Molecular Information Processing: From Single Molecules to Supramolecular Systems and Interfaces – from Algorithms to Devices – Editorial Introduction

Abstract

Fast development of electronic computers with continuous progress [1] resulting in doubling their complexity every two years was formulated as the Moore's law in 1965 [2] (Figure 1.1). However, because of reaching physical limits for miniaturization of computing elements [3], the end of this exponential growth is expected soon. Economic [4] and fundamental physical problems (including limits placed on the miniaturization by quantum tunneling [5] and by the universal light speed [6]), which cannot be overcome in the frame of the existing paradigm, abolish all forms of future sophistication of computing systems. The inevitably expected limit to the development of the computer technology based on silicon electronics motivates various directions in unconventional computing [7] ranging from quantum computing [8], which aspires to achieve significant speedup over the conventional electronic computers for some problems, to biomolecular computing with a ''soup'' of biochemical reactions inspired by biology and usually represented by DNA-based computing [9].Chemical computing, as a research subarea of unconventional computing, aims at using molecular or supramolecular systems to perform various computing operations that mimic processes typical of electronic computing devices [7]. Chemical reactions observed as changes of bulk material properties or structural reorganizations at the level of single molecules can be described in terms of information processing language, thus allowing for formulation of chemical processes as computing operations rather than traditional chemical transformations.The idea of using chemical transformations for information processing originated from the concept of ''artificial life'' as early as in 1970s, when artificial molecular machines were inspired by chemistry and brought to computer science [10]. Theoretical background for implementing logic gates and finite-state machines based on chemical flow systems and bistable reactions was developed in 1980s and 1990s [11], including application of chemical computing to solving a hard-to-solve problem of propositional satisfiability [12]. However, the practical realization of the theoretical concepts came later when already known Belousov-Zhabotinsky chemical oscillating systems [13] (Figure 1.2) were applied for experimental design of logic gates [14]. Extensive research in the area of reaction-diffusion computing systems [15] resulted in the formulation of conceptually novel circuits performing Molecular and Supramolecular Information Processing: From Molecular Switches to Logic Systems, First Edition. Edited by Evgeny Katz.

Co-Registered Molecular Logic Gate with a CO-Releasing Molecule Triggered by Light and Peroxide

“…Even applications of molecule-based computation have been found in the design of smart materials, in the delivery/activation of drugs, and in clinical diagnostics . However, structural integration and concatenation of molecular logic gates in circuits represents one of the biggest challenges . We demonstrated the flexibility and implementation power of a fluorescent implication gate with the wiring algorithm approach (sugar computer) on a tic-tac-toe automaton .…”

“…For example, the fluorescent output shows the calculation process, whereas the output matter can be used as an input for the following chemical logic gate (concatenation). Only few molecular logic gates can process effectively light and matter. , Co-registering those inputs in molecular logic gates and processing them into the concomitant outputs of light and matter is rare in literature . However, combining matter and light in inputs (e.g., light and glutathione) is widely available in chemically activated photodynamic therapy (PDT) .…”

“…“OR” gates are logic functions in full adders for the construction of computers . CORM A in combination with light and matter can now be used as co-registered “OR” gate; fluorescence implies a visible output, whereas the concomitant output CO can be used as an input for a concatenated chemical logic gate …”

Modified Electrodes and Electrochemical Systems Switchable by Light Signals

“…While Boolean logic gates mimicked with molecular and biomolecular systems logically process chemical and physical input signals, they do not store the results of the information processing. The memory units, particularly based on flip‐flop systems are important components of future unconventional computing devices .…”

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

“…Biomolecular information processing (biocomputing) [1, 2] is a rapidly developing research subarea of chemical computing [3, 4] and more generally of unconventional computing [5]. Sophisticated processes realized in protein/enzyme [2, 6], DNA/RNA [7, 8] and whole cell [9] systems are considered for information processing, ultimately aiming at biomolecular computers [10] operating faster (or more efficiently in some applications) than electronic systems due to massive parallelism [7] or novel bioinspired computational approaches [11].…”