Image Signal Acquisition System For SPR Micro-Array Based On Phase Detection

High-throughput SPR (Surface Plasmon Resonance) microarray detectiontechnique, which is a powerful tool for the study of proteomics and drugdiscovery and development, is currently a hot research topic. Phase detectionhas the highest resolution in all SPR detection methods;its resolution ishighly dependent on data acquisition and analysis, including photoelectricconversion, ADC (Analog-to-Digital Converter), data transfer and algorithm.In this thesis, the image signal acquisition system and data analysis formicro-array biosensor based on phase detection is studied and carried out.Firstly, the foundation of acquring image and method of data analysis for SPRphase detection are carefully studied. Secondly based on these studying, animage acquisition system which using high resolution black and white CCD(Charge Coupled Device) sensor is designed. Finally, experiments are carriedout for testing this system by resolution and sensitivity.Mainly, there are there methods of data analysis for studying micro-arraybased on phase detection SPR at present, including correlation, sinusoidalfitting, and FTP (Fourier Transform Process). Their resolution is concernedwith spatial sampling frequency, number of signal periods and bits of ADC.By mathematic simulations, the relationships among them have been carefullystudied, and optimized parameters have been gotten for guiding to designimage capturing system.At present, the image signal of micro-array biosensor based on phasedetection SPR is the interference patterns which are spatially distributedsignals. In order to achieve high resolution for the detection, mostly highresolution black and white CCD sensor is used. There are several sources ofnoise which influence the resolution of the image acquisition system,including noise of CCD sensor, circuit noise, ADC transform error, and so on.So, it is important for properly designing circuit to achieve high resolution.Meanwhile, the numerated image signal should transfer to PCs immediatelyfor real-time data analysis. Finally, an image acquisition system is designedby using high resolution black and white CCD sensor, special ADC whichtransforms analog singles to digital signals, and USB (Universal Serial Bus)which transfer digital signals to PCs.The image acqurisition system is carried out by hardware design andsoftware design. The hardware is mainly including analog drivers for CCDsensor, ADC transforming circuit, USB transferring circuit and CPLD(Complex Programmable Logic Device) controlling circuit. The software ismainly including USB firmware, system driver, and application software.By debugging and testing the circuit and software, the image signals arefinally gotten. And by experiments, the quality of the image is analyzed,including resolution, sensitivity and noise. The insufficiency of the systemhas been pointed out and the way how to prove it has also been pointed out.