Biofuel cells controlled by logically processed biochemical signals: towards physiologically regulated bioelectronic devices.

Biofuel cells with a switchable power release controlled by biochemical signals, which can be logically processed by biomolecular computing systems, have been designed. The switchable properties of the biofuel cells were based on the polymer-brush-modified electrodes with the activity dependent on the solution pH value. The pH changes generated in situ by biocatalytic reactions allowed the reversible activation-inactivation of the bioelectrocatalytic interfaces-thus affecting the activity of the entire biofuel cells. Boolean logic operations performed by either enzyme- or immune-based systems were functionally integrated with the switchable biocatalytic process allowing logic control over them. Scaling up the complexity of the biocomputing systems to complex multi-component logic networks with a built-in "program" resulted in the control of the bioelectronic systems by multi-signal patterns of biochemical inputs. Future implantable biofuel cells producing electrical power on-demand depending on physiological conditions are feasible, as the result of the present research.