Enzyme-Based Logic: OR Gate with Double-Sigmoid Filter Response

TL;DR

This paper reports the first biomolecular OR gate with a double-sigmoid response, demonstrating noise filtering and optical detection using enzyme chemistry and pH control.

Contribution

It introduces a novel enzyme-based OR gate with double-sigmoid response and analyzes its noise-filtering capabilities through theoretical modeling.

Findings

Successful implementation of enzyme-based OR gate with double-sigmoid response

Effective noise handling through pH-controlled filtering

Optical detection of gate output via chromogen oxidation

Abstract

The first realization of a biomolecular OR gate function with double-sigmoid response (sigmoid in both inputs) is reported. Two chemical inputs activate the enzymatic gate processes resulting in the output signal: chromogen oxidation, which occurs when either one of the inputs or both are present (corresponding to the OR binary function), and can be optically detected. High-quality gate functioning in handling of sources of noise is enabled by "filtering" involving pH control with an added buffer. The resulting gate response is sigmoid in both inputs when proper system parameters are chosen, and the gate properties are theoretically analyzed within a model devised to evaluate its noise-handling properties.