Enzyme transistor circuits for reaction-diffusion computing

This paper explores the possibility of constructing massively parallel computing systems using molecular electronics technology. By employing specificity of biological molecules, such as enzymes, new integrated circuit architectures which are essentially free from interconnection problems could be constructed. To clarify the proposed concept, this paper presents a functional model of a basic biomolecular switching device called an enzyme transistor. The enzyme transistor is, in a sense, an artificial catalyst which selects a specific substrate molecule and transforms it into a specific product. Using this primitive function, various wire-free computing circuits can be realized. Examples described in this paper include basic analog amplifiers and digital logic circuits. This paper also presents the design of an excitable enzyme transistor circuit and demonstrates the potential of enzyme transistors for creating reaction-diffusion dynamics that performs useful computations in a massively parallel fashion.