An enzyme logic bioprotonic transducer

Translating ionic currents into measureable electronic signals is essential for the integration of bioelectronic devices with biological systems. We demonstrate the use of a Pd/PdH_x electrode as a bioprotonic transducer that connects H⁺ currents in solution into an electronic signal. This transducer exploits the reversible formation of PdH_x in solution according to PdH虠Pd + H⁺ + e^-, and the dependence of this formation on solution pH and applied potential. We integrate the protonic transducer with glucose dehydrogenase as an enzymatic and gate for glucose and NAD⁺. PdH_x formation and associated electronic current monitors the output drop in pH, thus transducing a biological function into a measurable electronic output.