Open Access
Albumin-based optical and electrochemical biosensors for PFAS detection: a comparison
(Springer, 2023) Moro, G.; Chiavaioli, Francesco; Zubiate Orzanco, Pablo; Del Villar, Ignacio; Baldini, Francesco; De Wael, K.; Moretto, L. M.; Giannetti, Ambra; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
The widespread industrial use of per- and polyfluoroalkyl substances (PFAS) have engendered the release of these manmade chemicals in the environment with harmful effects on animal and human health. To monitor PFAS levels in drinking waters, sensitive and versatile sensing strategies are urgently required. Since many perfluoroalkyl carboxylic acids, such as perfluorooctanoic acid (PFOA), are fatty acid-mimic, delipidated human serum albumin (HSA) can be applied as biorecognition element for the design of novel PFAS sensors. Here, two albumin-based biosensing strategies are described and compared: i) a lossy mode resonance (LMR) fiber optic one and ii) an impedimetric portable one developed on screen-printed electrodes. In both biosensing platforms, HSA was covalently immobilized via EDC/NHS chemistry using the carboxylic moieties of the polymeric layers previously deposited at the transducer surface. Afterwards, the conformational changes related to the formation of HSA/PFOA complex were followed considering: i) the LMR spectral shifts for the optical platform and ii) the changes of absolute impedance for the impedimetric one. The performance and future developments of both PFOA biosensors are discussed.
Open Access
Fiber-based label-free D-dimer detection for early diagnosis of venous thromboembolism
(SPIE, 2020) Zubiate Orzanco, Pablo; Urrutia Azcona, Aitor; Ruiz Zamarreño, Carlos; Fernández Irigoyen, Joaquín; Giannetti, Ambra; Baldini, Francesco; Díaz Lucas, Silvia; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Santamaría Martínez, Enrique; Del Villar, Ignacio; Chiavaioli, Francesco; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
D-dimer is a useful diagnostic biomarker for deep vein thrombosis or pulmonary embolism, collectively referred to as venous thromboembolism (VTE). The ability to detect in real-time the amount of D-dimer with a fast and reliable method is a key step to anticipate the appearance of these diseases. The combination of fiber-optic-based platforms for biosensing with the nanotechnologies is opening up the chance for the development of in situ, portable, lightweight, versatile, reliable and high-performance optical sensing devices towards lab-on-fiber technology. The generation of lossy mode resonances (LMRs) by means of the deposition of nm-thick absorbing metal-oxide films on special geometric-modified fibers allows measuring precisely and accurately surface refractive index changes, which are due to the binding interaction between a biological recognition element and the analyte under investigation. This approach enhances the light-matter interaction in a strong way, thus turning out to be more sensitive compared to other optical technology platforms, such as fiber gratings or surface plasmon resonance. Here, the results of a highly specific and sensitive biosensor for the detection of D-dimer based on LMR in fiber-optics are presented by monitoring in real-time the shift of the LMR related to the biomolecule interactions thanks to a conventional wavelength-interrogation system and an ad-hoc developed microfluidics. A detection limit of 100 ng/mL, a value 5-fold below the clinical cutoff value, has been attained for D-dimer spiked in human serum. The comparison of the results achieved with proteomics-based methodologies, which allows for the identification of betaand gamma-chains of fibrinogen, demonstrates the ability of our platform to specifically (>90%) recognize D-dimer.
Open Access
D-shape optical fiber pH sensor based on lossy mode resonances (LMRs)
(IEEE, 2016-01-07) 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 pH sensor based on Lossy Mode Resonances (LMRs) is presented. PAH/PAA polymeric thin-films fabricated onto side-polished D-shaped optical fibers are used as LMR supporting coatings. The thickness of PAH/PAA coatings can be modified as a function of the external medium pH. As a consequence of this variation, the effective refractive index of the structure will change, producing a shift of the LMR. The fabricated sensor has been used to measure pH from 4.0 to 5.0. This pH sensor showed a sensitivity of 101.3 nm per pH unit, which means a resolution of ~6×10-4 pH units by using a conventional communications Optical Spectrum Analyzer (OSA), which is an improvement over commercial pH sensors.
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).
Open Access
Molecules assembly toward fiber optic nanosensor development
(SPIE, 2004-06-09) Matías Maestro, Ignacio; Del Villar, Ignacio; Arregui San Martín, Francisco Javier; Claus, Richard O.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Different optical fiber sensor configurations based on a LBL nano-technique will be presented. With this technique it is possible to fabricate different structures such as nano Fabry Perot interferometers, optical fiber gratings and any other one dimensional photonic bandgap structures that may be used either for sensing applications or for the implementation of other fiber optic devices. Some of the proposed fiber optic sensors have been fabricated and their main characteristics are their negligible temperature dependence, their fast response, the possibility of using low cost LEDs instead of lasers or even the possibility of operating at different wavelengths.
Open Access
Mode transition during deposition of nanoscale ITO coatings on tilted fiber Bragg gratings
(Optica Publishing Group, 2022) Imas González, José Javier; Albert, Jacques; Del Villar, Ignacio; 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
The mode transition phenomenon is experimentally demonstrated in tilted fiber Bragg gratings (TFBG) through the deposition of an indium tin oxide (ITO) thin film employing a DC sputtering machine.
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.
Open Access
All fiber interferometer for ice detection
(Optica Publishing Group, 2018) Arozarena Arana, Jesús Antonio; Socorro Leránoz, Abián Bentor; Del Villar, Ignacio; Díaz Lucas, Silvia; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC
This work presents an etched single-mode - multimode - single-mode structure that detects the solid-to-liquid change of state of the water due to an increased refractive index sensitivity within the 1.308 - 1.321 RIU range
Open Access
Asymmetrically and symmetrically coated tapered optical fiber for sensing applications
(SPIE, 2015) Del Villar, Ignacio; Socorro Leránoz, Abián Bentor; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The deposition of a non-metallic thin-film in a symmetrically coated tapered optical fiber leads to the generation of resonances due to guidance of a mode in the thin-film. At certain conditions, the resonances overlap each other, which can be avoided with an asymmetric coated tapered optical fiber, which permits to obtain resonances for TM and TE polarization separately. Numerical results showing the sensitivity to coating thickness and surrounding medium refractive index are also presented for both polarizations.
Open Access
Sensitivity enhancement by diameter reduction in low cutoff wavelength single-mode multimode singlemode (SMS) fiber sensors
(IEEE, 2017) Goñi Carnicero, Jaime; Del Villar, Ignacio; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Two different low cutoff wavelength single-mode fibers were used in single-mode multimode single-mode (SMS) configuration with the aim of designing sensors operating at short wavelengths, where optical sources and spectrometers are less expensive than in telecommunications bands. The diameter of the SMS structure was reduced with an etching process based on hydrofluoric acid immersion. The results prove that the devices can operate at wavelength ranges from 600 to 1200 nm and that multiple peaks can be obtained, each one with a different sensitivity that is proportional to the wavelength. Moreover, a fivefold increase in sensitivity to refractive index can be obtained. This high sensitivity indicates the possibility to apply this simple and cost-effective device in other applications such as biosensors or chemical sensors.