Composite particles

A composite material suitable for extracting a biological material from a fluid, the composite material comprising:

• at least one buoyant component that is buoyant with respect to said fluid;
• a magnetic component comprising a ferromagnetic material and a paramagnetic material;
• and
• at least one active component capable of binding with a nucleic acid, protein, or bio/organic material;
• wherein the at least one buoyant component, the magnetic component, and the at least one active component are interconnected to provide the composite material, and the composite material comprises a sufficient amount of the magnetic component and the at least one active component to adjust the bulk density of the composite material to more than the specific gravity of the fluid and no greater than about 115% of the specific gravity of said fluid.

A composite material that may be suspended in a fluid for removing a substance contained in the fluid, the composite material comprising:

• a composition of a buoyant component having a magnetic material incorporated therein at an amount sufficient to cause the magnetic material to be susceptible to an induced magnetic field;
• and
• an active material that is active with respect to the substance to be removed;
• wherein the composite material has a bulk density greater than the specific gravity of the fluid and no greater than 115% of the specific gravity of said fluid.