2D Nanomaterials wrapped Janus micromotors with built-in multiengines for bubble, magnetic, and light driven propulsion

Graphene oxide, graphdyine oxide, and blackphosphorus coated micromotors integrating "three engines" for motion control using different stimuli such as chemical fuel, light, and magnetic fields are described. Micromotors can be massproduced by wrapping gold-sputtered polystyrene microspheres with the 2D nanomaterials, followed by simultaneous assembly of Pt or MnO2 nanoparticles (NPs) as bubble (catalytic)-engines, Fe2O3 NPs as magnetic engines, and quantum dots (QDs) as light engines. The design and composition of micromotors are key to get the desired propulsion performance. In bubble-magnetic and bubble-light mode, a built-in acceleration system allows micromotor speed to be increased up to 3.0 and 1.5 times after application of the magnetic field or light irradiation, respectively. In the bubble-magnetic-light mode, such speed increase can be combined in a single unit for on-demand braking and accelerating systems. Fluid dynamics simulations illustrate that such adaptative behavior and improved propulsion efficiency is produced by a better distribution of the fuel and thus energy propelling the micromotor by activation of the magnetic and/or light engines. The new micromotors described here, which combine multiple engines with functional nanomaterials, hold considerable promise to develop novel nanovehicles with adaptative behavior to perform complex tasks in lab-on-a-chips or dynamic micropatterning applications.Ministerio de Ciencia e InnovaciónComunidad de MadridEuropean Commissio

Diseño y evaluación de materiales didácticos bilingües con TICs para prácticas de laboratorio de Química

[EN] The new scenario of the European Higher Education Area and the increase of Erasmus student agreements has led to a rise in the number of subjects in English. All this has resulted in an increase in the participation of foreign students in undergraduate and graduate programs. There is also a growing demand on the part of the general student body to learn new subjects in English with the aim of increasing their future international employability. The use of a second language requires an adequate design of the specific didactic material without prejudice of the learning process. In this context, ICTs have been revealed as a new strategy to minimize the disadvantages listed above. The objective of this work is the development of bilingual Spanish-English teaching material with the aim of facilitating the study and guiding the student in the learning and self-evaluation of experimental subjects in Chemistry. The new technologies will be used as PowerPoint presentations to develop an interactive laboratory notebook that will be implemented in the Moodle platform. A second objective was the evaluation of the material by biology and chemistry Erasmus bachelor’s degree students.[ES] El establecimiento del Espacio Europeo de Educación Superior y el incremento de convenios de intercambio de estudiantes Erasmus ha conducido a un aumento en la oferta de asignaturas en inglés. Todo ello ha repercutido en un aumento en la participación de estudiantes extranjeros en programas de grado y postgrado. Existe además una creciente demanda por parte del alumnado general en el aprendizaje de nuevas materias en inglés con el objetivo de incrementar su empleabilidad internacional futura. La utilización de un segundo idioma requiere un diseño adecuado del material didáctico específico sin perjuicio del proceso realización-interpretación-aprendizaje. En este contexto, las TICs se han revelado como una nueva estrategia para minimizar las desventajas enumeradas anteriormente. El objetivo de este trabajo es el desarrollo de material docente bilingüe español-inglés con el objetivo de facilitar el estudio y guiar al alumno en el aprendizaje y autoevaluación de asignaturas de experimentación en Química. Con este fin, se emplearon las nuevas tecnologías tales como presentaciones en PowerPoint para desarrollar un cuaderno interactivo de laboratorio que se implementó en la plataforma Moodle. Un segundo objetivo consistió en la evaluación del material desarrollado por parte de estudiantes internacionales Erasmus de grados en Química y Biología.Jurado Sánchez, B.; De La Asunción-Nadal, V.; García Carmona, L.; Pacheco Jerez, M.; María-Hormigos, R.; Sierra Gómez, T. (2019). Diseño y evaluación de materiales didácticos bilingües con TICs para prácticas de laboratorio de Química. En IN-RED 2019. V Congreso de Innovación Educativa y Docencia en Red. Editorial Universitat Politècnica de València. 252-259. https://doi.org/10.4995/INRED2019.2019.10367OCS25225

MoSBOTs: Magnetically Driven Biotemplated MoS2_2‐Based Microrobots for Biomedical Applications

