Enzyme Logic Gate with Summation Function Based on Putidaredoxin Reductase/Cytochrome c Enzyme Reaction

Various kinds of biologic gates have been developed to realize biocomputing system with enzyme reactions. However, logic gate with summation function based on putidaredoxin reductase and cytochrome c has not been reported yet. Here, we developed biologic gate with summation function. To fabricate the biologic gate system, putidaredoxin reductase was immobilized on two gold electrodes for input system and cytochrome c was immobilized on one gold electrode for reading output signal. Then polydimethylsiloxane based microfluidic chip was fabricated on the gold electrodes and each electrode was connected with microfluidic channels. To operate the biologic gates, two AND gates with putidaredoxin reductase and one OR gate with cytochrome c was checked by confirming enzyme reactions firstly. And then, we checked summation function with fabricated two AND gates and one OR gate. The benzoquinone injected to each putidaredoxin reductase was acted as input and it was defined to ‘0’, ‘1’ and ‘2’ by different concentrations. Two input signals were flowed to cytochrome c and summated signal was checked by cyclic voltammetry. The summated output signals were defined from ‘0’ to ‘4’ with various thresholds of current intensity. Proposed enzyme logic gate with summation function can be applied to bioprocessing and biocomputing system.