Cell sorters play important roles in biological and
medical applications, such as cellular behavior study and
disease diagnosis and therapy. This work presents a label-
free microfluidic sorter that has a downstream-pointing
magnetic elastic diverter. Different with most existing mag-
netic sorters, the proposed device does not require the target
microobjects to be intrinsically magnetic or coated with
magnetic particles, giving users more flexibility in sorting
criteria. The diverter is wirelessly deformed by an applied
magnetic field, and its deformation induces a fluid vortex
that sorts incoming microobjects, e.g., cells, to the collec-
tion outlet. The diverter does not touch samples in this
process, reducing the sample contamination and damage
risks. This sorter uses a magnetic field generated by off-
chip electromagnetic coils that are centimeters away from
the device. With simple structure and no on-chip circuits
or coils, this device can be integrated with other lab-on-a-
chip instruments in a sealed chip, ameliorating the safety
concerns in handling hazardous samples. The parallel and
independent control of two such diverters on a single chip

• A generic label-free microfluidic microobject sorter using a magnetic elastic diverter