Various magnetic tools used in the conventional closed-channel microfluidic platform. (a) Magnetic metal impeller at the Y-junction of the microfluidic channel. (b) Membrane micropump driven by the attached magnetic metal piece. Reproduced with permission from Ni et al., Microelectron. Eng. 117, 35–40 (2014). Copyright 2014 Elsevier. (c) Micro-gear pump made of magnetic composites. (d) Magnetic soft membrane pump. Reproduced with permission from Said et al., Sens. Actuators, A 245, 85–96 (2016). Copyright 2016 Elsevier. (e) A magnetic composite particle sorter.