A lamination micro mixer for μ-immunomagnetic cell sorter

We report successful design, fabrication and testing of a novel lamination micro mixer to be integrated in the micro-scale immunomagnetic cell sorter (mu-IMCS), which should be a key device for clinical applications of regenerative medicine. This paper covers, (i) the concept of [mu-IMCS, (ii) design and fabrication of lamination mixer using MEMS technologies, (iii) numerical analysis for the evaluation of the mixer performance, and (iv) experimental evaluation of target cell capturing with the present micro mixer. In order to reduce the sedimentation loss of the cells and the magnetic beads, the conduits in the mixer are designed in such a way that the stream is turned over 180 degree. It is found in the CFD analysis that the present lamination mixer realizes better mixing and lower sedimentation loss than the one without rotation in the previous study. Experiments reveal that the cell capture rate is (i) increased by up to 8.6 times compared with that in a straight channel, and (ii) decreased with decreasing the residence time. It is also demonstrated in a preliminary experiment that CD31 expressions of HUVEC and hMSC obtained with the present micro mixer are in good agreement with the data obtained with a conventional cell sorting system. Therefore, the present mixer should be a viable component in a mu-IMCS.