Design of Arithmetic and Control Cells for a DNA Binary Processor

Recently a great deal of interest has been shown by researchers on developing a bio-molecule based computer. The basic building blocks of such a computer are arithmetic units and memory. These units can be designed using Boolean logic gates as in the case of electronic circuits. Instead of using silicon based technology, Boolean logic gates can be generated from biological systems. One such system can be generated by a DNA reaction mechanism based on a reversible strand displacement process. A generalized pipeline architecture employing DNA reaction chain mechanism for the arithmetic operations such as addition, subtraction, multiplication, and division is discussed in this paper. A single control line is used in the pipeline array to control the different modes of operations. The primary functional blocks in a pipelined array are arithmetic unit and control unit. These units are made up of basic Boolean logic gates. To implement these gates, a DNA strand displacement process is employed. A set of integrating and amplifying gates are used in cascade with different threshold values to build different digital logic operations. The main advantage of such a system is that the arithmetic operations can be overlapped in the pipeline and thus a high speed operation is possible. Such a general Boolean model will be a step towards the development of a bio-computer. The ultimate goal of such a method is to design an automated system using logic gates, which make decisions within living cells.