抄録
We propose here novel microfluidic devices for continuous particle separation in laminar flow systems. First, aqueous two-phase flow systems can be stably formed in a pinched microchannel for the affinity partitioning of relatively large biomaterials, such as cells or organelles. These biological particles can be separated continuously according to their surface affinity to each phase, independent of gravitational influences. Plant cells were used as model particulates, and the partitioning performance in a pinched microchannel was compared that in a straight microchannel. The results suggested that this system would become a useful tool for the preparation of useful biological particulates, because of its simplicity and applicability.
Second, we have proposed a new method for the continuous and accurate size separation of particles using fluid focusing and spreading in a pinched microchannel, named 'pinched flow fractionation (PFF)'. Particles suspended in liquid were continuously introduced into a microchannel having a specific geometry, and were aligned to one sidewall by the other liquid flow without particles, and then separated according to their sizes by the spreading flow profile inside the channel. For the application of this method, we have successfully performed separation of the mixture of micro polystyrene beads. These methods utilize only the nature of pinched microchannels, and are highly advantageous because of their accuracy, applicability and simplicity in operation.
