Double-layer optical fiber interferometer with bio-layer-modified reflector for label-free biosensing of inflammatory proteins

• Published in: Scientific reports Vol. 14; no. 1; pp. 23127 - 11
• Main Authors: Burnat, Dariusz, Janik, Monika, Kwietniewski, Norbert, Martychowiec, Agnieszka, Musolf, Paulina, Bartnik, Krzysztof, Koba, Marcin, Rygiel, Tomasz P., Niedziółka-Jönsson, Joanna, Śmietana, Mateusz
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04-10-2024; Nature Publishing Group; Nature Portfolio
• Subjects: 631/250/254; 639/624/1075; 639/624/1107; 639/624/399; 639/925/357/551; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Biosensors; Ferritin; Hafnium; Humanities and Social Sciences; Humans; Inflammation - diagnosis; Inflammation - metabolism; Inflammatory protein; Interferometry; Interferometry - methods; Label-free biosensing; multidisciplinary; Myeloperoxidase; Nanostructures - chemistry; Optical fiber sensor; Optical Fibers; Peroxidase; Peroxidase - metabolism; Refractometry; Science; Science (multidisciplinary); Sensors; Thin film; Thin films; Titanium - chemistry; Titanium dioxide; Label-free biosensing; Optical fiber sensor; In vivo sensing; Myeloperoxidase; Inflammatory protein; Interferometry; Thin film
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-024-70058-6

This work discusses label-free biosensing application of a double-layer optical fiber interferometer where the second layer tailors the reflection conditions at the external plain and supports changes in reflected optical spectrum when a bio-layer binds to it. The double-layer nanostructure consists of precisely tailored thin films, i.e., titanium (TiO
2
) and hafnium oxides (HfO
2
) deposited on single-mode fiber end-face by magnetron sputtering. It has been shown numerically and experimentally that the approach besides well spectrally defined interference pattern distinguishes refractive index (RI) changes taking place in a volume and on the sensor surface. These are of interest when label-free biosensing applications are considered. The case of myeloperoxidase (MPO) detection—a protein, which concentration rises during inflammation—is reported as an example of application. The response of the sensor to MPO in a concentration range of 1 × 10
−11
–5 × 10
−6
 g/mL was tested. An increase in the MPO concentration was followed by a redshift of the interference pattern and a decrease in reflected power. The negative control performed using ferritin proved specificity of the sensor. The results reported in this work indicate capability of the approach for diagnostic label-free biosensing, possibly also at in vivo conditions.