Figure 6
(A) Illustration of a spiral microchannel where the fluid direction is from outside to inside. I. Firstly, several groups (e.g., Bhagat et al.9, Papautsky et al.66,77, etc.) have shown the capability of rectangular spiral microfluidics for such applications as flow cytometry or microparticle/cell separation. The fabrication of these devices was based on photolithography. II. Gaining the efficiency of micromilling, many groups (e.g., Guan et al.67, Warkiani et al.20, etc.) made an attempt to get the advantage of trapezoidal spiral microchannel for particle/cell filtration and fractionation. III. In this study, for the first time, we have shown the fabrication of a right-angled triangular spiral microchannel with the aid of additive manufacturing. (B) Schematic illustration of the microchannel where the inset shows the cross-section of the microchannel. (C) Results reveal that for particles larger than 10 µm, a tight focusing band appears at the outlet of the channel. Also, for larger particles at high flow rates (i.e., 4 ml/min) double-band focusing appears. (D) dimensions of the right-angled triangular spiral microchannel where the inner wall is 210 µm and the width is 600 µm. The hydraulic diameter of this channel is similar to a spiral with a trapezoidal cross-section and the dimension of 80 × 130 × 600 µm. (E) Illustration of a right-angled triangular cross-section, which shows the accuracy of the fabrication process.
