Research On Biomolecular Interaction Detection Based On Phase Modulation SPR Imaging

Proteomics has become a hot issue in life science research, which takes protein-protein interaction analysis as a major task. Unlike gene which is a stable chain composed of A-C and T-G base pairs, protein is composed of 20 different amino acids and shows complex spatio-temporal characteristics. Labeling methods for gene detection can not completely meet the requirements of protein detection. It is currently in urgent need of sensitive, labeless, real-time and high throughput protein detection methods. A novel SPR imaging biomolecular interatction detection method based on time domain phase modulation is presented in this thesis. It can sensitively acquire real-time phase change caused by biomolecular interaction based on interference imaging, and resolve related bioinformation, which is a potential tool for proteomics research. Focusing on this method, research has been done as follows:Phase detection sensitivity and refractive index detection range of the SPR sensor are analyzed. Based on SPR multi-diectric-layer model, phase-refractive index curves are obtained by numerical simulation. Results show that the thickness of gold layer determines the sensitivity and the dynamic range, and the incident angle determines the position of the linear detection range, which gives a criterion of sensor design in application.Phase detection precision of SPR imaging sensing based on TDPM is analyzed. Based on numerical simulation, phase extraction precision of the Stoilov algorithm is analyzed and compared with other algorithms, such as the Carre algorithm and the Hariharan algorithm. Results suggest that the Stoilov algorithm is more appropriate to SPR real-time phase detection.Experimental apparatus of SPR imaging biomolecular interaction detection based on TDPM is established. Preceded by analyzing the apparatus's noise sources and surpression, its performance is tested by NaCl solution at different concentrations. Results show that the sensitivity is 1.8×104°/RIU, the dynamic range is larger than 0.005RIU, the refractive index drifting is smaller than 3×10-6RIU in 30 minutes, and the refractive index resolution is 1.4×10-6RIU at detection throughput below 20.Biomolecular interaction is detected. 2×2 rabit IgG array chip is prepared and its interaction with the goat-anti-rabbit IgG is detected by the experimental apparatus. SPR curves of the interaction are obtained and kinetic parameters are calculated.It is proved that this method is high sensitive, labeless, real-time and capable of array detection, which can meet the requirements of proteomics research. Moreoever, the experimental apparatus and results provide a good foundation for design and development of the principle prototype.