2D layered molybdenum disulfide (MoS$_2$) nanomaterials are a promising platform for biomedical applications, particularly due to its high biocompatibility characteristics, mechanical and electrical properties, and flexible functionalization. Additionally, the bandgap of MoS$_2$ can be engineered to absorb light over a wide range of wavelengths, which can then be transformed into local heat for applications in photothermal tissue ablation and regeneration. However, limitations such as poor stability of aqueous dispersions and low accumulation in affected tissues impair the full realization of MoS$_2$ for biomedical applications. To overcome such challenges, herein, multifunctional MoS$_2$-based magnetic helical microrobots (MoSBOTs) using cyanobacterium Spirulina platensis are proposed as biotemplate for therapeutic and biorecognition applications. The cytocompatible microrobots combine remote magnetic navigation with MoS$_2$ photothermal activity under near-infrared irradiation. The resulting photoabsorbent features of the MoSBOTs are exploited for targeted photothermal ablation of cancer cells and on-the-fly biorecognition in minimally invasive oncotherapy applications. The proposed multi-therapeutic MoSBOTs hold considerable potential for a myriad of cancer treatment and diagnostic-related applications, circumventing current challenges of ablative procedures

Chromogenic and Fluorogenic Probes for the Detection of Illicit Drugs

[EN] The consumption of illicit drugs has increased exponentially in recent years and has become a problem that worries both governments and international institutions. The rapid emergence of new compounds, their easy access, the low levels at which these substances are able to produce an effect, and their short time of permanence in the organism make it necessary to develop highly rapid, easy, sensitive, and selective methods for their detection. Currently, the most widely used methods for drug detection are based on techniques that require large measurement times, the use of sophisticated equipment, and qualified personnel. Chromo- and fluorogenic methods are an alternative to those classical procedures.We thank the Spanish Government [projects MAT2015-64139-C4-1-R and AGL2015-70235-C2-2-R (MINECO/FEDER)] and the Generalitat Valenciana (project PROMETEOII/2014/047) for support. S.E.S thanks the Ministerio de Economia y Competitividad for his Juan de la Cierva contract. 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Electrochemistry: A basic and powerful tool for micro- and nanomotor fabrication and characterization

Electrochemistry, although an ancient field of knowledge, has become of paramount importance in the synthesis of materials at the nanoscale, with great interest not only for fundamental research but also for practical applications. One of the promising fields in which electrochemistry meets nanoscience and nanotechnology is micro/nanoscale motors. Micro/nano motors, which are devices able to perform complex tasks at the nanoscale, are commonly multifunctional nanostructures of different materials - metals, polymers, oxides- and shapes -spheres, wires, helices- with the ability to be propelled in fluids. Here, we first introduce the topic of micro/nanomotors and make a concise review of the field up to day. We have analyzed the field from different points of view (e.g. materials science and nanotechnology, physics, chemistry, engineering, biology or environmental science) to have a broader view of how the different disciplines have contributed to such exciting and impactful topic. After that, we focus our attention on describing what electrochemical technology is and how it can be successfully used to fabricate and characterize micro/nanostructures composed of different materials and showing complex shapes. Finally, we will review the micro and nanomotors fabricated using electrochemical techniques with applications in biomedicine and environmental remediation, the two main applications investigated so far in this field. Thus, different strategies have thus been shown capable of producing core-shell nanomaterials combining the properties of different materials, multisegmented nanostructures made of, for example, alternating metal and polymer segments to confer them with flexibility or helicoidal systems to favor propulsion. Moreover, further functionalization and interaction with other materials to form hybrid and more complex objects is also shown

Transition metal dichalcogenide-based micromotors: innovative designs, propulsion mechanisms and applications

