Sensitive detection of C-reactive protein using optical fiber Bragg gratings

• The clad etched fiber Bragg grating (eFBG) sensors with graphene oxide (GO) for CRP detection.
• GO functionalized with anti CRP antibody coated eFBG has shown the enhanced sensitivity (10μg/L).
• An accurate detection of low concentration of CRP is achieved even in the presence of interfering factors.
• Linear range of detection includes the clinical range of CRP.

An accurate and highly sensitive sensor platform has been demonstrated for the detection of C-reactive protein (CRP) using optical fiber Bragg gratings (FBGs). The CRP detection has been carried out by monitoring the shift in Bragg wavelength (ΔλBΔλB) of an etched FBG (eFBG) coated with an anti-CRP antibody (aCRP)-graphene oxide (GO) complex. The complex is characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy. A limit of detection of 0.01 mg/L has been achieved with a linear range of detection from 0.01 mg/L to 100 mg/L which includes clinical range of CRP. The eFBG sensor coated with only aCRP (without GO) show much less sensitivity than that of aCRP–GO complex coated eFBG. The eFBG sensors show high specificity to CRP even in the presence of other interfering factors such as urea, creatinine and glucose. The affinity constant of ∼1.1×1010M−1 has been extracted from the data of normalized shift (ΔλB/λBΔλB/λB) as a function of CRP concentration.