An in vitro method of separating an activated cell from a plurality of other cells comprising: a) contacting a crude fluid composition comprising a cell capable of activation and the plurality of other cells with one or more carriers, wherein at least one carrier comprises a cell activator, wherein the cell activator is at least partially associated with the cell capable of activation by the cell activator upon or after contact to generate a carrier associated cell complex, wherein the association of the cell activator with the cell capable of activation by the cell activator at least partially activates the cell capable of activation, wherein the carrier associated cell complex comprises an increased size relative to cells in the plurality of other cells, and wherein a size of the carrier associated cell complex is greater than or equal to a critical size, and cells in the plurality of other cells comprise a size less than the critical size; b) applying the sample to a device, wherein the device comprises an array of obstacles arranged in rows; wherein the rows are shifted laterally with respect to one another, wherein the rows are configured to deflect a particle greater than or equal to the critical size in a first direction and a particle less than the critical size in a second direction; and c) flowing the sample through the device, wherein the association of the carrier comprising the cell activator with the cell capable of activation by the cell activator provides for an increase in size of the complex relative to the unbound cell such that the carrier associated cell complex is deflected by the obstacles in the first direction, and the cells in the plurality of other cells are deflected in the second direction, thereby separating the activated cell from the other cells of the plurality; d) collecting a fluid composition comprising the separated carrier associated cell complex. a) contacting a crude fluid composition comprising a cell capable of activation and the plurality of other cells with one or more carriers, wherein at least one carrier comprises a cell activator, wherein the cell activator is at least partially associated with the cell capable of activation by the cell activator upon or after contact to generate a carrier associated cell complex, wherein the association of the cell activator with the cell capable of activation by the cell activator at least partially activates the cell capable of activation, wherein the carrier associated cell complex comprises an increased size relative to cells in the plurality of other cells, and wherein a size of the carrier associated cell complex is greater than or equal to a critical size, and cells in the plurality of other cells comprise a size less than the critical size; wherein at least one carrier comprises a cell activator, wherein the cell activator is at least partially associated with the cell capable of activation by the cell activator upon or after contact to generate a carrier associated cell complex, wherein the association of the cell activator with the cell capable of activation by the cell activator at least partially activates the cell capable of activation, wherein the carrier associated cell complex comprises an increased size relative to cells in the plurality of other cells, and wherein a size of the carrier associated cell complex is greater than or equal to a critical size, and cells in the plurality of other cells comprise a size less than the critical size; b) applying the sample to a device, wherein the device comprises an array of obstacles arranged in rows; wherein the rows are shifted laterally with respect to one another, wherein the rows are configured to deflect a particle greater than or equal to the critical size in a first direction and a particle less than the critical size in a second direction; and wherein the device comprises an array of obstacles arranged in rows; wherein the rows are shifted laterally with respect to one another, wherein the rows are configured to deflect a particle greater than or equal to the critical size in a first direction and a particle less than the critical size in a second direction; and c) flowing the sample through the device, wherein the association of the carrier comprising the cell activator with the cell capable of activation by the cell activator provides for an increase in size of the complex relative to the unbound cell such that the carrier associated cell complex is deflected by the obstacles in the first direction, and the cells in the plurality of other cells are deflected in the second direction, thereby separating the activated cell from the other cells of the plurality; wherein the association of the carrier comprising the cell activator with the cell capable of activation by the cell activator provides for an increase in size of the complex relative to the unbound cell such that the carrier associated cell complex is deflected by the obstacles in the first direction, and the cells in the plurality of other cells are deflected in the second direction, thereby separating the activated cell from the other cells of the plurality; d) collecting a fluid composition comprising the separated carrier associated cell complex.