El objetivo principal de esta Tesis Doctoral ha sido el diseño y el desarrollo de nuevos micromotores y micro robots basados en dicalcogenuros de metales de transición (TMD por sus siglas en inglés, transition metal dichalcogenides) de WS2 y MoS2. Asimismo, se han estudiado diferentes mecanismos de propulsión de estos -catalíticos, fotoforéticos y magnéticos- y se ha explorado su potencial aplicativo en ámbitos como el (bio)analítico, el biomédico y la remediación ambiental. Como punto de partida, en un primer bloque, se sintetizaron y caracterizaron micromotores tubulares catalíticos basados en TMD empleando protocolos de electrodeposición asistida en membrana. A continuación, se estudió la propulsión catalítica, explorándose su aplicabilidad para la eliminación de contaminantes modelo y como plataformas biosensoras ultraminiaturizadas para la detección fluorescente selectiva y sensible de endotoxinas bacterianas de Escherichia coli empleando péptidos de afinidad y en aproximaciones analíticas OFF-ON. Alternativamente, en este bloque, se estudiaron los efectos de la aplicación de campos magnéticos y electromagnéticos yuxtapuestos en la propulsión de estos micromotores catalíticos basados en TMD. En ambos casos se obtuvo un aumento de la velocidad de los micromotores, pudiéndose establecer que dicho aumento fue dependiente de la geometría del micromotor en el caso de la propulsión magnética y de la composición de la capa externa de los micromotores en el caso de la propulsión mediante aplicación de radiación electromagnética. En un segundo bloque, y en aras de estudiar alternativas biocompatibles a la propulsión catalítica, se evaluó la aplicabilidad de micromotores de TMD propulsados exclusivamente por luz. En primer lugar, se estudió experimentalmente el fenómeno colectivo observado con velocidades de hasta 6000 µm s-1 y se estudió el mecanismo de propulsión de estos micromotores, identificándose como un mecanismo fotoforético. Una vez caracterizado el movimiento, se aprovechó la reactividad de los TMD para modificar los micromotores superficialmente con nanopartículas de oro, para seguidamente emplearlos como sustratos SERS guiados por luz, consiguiéndose obtener un aumento en el límite de detección de un analito modelo (cristal violeta) de hasta 18 veces. Alternativamente, se emplearon estos micromotores para la eliminación de biopelículas bacterianas de Escherichia coli y Staphylococcus aureus, en base a su capacidad para la generación de especies reactivas de oxígeno. Por último, se sintetizaron micromotores de TMD con propiedades fotoforéticas y núcleos magnéticos para la captura, degradación y eliminación de partículas de poliestireno como microplástico modelo relevante en el medio ambiente. Por último, en el tercer bloque de esta Tesis Doctoral, se sintetizaron y caracterizaron micro robots de TMDs. Para ello se realizó una síntesis hidrotermal de MoS2 sobre biomoldes de cianobacterias Spirulina platensis decorados con partículas magnéticas y, en un proceso postsintético, decorados con nanopartículas de oro. Estos micro robots, mediante una actuación magnética controlada, se emplearon para la destrucción selectiva de células de cáncer debido a sus propiedades fototérmicas así como para realizar operaciones de bioreconocimiento empleando el par estreptavidina-biotina como modelo

Engineering Janus micromotors with WS2 and affinity peptides for turn-on fluorescent sensing of bacterial lipopolysaccharides

Herein we describe an “OFF-ON” Janus micromotor approach for the fast (5 min) and sensitive determination (limit of detection, 120 pM) of Escherichia coli O111:B4 lipopolysaccharide (LPS) associated with sepsis shock in microliter samples. The OFF-ON strategy relies on the loading of a specifically designed rhodamine-labeled affinity peptide into WS2–Pt–Fe2O3 polycaprolactone Janus micromotors. Specific attachment of the peptide with the WS2 via electrostatic and hydrophobic interactions results in fluorescent quenching, which is subsequently recovered by the detachment of the probe in the presence of the target LPS. Peptide loading into the micromotor structure increases the overall stability for over 2 months without any change in its properties and excellent analytical performance. No fluorescence recovery is observed in the presence of LPS with a similar structure, illustrating the high selectivity of the protocol, along with quantitative recoveries in human serum and bacteria cultures. The method was validated against the gold standard Limulus Amoebocyte lysate assay in real bacteria culture containing naturally occurring LPS, with similar recoveries in both cases. The micromotors hold great potential to carry out analytical measurements in real-time with small amounts of sample and reagents, allowing for fast detection of deadly toxins with high clinical relevance.Spanish Ministry of Economy, Industry and CompetitivenessSpanish Ministry of Education and UniversitiesCommunity of MadridTRANSNANOAVANSENSUniversidad de AlcaláDepto. de Química en Ciencias FarmacéuticasFac. de FarmaciaTRUEpu

