Persona: María Hormigos, Roberto
Cargando...
Dirección de correo electrónico
rob.maria@ccia.uned.es
ORCID
0000-0001-8002-3998
Fecha de nacimiento
Proyectos de investigación
Unidades organizativas
Puesto de trabajo
Apellidos
María Hormigos
Nombre de pila
Roberto
Nombre
14 resultados
Resultados de la búsqueda
Mostrando 1 - 10 de 14
Publicación Microrobots in food science and technology(2025-12-03) María Hormigos, Roberto; Mayorga-Martinez, Carmen C.; Pumera, MartinThe global food supply chain is highly susceptible to spoilage and contamination risks, posing severe health hazards to consumers. This creates the need for preservation and safety-monitoring methods to reduce the exposure of both industries and consumers to these risks. Recent innovations using functional materials to construct nano- and microrobots of different shapes and sizes show substantial improvements in optimizing various food processes. Here we review the benefits of applying autonomous functional microrobotics to food science and technology, focusing on applications in food safety control, preservation and processing. We identify current limitations specific to each application and general constraints that must be overcome to transition from proof of concept to real-world implementation in the food industry.Publicación Surfactant-Free β-Galactosidase Micromotors for “On-The-Move” Lactose Hydrolysis(Wiley Online Library, 2018) Jurado Sánchez, Beatriz; Escarpa, Alberto; María Hormigos, RobertoSurfactant-free β-galactosidase micromotors are explored here as moving biocatalyst for highly efficient lactose hydrolysis from raw milk. The coupling of the hydrolytic properties of such enzyme with the efficient movement of carbon nanotube tubular micromotors results in nearly 100% lactose hydrolysis and two fold removal efficiency as compared with static conditions and with free enzyme. The incorporation of an inner Ni layer allows its reusability to operate in batch mode. The rough micromotor surface area allows the immobilization of a high loading of β-galactosidase and results in an increase in the enzyme affinity toward lactose. The new micromotor concept opens new avenues for the use of micromotors as moving immobilized biocatalyst to improve the technological process not only in food industry but also in other fields.Publicación Preclinical Validation of an Electrochemical Sensor for Alcohol Consumption Monitoring in a Polydrug Self-Administration Animal Model(MDPI, 2025-03-08) Garrido Matilla, Lucía; María Hormigos, Roberto; Monago Maraña, Olga; Marcos, Alberto; Ambrosio Flores, Emilio; González Crevillén, AgustínAn electrochemical sensor for identification and monitoring of alcoholism was preclinically validated by analyzing plasma from polydrug-consuming rats (alcohol and cocaine). The sensor measures by adsorptive transfer square wave voltammetry the glycosylation level of transferrin, which is an alcoholism biomarker, through a recently reported parameter called the electrochemical index of glycosylation (EIG). Three rat groups were designed: saline group, cocaine group, and cocaine–alcohol group. Moreover, two periods of withdrawal were studied, after 2 days and 30 days. The alcohol–cocaine group after 2 days of withdrawal showed significantly lower EIG values (p < 0.1) than the rest of groups and also alcohol–cocaine group after 30 days of withdrawal, so the sensor was able to identify the alcohol consumption in rats and to monitor the recovery of glycosylation level after 30 days of withdrawal, even combined with cocaine. Furthermore, the effect of sex was also considered. Receiver operating characteristic (ROC) curves were developed for each sex and the corresponding cut-off values were determined. The sensor showed a clinical sensitivity of 70% for male and 75% for female, and a specificity of 67% for both sexes. This preclinical validation demonstrated the possibilities of this sensor for point of care testing of alcoholism, even in cocaine addicts, making it a potential tool for diagnosis and monitoring of alcohol consumption in detox treatments for humans.Publicación Carbon Allotrope Nanomaterials Based Catalytic Micromotors(American Chemical Society, 2016-12-27) Jurado Sánchez, Beatriz; Vázquez, Luis; Escarpa, Alberto; María Hormigos, RobertoCarbon allotropes nanomaterials are explored here for the preparation of highly efficient tubular micromotors: 0D (C60 fullerene), 1D (carbon nanotubes), 2D (graphene), and 3D (carbon black, CB). The micromotors are prepared by direct electrochemical reduction or deposition of the nanomaterial into the pores of a membrane template. Subsequent electrodeposition of diverse inner catalytic layers (Pt, Pd, Ag, Au, or MnO2) allows for efficient bubble-propulsion in different media (seawater, human serum, and juice samples). Atomic-force microscopy (AFM) and scanning electron microscopy characterization reveals that the micromotors exhibit a highly rough outer surface and highly microporous inner catalytic structures. A key aspect derived from the AFM characterization is the demonstration that the rough outer surface of the micromotors can greatly affect their overall speed. To date, the literature has only focused on studying the effect of the inner catalytic layer upon their speed and