Open Access
Micro sized interdigital capacitor for humidity detection based on agarose coating
(2021) Vitoria Pascual, Ignacio; Armas, Dayron; Coronel Camones, Carlos Manuel; Ozcariz Celaya, Aritz; Ruiz Zamarreño, Carlos; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
A micro sized interdigital capacitor has been proposed for the detection of relative humidity. The photolithography technique enables the fabrication of fingers with a size of 10x500 um. A thin film of agarose functionalizes the sensor for humidity sensing, which improves its performance by 155 times, obtaining a sensitivity of 32.98 pF/%RH.
Open Access
Optical sensors based on lossy-mode resonances
(Elsevier Science, 2017) Matías Maestro, Ignacio; Ascorbe Muruzabal, Joaquín; Acha Morrás, Nerea de; López Torres, Diego; Zubiate Orzanco, Pablo; Sánchez Zábal, Pedro; Urrutia Azcona, Aitor; Socorro Leránoz, Abián Bentor; Rivero Fuente, Pedro J.; Hernáez Sáenz de Zaitigui, Miguel; Elosúa Aguado, César; Goicoechea Fernández, Javier; Bariáin Aisa, Cándido; Corres Sanz, Jesús María; Ruiz Zamarreño, Carlos; Arregui San Martín, Francisco Javier; Del Villar, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC
Open Access
Optical biosensors: a quick overview
(2021) Imas González, José Javier; Ruiz Zamarreño, Carlos; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This work aims to provide a brief overview of the latest trends in the domain of optical biosensors.
Open Access
Photonic chip breath analyzer
(SpringerOpen, 2025-06-03) Gallego Martínez, Elieser Ernesto; Matías Maestro, Ignacio; Ruiz Zamarreño, Carlos; 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 introduces a novel single-package optical sensing device for multiple gas sensing, which is suitable for breath analysis applications. It is fabricated on a coverslip substrate via a sputtering technique and uses a planar waveguide configuration with lateral incidence of light. It features three sequentially ordered strips of different materials, which serve to increase the multivariate nature of the response of the device to different gases. For the proof-of-concept, the selected materials are indium tin oxide (ITO), tin oxide (SnO2), and chromium oxide III (Cr2O3), while the selected gases are nitric oxide (NO), acetylene (C2H2), and ammonia (NH3). The sensing mechanism is based on the hyperbolic mode resonance (HMR) effect, with the first-order resonance obtained for each strip located in the near infrared region. The multivariate response of the resonances and the correlation with the concentration of each gas allow training a machine learning (ML) model based on a nonlinear autoregressive neural network, enabling the accurate prediction of the concentration of each gas. The obtained limit of detection for all the gases was in the order of a few parts per billion. This innovative approach coined as the multivariate optical resonances spectroscopy demonstrates the potential of HMR-based optical sensors in combination with ML techniques for ultra-sensitive multi-gas detection applications using a single device.
Open Access
Low-cost optical fiber multimode interference biosensor based on a glucose sensitive Glucose-Oxidase enzyme thin-film
(Elsevier, 2024-12-04) Rodríguez Rodríguez, Wenceslao Eduardo; Rodríguez Rodríguez, Adolfo Josué; Juárez-Saldivar, Alfredo; Ruiz Zamarreño, Carlos; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
In this research we report a contribution for the development of low-cost fiber optical biosensors fabricated by the Single Mode-Multi Mode-Single Mode configuration applied for the glucose monitoring considering clinical concentrations ranges in aqueous analytes. Designed devices are evaluated using health standard detection ranges, such as healthy, pre-diabetic, and diabetic stages operating at the visible spectral region. The sensing regions has been prepared by the etching technique in order to improve the interaction between the evanescent wave with the surrounding medium followed by functionalization of enzyme oxidase glucose via the electrostatic self-assembly using by Poly(allylamine hydrochloride) as an immobilizer matrix. The increase of bilayers number over the sensor surface permits us to demonstrate the enhancement of sensitivity and limit of detection. Experimental results permitted the glucose characterization in the range from 0.3 to 2.4 mg mL-1 obtaining a response time of 9 s and a sensitivity of 1.8 nm/(mg mL-1) allowing to detect hypoglycemia and diabetes stages according to the World Health Organization standards.
