Design And Data Analysis Of A Controllable CCD-based Optical Surface Plasmon Resonance Bioanalyzer

Optical surface plasmon resonance (SPR) biosensor is a rapid and efficient biological sensitive detection device in real-time biological measurement. With the characteristics of label free, non-destructive and real-time online detection, it has been widely used in the analysis of food safety, environmental protection, clinical medicine, pharmaceutical research and agriculture. In the process of biomolecular interaction, optical SPR biosensors that can real-time monitoring of biomolecular reaction rate and affinity has provided a strong support for the protein function analysis, pharmaceutical development, genomics and proteomics. Optical SPR biosensor can monitor the binding and dissociation process of antigen and antibody (ligand and receptor) in real time. According to the association and dissociation curve, it has been quantitatively analyzed on coupling biomolecular of biological sensitive membrane established on the Au film of SPR biosensor. By the curve-fitting calculation of kinetic data and affinity constants of the biomolecular interaction, it is great significance to study the kinetics process of biomolecular interaction.This thesis presents the design scheme of a novel controllable CCD-based optical SPR bioanalyzer. The controllable CCD-based optical SPR bioanalyzer detection platform was constructed successfully. The structure, photoelectric signal detection and data processing algorithm of the controllable CCD-based optical SPR bioanalyzer were given. DC motor drived by a laser line generator in a variable speed reciprocating motion on the guide rail was used to complet the scanning angle on the Au film deposited on the surface of the SPR biosensor. By the calculation using the rectangular prism instead of the traditional equilateral triangular prism to analyze the sensitivity of the SPR biosensor, the rectangular prism was chosen to construct the SPR platform which is not only be convenient installed and adjusted, but also can be avoid the constraints of incident light angle interference.Using the A44E Hall sensor to detect the laser line displacement signals transmitted from the microcontroller STC89C51, the Keil C software was used to program embedded into the microcontroller STC89C51. The area array CCD which was used to collect the image data was controlled by the interrupt signal, the image acquisition time and location.In order to obtain the lowest response unit from the optical SPR bioanalyzer, the image data was dealt by the limiting amplitude filter, centroid algorithm, the median filtering. The dynamic baseline was considere in the centroid algorithm. Using the volume fraction ethanol solution of 10%,25%,30%,40%,50% and 60%, the performance of the controllable CCD-based optical SPR bioanalyzer was validated experimentally. The relationship curve between the resonance optical SPR pixel positions and the volume fraction of ethanol was established. The results show that the controlled CCD-based optical SPR bioanalyzer used in the detection of the volume fraction of ethanol solution has a better linear relationship and higher sensitivity. The correlation coefficient of 0.9988 and the sensitivity of 845.60 (resonance pixels position per volume fraction ethanol) were obatined. This paper proposes a novel method to implement the kinetic data analysis of biomolecular interaction using the Marquardt algorithm based on Gauss-Newton algorithm. The Pseudo First Order kinetic model of biomolecular interaction was established firstly. Then the data of molecular interaction of hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (HBsAb) was obtained by the homemade bioanalyzer. Finally, we used this kinetic model formed by Marquardt algorithm to perform the nonlinear curve fitting for the calculation of the association and dissociation parameters. The results show that Marquardt algorithm does not only reduce the dependence of initial value to avoid divergence but also greatly reduce the iterative regression times.To meet the development requirements of the portable bioanalyzer, the controllable CCD-based optical SPR bioanalyzer is needed. It not only solved the resulting interfere phenomenon occurred in the area array CCD of an angle-scanning optical SPR bioanalyzer due to the laser line generator mismatched between collection frequency and laser rate, but also solved the problem of area array CCD acquisition stagnation phenomenon caused by too large data acquired from the area array CCD, greatly improved the detection efficiency and accuracy. With area array CCD technology constantly innovation and widely used in rapid detection, the area array CCD image acquisition can satisfy the detection of multi-channel and multi-material requirement, therefore the controllable CCD-based optical SPR bioanalyzer has a wide development prospects.