Artículos de revista INAMAT2 - INAMAT2 aldizkari artikuluak

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Open Access
An antibacterial submicron fiber mat with in situ synthesized silver nanoparticles
(Wiley, 2012) Rivero Fuente, Pedro J.; Urrutia Azcona, Aitor; Goicoechea Fernández, Javier; Rodríguez, Yoany; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
This work presents an alternative approachfor fabricating electrospun submicron highly hydrophilicfiber mats loaded with silver nanoparticles. These fiber matsshow a high efficient antibacterial behavior, very attractivefor applications like wound healing and skin regenerationprocesses. The fabrication method is divided in two steps.First, poly(acrylic acid) (PAA) and b-cyclodextrin (b-CD)submicron fibers were electrospun and further stabilizedusing a thermal treatment, yielding stable hydrogel-likefibers with diameters ranging from 100 nm up to severalmicrons. In the second step, silver ions were loaded into thefibers and then reduced to silver nanoparticles in-situ. Theelectrospinning parameters were adjusted to achieve thedesired properties of the fiber mat (density, size) and after-wards, the characteristics of the silver nanoparticles(amount, size, aggregation) were tuned by controlling thesilver ion loading mechanism. Highly biocide surfaces wereachieved showing more than 99.99% of killing efficiency.The two-step process improves the reproducibility and tun-ability of the fiber mats. To our knowledge, this is the firsttime that stable hydrogel fibers with a highly biocide behav-ior have been fabricated using electrospinning.
Open Access
An antibacterial surface coating composed of PAH/SiO2 nanostructurated films by layer by layer
(Wiley, 2010) Urrutia Azcona, Aitor; Rivero Fuente, Pedro J.; Ruete Ibarrola, Leyre; Goicoechea Fernández, Javier; Fernández Valdivielso, Carlos; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería; Ingeniaritza; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC
In this work we propose a novel antibacterial coating composed of SiO2 and the polymer Poly(allylamine hydrochloride) (PAH). The coating was fabricated by the technique Layer-by-Layer (LbL). This technique has already been used in previous works, and it has the advantage that it allows to control the construction of nanosized and well organized multilayer films. Here, the new nanotexturized LbL SiO2 surface acts as antibacterial agent. The fabricated coatings have been tested in bacterial cultures of genus Lactobacillus to observe their antibacterial properties. It has been demonstrated these PAH/SiO2 coating films have a very good antimicrobial behaviour against this type of bacteria.
Open Access
Cátedra Mujer, Ciencia y Tecnología de la UPNA
(Gobierno de Navarra, 2023) Aranguren Garacochea, Patricia; Barrenechea Tartas, Edurne; Catalán Ros, Leyre; Díaz Lucas, Silvia; Jurío Munárriz, Aránzazu; Martínez Ramírez, Alicia; Millor Muruzábal, Nora; Gómez Fernández, Marisol; San Martín Biurrun, Idoia; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Institute for Advanced Materials and Mathematics - INAMAT2
La Cátedra Mujer, Ciencia y Tecnología de la Universidad Pública de Navarra (UPNA) tiene como objetivo aumentar la participación de las mujeres en campos de ciencia y tecnología. La cultura y la divulgación científicas son el eje principal de la actividad de la Cátedra. Dicha actividad engloba: la representación teatral Yo quiero ser científica, talleres experimentales y conferencias y exposiciones para todos los públicos y edades. Más de 6000 personas han visto la obra de teatro, más de 1500 estudiantes de ESO han participado en los talleres y el material audiovisual ha recibido más de 20000 visitas.
Open Access
Determination of hazardous vapors from the thermal decomposition of organochlorinated silica xerogels with adsorptive properties
(Elsevier, 2024) Rosales Reina, María Beatriz; Cruz Quesada, Guillermo; Pujol, Pablo; Reinoso, Santiago; Elosúa Aguado, César; Arzamendi Manterola, Gurutze; López Ramón, María Victoria; Garrido Segovia, Julián José; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
The incorporation of organic groups into sol-gel silica materials is known to have a noticeable impact on the properties and structure of the resulting xerogels due to the combination of the properties inherent to the organic fragments (functionality and flexibility) with the mechanical and structural stability of the inorganic matrix. However, the reduction of the inorganic content in the materials could be detrimental to their thermal stability properties, limiting the range of their potential applications. Therefore, this work aims to evaluate the thermal stability of hybrid inorganic-organic silica xerogels prepared from mixtures of tetraethoxysilane and organochlorinated triethoxysilane precursors. To this end, a series of four materials with a molar percentage of organochlorinated precursor fixed at 10%, but differing in the type of organic group (chloroalkyls varying in the alkyl-chain length and chlorophenyl), has been selected as model case study. The gases and vapors released during the thermal decomposition of the samples under N2 atmosphere have been analyzed and their components determined and quantified using a thermogravimetric analyzer coupled to a Fourier-transform infrared spectrophotometer and to a gas chromatography-mass spectrometry unit. These analyses have allowed to identify up to three different thermal events for the pyrolysis of the organochlorinated xerogel materials and to elucidate the reaction pathways associated with such processes. These mechanisms have been found to be strongly dependent on the specific nature of the organic group.