Open Access
Fiber-optic pH sensors fabrication based on selective deposition of neutral red
(IEEE, 2009-01-22) Hernáez Sáenz de Zaitigui, Miguel; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ruiz Zamarreño, Carlos; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, a novel application of the electric field directed layer-by-layer self assembly (EFDLA) selective deposition method for the fabrication of optical fiber pH sensors is presented. Here, indium tin oxide (ITO) coated optical fibers have been fabricated via a dip-coating deposition method. These fibers are used as electrodes in the EFDLA protocol in order to deposit selectively the sensitive layer. Neutral Red (NR) colorimetric pH sensitive indicator and the polymers poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH) are used in order to obtain a pH sensitive nanostructured coating onto ITO coated optical fibers. The results obtained in this work revealed that the LbL material adsorption on the electrodes can be enhanced or even inhibited when applying a specific direct current voltage between them under some other specific fabrication parameters. Particularly, the response of these sensors to variations of the pH in the surrounding medium was studied when the pH of the solutions used for the fabrication of the films was adjusted to 7.0 and the potential applied between electrodes was set to 2.5 V. These sensors showed fast response time and high repeatability.
Open Access
Ultra-low detection limit lossy mode resonance-based fibre-optic biosensor
(Optica Publishing Group, 2018) Chiavaioli, Francesco; Zubiate Orzanco, Pablo; Del Villar, Ignacio; Ruiz Zamarreño, Carlos; Giannetti, Ambra; Tombelli, Sara; Trono, Cosimo; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Baldini, Francesco; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
We report on ultra-low detection limit lossy mode resonance-based fibre-optic biosensor coated with nm-thick tin dioxide film, which allows measuring fibre-surrounding medium changes with very high sensitivity for label-free and real-time biomolecular interaction analysis
Open Access
D-shape optical fiber refractometer based on TM and TE lossy mode resonances
(SPIE, 2014) Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
The fabrication and characterization of an optical fiber refractometer based on Lossy Mode Resonances (LMR) is presented. TiO2/ poly (sodium 4-styrenesulfonate) coatings deposited on side-polished D-shaped optical fibers are used as LMR supporting coatings. LMRs are sensitive to the external medium refractive index and D-shaped optical fibers enable the observation of TE and TM LMR polarizations. These refractometers based on TE and TM LMR showed an average sensitivity of 2737 nm/RIU and 2893 nm/RIU respectively for a surrounding medium refractive index (SMRI) range from 1.35 to 1.41.
Embargo
Hyperbolic mode resonance-based acetone optical sensors powered by ensemble learning
(Elsevier, 2024) Gallego Martínez, Elieser Ernesto; Ruiz Zamarreño, Carlos; Meurs, Joris; Cristescu, Simona M.; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The current work describes and compares the performance of hyperbolic mode resonance (HMR)-based sensors for the detection of acetone at parts per billion (ppb) concentrations using ensemble machine learning (EML) techniques. A pair of HMR based-sensors with resonances located in the visible (VIS) and mid infrared (MIR) regions were obtained in order to train a set of ensemble machine learning models. The response of the detection system formed by both devices in the VIS and MIR regions, with the help of the EML system, allowed the limit of detection (LoD) of the sensors to be reduced by an order of magnitude. It is the first time that HMR-based sensors are shown in practical applications, at the same time that their performance is improved using EML techniques. This opens new avenues for the use of this type of HMR-based sensors for the detection of other substances, in addition to improving the performance of any optoelectronic sensor using EML techniques.
Open Access
Short single strand DNA detection by means of Lossy Mode Resonance based fiber-optic sensor
(IEEE, 2019-01-14) Zubiate Orzanco, Pablo; Ciáurriz Gortari, Paula; Tellechea Malda, Edurne; Santano Rivero, Desiree; Del Villar, Ignacio; Urrutia Azcona, Aitor; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ruiz Zamarreño, Carlos; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA26
Development of DNA and RNA biosensors and the associated diagnostic tests have gained growing interest in recent years. In particular, short RNA chains (around 25 oligonucleotides), known as micro RNAs, can be associated different stroke and neurodegenerative diseases. Here, we present the utilization of highly sensitive fiber optic sensor based on Lossy Mode Resonance (LMR) for the detection of single strand complementary DNA (ssDNA) associated to Huntington disease (Hsa-miR-34b).