Label-free detection of C-reactive protein using reflectometric interference spectroscopy-based sensing system

Area of Science:

• Biomedical Engineering
• Biosensing Technology
• Analytical Chemistry

Background:

• Reflectometric interference spectroscopy (RIfS) is a label-free, time-resolved technique adept at detecting antibody-antigen interactions.
• Sensitive detection of C-reactive protein (CRP) is crucial for diagnosing various inflammatory conditions.
• Existing biosensing platforms, such as surface plasmon resonance (SPR), can be expensive and complex.

Purpose of the Study:

• To develop a continuous flow biosensor for sensitive C-reactive protein (CRP) detection using RIfS.
• To establish an effective method for immobilizing monoclonal antibodies against CRP (anti-CRP) onto a silicon nitride (SiN) chip.
• To demonstrate the feasibility of an inexpensive, silicon-based biosensor as an alternative to SPR.

Main Methods:

• Surface modification of SiN chips using trimethylsilylchloride (TMS) and UV irradiation to generate silanols.
• Amination, carboxymethyldextran (CMD) grafting, and subsequent immobilization of Protein A for oriented anti-CRP surface creation.
• Real-time monitoring of immobilization steps using the RIfS system.

Main Results:

• An optimized immobilization strategy involving Protein A and CMD significantly enhanced detection sensitivity.
• The RIfS system successfully demonstrated the detection of CRP using the developed biosensor.
• The fabricated biosensor utilizes inexpensive silicon-based chips and a simple optical setup.

Conclusions:

• The developed RIfS biosensor with oriented anti-CRP immobilization provides a highly sensitive platform for CRP detection.
• This cost-effective and simple biosensing system holds potential for various life science applications.
• The technology can serve as a viable alternative to more expensive SPR-based sensors for detecting diverse target molecules.