Chalcogenides-based Tubular Micromotors in Fluorescent Assays

WS2/Pt and MoS2/Pt bubble propelled micromotors are used as “on-the-fly” sensing platforms in bioassays, using a highly selective affinity peptide probe for “OFF-ON” detection of Escherichia coli as a model endotoxin. The different outer micromotor surface characteristics play an important role in the sensing performance. The relatively high outer surface of WS2/Pt micromotors results in a 3.5-fold increase in sensitivity compared to MoS2/Pt micromotors due to enhanced peptide probe loading and release. The peptide-modified WS2 micromotors are used as a low-cost and high-throughput approach for the determination of E. coli endotoxin after only 60 s, with a limit of detection of 1.9 ng mL–1 and high selectivity. The method has been validated using spiked samples (tap water, blood serum, and saliva) and bacteria media (blank broth, Staphylococcus aureus, and E. coli). The concept can be extended to the analysis of other (bio)-analytes and easily incorporated into portable instrumentation, holding great promise in a myriad of clinical, environmental, or food-safety applications.Spanish Ministry of Science, Innovation and UniversitiesSpanish Ministry of Economy, Industry and CompetitivenessCommunity of Madrid-UAHSpanish Ministry of Economy, Industry and CompetitivenessDepto. de Química en Ciencias FarmacéuticasCAI Ciencias de la Tierra y ArqueometríaTRUEpu

Near infrared-light responsive WS2 microengines with high-performance electro- And photo-catalytic activities

[EN] Tungsten disulfide (WS)-based micromotors with enhanced electrochemical and photo-catalytic activities are synthesized using a greatly simplified electrochemical deposition protocol at room temperature involving exclusively tungstic acid and sulfate as metal and sulfur sources without further building chemistry. The WS-based micromotors exhibit dual electrochemical and photo-catalytic behavior in the inner and outer layers, respectively, due to the combination of the unique properties of the sp hybridized WS outer layer with highly reactive WS-induced inner catalytic layers, accounting for this material's exclusive enhanced performances. A rough inner Pt-Ni layer allows tailoring the micromotor propulsion, with a speed increase of up to 1.6 times after external control of the micromotor with a magnetic field due to enhanced fuel accessibility. Such a coupling of the attractive capabilities of WS with enhanced micromotor movement holds considerable promise to address the growing energy crisis and environmental pollution concerns.V. de la Asunción-Nadal acknowledges the FPI fellowship received from the University of Alcalá. B. J.-S. acknowledges support from the Spanish Ministry of Science, Innovation and Universities (RYC-2015-17558, co-financed by EU) and the University of Alcalá (CCG2018/EXP-018). AE acknowledges Financial support from the Spanish Ministry of Science, Innovation and Universities (CTQ2017-86441-C2-1-R) and theTRANSNANOAVANSENS program (S2018/NMT-4349) from the Community of Madrid. LV acknowledges Financial support from the Spanish Ministry of Science, Innovation and Universities (MAT2017-85089-C2-1-R)

Photoresponsive MoS2 and WS2 microflakes as mobile biocide agents

A fuel-free strategy for the eradication of Escherichia coli and Staphylococcus aureus biofilms using WS2 and MoS2 photophoretic microflakes is described. The microflakes were prepared by liquid-phase exfoliation of the materials. Under electromagnetic irradiation at 480 or 535 nm, the microflakes experience a fast collective behavior at speeds of over 300 mu m s(-1) due to photophoresis. Simultaneously to their motion, reactive oxygen species are generated. The fast microflake schooling into multiple moving swarms results in a highly efficient "collision" platform that disrupts the biofilm, enhancing radical oxygen species' contact with the bacteria for their inactivation. As such, removal biofilm mass rates of over 90% and 65% are achieved using the MoS2 and WS2 microflakes in the treatment of Gram-negative E. coli and Gram-positive S. aureus biofilms after 20 min. Much lower removal biofilm mass rates (30%) are obtained under static conditions, revealing the crucial role of microflake movement and radical generation in the active eradication of biofilms. Much higher removal efficiencies are observed in biofilm deactivation as compared with the use of free antibiotics, which are not able to destroy the densely packed biofilms. The new moving microflakes hold considerable promise for the treatment of antibiotic-resistant bacteria.Ministerio de Economía, Industria y CompetitividadEuropean CommissionMinisterio de Ciencia e Innovació