Opto-electrochemical sensing of C-reactive protein using optical fiber lossy-mode resonance sensor

Abstract

This work describes an experimental study towards label-free sensing of C-reactive protein (CRP) – a protein recognized as a inflammation marker. A multimode optical fiber with a section of its core coated with indium tin oxide (ITO) thin film was used as a sensor. ITO film allows for guiding lossy modes and can simultaneously be used as a transparent electrode for electrochemical measurements. Therefore, optical and electrochemical detection based on a single sensor was possible. Such a dual-domain approach is practical, especially when the results in one of the domains are not accurate enough, which was the case in this work. A case of different functionalization methods of ITO surface was also pointed out. The proposed sensor allows for recognition as low as ng/mL.