Cell patterning,which enables us to locate cells at specific positions,is very vital for tissue engineering,and many methods have been reported to perform such technique [1-3].Recently,with the massive research on magnetic patterned media,the manipulation of magnetic domain structures on micron- and nano-sized patterned magnetic thin films becomes possible.In this study,we perform magnetic cell patterning by controlling the positions of magnetic domain walls in concentric ring-shaped ferromagnetic thin films.In contrast to biomolecular bindings,such as the binding between antibody and antigen that are hard to unbind once the binding is formed on the substrate,the positioning of magnetically labeled cells can be freely manipulated through controlling the locations of the domain walls by applying different magnetic fields.Figure 1(a) shows the schematic of the cells attracted by the stray fields generated by the domain walls in concentric ferromagnetic rings.It is known that domain walls are formed at the two ends of a ferromagnetic ring after a strong external magnetic field is applied.Due to the high aspect ratio between the ring circumference and ring line width,domains walls remain even after the field is removed.Because of the high magnetic pole densities accumulated in the vicinity of the head-to- head/tail-to-tail domain walls,a strong stray field is produced near the local areas of the domain walls.When the magnetic labeled Jurkat cells that contain magnetic nano- particles sediment on the array of concentric rings,the local magnetic force produced by the strong stray field pulls the cells onto the domain wall regions.Figure 1(b) shows the sedimentation of the magnetic cells onto a magnetic film with 20 concentric rings in the remanent state that are initially magnetized in y-direction.It is found that the cells are focused around the domain wall regions and form an obvious band of cells.In Fig.1(c),one group of magnetic cells precipitate onto the patterned magnetic film in the remanent state after applying a 1 kOe field in y-direction,followed by the precipitation of another group of cells onto the magnetic rings in the remanent state after applying a 1 kOe field in x-direction,to make a pair of perpendicular bands of cells is formed along x- and y-directions.Our proposed method allows cells be effectively manipulated and patterned into various kinds of structures by designing various kinds of patterned magnetic thin films.