performance and has underestimated the effect of the outer surface layer. The speed of carbon-based micromotors is a compromise between two opposite forces: the increased catalytic activity because of improved fuel decomposition in the inner catalytic layer, which propels their advance, and the friction of the rough outer surface with the fluid, which is opposed to it. The largest outer surface area associated with the highest surface roughness of C60 fullerene and carbon black-Pt micromotors leads to a large friction force, which results in a reduced speed of ∼180 μm/s (1% H2O2). In contrast, for carbon-nanotube-Pt based micromotors, the dominant force is the high catalytic activity of the micromotor, which allows them to reach ultrafast speeds up to 440 μm/s (1% H2O2). The new protocol opens new avenues for the universal preparation of carbon based multifunctional micromotors for a myriad of practical applications exploiting the features of carbon allotropes.Publicación Wearable sensor for solar ultraviolet A radiation monitoring based on a basic bismuth nitrate / graphene quantum dots composite(Elsevier, 2025-11-26) María Hormigos, Roberto; Monago Maraña, Olga; Zapardiel Palenzuela, Antonio; González Crevillén, Agustín; Universidad Nacional de Educación a Distancia (UNED)/SantanderUltraviolet A (UV-A) radiation from the Sun is a significant risk factor for skin cancer owing to long-term exposition for outdoor workers. The growing need for wearable health monitoring devices demands real-time UV-A sensors with high analytical performance to avoid skin conditions resulting from prolonged UV-A exposure. In this work, we aimed to develop a novel, power-less, low-cost, long-term-stable, and flexible wearable sensor. Such a sensor is based on basic bismuth nitrate (BBN) covered with graphene quantum dots (GQDs) as a photodetector. BBN@GQD photoelectrical material was produced by a very low-cost pyrolytic procedure in gram-scale quantities on a simple hot plate. GQDs improved photoelectrical activity of BBN, yielding good responsivity of 0.25 mA·W−1 (at 0 V bias, incident light intensity 17 μW·cm−2 and 365 nm wavelength). The combination of BBN@GQD and ITO electrodes provided a very sensitive and selective photodetector (a limit of detection of 1.6 ± 0.6 μW·cm−2 light intensity at 0 V bias for 365 nm UV-A wavelength), better than most current UV-A photodetectors. Its high sensitivity at 0 V bias enables its employment as a functional power-free real-time UV-A monitor device. Moreover, the wearable sensor showed acceptable reproducibility (18.9 % relative standard deviation at 12.5 μW·cm−2 light intensity) and long-term stability (up to 1 month of storage). This work proposes a promising wearable device for UV-A monitoring in an outdoor environment, using a new photosensitive material (BBN@GQD), which offers new opportunities in the development of UV photodetectors.Publicación Carbon nanotubes-ferrite-manganese dioxide micromotors for advanced oxidation processes in water treatment(Royal Society of Chemistry, 2018) Pacheco Jerez, Marta; Jurado Sánchez, Beatriz; Escarpa, Alberto; María Hormigos, RobertoMultifunctional SW-Fe2O3/MnO2 tubular micromotors are used for ‘on-the-fly’ advanced water oxidation of industrial organic pollutants. Catalytic decomposition of H2O2 as an oxidation agent results in the production of oxygen bubbles and hydroxyl radicals for complete mineralization of model pollutants into CO2 and H2O. The carbon backbone with Fe2O3 nanoparticles results in a rough catalytic layer for increased speed (16-fold acceleration as compared with smooth counterparts) and a higher radical production rate. The micromotors can propel autonomously in complex wastewater samples (400 μm s−1, 2% H2O2) using a biocompatible surfactant and obviating the need for expensive Pt catalysts. Such self-propelled micromotors act as highly efficient dynamic oxidation platforms that offer significantly shorter and more efficient water treatment processes, reducing the use of chemical reagents. The effective operation of the SW-Fe2O3/MnO2 micromotors is illustrated towards the oxidative degradation of mg L−1 levels of Remazol Brilliant blue and 4-chlorophenol. Factors influencing the micromachine-enhanced oxidation protocol, such as the pH, navigation time and number of motors, have been investigated. High degradation rates of ∼80% are obtained for both pollutants following 60 min treatment of spiked wastewater samples at pH 4.0–5.0. The unique magnetic properties of the outer Fe2O3 layer allow the reusability of the micromotors and its convenient recovery and disposal after treatment. Such attractive performance holds considerable promise for its application in large scale water treatment systems and for a myriad of environmental, industrial and security defense fieldsPublicación Self-Propelled Micromotors for Naked-Eye Detection of Phenylenediamines Isomers(ACS Publications, 2018) Jurado Sánchez, Beatriz; Escarpa, Alberto; María Hormigos, RobertoTubular micromotors composed of a hybrid single-wall carbon nanotube (SW)−Fe2O3 outer layer and powered by a MnO2 catalyst are used for phenylenediamines isomers detection and discrimination. Catalytic decomposition of H2O2 as fuel results in the production of oxygen bubbles