A microfluidic device includes: a shape memory substrate having a shape memory polymer matrix and a plurality of particles embedded in the shape memory polymer matrix, the shape memory polymer matrix being thermally transformable from a temporary shape to an original shape, the particles being made from a magnetically coercive material; and a microfluidic chip attached sealingly to the shape memory substrate and defining a microfluidic channel. The shape memory polymer matrix is indented inwardly to form an indented space in fluid communication with the microfluidic channel when the shape memory polymer matrix is heated to transform from the temporary shape to the original shape.