REAL-TIME MONITORING OF IMMUNOCHEMICAL INTERACTIONS WITH A TANTALUM CAPACITANCE FLOW-THROUGH CELL

A flow-through cell for the real-time capacitance monitoring of immunochemical interactions has been developed. It consists of a tantalum strip onto which tantalum oxide was grown electrochemically to a layer thickness as small as 5 nm. Antibody or antigen was immobilized onto the tantalum oxide surface, and binding of the corresponding analyte resulted in modification of the electrical capacitance of the system. With mouse IgG as the ligand, real-time monitoring of anti-mouse-IgG In the nanogram per milliliter range was possible. The behavior of the system with respect to analyte size and concentration was investigated. The tantalum/tantalum oxide/electrolyte system can be manufactured easily and reproducibly.