with methacrylic anhydride. However, it is difficult to obtain a single hydrogel that meets all the desirable properties for tissue engineering. In particular, GelMA hydrogels lack versatility in their mechanical properties and lasting 3D structures. In this work, a library of composite biomaterials to obtain versatile, lasting, and mechanically tunable scaffolds are presented. Two polysaccharides, alginate and carboxymethyl cellulose chemically functionalized with methacrylic anhydride, and a synthetic material, such as poly(ethylene glycol) diacrylate are combined with GelMA to obtain photopolymerizable hydrogel blends. Physical properties of the obtained composite hydrogels are screened and optimized for the growth and development of skeletal muscle fibers from C2C12 murine cells, and compared with pristine GelMA. All these composites show high resistance to degradation maintaining the 3D structure with high fidelity over several weeks. Altogether, in this study a library of biocompatible novel and totally versatile composite biomaterials are developed and characterized, with tunable mechanical properties that give structure and support myotube formation and alignment.

In this work, we have applied particle manipulation based on negative dielectrophoresis (n-DEP) to develop rapid and separation-free immunosensing systems. Two widely used pesticides, atrazine and bromopropylate, were used as target molecules to demonstrate competitive immunosensing based on the rapid manipulation of microparticles. A suspension of the fluorescence microparticles modified with a specific antibody was injected into the n-DEP device consisting of the interdigitated microarray (IDA) electrode and indium-tin-oxide (ITO) substrate immobilized by protein conjugation with antigen. The application of 2 MHz AC voltage (16 V peak-to-peak) to the IDA forced most of the particles to form a line pattern on the upper ITO over the gaps of IDA within 60s. In the absence of analytes, patterned microparticles were irreversibly captured on the ITO by the construction of immuno-complexes. When the microparticles bearing anti-atrazine IgG antibody were suspended in an analyte (atrazine) solution, irreversible capturing of microparticles on the ITO was inhibited because of the occupation of the binding sites of the antibodies with free-atrazine. As a result, the analyte molecules were re-dispersed from the ITO to disintegrate the line formation after turning off the voltage. We could discriminatively detect the fluorescence intensity of the captured microparticles at the designated areas from that of the uncaptured microparticles suspended in the solution. Thus, the separation steps usually required for conventional immunoassay are eliminated in the present procedure. A pre-incubation of microparticles for 3 min in an orange juice solution containing analyte allowed for the determination of the atrazine and bromopropylate concentrations with a limit of detection of 4 and 1.5 microg L(-1), respectively, providing sufficient detectability to achieve international regulations regarding pesticide residues in food samples. The assay was significantly accelerated by the rapid particle manipulation with n-DEP and totally accomplished within 5 min. We also demonstrated the possibility of the simultaneous determination of two pesticide residues by using the DEP devices with two channels modified with specific competitors for atrazine and bromopropylate.

This paper reports for the first time the development of an immunoassay for the analysis of the miticide bromopropylate (BP). The chemical structure of the immunizing haptens was designed to maximize the recognition of the bis-bromophenyl group of BP. Thus, the assay uses polyclonal antibodies raised against 2,2-bis(4-bromophenyl)-N-2-hydroxyacetamide-butanoic acid (hapten 2) conjugated to keyhole limpet hemocyanin from horseshoe crab. A heterologous indirect competitive enzyme-linked immunosorbent assay (ELISA) has been developed that can detect BP down to 0.14 microg L(-1). The assay has been proven to tolerate a wide range of ionic strengths and pH values. Studies on the selectivity of this immunoassay have demonstrated a high recognition of related pesticides that contain a bis-halophenyl group in their structure. Other pesticides do not interfere in the analysis of BP using this immunochemical technique. Preliminary experiments have shown that BP can be directly analyzed in white wine samples down to 0.16 microg L(-1) without the necessity of a cleanup procedure prior to the ELISA.

A novel design of an interdigitated electrode array impedimetric sensor is proposed with electrode digits separated by an insulating barrier. This configuration results in that the major part of the electric current between electrodes follows close to the surface of the barrier and not through the solution thus permitting to enhance the sensitivity to possible chemical reactions on its surface. As a model system the effect of electrostatically assembled polyelectrolyte layers deposited using layer-by-layer method on the sensor impedance was studied. The sensitivity of the devices depends on the barrier height and is considerably enhanced comparing to conventional flat sensor structures. Devices may be used as a transducer for direct label-free biosensor development. Keywords: Iterdigitated electrode array, Impedance, Sensor, Layer-by-layer, Biosensor

A novel conductimetric immunosensor for atrazine detection has been designed and developed. This immunosensor is mainly based on antibodies labelled with gold nanoparticles. Additionally, the immunosensor consists of an array of two coplanar non-passivated interdigitated metallic μ-electrodes (IDμE) and immunoreagents specifically developed to detect this pesticide. The chemical recognition layer was covalent immobilized on the interdigital space. Immunochemical detection of the concentration of atrazine is achieved by a competitive reaction that occurs before the inclusion of the labelled antibodies. It is shown that the gold nanoparticles provide an amplification of the conductive signal and hence makes possible to detect atrazine by means of simple DC measurements. The conductimetric immunosensor and its biofunctionalization steps have been characterized by chemical affinity methods and impedance spectroscopy. This work describes the immunosensor structure, fabrication, physico-chemical and analytical characterization, and the immunosensor response using conductivity measurements. The immunosensor developed detects atrazine with limits of detection in the order of 0.1–1 μg L−1, far below the maximum residue level (MRL) (100 μg L−1) established by European Union (EU) for residues of this herbicide in the wine. Although in this paper the competitive reaction occurs in buffer, an initial study of the wine matrix effect is also described.

A novel impedimetric immunosensor for atrazine detection, a widely used pesticide, is described. It is based on a two coplanar non-passivated interdigitated metallic μ-electrodes (IDμE) and the differential measurement of the impedance frequency spectrum. No redox electrodes have been included in the sensor. The chemical recognition layer was deposited on top of the interdigitated μ-electrodes area (fingers and inter-digits space). Immunochemical detection of the atrazine concentration is achieved by a competitive reaction without using any label. Furthermore immunoreagents specifically developed to detect this pesticide have been used. The immunosensor and its functionalization steps have been characterized by means of chemical affinity methods and impedance spectroscopy. This work describes immunosensor development and its physico-chemical and analytical characterization. The immunosensor shows a limit of detection of 8.34 ± 1.37 μg L −1 , which is lower than the Maximum Residue Level (MRL) (100 μg L −1 ) established by EU (European Union) for residues of atrazine as herbicide in the wine grapes and other foodstuff products.

Gradient biomaterials have been developed and employed as an important tool in tissue engineering and biology research since the discovery that tissues and organs are non-homogeneous, exhibiting natural functional gradients in their structure or composition. Gradient biomaterials consist of relatively gradual continuous transitions in either compositional or mechanical properties. They have been used to study cellular responses such as cell adhesion, migration, proliferation, and differentiation, and may also be useful tools in drug discovery and development. Gradients made of hydrogels and nanofibers are widely used scaffolds in tissue engineering, which have aroused great interest owing to their tunable properties and analogy to the microenvironment of native tissues. In this chapter, we classify gradient biomaterials into two main cohorts, physical and chemical/biological gradients, and describe their features and applications, particularly as tooth or bone tissue scaffolds.