الفهرس 
1.1 IntroductionOnly 14 pages are availabe for public view
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Abstract
Developing intelligent molecular systems for the desired functions is a significant current research topic in the field of nanoscience. Several materials have been explored to construct interesting systems such as molecular motors, molecular walkers, and Boolean logic circuits. Deoxyribonucleic acid (DNA) is one of the most widely used materials as the Watson-Crick base pairing makes it a versatile substrate. A significant achievement in DNA nanoscience has been the construction of large-scale logic circuits. Despite that, most of the prior works have focused on developing the single-use DNA logic circuits. These single-use circuits can perform robust computations. However, the computing material, such as gate strands, cannot be reused to achieve the same (or a different) operation. Such reusable behavior is essential for applications such as feedback and sequential logic computation.
In this thesis, the emergence of DNA computing logic circuits will be reviewed, with highlighting the reusable DNA nanodevices. Since DNA has the power to do computations, it was used to build various types of computing devices. Many different designs and theoretical models were presented to solve complex problems. Moreover, the research was extended to make large-scale circuits, both analog and digital-logic combinational circuits. Most of those proposed designs were meant to be used once. After using the circuit to solve the intended problem, the whole circuit becomes waste. That problem encouraged researchers to find solutions to restore and reuse the circuits. The field of DNA computing can make use of those resettable circuits to build essential circuits like sequential logic, oscillators, and multiple-access memories. Moreover, two novel design strategies are proposed for building renewable DNA logic circuits. The first, is the renewable DNA seesaw circuits based on photo-regulating elements. That was verified by simulations using visual DSD. The second is a renewable hairpin-based motif, that can be used to implement a Boolean logic gate. Those logic implementations were done experimentally and the overall sample preparation convenient and straightforward.