Abstract
This study demonstrated a method for accelerating the reaction of the micro-bead protein immunoassay via mixing of the beads with the sample. According to the previous studies, when the scale of the protein immunoassay is small, such as micro-spot protein microarray, the theoretical reaction rate of the protein immunoassay microarray is fast. But when the concentration of the sample is very low, the reaction rate becomes very slow and it takes a long time to equilibrium the reaction. The effect of diffusion is very significant especially in low concentration and low volume. In this study, the micro-bead protein immunoassay was used to reduce the diffusion distance and increase the reaction surface. Manipulation of the beads by optical dielectrophoretic force was to mix the beads with the sample fluid. Mixing increased the probability of collision between the beads and protein. The streptavidin-coated beads were manipulated by the dielectrophoretic force induced by the light generated from the liquid crystal display (LCD) projector. The beads traveled through the biotin solution in the chamber on the chip. The movement of beads largely increased the collision probability between streptavidin on the beads and biotin in the fluids. Mixing was proved to increase the reaction rate of the micro-bead protein immunoassay via the manipulation by optical dielectrophoretic force. In this thesis, the time to reach equilibrium has been reduced to one third of that of the static incubation condition. The fluorescence intensity has also been increased to three times stronger than that of the condition of non-mixing. The limitation of detection of the mixing chip can be 100nM.