Open Access
Electromagnetic vibrational harvester based on U-shaped ferromagnetic cantilever: a novel two-magnet configuration
(Elsevier, 2024-09-07) Gandía Aguado, David; Garayo Urabayen, Eneko; Beato López, Juan Jesús; Royo Silvestre, Isaac; Cruz Blas, Carlos Aristóteles de la; Tainta Ausejo, Santiago; Gómez Polo, Cristina; Ciencias; Zientziak; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC
Electromagnetic vibrational harvesters are low-cost devices featuring high-power densities and robust structures, often used for capturing the energy of environmental vibrations (civil infrastructures, transportation, human motion, etc.,). Based on Faraday's law, energy generation relies on the modification of the magnetic field distribution within a magnetic element caused by mechanical vibrations inducing an electromotive force (EMF) in a pick-up coil. However, the practical implementation of this type of vibrational harvester is currently limited due to the reduced generated power under low-frequency vibrations. In this work, an electromagnetic vibrational harvester is experimentally characterized and analyzed employing magnetic circuit analysis. The harvester consists of a ferromagnetic U-shaped cantilever, a NdFeB magnet and a ferrite magnet used as ¿magnetic tip mass¿ to enhance the magnetic flux changes under vibrations of frequency < 100 Hz. For this configuration, an experimental voltage of ¿ 1.2 V peak-to-peak (open circuit) was obtained at a resonant frequency of 77 Hz, enabling the subsequent electronic rectification stage. Additionally, Finite Element Method (FEM) is used to explore different design possibilities including the modeling of complex geometries, mechanical properties and non-linear magnetic materials, enabling the tuning of the resonance frequency from 51 to 77 Hz, keeping constant the induced voltage.
Open Access
Electrospun nanofiber mats for evanescent optical fiber sensors
(Elsevier, 2013) Urrutia Azcona, Aitor; Goicoechea Fernández, Javier; Rivero Fuente, Pedro J.; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this work, a study about the optical response of electrospun nanofiber (ENF) coatings for their use in evanescent optical fiber sensors is presented. Several types of ENF mats composed of poly(acrylic acid) (PAA) were developed with different ENF diameters and densities. These ENF mats were deposited onto an optical fiber core in order to fabricate humidity evanescent optical fiber sensors. The devices were exposed to relative humidity (RH) variations from 30% RH to 95%RH. The transfer functions of the devices (transmitted optical power versus relative humidity) presented two well-differenced behaviors depending on the ENF diameter and the ENF mat density. The devices with lower ENF diameters and higher mat density showed an increase in the transmitted optical power when RH increased. On the contrary, the devices with higher ENF diameters and lower mat density showed a decrease in the transmitted optical power when RH increased. In addition to this, sensors with thinner ENF overlays, showed a higher sensitivity. In order to study the response time of these devices, the ENFs sensors were submitted to human breathing cycles and presented a response time around 340 ms (exhalation). In spite of the high RH conditions of this experiment, the devices showed a recovery time around 210 ms and a negligible hysteresis or drift with respect to the initial condition (inhalation).
Open Access
Humidity sensor based on silver nanopartlcles embedded in a polymeric coating
(Sciendo, 2012) Rivero Fuente, Pedro J.; Urrutia Azcona, Aitor; Goicoechea Fernández, Javier; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería; Ingeniaritza; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC
In this work, it is presented a novel optical fiber humidity sensor based on silver nanoparticle-loaded polymeric coatings built onto an optical fiber core. The polymeric film was fabricated using the Layer-by-Layer assembly technique. The silver nanoparticles (Ag NPs) were characterized using transmission electron microscopy (TEM and UV-VIS spectroscopy. A Localized Surface Plasmon Resonance (LSPR) attenuation band is observed when the thickness of the coating increases, and showed a very good sensitivity to Relative Humidity (RH) variations, suitable for high performance applications such as human breathing monitoring.
