A label-free fiber optic SPR biosensor for specific detection of C-reactive protein

Yuzhi Chen,Xueming Hong,Xuejin Li,Zhigang Mai,Liang Li,Qingning Su,Jiaqi Wang,Wenjia Wang

doi:10.1038/s41598-017-17276-3

Abstract

A highly sensitive and label-free fiber optic surface plasmon resonance (SPR) biosensor for specific detection of C-reactive protein (CRP) is proposed and demonstrated. We take dopamine as a cross-linking agent to immobilize the anti-CRP monoclonal antibody, which is an efficient and simple method for specific modification of the fiber optic SPR sensor. The modified sensor can successfully detect CRP specifically. We realize the fabrication of a disposable fiber optic SPR sensor for the CRP specific detection. Through optimizing the immobilization time of anti-CRP monoclonal antibody and the reaction time of antigen and antibody experimentally, the sensor shows a satisfactory linear response (R2 = 0.97) to CRP concentration within the range from 0.01 to 20 μg/ml. Moreover, the highest CRP sensitivity is obtained at 1.17 nm per lg (μg/ml). With the advantages of simple structure and easy fabrication, our sensor is convenient to be batch produced and controlled with good consistency, which is especially suitable for the fabrication of disposable biosensor. It makes sense that our detection can effectively avoid the cross pollution caused by repeated use of the sensor.

Highlights

Different from the above detection methods, fiber optic surface plasmon resonance (SPR) sensing is a new biochemical detection method with the advantages of compact footprint, label-free detection, real-time monitoring, rapid detection and non-invasive measurements[10,11,12]
We propose and demonstrate a label-free fiber optic SPR biosensor for specific detection of C-reactive protein (CRP) concentration
We realize the fabrication of disposable fiber optic SPR sensor for the CRP specific detection

Summary

Results and Discussion

Performance evaluation of the fiber optic SPR sensor. Figure 1(a) shows normalized reflection spectra of the fiber optic SPR sensor in measuring NaCl solutions with different concentrations. The specific target detection ability is analyzed through comparatively testing the CRP and bovin serum albumin (BSA) solutions with the same concentration by the anti-CRP monoclonal antibody immobilized sensor. The anti-CRP monoclonal antibody immobilized sensors are used for detecting 50 μg/ml solutions of CRP and BSA diluted in PBS buffer, respectively. The sensors in the second step are immersed in PBS buffer again The shifts of their resonance wavelengths of the two sensors in each of the three steps are shown in Fig. 2(a) and 2(c), respectively. The PDA functionalized sensors are immersed in 50 μg/ml solutions of anti-CRP monoclonal antibody and Eab antibody (the antibody with no response to CRP) diluted with PBS buffer for 4 hours, respectively. The resonance wavelength shift is proportional to the CRP concentration

Methods

Author Contributions

Additional Information