Parallel Detection Of Refractive Index Changes In A Porous Silicon Microarray Based On Digital Images

Porous Silicon?PSi?has many advantages,such as large specific surface area,good biological activity,strong adsorption force and good biocompatibility,so it is widely applied to the substrate materials of optical biosensor.The microarray chip based on PSi has the advantages of label free and quantitative in biological detection.In recent years,the exploration and research of these applications set off the upsurge.Based on the digital image of PSi microarray,a new high-sensitivity method for measuring the change of refractive index is proposed in thispaper.Underthe excitation of the helium neon laser,the reflected light image of PSi microcavity array unit is obtained by digital imaging device.We calculate the refractive index change of the array element by the change of gray value of image.The method can detect the variation of refractive index of every array element,and the minimum can reach 10^-4,it can be used to detect refractive index change which caused by biological reactions in PSi microarray,therefore,a label free,fast and parallel biological detection is realized.The research content of this paper consists of three parts:1.The PSi microcavity microarray chip was successfully prepared,the Array distribution is 9×9 and the diameter is 500?m.2.simulate the relationship between the vacancy trap state wavelength and incident angle by using transfer matrix method,based on this relationship,the mechanism of angle measurement is studied.At the same time,simulate the relationship between the change of refractive index and incident angle and the relationship between the amount of reflectivity and the incidence angle by transfer matrix method.3.The microarray chips based on PSi are prepared,the reflected light image with microcavity array unit is obtained by digital imaging device,using digital processing software to transform image into grayscale,the middle region of the array unit is segmented in the maximum range,then the average gray value in the region is calculated,and the change amount of the gray value is used to reflect the change of the refractive index.This method can detect the refractive index change of every array unit with a minimum of 10^-4.Therefore,the change of refractive index caused by biological specific binding can be detected,and then label free,fast and parallel biological detection can be realized.