Thin Film Conductive Matrices for Electrochemical Biosensors

The proliferation of nuclear, biological and chemical (NBC) weapons presents a continuing need for the Army to develop sensors that are "faster, cheaper and better". The requirement is for "multi-agent sensors and detectors providing real-time detection and identification of chemical/biological agents". As a result, the tri-services have had an ongoing interest in biosensors, a class of point sensors which employs the exquisitely selective affinity of biological molecules, typically enzymes or antibodies, for their substrates. An issue with biosensors is to provide a means of immobilizing the biomolecule in a matrix that can be employed for signal transduction while still retaining their favorable biochemical properties. A novel thin film matrix comprising conductive hydrated metal oxide is proposed. We have demonstrated that large biomolecules can be incorporated into these films on electrode surfaces at room temperature from stabilizing buffer solutions, and that the biomolecules retain their activity for substrate. These unique materials can act both as amperometric and as pH (potentiometric) transducers. Phase I will demonstrate a model matrix system employing several immobilized enzymes with electro-active or acidic/basic products. The ultimate goal is a family of robust, highly selective inexpensive, small electrochemical instruments that fulfill the Army's mission at a reduced cost compared to existing alternatives, consistent with the Army's Operating and Support Cost Reduction (0SCR) Program. Robust, specific, real-time multi-sensors for chemical and biological agents; glucose monitors for diabetic maintenance; sensors for environmental air-and water pollutants, such as pesticides; sensors for clinical blood analysis, drugs of use and abuse, alcohol markers, etc.