Open Access
A lock-in amplifier for magnetic nanoparticle detection using GMI sensors
(IEEE, 2024-09-30) Algueta-Miguel, Jose M.; Beato López, Juan Jesús; López Martín, Antonio; Gómez Polo, Cristina; Ciencias; Zientziak; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC
A digital lock-in amplifier (LIA) for contactless magnetic nanoparticle (MNP) detection using giant magnetoimpedance (GMI) sensors is presented. The proposed approach is based on the simultaneous detection of the second harmonic amplitude and phase. A Xilinx Artix-7 field-programmable gate array (FPGA) has been employed for efficiently implementing the phase-sensitive detection (PSD) and the subsequent digital processing. The analog GMI sensor interface has been designed for minimizing the dependence of the excitation current on the GMI sensor impedance, also enhancing the rejection of the parasitic second-order distortion produced by the setup. A subsampling process of the analog outputs has been applied, both increasing the effective resolution of the analog-to-digital converter (ADC) and facilitating signal recovery. The proposed system improves the MNP detection capability reported in previous works using the second harmonic amplitude. Moreover, a characterization of the phase response, which had not been previously studied in the literature, is also provided.
Open Access
Magnetic binary encoding system based on 3D printing and GMI detection prototype
(Elsevier, 2022) Beato López, Juan Jesús; Algueta-Miguel, Jose M.; Galarreta Rodríguez, Itziar; López Ortega, Alberto; Garayo Urabayen, Eneko; Gómez Polo, Cristina; Aresti Bartolomé, Maite; Soria Picón, Eneko; Pérez de Landazábal Berganzo, José Ignacio; Ciencias; Zientziak; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this work, the feasibility of a magnetic binary encoding system using 3D printing technology is analyzed. The study has a double interest, that is, the possibility of printing a 3D piece that contains the codified information and the development of a system for its decoding. For this purpose, magnetic nanoparticles (magnetite Fe3O4) were embedded in a polymeric matrix of Polylactic Acid (PLA) and Poly-ε-caprolactone (PCL). Similar to a conventional barcode, a rectangular piece with an alternating pattern of strips with absence (only polymer) and a 5 wt% of embedded magnetic nanoparticles was 3D printed employing the Fused Deposition Modelling tech- nique (FDM). The information was decoded by means of a Giant Magnetoimpedance (GMI) sensor-based pro- totype, by scanning the surface of the piece and measuring the changes in the magnetic field. As sensor nucleus, an amorphous soft magnetic wire of nominal composition (Co0.94 Fe0.06)72.5 Si12.5 B15 was employed. The decoding prototype incorporates a homemade electronic sensor interface that permits, at the time, the GMI sensor excitation and the subsequent signal conditioning to optimize its response. The output signal enables the detection of the magnetite nanoparticles and the magnetic decoding of the encoded information (“1” and “0”, presence or absence of the magnetic nanoparticles, respectively).
Open Access
Optical fiber sensors based on gold nanorods embedded in polymeric thin films
(Elsevier, 2018) Urrutia Azcona, Aitor; Goicoechea Fernández, Javier; Rivero Fuente, Pedro J.; Pildain Lería, Ander; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
In this work, we present a study about the generation and analysis of optical resonances caused by gold nanorods (GNRs) embedded in films. GNRs were embedded in polymeric thin films using the Layerby-Layer nanoassembly (LbL) deposition technique. Polymer/GNRs thin films of different thicknesses were deposited on the surface of cladding removed optical fibers for sensing. The spectral responses of the optical fiber sensors were monitored during the build-up of the thin films. The generation of two Localized Surface Plasmon Resonances (LSPRs) associated to the GNRs was observed in thinner coatings. These devices with around 12 polymer/GNRs bilayers were characterized as refractometers, providing an intensity-based sensitivity up to 75.69 dB/RIU. For thicker polymer/GNRs overlays, both LSPRs bands were also generated and, additionally, it was observed a new Lossy Mode Resonance (LMR) band due to modes coupled to the sensitive coating. The dependence of these three resonance bands with the surrounding refractive index was studied. Finally, these sensors were tested in a climatic chamber in the 20-90% relative humidity (RH) range and the LMR showed a good sensitivity to RH changes while the LSPR bands remained very stable in comparison. Results showed an excellent sensitivity of 11.2 nm/%RH for the LMR, confirming the potential of this type of optical fiber sensor based on the combination of LSPRs and LMRs bands.
