A Compact Biosensor for Binding Kinetics Analysis of Protein–Protein Interaction

Kinetics analysis of specific interactions of proteins is important for elucidating the molecular mechanism and the cellular process. In this work, we demonstrated a portable sensor based on fiber-optic (FO) surface plasmon resonance (SPR) sensing elements which can be used to detect the kinetics of protein-protein interaction. The sensor was built by FO-SPR sensing elements, an optical fiber, a red light-emitting diode (LED) and a detection platform based on smartphone. We set reference channel and control channel to compensate the fluctuations of the LED power, ambient temperature and refractive index (RI) of the buffer. Our sensor can monitor the interaction process in real-time and give valuable dynamic information. To verify its performance, the interactions between Ranse B/protein A and Con A/IgG were used as model systems. The sensor was examined by the recognitions of Con A and IgG on functionalized gold film, and the detection data was used to calculate the kinetic rate constant and binding constant of the reaction. The results demonstrate the superiority of our sensor in biomolecular recognition and kinetics analysis.