Authors:
Giuseppe Quero
1
;
Marco Consales
1
;
Renato Severino
1
;
Patrizio Vaiano
1
;
Alessandra Boniello
1
;
Annamaria Sandomenico
2
;
Menotti Ruvo
2
;
Anna Borriello
3
;
Laura Diodato
3
;
Simona Zuppolini
3
;
Michele Giordano
3
;
Immacolata Cristina Nettore
4
;
Annamaria Colao
4
;
Paolo Emidio Macchia
4
;
Flavio Santorelli
5
;
Antonello Cutolo
6
and
Andrea Cusano
6
Affiliations:
1
University of Sannio, Italy
;
2
Consiglio Nazionale delle Ricerche (IBB-CNR) and Centro Interuniversitario di Ricerca sui Peptidi Bioattivi (CIRPeB), Italy
;
3
Composites and Biomaterials (IPCB) -CNR, Italy
;
4
University of Napoli “Federico II", Italy
;
5
Hospital Consulting SpA, Italy
;
6
Optoelectronics Group, Dept. of Engineering and University of Sannio, Italy
Keyword(s):
Long Period Fiber Grating (LPG), Optical Fiber Biosensor, Reflection Type LPG, Thyroglobulin.
Abstract:
We report an innovative fiber optic biosensor based on Long Period Gratings (LPGs) working in reflection configuration for real time monitoring of human Thyroglobulin (Tg), a protein marker of differentiated thyroid cancer. A standard LPG is first transformed in a practical probe working in reflection mode, and then it is coated with a single layer of atactic polystyrene (aPS) in order to increase its surrounding refractive index sensitivity and to provide, at the same time, the desired interfacial properties for a stable anti-Tg antibody. The functionalized reflection-type LPG biosensor clearly demonstrates the effectiveness and sensitivity of the developed biosensing platform, allowing the real time and label-free detection of Tg in the needle washouts of fine-needle aspiration biopsies, at concentrations useful for pre- and post-operative assessment of the biomarker levels. Analyte recognition and capture were confirmed with a parallel on fiber ELISA-like assay using, in pilot tes
ts, the biotinylated protein and HRP-labeled streptavidin for its detection. Dose-dependent experiments showed that the detection is linearly dependent on concentration within the range between 0 and 4 ng/mL, while antibody saturation occurs for higher protein levels.
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