Abstract: Systems and methods for isolating and characterizing various target materials of a suspension are disclosed. A suspension suspected of containing the target materials is added to a tube. A float with a specific gravity corresponding to that of the target material is inserted into the tube. The tube, float, and suspension are centrifuged together causing the various materials suspended in the suspension to separate into different layers along the axial length of the tube according to their specific gravities. The float and/or tube are configured to drive the various target materials to a region of space between the float and inner wall of the tube.

Abstract: Methods and systems for using drugs as biomarkers to investigate the status of biological systems are disclosed. A drug is conjugated with a light emitting dye that emits light in a channel of the electromagnetic spectrum when an appropriate stimulus is applied. In one aspect, a suspension suspected of containing target particles is added to a tube along with the conjugated drug/dye complex and a float. Centrifugation of the tube, float, and suspension causes various components to separate along the axial length of the tube. Binding of the drug/dye complex to the target particles can be assessed by applying an appropriate stimulus to the tube, which, in turn, causes the fluorescent dyes to emit light in the channel. The level of fluorescence of the target particles located between the float and the inner wall of the tube can be used to assess use of the drug in therapy.