Abstract: Systems and methods that can be used to detect materials of interest in a suspension are disclosed. A suspension suspected of containing a material of interest and a float are added to a tube. When the tube, float and suspension are centrifuged together, the float expands the axial length of a layer that contains the material of interest between the outer surface of the main body of the float and the inner wall of the tube. The float includes features located on the main body of the float that enhance mixing of various agents to be added to the suspension. The features may also increase the flow of the suspension fluid and materials around the float during centrifugation.