Investigation Of Light Propagation Properties In Immunochromatographic Strip

Immunochromatography optical and biological detection equipment is a typical kind of POCT instruments, having advantages such as:sensitive, rapid, flexibility, stability, portability and so on. To further enhance the performance of such devices, this paper discusses how to improve the detection level of immune chromatographic analyzers based on light propagation characteristics in immunochromatographic strip for the first time. Immunochromatographic strip belongs to the light turbid media just like biological tissues, so that we can introduce the analysis method of tissue optics to the study of light propagation characteristics in immunochromatographic strips.In this paper, the absorption coefficient and the reduced scattering coefficient of immunochromatographic strip are obtained by the single integrating sphere method and the inverse adding-doubling method. Henyey-Greenstein phase function model and infinitely long cylinder model are used to simulate the light propagation characteristics in immunochromatographic strip. The results of infinite cylinder model is very different from experimental measurements by single integrating sphere, but Henyey-Greenstein phase function model fits well. So we study the light propagation characteristics of the immunochromatographic strip and explore how the optical properties affect the light propagation characteristics based on the Henyey-Greenstein phase function model. We have the following conclusions for how to improve the detection level of immune chromatography analyzers.By the excitation light propagation characteristics in immunochromatographic strip, we can know that detecting fluorescence in a large angle deviation from the normal orientation of the interface in reflection space can reduce the interference of the excitation light, thereby improving the SNR. By the effects of various optical characteristic parameters on the propagation characteristics, we can know that choosing immunochromatographic strips with smaller anisotropy factor, greater thickness, and larger scattering coefficient can further reduce the interference of the excitation light, thereby improving the SNR. Combining the effects of various optical characteristic parameters on the propagation characteristics and the distribution of the fluorescent particles in immunochromatographic strips, we can enhance the excitation of fluorescence by choosing immunochromatographic strips with different optical characteristic parameters, thereby improving the SNR.Through the study of light propagation in immunochromatographic strips, the distribution of scattering optical field and how optical characteristic parameters affecting the distribution of scattering optical field and internal optical field can be obtained, providing a theoretical basis for how to improve the detecting level of immunechromatographic analyzers.