Total Reflection Phenomenon Analysis in Dynamic Laser Scattering Measurements for Individual Label Free Cells

摘要

Dynamic laser scattering measurement of individual cells is a quick and non-intrusive measurement method in biomedical engineering. It is based on hydraulic focusing technology to make label free cells pass through laser detecting zone. But scattering laser light total reflection phenomenon existing in all kinds of flow cell structures has significant effect on scattering signal to noise ratio (SNR). In this paper geometrical optics methods are utilized to study laser light total reflection phenomenon in different hydraulic focusing states and flow cell interfaces. Various influences factors of devices structures and cells focused positions are discussed to figure out the effective methods of avoiding the total reflection phenomenon, in which the flow cell refractive index, the average refractive index of detected sample and buffer solution and cells focused positions are found to be the most important factors. These analysis results are not only vital in improving tiny label free cells laser scattering SNR, but also can provide useful criterions for selecting and optimizing engineering system parameters for dynamic individual cells scattering measurement system.