Advances in laser ablation synthesized silicon-based nanomaterials for the treatment of bacterial infection.

Nanomaterials have unique properties and characteristics derived from their shape and small size that are not present in bulk materials. If size and shape are decisive, the synthesis method used, which determines the above parameters, is equally important. Among the different nanomaterial’s synthesis methods, we can find chemical methods (microemulsion, sol-gel, hydrothermal treatments, etc.), physical methods (evaporation-condensation, laser treatment, etc.) and biosynthesis. Among all of them, the use of laser ablation that allows obtaining non-toxic nanomaterials (absence of foreign compounds) with a controlled 3D size, has emerged in recent years as a simple and versatile alternative for the synthesis of a wide variety of nanomaterials with numerous applications. This manuscript reviews the latest advances in the use of laser ablation for the synthesis of silicon-based nanomaterials, highlighting its usefulness in the prevention of bacterial infection

Nanomateriales de sílice mesoestructurada: aplicación en infección y cáncer

La nanomedicina es una disciplina científica que ha experimentado un gran apogeo en los últimos años, lo que ha permitido mejorar la calidad y la expectativa de vida en la sociedad contemporánea. Gracias a ella se han desarrollado nuevos nanomateriales, agentes terapéuticos y técnicas innovadoras para el diagnóstico, la prevención y el tratamiento de diversas enfermedades. Todo ello a partir de la comprensión de las bases moleculares de las distintas patologías, como enfermedades infecciosas, inmunes, neurodegenerativas, cáncer, etc. La presente Tesis Doctoral se ha centrado en el desarrollo de biomateriales inteligentes para la prevención y/o el tratamiento de dos patologías diferentes, la infección bacteriana ósea y el cáncer, ambas de gran prevalencia e impacto sanitario y económico en la sociedad actual. Como punto de partida se han seleccionado los Nanomateriales de Sílice Mesoestructurada (NSM) por sus excelentes cualidades y su gran versatilidad, y se han diseñado y desarrollado estrategias innovadoras para dotar a estos sistemas de la funcionalidad adecuada dependiendo de los requisitos necesarios para tratar cada patología. Lao-Tsé, un antiguo filósofo chino considerado el fundador del taoísmo, dijo “Lo que le da su valor a una taza de barro es el espacio vacío que hay entre sus paredes”. Este proverbio refleja perfectamente la esencia de los NSM cuya principal característica es el elevado volumen de poro y el gran área superficial que presentan entre sus paredes de sílice amorfa. Sin embargo no es esta su única cualidad, ya que poseen una mesoestructura con tamaños de poro modificables, una estrecha distribución de tamaños de poro, una arquitectura porosa sistemáticamente controlable, y una superficie fácilmente funcionalizable; cualidades que convierten a estos nanomateriales en candidatos idóneos para la administración controlada de fármacos..

Smart Mesoporous Nanomaterials for Antitumor Therapy

The use of nanomaterials for the treatment of solid tumours is receiving increasing attention by the scientific community. Among them, mesoporous silica nanoparticles (MSNs) exhibit unique features that make them suitable nanocarriers to host, transport and protect drug molecules until the target is reached. It is possible to incorporate different targeting ligands to the outermost surface of MSNs to selectively drive the drugs to the tumour tissues. To prevent the premature release of the cargo entrapped in the mesopores, it is feasible to cap the pore entrances using stimuli-responsive nanogates. Therefore, upon exposure to internal (pH, enzymes, glutathione, etc.) or external (temperature, light, magnetic field, etc.) stimuli, the pore opening takes place and the release of the entrapped cargo occurs. These smart MSNs are capable of selectively reaching and accumulating at the target tissue and releasing the entrapped drug in a specific and controlled fashion, constituting a promising alternative to conventional chemotherapy, which is typically associated with undesired side effects. In this review, we overview the recent advances reported by the scientific community in developing MSNs for antitumor therapy. We highlight the possibility to design multifunctional nanosystems using different therapeutic approaches aimed at increasing the efficacy of the antitumor treatment

Didactic unit on the chemical changes involved in the greenhouse effect

En este trabajo se proponen actividades secuenciadas como parte de una unidad didáctica sobre la enseñanza de los cambios químicos que intervienen en el efecto invernadero para abordar el aprendizaje de la Química con sentido y desarrollar, no solo la comprensión de los contenidos científicos, sino también cómo se construyen. En concreto, se ha diseñado con la intención de promover objetivos competenciales relacionados con los fundamentos de la disciplina que permitan dar respuesta a las cuestiones estructurantes surgidas del contexto implicado. La unidad didáctica integra actividades centradas en el alumnado, como investigaciones en las que se recogen e interpretan datos para el establecimiento de conclusiones, tareas de argumentación o el aprendizaje basado en juegos. Una prueba inicial con alumnado de 2º de ESO ha permitido establecer su idoneidad para este nivel educativo, resultando un recurso relevante y motivador para la introducción de los contenidos seleccionados.This article reports on a didactic unit of sequenced activities on the chemical changes involved in the greenhouse effect. The purpose of the unit is to make chemistry learning meaningful for students and develop not only their understanding of the scientific content itself but also how the information is obtained. The activities are designed to equip students with competencies related to the fundamental principles of chemistry which will enable them to respond to structural questions arising from the context of study. The activities in the unit are student-focused and include research (data collection and interpretation and formulation of conclusions), argumentation and game-based learning. An initial trial with second-year students showed the activities to be a suitable, relevant and motivating resource for introducing content of this type at this level

