Department of Mechanical Engineering, School of Engineering, Tokyo Institute of Technology, Tokyo, Japan.
Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, Fukuoka, Japan.
Sci Rep. 2023 Mar 27;13(1):4994. doi: 10.1038/s41598-023-32233-z.
Deterministic lateral displacement (DLD) is a promising technology that allows for the continuous and the size-based separation of suspended particles at a high resolution through periodically arrayed micropillars. In conventional DLD, the critical diameter (D), which determines the migration mode of a particle of a particular size, is fixed by the device geometry. Here, we propose a novel DLD that uses the pillars of a thermo-responsive hydrogel, poly(N-isopropylacrylamide) (PNIPAM) to flexibly tune the D value. Upon heating and cooling, the PNIPAM pillars in the aqueous solution shrink and swell because of their hydrophobic-hydrophilic phase transitions as the temperature varies. Using the PNIPAM pillars confined in a poly(dimethylsiloxane) microchannel, we demonstrate continuous switching of particle (7-μm beads) trajectories (displacement or zigzag mode) by adjusting the D through temperature control of the device on a Peltier element. Further, we perform on/off operation of the particle separation (7-μm and 2-μm beads) by adjusting the D values.
确定性侧向位移（DLD）是一种很有前途的技术，通过周期性排列的微柱可以实现悬浮颗粒的连续和基于尺寸的高分辨率分离。在传统的 DLD 中，决定特定尺寸颗粒迁移模式的临界直径（D）由器件几何形状固定。在这里，我们提出了一种使用热响应水凝胶聚（N-异丙基丙烯酰胺）（PNIPAM）的微柱来灵活调节 D 值的新型 DLD。在加热和冷却过程中，由于温度变化导致的疏水-亲水相转变，PNIPAM 微柱在水溶液中会发生收缩和溶胀。我们使用限制在聚二甲基硅氧烷微通道中的 PNIPAM 微柱，通过在 Peltier 元件上控制设备的温度来调节 D，从而证明了通过调整 D 值可以连续切换颗粒（7μm 微球）轨迹（位移或之字形模式）。此外，我们通过调节 D 值来实现颗粒（7μm 和 2μm 微球）分离的开/关操作。
