This current paper presented the kinetic analysis and model building using the Marquardt algorithm based on Gauss-Newton iteration for biomolecular interaction. This algorithm for biomolecular interaction analysis of the optical surface plasmon resonance was applied to implement the nonlinear fitting of association and disassociation process of the receptor to ligand (or the antibody to antigen). Finally, the kinetic parameters were obtained from the fitting curve established by the Marquardt algorithm. The results show that the Marquardt algorithm does not only reduce the dependence of initial value to avoid the divergence but also can greatly reduce the iterative regression times. The correlation coefficient R-squared of the original curve formed by OriginPro and the fitting curves constructed using the Marquardt algorithm in association process and in disassociation process were 0.99158 and 0.99693, respectively. Correspondingly, the kinetic parameters and affinity constants were evaluated using the obtained data from the fitting results.

An optical surface plasmon resonance(SPR) biosensor detection system was designed,which was used to detect estradiol in environmental estrogens and composed of an integrated optical SPR biosensor,a micro-flow cell,a clamp,a touch monitor screen and an electrical control unit(ECU) incorporated with a photoelectric conversion board and a USB interface board.In this study,the antigen-estradiol was immobilized to the surface of the biosensor chip,then the antigen-estradiol samples at 25,50,100,200 mg·L-1 were respectively added into the standard solution of antibody-estradiol for pre-reaction,and the mixture solution after pre-reaction flowed through the surface of the SPR biosensor chip,obtaining the standard curve for detecting estradiol,and coefficient of correlation is 0.997 8.