Apparatus and method for reversibly removing ligands from carriers

A method for reversibly removing oxygen from an oxygen carrier, which comprises:

• (a) contacting a fluid containing a binding-state oxygen carrier to which oxygen is bound with a first electrochemical electrode wherein said binding-state oxygen carrier undergoes a redox reaction to form a nonbinding-state oxygen carrier and free oxygne;
• (b) collecting free oxygen from said fluid through a gas permeable membrane into a region having a partial pressure of oxygen lower than the partial pressure of oxygen in said fluid;
• (c) contacting the fluid obtained from step (b) containing said nonbinding-state oxygen carrier with a second electrochemical electrode wherein said nonbinding-state oxygen carrier undergoes a redox reaction to reform said binding-state oxygen carrier;
• (d) contacting the fluid obtained from step (c) containing said binding-state oxygen carrier with an oxygen source, whereby oxygen binds to said binding-state oxygen carrier;
• and
• (e) repeating steps (a)-(d).

A method for reversibly removing a ligand from a ligand carrier, which comprises:

• (a) contacting a fluid containing a binding-state ligand carrier to which said ligand is bound with a first electrochemical electrode wherein said binding-state ligand carrier undergoes a redox reaction to form a nonbinding-state ligand carrier and free ligand;
• (b) removing free ligand from the fluid obtained in step (a);
• (c) contacting the fluid obtained from step (b) containing said nonbinding-state ligand carrier with a second electrochemical electrode wherein said nonbinding-state ligand carrier under goes a redox reaction to reform said binding-state ligand carrier;
• (d) contacting the fluid obtained from step (c) containing said binding-state ligand carrier with a ligand source, whereby said ligand binds to said binding-state ligand carrier;
• and
• (e) repeating steps (a)-(d);
• wherein said binding-state ligand carrier is hemoglobin, a hemocyanin, a hemerythrin, a synthetic heme, heme complexed with a nitrogenous base, a tetradentate non-heme organo-metallic compound, or a chemically modified hemoglobin or hemocyanin.