A biocatalytic cascade with several output signals—towards biosensors with different levels of confidence

Abstract

The biocatalytic cascade based on enzyme-catalyzed reactions activated by several biomolecular input signals and producing output signal after each reaction step was developed as an example of a logically reversible information processing system. The model system was designed to mimic the operation of concatenated AND logic gates with optically readable output signals generated at each step of the logic operation. Implications include concurrent bioanalyses and data interpretation for medical diagnostics.

Enantioselective Synthesis of Amino­indan Carboxylic Acid Derivatives by the Catalytic Intramolecular [2+2+2] Cycloaddition of Amino‐Acid‐Tethered Triynes

“…If the signal‐processing system needs to have several output signals and when it is organized in one solution, the output signals must have different optical properties represented by different chemical species. For example, one of the recently reported systems with several inputs and three outputs used individually readable absorbance changes corresponding to NADH and ABTS ox ( λ max 340 and 420 nm, respectively) and a fluorescence output produced by the luciferase–luciferin system in the presence of ATP ( λ max 552 nm) 65. If output signals are read by any other means, for example using redox species analyzed electrochemically, the problem still persists since the produced species should be chemically different enough to demonstrate different redox potentials that are individually readable by cyclic voltammetry or by any other electrochemical technique.…”

Reversible Logic Gates Based on Enzyme‐Biocatalyzed Reactions and Realized in Flow Cells: A Modular Approach

“…For example, one of the recently reported systems with several inputs and three outputs used individually readable absorbance changes corresponding to NADH and ABTS ox (l max 340 and 420 nm, respectively) and a fluorescence output produced by the luciferase-luciferin system in the presence of ATP (l max 552 nm). [65] If output signals are read by any other means, for example using redox species analyzed electrochemically, the problem still persists since the produced species should be chemically different enough to demonstrate different redox potentials that are individually readable by cyclic voltammetry or by any other electrochemical technique. This requirement puts serious limitations on the use of biochemical reactions.…”

Enzyme‐Based Logic Gates and Networks with Output Signals Analyzed by Various Methods

“…The bar chart (Figure D) shows all experimentally measured output signals for eight combinations of the inputs. The present system exemplifies application of bioluminescence as a method for observing output signals generated in the presence of ATP, which is a very common component of various enzyme‐based logic systems of various complexity . Another system mimicking a branched logic network was based on bioluminescence produced upon oxidation of luminol catalyzed by horseradish peroxidase (HRP) in the presence of enzymatically produced H 2 O 2 .…”