Open Access
Direct functionalization of TiO2/PSS sensing layer for an LMR-based optical fiber reusable biosensor
(IEEE, 2023) Santano Rivero, Desiree; Socorro Leránoz, Abián Bentor; Del Villar, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA2033
Functionalization plays a crucial role in the development of biosensors. In this study, bioreceptors were directly immobilized onto the surface of a sensing layer after physical activation, avoiding the need for longer and more complex functionalization systems. This direct immobilization was applied to an optical sensing platform based on lossy mode resonances (LMRs) generated by a thin-film of titanium (IV) dioxide/poly(sodium 4-styrenesulfonate) (TiO 2 /PSS). To generate the LMR, a 200-micron bare optical fiber was coated with TiO 2 /PSS using the layer-by-layer self-assembly technique. The PSS of the sensing layer was then physically activated using either UV-ozone or plasma to immobilize anti-rabbit IgG bioreceptors. This enabled specific and label-free detection of rabbit IgG concentrations ranging from 0.002 to 2 mg/ml. The results presented in this work include real-time detection of rabbit IgG, a comparison between the two activation techniques (UV-ozone and plasma), and an analysis of the biosensor’s reusability over four consecutive cycles, which demonstrates the promising potential of the TiO 2 /PSS sensing layer for biosensing applications.
Open Access
Ultrahigh sensitive detection of tau protein as Alzheimer's biomarker via microfluidics and nanofunctionalized optical fiber sensors
(Wiley, 2022) Chiavaioli, Francesco; Santano Rivero, Desiree; Del Villar, Ignacio; Socorro Leránoz, Abián Bentor; Zhang, Xuejun; Li, Kaiwei; Santamaría Martínez, Enrique; Fernández Irigoyen, Joaquín; Baldini, Francesco; Van den Hove, Daniel L. A.; Shi, Lei; Bi, Wei; Guo, Tuan; Giannetti, Ambra; Matías Maestro, Ignacio; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Alzheimer’s disease (AD) is one of the most common neurodegenerative illnesses displaying the highest death rate in the elderly. However, the existing AD diagnostic system remains elusive due to lack of a technology that may ensure enough sensitivity and reproducibility, detection accuracy, and specificity. Herein, a straightforward approach is reported to realize lab-on-fiber (LoF) technology for AD biomarker detection based on a D-shaped single-mode fiber combined with nanometer-scale metal-oxide film. The proposed sensing system, which permits the generation of lossy-mode resonance (LMR), remarkably increases the evanescent field of light guided through the fiber, and hence the fiber-surrounding medium interaction. Moreover, such optical sensors are highly repeatable in results and can safely be embedded into a compact and stable microfluidic system. Herein, the specific detection of Tau protein (as one of the classical AD biomarkers that is highly correlated with AD progression) in a complex biofluid with a detection limit of 10 12 M and over a wide concentration range (10 3 –10 μg mL 1 ) is successfully demonstrated. The proposed LoF biosensor is an appealing solution for rapid, sub-microliter dose and highly sensitive detection of analytes at low concentrations, hereby having the potential toward early screening and personalized medicine in AD.
Open Access
UV light detection with side polished CYTOP fiber
(IEEE, 2023) Ayechu Abendaño, Ada; Santano Rivero, Desiree; López Vargas, Juan David; Matías Maestro, Ignacio; Del Villar, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Cyclic transparent optical polymer (CYTOP) fiber, used mainly in strain detection and refractive index characterization of liquids, can be polished for the detection of ultraviolet (UV) light radiation. The study investigates the transmission spectra of CYTOP fiber exposed to different intensities of UV light, demonstrating a linear relationship. A simplified system using a single wavelength, i.e., 395 nm, shows real-time performance of the sensor in a range from 1 to 15 mW. The results reveal the potential of CYTOP fiber as a UV sensor with a sensitivity of 0.65%/mW and a limit of detection of 0.3 mW, offering implications for monitoring UV radiation exposure and related health risks. In addition, the effect of the UV light was also observed at longer wavelengths with a lower intensity variation, which suggests that CYTOP fiber could be used for transmitting the UV radiation detection in telecommunications bands.
Open Access
Optimization of fiber optic biosensors based on lossy mode resonances
(2024) Santano Rivero, Desiree; Del Villar, Ignacio; Socorro Leránoz, Abián Bentor; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektriko eta Elektronikoaren eta Komunikazio Ingeniaritzaren; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Este trabajo de tesis se centra en el desarrollo y la optimización de biosensores de fibra óptica basados en resonancia de modos con pérdidas (lossy mode resonances, LMR). Tras un análisis exhaustivo de la situación actual, donde se describen y comparan los diferentes tipos de biosensores de fibra óptica entre sí en base a parámetros como sensibilidad, FoM, FMHW y LoD, se desarrollaron diferentes biosensores basados en LMR. Se trabajó con tres estructuras ópticas diferentes: multimodo sin nucleo multimodo o multimode coreless multimode (MCM), fibra de 200 μm sin cladding y fibra tipo D. En ellas se generaron LMRs a través de dos técnicas de deposición de películas delgadas, oxido de estaño mediante sputtering y TiO2/PSS mediante layer by layer sefl asembly. Se demostró la viabilidad de los biosensores basados en LMR desarrollados con las diferentes estructuras de fibra óptica. Con ellos, se pudo detectar biomarcadores de importancia clínica como el biomarcador del Alzheimer proteína Tau o biomarcadores de gravedad durante la infección Covid19: las proteínas C reactiva y dímero D. Además, estas estructuras han permitido implementar optimizaciones sobre biosensores de fibra óptica como el desarrollo de biosensores reutilizables, regenerables y multiparamétricos.
Open Access
Biophotonic platform for detection of hallmarks of Alzheimer's disease via combined microfluidics and nanofunctionalized fiber sensors
(IEEE, 2023) Santano Rivero, Desiree; Lijiao, Zu; Jiwei, Xie; Peng, Liu; Zhang, Xuejun; Shi, Lei; Socorro Leránoz, Abián Bentor; Matías Maestro, Ignacio; Giannetti, Ambra; Baldini, Francesco; Santamaría Martínez, Enrique; Fernández Irigoyen, Joaquín; Li, Kaiwei; Bi, Wei; Van den Hove, Daniel L. A.; Del Villar, Ignacio; Guo, Tuan; Chiavaioli, Francesco; Ciencias de la Salud; Osasun Zientziak; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
The emergence of Covid-19 pandemic has drawn large attention to vulnerable people affected by major diseases. According to the World Health Organization (WHO), more than 55 million people worldwide suffer from dementia. Alzheimer's disease (AD) is the predominant type of dementia, accounting for 60-70% of cases [1]. A long-standing challenge is to attain early diagnosis of AD hallmarks (tau protein, ¿P; amyloid beta, A¿) by detecting them in biological fluids, thus avoiding the labor of specialized hospital personnel and the high cost of imaging examinations. Different biological fluids are being used to detect AD biomarkers, such as cerebrospinal fluid (CSF), serum, blood-plasma [2]. Biomarker level in CSF has been shown to increase in the very early stages of the disease where its elevated value makes higher the risk of a quicker development of AD dementia. Traditional methods for biomarker detection are mostly based on ELISA or mass spectrometry, which possess well-known disadvantages in comparison with electrochemical or optical approaches [3,4].