A 3-dimensional dielectrophoretic sorting device, the device comprising: a first electrode layer (320, 420); a second electrode layer (322, 422); and an electrically-insulating layer (324, 424) interposed between the first electrode layer (320, 420) and the second electrode layer (322, 422), wherein: the electrically-insulating layer includes a first sub-layer and a second sub-layer; a first passage (326, 426) is located in the first sub-layer, a second passage (330, 430) is located in the second sub-layer, the first electrode layer (320, 420), the second electrode layer (322, 422), and the electrically-insulating layer (324, 424) form a substantially planar assembly, the first electrode layer (320, 420) is on an opposite side of the first sub-layer from the second sub-layer, the second electrode layer (322, 422) is on an opposite side of the second sub-layer from the first sub-layer, the first passage (326, 426) and the second passage (330, 430) follow a common path within a DEP separation region of the electrically-insulating layer (324, 424) and are in direct fluid communication with one another within the DEP separation region, the first passage (326, 426) and the second passage (330, 430) each have a different cross-sectional width perpendicular to the common path and perpendicular to a normal of the substantially planar assembly, and the first passage (326, 426) diverges from the second passage (330, 430) in a post-DEP separation region, the post-DEP separation region located downstream of the DEP separation region. a first electrode layer (320, 420); a second electrode layer (322, 422); and an electrically-insulating layer (324, 424) interposed between the first electrode layer (320, 420) and the second electrode layer (322, 422), wherein: the electrically-insulating layer includes a first sub-layer and a second sub-layer; a first passage (326, 426) is located in the first sub-layer, a second passage (330, 430) is located in the second sub-layer, the first electrode layer (320, 420), the second electrode layer (322, 422), and the electrically-insulating layer (324, 424) form a substantially planar assembly, the first electrode layer (320, 420) is on an opposite side of the first sub-layer from the second sub-layer, the second electrode layer (322, 422) is on an opposite side of the second sub-layer from the first sub-layer, the first passage (326, 426) and the second passage (330, 430) follow a common path within a DEP separation region of the electrically-insulating layer (324, 424) and are in direct fluid communication with one another within the DEP separation region, the first passage (326, 426) and the second passage (330, 430) each have a different cross-sectional width perpendicular to the common path and perpendicular to a normal of the substantially planar assembly, and the first passage (326, 426) diverges from the second passage (330, 430) in a post-DEP separation region, the post-DEP separation region located downstream of the DEP separation region. the electrically-insulating layer includes a first sub-layer and a second sub-layer; a first passage (326, 426) is located in the first sub-layer, a second passage (330, 430) is located in the second sub-layer, the first electrode layer (320, 420), the second electrode layer (322, 422), and the electrically-insulating layer (324, 424) form a substantially planar assembly, the first electrode layer (320, 420) is on an opposite side of the first sub-layer from the second sub-layer, the second electrode layer (322, 422) is on an opposite side of the second sub-layer from the first sub-layer, the first passage (326, 426) and the second passage (330, 430) follow a common path within a DEP separation region of the electrically-insulating layer (324, 424) and are in direct fluid communication with one another within the DEP separation region, the first passage (326, 426) and the second passage (330, 430) each have a different cross-sectional width perpendicular to the common path and perpendicular to a normal of the substantially planar assembly, and the first passage (326, 426) diverges from the second passage (330, 430) in a post-DEP separation region, the post-DEP separation region located downstream of the DEP separation region.