Methods for biological substance analysis employing internal magnetic gradients separation and an externally-applied transport force

A method of identifying immunophenotypic subpopulations of biological substances suspended in a fluid medium, comprising the steps of:

• adding to the fluid medium a quantity of magnetically-responsive particles having a binding affinity for the biological substances;
• adding to the fluid medium a plurality of probes having respective distinct fluorochromes;
• placing the fluid medium in a separation vessel having a transparent wall defining one side of a chamber, and having a ferromagnetic capture structure supported along the transparent wall;
• positioning the vessel in a magnetic field for inducing an internal gradient in the vicinity of the capture structure sufficient to immobilize the biological substances along the transparent wall adjacent to the capture structure;
• illuminating the vessel with optical radiation adapted to excite at least a selected one of the fluorochromes;
• and
• observing the optical response of the selected fluorochrome.

A method of differentiating red blood cell subpopulations in a fluid sample, comprising the steps of:

• rendering red blood cells in the fluid sample to be magnetically responsive;
• placing the fluid sample in a separation vessel having a transparent wall defining one side of a chamber, and having a ferromagnetic capture structure supported along the transparent wall;
• positioning the vessel in a magnetic field for magnetizing the magnetically responsive red blood cells and for inducing an internal gradient in the vicinity of the capture structure sufficient to attract and immobilize the cells along the transparent wall adjacent to the capture structure;
• and
• observing red blood cells immobilized adjacent the capture structure.