Development of a Flow Cytometry Based Miniature Chemical Fluid Analysis System Using Fluorescent Microbeads

摘要

We present a demonstration of an optical microfluidic system for rapid and simultaneous measurement of several fluid analytes in a microscale volume that is based on fluorescent indicators immobilized on polymer microbeads. The fluorescence properties of such "reporter beads" can be a function of the concentration of an analyte, and can be monitored in a silicon microfabricated flow channel. The sizes of microbeads can be determined by the scattering signal, so this system can be used to analyze several analytes at the same time by using beads of different sizes that are sensitive to different analytes. The fluorescent indicator Carboxy-SNAFL 1 was immobilized on amino-functionalized polystyrene beads of 5μm diameter. The intensities of two fluorescent peaks (at 560 nm and at 620 nm) were measured and their ratio was dependent on the pH value of the analyte. A 488 nm air-cooled argon laser was used to excite the fluorescent beads flowing through a microfabricated V-groove channel. Two miniature photomultiplier modules and interference filters were used to simultaneously measure both fluorescence intensities.