On-chip diagnostic device
Functionalized superparamagnetic beads are the biomedical industry workhorse for tagging, manipulating, and detecting chemical and biological species in a fluid environment. This work makes a significant step forward in the field of on-chip magnetic bead handling by using magnetic domain walls as mobile traps for beads. We show that the bead-DW magnetostatic interaction enables transport along specifically designed track structures, and the interaction between bead and domain wall provides a means to sense and characterize magnetic beads without the need for specific chemistry. The integration of transport and measurement on chip is a step toward the development of multifunctional precision magnetic lab-on-bead devices.