Open Access
Printed optical waveguide temperature sensor with rhodamine-doped core
(IEEE, 2024-06-08) Dávila Galiana, Rebeca Beatriz; Matías Maestro, Ignacio; Zabala, Silvia; Socorro Leránoz, Abián Bentor; Rivero Fuente, Pedro J.; Corres Sanz, Jesús María; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako Gobernua
This letter demonstrates the fabrication of a temperature optical sensor by printing the corresponding sensitive optical waveguide directly onto a flexible flat substrate. The printed waveguide was carried out using a coaxial needle and an electrohydrodynamic (EHD) machine. The fluorescent organic compound, rhodamine B, was used for doping the core of the printed waveguide as temperature sensible dye. The optical sensitive waveguide manufactured is compact, ensuring coupling with the input and output optical fibers. The response of the printed optical sensor was evaluated to temperature variations by measurement of both, the peak intensity and the wavelength of the fluorescence spectra. The experimental characteristic and sensitivity of the sensor were obtained.
Open Access
Single-stage in situ synthesis of silver nanoparticles in antibacterial self-assembled overlays
(Springerlink, 2012) Urrutia Azcona, Aitor; Rivero Fuente, Pedro J.; Ruete Ibarrola, Leyre; Goicoechea Fernández, Javier; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
In this work, a novel single-stage process for in situ synthesis of Ag nanoparticles (NPs) using the layer-bylayer (LbL) technique is presented. The Ag NPs were formed into nanotextured coatings based on sequentially adsorbed poly(allylamine hydrochloride) (PAH) and SiO2 NPs. Such highly porous surfaces have been used in the fabrication of highly efficient ion release films for applications such as antibacterial coatings. In this approach, the amino groups of the PAH acted as reducing agent and made possible the in situ formation of the Ag NPs. This reduction reaction occurred during the LbL process as the coating was assembled, without any further step after the fabrication and stabilization of the multilayer film. Biamminesilver nitrate was used as the Ag+ ion source during the LbL process and it was successfully reduced to Ag NPs. All coatings were tested with gram-positive and gram-negative bacterial cultures of Escherichia coli, Staphylococcus aureus, and Lactobacillus delbrueckii showing an excellent antimicrobial behavior against these types of bacteria (more than 99.9% of killing efficiency in all cases).
Open Access
Tuning the sensitivity of photonic sensors toward alkanes through the textural properties of hybrid xerogel coatings
(Wiley, 2025-01-15) Rosales Reina, María Beatriz; López Torres, Diego; Cruz Quesada, Guillermo; Espinal Viguri, Maialen; Elosúa Aguado, César; Reinoso, Santiago; Garrido Segovia, Julián José; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This work exemplifies how incorporating organosilane modifiers into silica matrices allows for tuning the optical response of reflection photonic sensors through customizing the textural properties of hybrid xerogel sensing films. Xerogels with propyl molar percentages 0, 5, and 10% are used to construct photonic probes (OFS0pTEOS, OFS5pTEOS and OFS10pTEOS, respectively) by dip-coating upon optimizing film deposition parameters. The time response of these probes toward a battery of volatile organic compounds (VOCs) comprising species with different functionality, size-shape, and polarity is systematically analyzed through ON/OFF experiments, revealing that a low propyl content makes the poor-responding OFS0pTEOS film highly sensitive toward non-aromatic, large molecules with low-polar or non-polar character in OFS5pTEOS. This sensor is particularly sensitive toward alkanes, with globular cyclohexane (cyHex) outperforming elongated n-hexane. Variable-temperature calibration curves obtained from step-by-step experiments and adsorption-desorption cycles corroborate these observations and allow hysteresis to be quantified. The response to cyHex closely follows VOC concentration changes with the most stable signal among analytes, leading to well-defined curves with low-to-negligible hysteresis. The isosteric enthalpies of cyHex adsorption are obtained for both the bulk material and the sensor, demonstrating labile adsorbate-adsorbent interactions ruling the sensor response and becoming more exothermic for larger VOC concentrations.