Electrochemical Bioelectronic Device Consisting of Metalloprotein for Analog Decision Making

Abstract

We demonstrate an analog type logical device that combines metalloprotein and organic/inorganic materials and can make an interactive analog decision. Myoglobin is used as a functional biomolecule to generate electrochemical signals, and its original redox signal is controlled with various mercapto-acids by the distance effect between myoglobin and a metal surface in the process of electron transfer. Controlled signals are modulated with the introduction of inorganic materials including nanoparticles and metal ions. By forming a hybrid structure with various constituents of organic/inorganic materials, several functions for signal manipulation were achieved, including enhancement, suppression, and shift. Based on the manipulated signals of biomolecules, a novel logical system for interactive decision-making processes is proposed by selectively combining different signals. Through the arrangement of various output signals, we can define interactive logical results regulated by an inherent tendency (by metalloprotein), personal experience (by organic spacer sets), and environments (by inorganic materials). As a practical application, a group decision process is presented using the proposed logical device. The proposed flexible logic process could facilitate the realization of an artificial intelligence system by mimicking the sophisticated human logic process.

Recent Advances in Biomolecule–Nanomaterial Heterolayer-Based Charge Storage Devices for Bioelectronic Applications

“…The use of metalloproteins—such as azurin, cytochrome c, ferritin, myoglobin, and hemoglobin—made the redox properties of the biomolecules accessible. For applying metalloproteins to electrochemical charge storage devices, native metalloproteins are required to be immobilized on inorganic substrates such as mercaptoundecanoic acid (11-MUA), mercaptohexanoic acid (6-MHA), mercaptoacetic acid (MAA), and 3,3′-dithiobis (sulfosuccinimidyl propionate) [ 87 , 88 , 89 ]. Usually, these organic molecules are composed of a head group, chain, and tail group.…”

“…Furthermore, the assembly of a biomolecule–nanomaterial–organic molecule heterolayer can be used for signal modulation to control the redox potential value and redox current intensity. Chung et al applied a biomolecule–nanomaterial–organic molecule heterolayer to an analog-type charge storage device for analog decision-making [ 87 ] ( Figure 4 C). Myoglobin was used to perform electrochemical signal generation because of the redox property of the iron ions in the myoglobin.…”

“…The figure displays the corresponding charging currents were observed when assigned to oxidation potential and reduction potential repeatedly for a total duration of 5 s. Reproduced with permission from [ 95 ], published by Elsevier, 2010. ( C ) Formation of bio-hybrid materials for the realization of proposed concept (left), specific device structure as a hardware-type platform for logic operations (right) [ 87 ], the figure has followed the terms of use under a Creative Commons Attribution 4.0 International Licenses. ( D ) Parameter definition and conceptual functions using output results (left), demonstration of defined regions (independent and interactive) using controlled electrochemical signal of metalloprotein (right) [ 87 ], the figure has followed the terms of use under a Creative Commons Attribution 4.0 International Licenses.…”

Development of Bioelectronic Devices Using Bionanohybrid Materials for Biocomputation System

“…In addition, conformational changes of biomolecules can be utilized to develop logic gates such as the conformational change of G-quadruplex DNA (G-rich DNA) as a bending shape and straightening shape that is dependent on the pH value [58]. Furthermore, these logic functions based on biomolecules can provide opportunities to mimic the analog human decision-making process [59] through controlling the combination of biomolecules and organic and inorganic materials. In this chapter, we will introduce research into biologic gates using biomolecules such as proteins and DNA and bioelectronic devices that mimic the analog human decision-making process.…”

“…In addition, bioelectronic noses and tongues based on biomolecular receptors have been researched recently to mimic the processes of real living organisms [75,76]. To demonstrate the analog decision-making process on a bioelectronic chip, our group developed an electrochemical bioelectronic device based on a bionanohybrid material composed of metalloprotein and organic/inorganic nanomaterials or metal ions [59]. Figure 6A shows a conceptual image of their research for mimicking analog decision-making through the analogously processed output signals by inputting two different external factors (negative input and positive input) via electrochemical investigation.…”