Enzyme-Based<b>NAND</b>and<b>NOR</b>Logic Gates with Modular Design

TLDR

Enzyme‑based NAND/NOR logic gates were constructed by coupling sucrose, maltose and phosphate‑activated reactions with maltose phosphorylase, invertase/amyloglucosidase, and an inverter module of alcohol dehydrogenase, glucose oxidase, microperoxidase‑11, ethanol and NAD⁺, yielding amplified NADH output that is reconverted to maltose and phosphate to enable modular concatenation. This modular, signal‑amplifying design demonstrates the feasibility of building complex logic networks from standard enzymatic elements analogous to electronic integrated circuits.

Abstract

The logic gates NAND/NOR were mimicked by enzyme biocatalyzed reactions activated by sucrose, maltose and phosphate. The subunits performing AND/OR Boolean logic operations were designed using maltose phosphorylase and cooperative work of invertase/amyloglucosidase, respectively. Glucose produced as the output signal from the AND/OR subunits was applied as the input signal for the INVERTER gate composed of alcohol dehydrogenase, glucose oxidase, microperoxidase-11, ethanol and NAD+, which generated the final output in the form of NADH inverting the logic signal from 0 to 1 or from 1 to 0. The final output signal was amplified by a self-promoting biocatalytic system. In order to fulfill the Boolean properties of associativity and commutativity in logic networks, the final NADH output signal was converted to the initial signals of maltose and phosphate, thus allowing assembling of the same standard units in concatenated sequences. The designed modular approach, signal amplification and conversion processes open the way toward complex logic networks composed of standard elements resembling electronic integrated circuitries.