Selective topotecan delivery to cancer cells by targeted pH-sensitive mesoporous silica nanoparticles

Topotecan (TOP), a water-soluble derivative of camptothecin, is a potent antitumor agent that is receiving growing attention for the treatment of several types of cancer. However, one of the major constraints in the clinical use of this drug is its inactivation at the physiological pH of 7.4. Mesoporous silica nanoparticles (MSNs) constitute promising nanocarriers to circumvent this issue. Herein TOP has been encapsulated into MSNs and the nanosystem has been provided with selectivity towards tumor cells, which permits releasing the active form of the molecule at the acidic cell compartments (endo/lysosomes; pH <= 5.5) following nanoparticle internalization. For this purpose, MSNs have been coated with a multifunctional gelatin shell that: (i) protects TOP from hydrolysis and prevents its premature release; (ii) acts as a pH-sensitive layer; and (iii) provides multiple anchoring points for the grafting of targeting ligands, such as folic acid (FA), for selective internalization in tumor cells. In vitro tests demonstrate that cancer cells that overexpress membrane cell surface markers with affinity towards FA, internalize a higher percentage of nanoparticles than healthy cells, which do not overexpress such markers. Moreover, the nanosystems are efficient at killing tumor cells, whereas they do not decrease the viability of normal cells. In contrast, free TOP failed to kill both cell lines, which can be ascribed to the inactivation of the drug. This novel nanodevice constitutes a step forward toward the design of novel weapons to fight against cancer

Mesoporous silica nanoparticles grafted with a light-responsive protein shell for highly cytotoxic antitumoral therapy

A novel phototriggered drug delivery nanocarrier, which exhibits very high tumor cytotoxicity against human tumoral cells, is presented. This device is based on mesoporous silica nanoparticles decorated with a biocompatible protein shell cleavable by light irradiation. The proteins that compose the protein shell (avidin, streptavidin and biotinylated transferrin) act as targeting and capping agents at the same time, avoiding the use of redundant systems. The light responsive behavior is provided by a biotinylated photocleavable cross-linker covalently grafted on the mesoporous surface, which suffers photocleavage by UV radiation (366 nm). Human tumoral cells incubated in the presence of a very low particle concentration enter into the apoptotic stage after a short irradiation time. Thus, the system described here could be applied to the treatment of exposed tumors that affect the skin, oesophagus, and stomach, among others, and are easily accessible for light irradiation

High resolution transmission electron microscopy: A key tool to understand drug release from mesoporous matrices

This work demonstrates that high resolution transmission electron microscopy (HRTEM) is an essential tool to understand drug delivery performance of mesoporous silica materials, mainly those submitted to functionalization processes involving harsh conditions that may affect the mesostructure. Herein an SBA-15-type mesoporous material bearing Si(CH2)(2)P(O)(OCH2CH3)(2) groups was synthesized following the co-condensation route. Then, the resulting material was treated with 37 wt% HCl to convert ethylphosphonate groups to ethylphosphonic acid groups. The proper dealkylation of ethoxy groups following acid treatment was confirmed by FTIR and CP-MAS H-1 -> C-13 solid state NMR, which indicated the presence of Si(CH2)(2)P(O)(OH)(2) functionalities in the treated sample. Characterization of mesoporous materials by XRD diffraction and N-2 adsorption points to well-ordered SBA-15 structures in both untreated and acid-treated samples. Nonetheless, a deep study by HRTEM reveals that the acid-treatment provokes noticeable loss of mesostructural order, only remaining small crystalline domains. This structural damage does not influence cargo loading but it severely affects the release of molecules confined into the mesopores, as concluded from in vitro delivery tests using cephalexin as model drug. Thus, whereas untreated sample showed a sustained diffusion-controlled drug release during more than 2 weeks, 100% of the loaded drug was released only after 10 h from treated sample. This abrupt burst effect cannot be explained on the basis of the existing matrix-drug interactions, whose nature and extension is quite similar under the release conditions for both samples. Thus, it can be only understood on the basis of the mesostructural damage revealed by HRTEM studies. (C) 2016 Elsevier Inc. All rights reserved

Mesoporous Silica Materials as Drug Delivery: “The Nightmare” of Bacterial Infection