and hydroxyl radicals for phenylenediamines dimerization to produce colorful solutions in colorimetric assays. The combination of Fe2O3 nanoparticles along with the irregular SW backbone results in a rough catalytic layer for enhanced hydroxyl radical production rate and improved analytical sensitivity. Such self-propelled micromotors act as peroxidase-like mobile platforms that offer efficient phenylenediamines detection and discrimination in just 15 min. Factors influencing the colorimetric assay protocol, such as the navigation time and number of motors, have been investigated. Low limits of detection (5 and 6 μM) and quantification (17 and 20 μM) were obtained for o-phenylenediamine and p- phenylenediamine, respectively. The magnetic properties of the outer SW−Fe2O3 hybrid layer allow the reusability of the micromotors in the colorimetric assay. Such attractive performance holds considerable promise for its application in sensing systems in a myriad of environmental, industrial, and health applications.Publicación Magnetic Hydrogel Microrobots as Insecticide Carriers for In Vivo Insect Pest Control in Plants(Wiley, 2022-12-30) María Hormigos, Roberto; Mayorga-Martinez, Carmen C.; Pumera, MartinThe cost of insect pests to human society exceeds USD70 billion per year worldwide in goods, livestock, and healthcare services. Therefore, pesticides are needed to prevent insect damage despite the secondary effects of these chemical agents on non-target organisms. Chemicals encapsulation into carriers is a promising strategy to improve their specificity. Hydrogel-based microrobots show enormous potential as chemical carriers. Herein, hydrogel chitosan magnetic microrobots encapsulating ethyl parathion (EP)-CHI@Fe3O4 are used to efficiently kill mealworm larvae (Tenebrio molitor). The mechanism takes advantage of pH-responsive chitosan degradation at Tenebrio molitor midgut pH to efficiently deliver pesticide into the mealworm intestinal tract in just 2 h. It is observed that under a transversal rotating magnetic field, mealworm populations show higher mortality after 30 min compared to free pesticide. This example of active pesticide carriers based on soft microrobots opens new avenues for microrobots applications in the agrochemical field as active chemical carriers.Publicación Prussian Blue/Chitosan Micromotors with Intrinsic Enzyme-like Activity for (bio)-Sensing Assays(ACS Publications, 2022) Molinero-Fernández, Águeda; Jurado Sánchez, Beatriz; Escarpa, Alberto; María Hormigos, Roberto; Novillo López, Miguel ÁngelPrussian Blue (PB)/chitosan enzyme mimetic tubular micromotors are used here for on-the-fly (bio)-sensing assays. The micromotors are easily prepared by direct deposition of chitosan into the pores of a membrane template and in situ PB synthesis during hydrogel deposition. Under judicious pH control, PB micromotors display enzyme mimetic capabilities with three key functions on board: the autonomous oxygen bubble propulsion (with PB acting as a catalase mimic for hydrogen peroxide decomposition), 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation (with PB acting as a peroxidase mimic for analyte detection), and as a magnetic material (to simplify the (bio)-sensing steps). In connection with chitosan capabilities, these unique enzyme mimetic micromotors are further functionalized with acetylthiocholinesterase enzyme (ATChE) to be explored in fast inhibition assays (20 min) for the colorimetric determination of the nerve agent neostigmine, with excellent analytical performance in terms of quantification limit (0.30 μM) and concentration linear range (up to 500 μM), without compromising efficient micromotor propulsion. The new concept illustrated holds considerable potential for a myriad of (bio)-sensing applications, including forensics, where this conceptual approach remains to be explored. Micromotor-based tests to be used in crime scenes are also envisioned due to the reliable neostigmine determination in unpretreated samples.Publicación Nanostructured Hybrid BioBots for Beer Brewing(American Chemical Society, 2023-04-12) María Hormigos, Roberto; Mayorga-Martinez, Carmen C.; Kinčl, Tomáš; Pumera, MartinThe brewing industry will amass a revenue above 500 billion euros in 2022, and the market is expected to grow annually. This industrial process is based on a slow sugar fermentation by yeast (commonly Saccharomyces cerevisiae). Herein, we encapsulate yeast cells into a biocompatible alginate (ALG) polymer along Fe3O4 nanoparticles to produce magneto/catalytic nanostructured ALG@yeast-Fe3O4 BioBots. Yeast encapsulated in these biocompatible BioBots keeps their biological activity (growth, reproduction, and catalytic fermentation) essential for brewing. Catalytic fermentation of sugars into CO2 gas caused a continuous oscillatory motion of the BioBots in the solution. This BioBot motion is employed to enhance the beer fermentation process compared to static-free yeast cells. When the process is finished, magnetic actuation of BioBots is employed for their retrieval from the beer samples, which avoids the need of additional filtration steps. All in all, we demonstrate how an industrial process such as beer production can be benefited by miniaturized autonomous magneto/catalytic BioBots.