Mesoporous silica materials (MSM) have a great surface area and a high pore volume, meaning that they consequently have a large loading capacity, and have been demonstrated to be unique candidates for the treatment of different pathologies, including bacterial infection. In this text, we review the multiple ways of action in which MSM can be used to fight bacterial infection, including early detection, drug release, targeting bacteria or biofilm, antifouling surfaces, and adjuvant capacity. This review focus mainly on those that act as a drug delivery system, and therefore that have an essential characteristic, which is their great loading capacity. Since MSM have advantages in all stages of combatting bacterial infection; its prevention, detection and finally in its treatment, we can venture to talk about them as the “nightmare of bacteria”

Proposal for a Breakout EDU in Kinematics for High School Juniors

Artículo incluído en la sección: Innovación en educación científica[Resumen] “Tienes 45 min para escapar con vida de esta habitación. Buena suerte”. Hace unos años esta frase le habría puesto los pelos de punta a cualquiera, hoy día es sinónimo de juego y diversión. La sociedad actual ha cambiado y por ello resulta necesario emplear nuevas metodologías que permitan motivar al alumnado al mismo tiempo que adquiere conocimientos y desarrolla competencias. Un breakoutedu es un recurso empleado en gamificación, una metodología activa que fomenta el aprendizaje incorporando elementos del juego en el aula. En nuestro trabajo nos proponemos el diseño de un breakoutedu para mejorar los aprendizajes de cinemática en 1º de Bachillerato a través del planteamiento de tres retos sucesivos, indicando contenidos y competencias trabajadas y siguiendo una metodología colaborativa. Por otra parte, establecemos una guía para el profesorado de ciencias para el diseño de sus propios breakoutedu, con la intencionalidad, a través de estas propuestas, de utilizar la motivación del alumnado para favorecer la adquisición de aprendizajes duraderos.[Abstract] ‘You have 45 minutes to escape this room alive. Good luck.’ A few years ago, this sentence would have made a person’s hair stand on end. Today it has become synonymous with play and fun, especially among young people. Society has changed, as have students, which is why we need new methodologies to motivate young people while they acquire knowledge and develop skills. A Breakout EDU is a resource used in gamification, an active learning methodology that incorporates elements of play in the classroom. This article proposes a design for a Breakout EDU to improve kinematics learning among high school juniors. The design comprises three challenges and is based on a collaborative methodology with clearly defined contents and skills targets. The article also provides a guide for science teachers to design their own Breakout EDUs, with the intention of harnessing student motivation for the promotion of lasting learning

A BreakoutEDU to evaluate gene expression contents in 4 ESO. Design, application and evaluation of the emotions of its implementation

El conocimiento sobre genética es esencial para construir una sociedad capaz de participar en debates sociocientíficos. Sin embargo, el proceso de enseñanza-aprendizaje de este tema conlleva numerosas dificultades, siendo preciso el desarrollo de nuevas estrategias educativas que faciliten su comprensión y su evaluación. Una alternativa podría ser la implementación de un BreakoutEDU, un tipo concreto de gamificación similar al famoso escape room, en el que el alumnado se enfrenta al desafío de abrir una caja. Para lograrlo el alumnado debe resolver una serie de retos durante los cuales adquiere o refuerza aprendizajes sobre los contenidos elegidos. Con esta idea, se establecen en este trabajo tres objetivos fundamentales: a) diseñar una actividad gamificada de tipo BreakoutEDU para evaluar los contenidos sobre expresión genética; b) estudiar las percepciones del alumnado sobre la actividad y las emociones experimentadas con la misma y c) analizar la adecuación y la utilidad de la actividad desde el punto de vista de la docente responsable del aula. El BreakoutEDU se ha implementado con un grupo de 28 alumnos/as y su evaluación se ha llevado a cabo mediante cuestionarios, plantillas de observación, videograbación y entrevista a la profesora responsable. El análisis cualitativo y cuantitativo de los resultados muestra que el BreakoutEDU diseñado resulta una buena estrategia para contextualizar, evaluar y acercar el contenido abstracto de la expresión genética.Knowledge about genetics is essential to build a society capable of participating in socio-scientific debates. However, the teaching-learning process of this subject involves many difficulties, requiring the development of new educational strategies, to facilitate its understanding and evaluation. An alternative could be the implementation of a BreakoutEDU, a specific type of gamification similar to the famous escape room, in which students face the challenge of opening a box. To achieve this, students must solve a series of challenges during which they acquire or reinforce learning about the chosen content. Thus, three main objectives are established in this work: a) to design a gamified activity of the BreakoutEDU type to evaluate the contents on gene expression; b) to study the students' perceptions of the activity and the emotions experienced with it and c) to analyze the suitability and usefulness of the activity from the point of view of the teacher in charge of the classroom. The BreakoutEDU has been implemented with a group of 28 students and its evaluation has been carried out by means of questionnaires, observation templates, videotaping and an interview with the teacher in charge. The qualitative and quantitative analysis of the results shows that the designed BreakoutEDU is a good strategy to contextualize, evaluate and approach the abstract content of gene expression